Tag Archives: programming

Command Solaris Version

command solaris version
command solaris version
Can anyone let me know if I loaded correctly Solaris 10 (based on how it looks)?

I just load up Solaris 10 on x86 last night … I think it loaded properly, but it seems that the "pigeon" version of Windows 95. Is this normal? I guess I am expecting something flashy … I am accustomed to XP, Vista, Knoppix, and OS X (damn!! I'm a fucking nerd!). The Java Enterprise Desktop a little more advanced and smooth, but the graphics of the ordinary desktop Solaris are a little lo-res (slightly grainy ?)… not in some kind of video card broken pass … more in a "I'm in second year and color with crayons the size of a horses leg" kind of way … If this is normal, it is OK because until this point, I used the command line … I just want to make sure there is not something that is running (like "button ugly" or "button 1992") and off (such as, "the super, killer, totally rad for graphics Max Record button that kicks @ ss ")… Any help or bad comments are greatly appreciated mouth … do not break my glasses!

These people might be able to help you .. http://www.bleepingcomputer.com/ Or give this yahoo tech. group … http://tech.groups.yahoo.com/group/Computer_Help_and_Discussion/ Both gave me great help. I hope this helps you. Good Luck!

Securely Delete Files in Ubuntu.

List Solaris Processes

list solaris processes
list solaris processes


How to make a CV

Due to the volume of resumes employers receive most of now use them kind of summary of monitoring or applicant tracking system. This automates many tasks necessary to track candidates, and makes also possible for an employer to find a curriculum vitae received months or years later. Because of the technology, its important to keep your CV a format that will be read and interpreted correctly by the systems. This used to be called a scanning "again because of the material used to scan paper resumes into the computer. Now, career Web sites and resumes received by e-mail are "analyzed" and stored in a database.
Once your resume is stored electronically, employers use keywords based on the resume stored with their open positions. To find resumes, employers (and recruiters) use keyword searches, usually a Boolean search.
Because technology involved in the analysis of the CV, it is important to keep the format of your resume very simple and clear. This means that you should generally avoid Fancy fonts, graphics and other "special effects" that do not always do it through the technology properly, at least for your Electronic resume (you can a more elaborate version of distributing job fairs, but it is really not necessary). A CV that is incorrectly formatted does not appear in a search for matching keywords, which greatly reduces your chances of landing interviews. I have seen some resumes come through with "gobbledygook" following the writer tries to use graphics or photos on their CV vitae.

Resume Format>>>
Here are some tips for formatting your resume:
• Use a simple font. Do not use a font to decorate. Times New Roman and Arial analyze more precisely the "standard" fonts for communication business, which is your resume.
• Use a standard font. For business communications, policies 10 and 12 points are the norm.
• Avoid using graphics, images, tables or graphs in your resume. They are rare to cross. If you have information that should be in this format, consider an addendum to your resume or, perhaps, a Web page that you created that stores information with a link to your web page CV.
• If you are applying for a job where it is important to demonstrate your creative talents format or get a job as a designer website or the position of graphic artists, to distribute copies of your resume fancy paper interviews. Better yet, send both a fantasy and the plain CV format, or create a fancy web resume and portfolio, and include the URL in your e-mail resume or cover letter
Technical Resume – Tips, Samples, Examples and models

Your resume remains one of the most important elements of your job search. A good CV writing that gives the employer a clear picture of your skills can help you stand out from the crowd. Here are links to some of my favorite tips CV, free resume samples and resume templates. I've also included links to resume actual employee that I hired in the past for various technical societies.

Resume Writing Tips – How not to write a CV
A recent survey of technical recruiters Hiring managers and asked for the top "pet peeves" – What they see on resumes and cover letters that make them less interested in speaking with a candidate. These are examples of how not to write your resume.
• Use of the current "Tense" in all jobs on the CV.
• Drawing up a curriculum vitae or a letter to the third person.
And grammar • Too many spelling errors.
• Use lowercase letters, lowercase font (10 pt or less) in order to cram as much information as possible on the CV.
• Photo CV (It is a cultural preference).
• a list of their personal interests and activities.
• Sending a attachment named 41808res.doc resume – use your name or descriptive label.
• Drawing up a curriculum vitae using formats table (columns).
• Use a CV that is password protected (without sending the password).
• references, including – but not professionals – just friends and colleagues.
• Having no contact information on the resume or include a phone number is no longer valid.
• When the e-mail from a candidate is not appropriate for the work environment. Example: BigFoxyMama @. Com
• Resumes that are too long. Most seem to believe that general descriptions relating to employment history for the past 10 years is sufficient.
• Repeat the filling, for example, the list of each software you have never touched a jurisdiction.
• Education writing So it is not clear whether the diploma was obtained.
• Job hopping, which could be contract positions, but that is not explained. (If you have been on short term contracts, be sure to specify that these are contract jobs).

Top 7 Tips for an effective resume
Ever heard the saying "you never get a second chance to make a first impression? Your resume gives a potential employer a powerful message about what kind of employees you would. With only a few seconds to capture the reader's attention and highlight your extensive expertise, you need to make the most of your curriculum vitae. Read on for tips and resume tips.
1. CV Tip 1: Spell Check and Reality Check "
Before submitting your resume, make sure to give him a spell using your word processor text. After check out, someone else give it a quick reality check "to ensure that the auditor Spelling does not miss anything and make sure you have not made a mistake that your computer can not catch. It is important that you get a second set of eyes to look at the document that could be responsible for your next job.
2. CV Tip 2: Not too long but not too short
How long should be your resume? It is always a difficult decision. Some experts believe a curriculum vitae of one page is the ideal length. I do not share unless you have few skills and experiences to share. Log in enough detail to give an accurate picture of your skills, but not As the reader falls asleep. You do not need to list all the projects you've worked on. Summarizing, but be inclusive.
3. Resume Tip 3: Data formatting
You have two versions of your resume available. An available online, and be submitted to interviews in person and job fairs. Fancy formatting with pretty fonts, lines, boxes and bullet points just does not make it through most computers. Everything you send or submit online should be simple formatting (spacing and paragraph breaks, for example).
4. Trick CV 4: Keywords are Key
When an employer is looking for a database, they use keywords. In general, they expect that the results are representative of what they want. That should say a thing or two to resume writer:
• Include relevant keywords in your CV because that is how you will be found.
• Do not stuff your resume with keywords that are irrelevant to your experience. A list of keywords which does not represent your expertise should be avoided.

Learn how to make a resume for more on keywords.
5. Resume Tip 5: Include basics
A technical summary should include the following information.
• One goal: 1-2 sentences describing what you want to customize the job you are applying.
• Education: All degrees you have completed or are working, and that appropriate courses or certifications. Only include your GPA if it is very high.
• Experience: List your previous employers and / or large projects you have worked. Start with the most recent.
• Technology Summary: List the technologies you know well.
6. CV Tip 6: several versions
If you are in more than one role (or have skills that could match more than one role), you should have several versions of your resume available that highlight these skills. For example, if you have years' experience as software engineer, and also have knowledge of project management, two resumes: a software engineer highlighting experience and another highlighting your experience project management.
7. CV7 Tip: make your CV viewable
Recruiters and hiring managers like to research and "source" for candidates. If your resume (or bio) is not a place where employers can find it, they do not know you exist. In addition to job sites regular.

Resume Writing – Guidelines for New Graduates

Writing a CV – A guide for new graduates

Purpose of Resume Writing
When you write your CV, it is important to keep in mind purpose of the resume. The summary is intended to generate interest in you as a candidate. Your resume should be written with the intent to obtain an interview, not a job. It does not list any single course, skills or achievements that you have. Remember, resumes get interviews, not jobs.
The curriculum vitae must do the following:
Create a positive first impression. This is done by highlighting your communication skills and making the summary easy to read. The CV should be concise and easy to follow.
Tell who you are. When you are writing your CV, you say that the reader who you are and why you should take into consideration for a position.
Describe what you learned. Especially for new graduate, your resume must highlight the courses and projects that apply for the job you hope to be hired.
List your accomplishments. Your resume should highlight the special achievements you have achieved. If you make a 4.0 while working full time, received a special award, or received any special recognition, it must appear in your accomplishments.
To make your resume easy and pleasant to read, you will follow certain guidelines CV format. The resume format is important because you want to make sure to maintain the reader's interest and, ultimately, be called for interview. A poorly formatted resume, one that is difficult to read, contains numerous errors, or does not flow well, is not likely achieve your goal.
Resume Format – General Guidelines
The guidelines below follow typical format CV and letter of business writing standards. These rules general format is a summary:
• Font size 10 or 12
• Perfectly typed about a margin of 1 inch (although e-mailing, because it will probably print)
• Use a single font. You can vary the size of focus, if necessary.
• Do not use different font styles. If you need to call attention to something, you can bold, but use this sparingly.
• Avoid capital letters and italics as they are hard to read.
Resume format – section titles
• Begin your resume with a title that includes your name, address, telephone number and e-mail address. This is usually centered at the top or left justified.
• Do not provide personal information such as age, sex or marital status.
• The resume objective, States of the type of position you are looking for. It seems very professional, if you customize the purpose of the position you are applying. Other than that, do not make this section too close.
• A well organized technical or career skills section can be placed after Objective. This should include the skills you have at least competent.
• The education section should identify your training University ad (s) attended Degree (s) conferred, major, and the average.
• The following section is an experience work and details the latest positions or areas of expertise first and continues in reverse chronological order. experience the project can be listed here if you do not have formal work experience. I also see a lot of internships and graduates Add of their major projects in this section.
• The achievements of the article comes last and highlights specific areas where you excel, including leadership activities, memberships and honors or awards.
Before writing your CV
Before you sit down to write your CV it is useful to consider a couple of points. The first is to think in terms of keywords, because employers will use them to search resumes.
Some examples keyword General
• Ability to … (Delegate, supervise, etc.), analytical ability, attention to detail, problem solving, results-oriented, communication skills, team leader, lead
Examples the technology industry:
• Software, systems, UNIX, Linux, SQL, Oracle, Java,. NET operating system, CAD systems mechanical design, OOP, SDLC, coded, programmed, managed, engineer, programmer, developer, network, Cisco, Microsoft
Tips for CV design
The following tips for resume design will ensure that your resume is easy to read and can be analyzed a resume database correctly.
• Keep the design simple summary. Using a standard CV format will allow this.
• Use standard font style (Times New Roman and Arial are standard.
• Use a font size of 10-14. The font size of 10 and 12 are standard, with some titles and titles in a larger font.
• Avoid "fancy" styles (italics, underline, bold, fancy fonts, etc..)
• Do not use horizontal or vertical lines, graphics, charts, tables and boxes. They do not analyze many of resume databases and they often print the funky looking.
• Use fonts for section headings in bold.
• Use common names for section titles (eg, education, experience, technical Sills, etc.)
• Put your name at the beginning of the CV, with contact information on separate lines, immediately after the name. I can not tell you how frustrating it is to have to read the entire resume to find an e-mail or by phone number.
• Avoid abbreviations, acronyms, except for the popular.
• Be concise in your descriptions of projects and experience work. Longer is not necessarily better!
After CV
After the recovery is written, make sure to read. See these tips for more ideas CV that will help ensure your resume gives the best first impression possible!
Print curriculum vitae, to see what it looks like a manager who could prefer hard copies. Adjust the spacing required. You want to print copies to take back with you to job fairs and interviews.
Sample Resume – Resume Sample Experienced New Grad
Sample Resume – New Grad
This sample is taken from a graduate experience new. Use this short excerpt from a guide to writing your own CV.

James Shah
1255 University Avenue
Sacramento, CA -95,825
(916) 555-1111
jshah @ email dot com

To obtain a challenging internship / full-time position in the computer science and software engineering.

MS in Computer Science, California State University, Sacramento, CA, USA GPA-3.7/4.0
BE in computer engineering CUShah College, India GPA-3.8/4.0
Skills Inventory
Programming languages: BASIC, C, C + +, VB6.0, Prolog, COBOL, VC + +, HTML, DHTML, J2EE, JSP, JAVA, ASP, ASP.NET, C #. NET, PHP, XML, JCL
Network Communication Protocols /: TCP / IP, Mobile IP, VoIP, 802.11
OS: UNIX, Linux, Sun Solaris, Windows NT, Windows 2000 Server, HP-UX, Mainframes
Base Data: Oracle 8i, SQL, MS Access 2000, FoxPro, Microsoft SQL Server 2000, MySQL 5.0, DB2

Analyst Intern Data, 6 May to 6 September the Vision Service Plan (VSP):
Migrating Web site metadata:
Phase 1: Move the old website to IIS again server: Since the web site metadata has been run on the old IIS box, we were faced with the speed and crashing everyday problems. If the first phase of this project was to move the current structure of the website is metadata ASP and MS Access Database to new server.
Phase 2: Migration of the database access to DB2: Because of the need and the problems of reliability, the database metadata was migrated from Access database DB2 database. I was responsible design the database schema, conversion of all queries in the format that DB2, and modify the ASP code to retrieve data correct using DB2 databases.

Step 3: Edit the front end: to make the Web site more user-friendly metadata, I have new design all ASP pages and added some additional equipment that can help users to find information easily. The new front is more organized and meets all standards of the intranet VSP.

Data Mart design and implementation of Engineering Department of CSU (MS Project): To maintain the quality of education in the CSU, the design of web site and accept feedback from the faculty of telling users, students and workers on the quality of education, the majors offered by current CSU course offerings, laboratory facilities and education level of faculty using ASP.NET and store the data in Data Mart using the facilities of OLAP Analysis Manager Microsoft SQL Server 2005 and generate useful reports using MS Excel Pivot Tables. The current statistics are on MS Access 2000.

Data link layer: Design and implemented a service link layer data using UNIX and C – Utilities Socket. The project includes all the features of the data link layer, as flow control, error checking using CRC-16 protocol, piggybacking, and using the compression algorithm to the client and the server.
Using the Instruction Execution pipeline: using hardware languages, Verilog, implement the 5 steps of the pipeline with N as the detection and correction of risk data between multiple instructions, which execute simultaneously in the pipeline and generate the corresponding control signal using the wired logic and firmware.

Voice Recognition: Software that can recognize the voice identifies the pitch and made a chart of comparison and the phone application to record your messages. Online Booking Hotel: Develop a 3-tier application for the hotel booking using J2EE, JSP, JDBC, SQL Server 4.1 Ma and HTML, the Tomcat server.
Design Compiler Utilities basis using SML: For source code and the definition Gral grammar, provide the analysis that can convert the source code given in the abstract syntax, static semantics provide validation code given, provide dynamic semantics to generate the desirable outcome for the data source code.
definition of problem solving using algorithms different: to develop different algorithms such as Divide and conquer, backtracking, dynamic programming, Branch and Bound to solve this problem.

Iguana Design SRS Vision Inc.: Under SDLC, SRS document design to specify the functional and nonfunctional requirements, which relate the product to be designed by Iguana Vision, Inc for the sole medical deductible. The scope of this paper is to describe the proposed entries, products, problems, solutions and logical problems and technical aspects of project management that can help make the design, development and validation of related decisions. Here Client wishes to extend their practice by providing a single supplier franchise license with a tour of key software to manage the business. A key part of the business is planning and managing appointments for different types of customer services through use case diagram, ERD, data dictionary, class diagram and UML modeling.
Relevant courses:
• Mobile Computing
• Programming Language Principles
• Advanced Computer Networks
Design Database •
• Data model and system Data Management
• Data Warehousing and Data Mining
• Software Engineering
• Management of telecommunications networks
• Algorithm and paradigms
• Computer Architecture
• Data Mining and Data Warehouse
Honors & Activities
Presented paper at national level on the "piracy" GP Shah College of Engineering and Technology, Surendranagar, India.
Head of the Technical Committee and organized symposium Technophile state level.
PROFILE: Honest, hardworking, motivated, excellent at written and oral communication skills, quick learner, team player, Able to adapt to working environments and new situations, possesses qualities of responsible leadership.

Example of a Software Engineer Resumes

Employee ow
555 Main Street
Sacramento, CA 95628
myname @ myemail dot com
(555) 555-1111

A focused results, customer-focused, articulate and analytical Senior Software Engineer, who can think "out of the box." Strong design integration and problem solving skills. Expert in Java, C #,. NET and T-SQL with database analysis and design. Clever in developing business plans, requirements specifications, user documentation and architectural systems research. Strong communication written and verbal. Interested in a career technically difficult in an environment of application development.
Experienced in:
• Web Development Engineer, all layers, the database services to user interfaces
• Support existing systems with backups of all cases from / to parallel systems
• Analysis and design of databases and user interfaces
• Management requirements
• Implement policies for software development lifecycle and procedures
• The project management and support of several
• Highly adaptable to rapidly changing technical environments with very strong organizational and analytical skills


E * Trade Financial, Sacramento, CA July 2002 – Present

Software Engineer (Systems Customer Service)
• Re-engineering systems and account software used by the teams brokerage. Web Developer for user interfaces to information requests commercial parallel systems of support.
• The system developed and new information for the concerns of users, Bug and Defect Tracking on the use and functionality of new interfaces.
• Coded designed using Web interfaces Java, XML, XSL, AJAX, and JWS.
• Support existing intranet system for employees, including design and development of society Advantage @ work system wide.
• Code and the support provided by ASP.NET, T-SQL, Microsoft SQL Server and Oracle 9i.
• Collaboration in development in-house development of new banking software interfaces. Supported existing system to provide individuals with newly created and ensured they were available in systems in parallel until the existing systems have been removed.
Intel Corporation, Folsom, CA 2000 January – July 2002
Systems Programmer (remote servers and SSL Product Analyst)
• Deployment and tested Remote Installation Services (RIS)-Server installed on Windows XP.
• Focused deployment server built and managed client builds.
• Updating of Visual Basic for Applications use in post-server built for customization of buildings.
• Research on RIS and Active Directory for future deployment in the world. The results presented in both the network operating system Network technology integration team and the team Microsoft Joint Development (JDP) at Intel. Produces a binding document for RIS and Active Directory to monitor the project to another team representative.
• Writing progress reports every two months, participated in weekly staff meetings and team meetings JDP to develop the processing of white paper.
• Provide technical support team SSL, inventory management.
• Participated testing and use of new SAP system as it has been integrated Intel.
• Managed chipset products for business units IO.
CSU Chico, Chico, CA 2000 – 2002
Department (Teaching Assistant Visual Basic)
Department of Computer (MS Office Supervisor Teaching Assistant Continued)
• Supervised all laboratory assistants, guiding the development of student projects.
• Provided one-on-one guidance with Visual Basic programming techniques of teaching.
• Drafting of projects, small program assignments.
• Presentation of structured learning laboratories where students can ask questions about Visual Basic Programming build and syntax.
• structured teaching guides prepared for Chapter material has congratulated the courses Professor.
• Provided custom software for tracking student progress throughout the semester. It included reports for the teacher on assessments, projects, laboratory work assignments, participation, and overall marks.

• Databases: MySQL, Oracle, Access, SAP
• Software: Microsoft Office, Remedy, Microsoft SQL Server, DB Artisan, Eclipse, Visual Studio.NET, FrontPage
• Languages: C #, Java, Visual Basic, ASP, XML, XSL, JWS, SQL and T-SQL

Califorina STATE UNIVERSITY, Chico, CA
BS Computer Science / Business Minor
4.0/4.0 GPA
That computer

3 Example of General resume

Example: Summary

First Name
87 Washington Street
Hopedale NY 11233
Phone: 555-555-5555
Email: xxxxx@xyz.edu


Hopedale, NY American Studies: BA,
GPA: 3.93

GEORGETOWN STUDY universities abroad
University of Trier, Germany (Summer 2005)

American University
Washington, DC: Washington Semester in American politics (Spring 2004)


U.S. Department of Education
Intern, Office of the Assistant Secretary (Spring 2005)
• Generated brief written synopsis of legislative action in use by the department, members of Congress and the general public through Site Ed.
• Research projects and presented the design of many policymakers and academic achievement to support the construction business schools as Centers of Community proposal.
Washington semester independent research project
American University (Spring 2004)
• examined how the increasing dependence of needy students on federal loans instead of grants for higher education has affected access to college and schooling, culminating in the 65-page document
Historical Society of Saratoga Springs
Research Assistant (Spring 2003)
• Search for archival materials, wrote the text panels and objects selected for an exhibition on historic Saratoga in 1930


Vice-President University Affairs
Student Government Association XYZ University (2003-2004)
• Chaired the body of 60 members representing each academic department and student perspectives on issues Curriculum
• Participation in policy decisions regarding the college-wide ethical issues such as the sale of cigarettes campus
• Made detailed oral and written actions reform programs in public forums students
Committee Presidential Search
XYZ University (2002-2004)
• Was one of two students at a college-wide committee designate the sixth president of XYZ University, through all stages, including:

o A detailed self-study institutional needs and objectives to determine the selection criteria
o Find and hire a consultant teaching top
No written evaluation of each candidate, interviews and final recommendation to the Board of Directors
Honors Forum Council
Student Body Representative XYZ University (2001-2002)
• Set goals and guidelines for the first two years Skidmore? 019s innovative, comprehensive program honors whose mission is to increase intellectual engagement and academic rigor of students? freshman and sophomore 019


Student Alumni Society: Founding member (2002-present)
Committee on academic freedom: Student Representative (2002-present)
Skidmore Orchestra: French Horn (2001-present)
American Studies Club Secretary (2001-present)


Mastery of written and spoken German
Extensive experience Office with Internet Explorer, HTML, Lexis-Nexis and Microsoft

Example 2: Summary

First Name
67-61 75th Street
Any city, NY 00000
(555) 555-5555 87 Washington Street xxxxxxxxxx@aol.com
Hopedale, NY 11233
(555) 555-5555



XYZ University
Bachelor of Arts, May 2000
Major: Psychology. Minor: Art Studio
Hopedale, NY

British American College London
Students during the spring semester 1999 London, England


• Assisted children ages 6-7 with the fundamentals of reading
• Assisted in capitalization, punctuation and printing
• Read stories aloud children begging at content
• Assisted by other activities, math homework to art projects
• Relaxation frustration by providing support and encouragement Hopedale, NY
1997-1999 Career Services XXX


• Gathered career of former surveys and hundreds of updated data files using Microsoft Access
• Maintain documentation files employer and credentials, consulting and recruiting information
• materials needed for the circulation of titles compiled applications skills
• Performed various administrative duties Hopedale, NY
Summer 1999 CityArt, INC.
• Sources Funding Sought corporations and foundations, using the resources at the Foundation Center
• Selected preliminary correspondence with philanthropists can
• Grant applications and documents prepared in support
• Helped with fundraising events cash benefits such as auction
• Provided general support office in New York, NY
Summer 1999 Museum of African Art

Artist Assistant

• Oversaw youth participants at the paint shop
• Aided by children in the creative process by providing support to painting
• The assistance of the leading artist in all phases of implementation the project, cleaning cloths suspended Workspace New York, NY
Fall 1995 NEW YORK GROUP Public Interest Research
• Collaboration with others to rebuild a Brownstone in Brooklyn, under the auspices of Habitat for Humanity
• Recruitment others to attend meetings and events NYPIRG
• the materials posted in the Queens College campus that promotes awareness Public questions Flushing, NY


Microsoft Word, Microsoft Access, Netscape, and databases research data, including PsychInfo. Travel through Europe.

Model curriculum vitae 3: Resume / students

First Name
email: xxxxxxx@xyz.edu

XYZ University
Hopedale, NY 11233
(555) 555-5555 PERMANENT ADDRESS
155 Essex Street
Anytown, CT 00000
(555) 555-5555

University of XYZ, Hopedale, New York
Candidate for a Bachelor of Arts, May 2000
Major: Government Minor 3.83 GPA: 3.87 Business GPA

The Williams School, New London, CT
High school, June 1995


Merrill Lynch & Co., Inc., New Haven CT, 1999 was
Made a rigorous course work closely with retail brokers and institutional examining U.S. markets and industries. Documented and analyzed equities, derivatives and bonds using the systems Merrill Lynch computer.

Hartford Superior Court, Hartford CT, Summer 1998
Conducted in-depth project studying daily flow in the palace justice, including data collection and analysis using Microsoft Excel. Participation in the correction of data and the filing of criminal and civil Offices flow cases.


Chairperson of social integrity, XYZ University, Fall 1999 – Present
Appointed by the Association of Student Government Executive Committee and confirmed by student members of the Senate that the social integrity of the Council. Students adjudicate and sanction violations of codes of conduct for students XXX. Members of the Council of lead in opinion and sanctions for students at the hearings and in writing. When driving in close collaboration with the Head of Residential Life and review policies XXX and the social code of honor.

Student Member Speakers Bureau XYZ University, Fall 1998 – Present
Assign funds to various organizations throughout the Community XXX put speakers on campus.


• Microsoft Office 2000
• Microsoft Excel
• Microsoft PowerPoint • Access
• WordPerfect
• Lotus 1-2-3 • IE 4.0 and Netscape 4.6
Adobe PhotoShop 5.0 •
• HTML / Web Publication

About the Author

Eclipse Solaris

eclipse solaris
eclipse solaris
Would you read and maybe buy this story its called: The Eclipse?

It’s about a girl that was born with powers like invisibility and mind reading skills.

They say every 200 years the lunar eclipse comes and solaris and lunar unite, they say every infant that is born that day has very special powers that may vary by the child and this is a story about one of them.

Jane! Jane are you there stop playing around! I know your in here!
Jaja you can’t catch me! I’m invisible!
We know Jane now stop it and come.
Okay Elizabeth.(she said with a frowning face)
Now and eat your dinner.
(sigh) Why can’t I ever use my powers for fun!
Because Jane, it’s not normal!
Don’t yell please, I hate it when you yell.
Well I hate it when you ask so many questions.
Were’s mom I want to go with her not you!
Your mom is not here right now!
I hate you!
Go too your room!
I wish I was never born!

That’ all I have for know

Uh, no. Your spelling and grammar needs a lot of work and there is nothing exciting about this at all, sorry.

Solar Controller Wiki

solar controller wiki
solar controller wiki

About GPS

Global Positioning System

The Global Positioning System (GPS) is the only fully functional Global Navigation Satellite System (GNSS). Utilizing a constellation of at least 24 medium Earth orbit satellites that transmit precise microwave signals, the system enables a GPS receiver to determine its location, speed/direction, and time.

Developed by the United States Department of Defense, it is officially named NAVSTAR GPS (Contrary to popular belief, NAVSTAR is not an acronym, but simply a name given by Mr. John Walsh, a key decision maker when it came to the budget for the GPS program[1]). The satellite constellation is managed by the United States Air Force 50th Space Wing. The cost of maintaining the system is approximately US$750 million per year,[2] including the replacement of aging satellites, and research and development. Despite these costs, GPS is free for civilian use as a public good.

GPS has become a widely used aid to navigation worldwide, and a useful tool for map-making, land surveying, commerce, and scientific uses. GPS also provides a precise time reference used in many applications including scientific study of earthquakes, and synchronization of telecommunications networks.

Simplified method of operation

A GPS receiver calculates its position by measuring the distance between itself and three or more GPS satellites. Measuring the time delay between transmission and reception of each GPS microwave signal gives the distance to each satellite, since the signal travels at a known speed – the speed of light. These signals also carry information about the satellites’ location and general system health (known as almanac and ephemeris data). By determining the position of, and distance to, at least three satellites, the receiver can compute its position using trilateration.[3] Receivers typically do not have perfectly accurate clocks and therefore track one or more additional satellites, using their atomic clocks to correct the receiver’s own clock error.

[edit] Technical description

Unlaunched GPS satellite on display at the San Diego Aerospace museum

Unlaunched GPS satellite on display at the San Diego Aerospace museum

[edit] System segmentation

The current GPS consists of three major segments. These are the space segment (SS), a control segment (CS), and a user segment (US).[4]

[edit] Space segment

The space segment (SS) is composed of the orbiting GPS satellites, or Space Vehicles (SV) in GPS parlance. The GPS design calls for 24 SVs to be distributed equally among six circular orbital planes.[5] The orbital planes are centered on the Earth, not rotating with respect to the distant stars.[6] The six planes have approximately 55° inclination (tilt relative to Earth’s equator) and are separated by 60° right ascension of the ascending node (angle along the equator from a reference point to the orbit’s intersection).[2]

Orbiting at an altitude of approximately 20,200 kilometers (12,600 miles or 10,900 nautical miles; orbital radius of 26,600 km (16,500 mi or 14,400 NM)), each SV makes two complete orbits each sidereal day, so it passes over the same location on Earth once each day. The orbits are arranged so that at least six satellites are always within line of sight from almost everywhere on Earth’s surface.[7]

As of September 2007, there are 31 actively broadcasting satellites in the GPS constellation. The additional satellites improve the precision of GPS receiver calculations by providing redundant measurements. With the increased number of satellites, the constellation was changed to a nonuniform arrangement. Such an arrangement was shown to improve reliability and availability of the system, relative to a uniform system, when multiple satellites fail.[8]

[edit] Control segment

The flight paths of the satellites are tracked by US Air Force monitoring stations in Hawaii, Kwajalein, Ascension Island, Diego Garcia, and Colorado Springs, Colorado, along with monitor stations operated by the National Geospatial-Intelligence Agency (NGA).[9] The tracking information is sent to the Air Force Space Command’s master control station at Schriever Air Force Base in Colorado Springs, which is operated by the 2d Space Operations Squadron (2 SOPS) of the United States Air Force (USAF). 2 SOPS contacts each GPS satellite regularly with a navigational update (using the ground antennas at Ascension Island, Diego Garcia, Kwajalein, and Colorado Springs). These updates synchronize the atomic clocks on board the satellites to within one microsecond and adjust the ephemeris of each satellite’s internal orbital model. The updates are created by a Kalman filter which uses inputs from the ground monitoring stations, space weather information, and various other inputs.[10]

GPS receivers come in a variety of formats, from devices integrated into cars, phones, and watches, to dedicated devices such as those shown here from manufacturers Trimble, Garmin and Leica (left to right).

GPS receivers come in a variety of formats, from devices integrated into cars, phones, and watches, to dedicated devices such as those shown here from manufacturers Trimble, Garmin and Leica (left to right).

[edit] User segment

The user’s GPS receiver is the user segment (US) of the GPS system. In general, GPS receivers are composed of an antenna, tuned to the frequencies transmitted by the satellites, receiver-processors, and a highly-stable clock (often a crystal oscillator). They may also include a display for providing location and speed information to the user. A receiver is often described by its number of channels: this signifies how many satellites it can monitor simultaneously. Originally limited to four or five, this has progressively increased over the years so that, as of 2006, receivers typically have between twelve and twenty channels.

A typical OEM GPS receiver module, based on the SiRF Star III chipset, measuring 15×17 mm, and used in many products.

A typical OEM GPS receiver module, based on the SiRF Star III chipset, measuring 15×17 mm, and used in many products.

GPS receivers may include an input for differential corrections, using the RTCM SC-104 format. This is typically in the form of a RS-232 port at 4,800 bit/s speed. Data are actually sent at a much lower rate, which limits the accuracy of the signal sent using RTCM. Receivers with internal DGPS receivers can outperform those using external RTCM data. As of 2006, even low-cost units commonly include Wide Area Augmentation System (WAAS) receivers.

Many GPS receivers can relay position data to a PC or other device using the NMEA 0183 protocol. NMEA 2000[11] is a newer and less widely adopted protocol. Both are proprietary and controlled by the US-based National Marine Electronics Association. References to the NMEA protocols have been compiled from public records, allowing open source tools like gpsd to read the protocol without violating intellectual property laws. Other proprietary protocols exist as well, such as the SiRF and MTK protocols. Receivers can interface with other devices using methods including a serial connection, USB or Bluetooth.

[edit] Navigation signals

Main article: GPS signals

GPS broadcast signal

GPS broadcast signal

Each GPS satellite continuously broadcasts a Navigation Message at 50 bit/s giving the time-of-day, GPS week number and satellite health information (all transmitted in the first part of the message), an ephemeris (transmitted in the second part of the message) and an almanac (later part of the message). The ephemeris data gives the satellite’s own precise orbit and is output over 18 seconds, repeating every 30 seconds. The ephemeris is updated every 2 hours and is generally valid for 4 hours, with provisions for 6 hour time-outs. The time needed to acquire the ephemeris is becoming a significant element of the delay to first position fix, because, as the hardware becomes more capable, the time to lock onto the satellite signals shrinks, but the ephemeris data requires 30 seconds (worst case) before it is received, due to the low data transmission rate. The almanac consists of coarse orbit and status information for each satellite in the constellation and takes 12 seconds for each satellite present, with information for a new satellite being transmitted every 30 seconds (15.5 minutes for 31 satellites). The purpose of the data is to assist in the acquisition of satellites at power-up by allowing the receiver to generate a list of visible satellites based on stored position and time, while an ephemeris from each satellite is needed to compute position fixes using that satellite. In older hardware, lack of an almanac in a new receiver would cause long delays before providing a valid position, because the search for each satellite was a slow process. Advances in hardware have made the acquisition process much faster, so not having an almanac is no longer an issue. An important thing to note about navigation data is that each satellite transmits only its own ephemeris, but transmits an almanac for all satellites.

Each satellite transmits its navigation message with at least two distinct spread spectrum codes: the Coarse / Acquisition (C/A) code, which is freely available to the public, and the Precise (P) code, which is usually encrypted and reserved for military applications. The C/A code is a 1,023 chip pseudo-random (PRN) code at 1.023 million chips/sec so that it repeats every millisecond. Each satellite has its own C/A code so that it can be uniquely identified and received separately from the other satellites transmitting on the same frequency. The P-code is a 10.23 megachip/sec PRN code that repeats only every week. When the “anti-spoofing” mode is on, as it is in normal operation, the P code is encrypted by the Y-code to produce the P(Y) code, which can only be decrypted by units with a valid decryption key. Both the C/A and P(Y) codes impart the precise time-of-day to the user. Frequencies used by GPS include

* L1 (1575.42 MHz): Mix of Navigation Message, coarse-acquisition (C/A) code and encrypted precision P(Y) code, plus the new L1C on future Block III satellites.

* L2 (1227.60 MHz): P(Y) code, plus the new L2C code on the Block IIR-M and newer satellites.

* L3 (1381.05 MHz): Used by the Nuclear Detonation (NUDET) Detection System Payload (NDS) to signal detection of nuclear detonations and other high-energy infrared events. Used to enforce nuclear test ban treaties.

* L4 (1379.913 MHz): Being studied for additional ionospheric correction.

* L5 (1176.45 MHz): Proposed for use as a civilian safety-of-life (SoL) signal (see GPS modernization). This frequency falls into an internationally protected range for aeronautical navigation, promising little or no interference under all circumstances. The first Block IIF satellite that would provide this signal is set to be launched in 2008.

[edit] Calculating positions

[edit] Using the C/A code

To start off, the receiver picks which C/A codes to listen for by PRN number, based on the almanac information it has previously acquired. As it detects each satellite’s signal, it identifies it by its distinct C/A code pattern, then measures the time delay for each satellite. To do this, the receiver produces an identical C/A sequence using the same seed number as the satellite. By lining up the two sequences, the receiver can measure the delay and calculate the distance to the satellite, called the pseudorange[12].

Overlapping pseudoranges, represented as curves, are modified to yield the probable position

Overlapping pseudoranges, represented as curves, are modified to yield the probable position

Next, the orbital position data, or ephemeris, from the Navigation Message is then downloaded to calculate the satellite’s precise position. A more-sensitive receiver will potentially acquire the ephemeris data quicker than a less-sensitive receiver, especially in a noisy environment.[13] Knowing the position and the distance of a satellite indicates that the receiver is located somewhere on the surface of an imaginary sphere centered on that satellite and whose radius is the distance to it. Receivers can substitute altitude for one satellite, which the GPS receiver translates to a pseudorange measured from the center of the earth.

Locations are calculated not in three-dimensional space, but in four-dimensional spacetime, meaning a measure of the precise time-of-day is very important. The measured pseudoranges from four satellites have already been determined with the receiver’s internal clock, and thus have an unknown amount of clock error. (The clock error or actual time does not matter in the initial pseudorange calculation, because that is based on how much time has passed between reception of each of the signals.[clarify][citation needed]) The four-dimensional point that is equidistant from the pseudoranges is calculated as a guess as to the receiver’s location, and the factor used to adjust those pseudoranges to intersect at that four-dimensional point gives a guess as to the receiver’s clock offset. With each guess, a geometric dilution of precision (GDOP) vector is calculated, based on the relative sky positions of the satellites used. As more satellites are picked up, pseudoranges from more combinations of four satellites can be processed to add more guesses to the location and clock offset. The receiver then determines which combinations to use and how to calculate the estimated position by determining the weighted average of these positions and clock offsets. After the final location and time are calculated, the location is expressed in a specific coordinate system, e.g. latitude/longitude, using the WGS 84 geodetic datum or a local system specific to a country.

[edit] Using the P(Y) code

Calculating a position with the P(Y) signal is generally similar in concept, assuming one can decrypt it. The encryption is essentially a safety mechanism: if a signal can be successfully decrypted, it is reasonable to assume it is a real signal being sent by a GPS satellite.[citation needed] In comparison, civil receivers are highly vulnerable to spoofing since correctly formatted C/A signals can be generated using readily available signal generators. RAIM features do not protect against spoofing, since RAIM only checks the signals from a navigational perspective.

[edit] Accuracy and error sources

The position calculated by a GPS receiver requires the current time, the position of the satellite and the measured delay of the received signal. The position accuracy is primarily dependent on the satellite position and signal delay.

To measure the delay, the receiver compares the bit sequence received from the satellite with an internally generated version. By comparing the rising and trailing edges of the bit transitions, modern electronics can measure signal offset to within about 1% of a bit time, or approximately 10 nanoseconds for the C/A code. Since GPS signals propagate nearly at the speed of light, this represents an error of about 3 meters. This is the minimum error possible using only the GPS C/A signal.

Position accuracy can be improved by using the higher-chiprate P(Y) signal. Assuming the same 1% bit time accuracy, the high frequency P(Y) signal results in an accuracy of about 30 centimeters.

Electronics errors are one of several accuracy-degrading effects outlined in the table below. When taken together, autonomous civilian GPS horizontal position fixes are typically accurate to about 15 meters (50 ft). These effects also reduce the more precise P(Y) code’s accuracy.

Sources of User Equivalent Range Errors (UERE) Source Effect

Ionospheric effects ± 5 meter

Ephemeris errors ± 2.5 meter

Satellite clock errors ± 2 meter

Multipath distortion ± 1 meter

Tropospheric effects ± 0.5 meter

Numerical errors ± 1 meter

[edit] Atmospheric effects

Inconsistencies of atmospheric conditions affect the speed of the GPS signals as they pass through the Earth’s atmosphere and ionosphere. Correcting these errors is a significant challenge to improving GPS position accuracy. These effects are smallest when the satellite is directly overhead and become greater for satellites nearer the horizon since the signal is affected for a longer time. Once the receiver’s approximate location is known, a mathematical model can be used to estimate and compensate for these errors.

Because ionospheric delay affects the speed of microwave signals differently based on frequency—a characteristic known as dispersion—both frequency bands can be used to help reduce this error. Some military and expensive survey-grade civilian receivers compare the different delays in the L1 and L2 frequencies to measure atmospheric dispersion, and apply a more precise correction. This can be done in civilian receivers without decrypting the P(Y) signal carried on L2, by tracking the carrier wave instead of the modulated code. To facilitate this on lower cost receivers, a new civilian code signal on L2, called L2C, was added to the Block IIR-M satellites, which was first launched in 2005. It allows a direct comparison of the L1 and L2 signals using the coded signal instead of the carrier wave.

The effects of the ionosphere generally change slowly, and can be averaged over time. The effects for any particular geographical area can be easily calculated by comparing the GPS-measured position to a known surveyed location. This correction is also valid for other receivers in the same general location. Several systems send this information over radio or other links to allow L1 only receivers to make ionospheric corrections. The ionospheric data are transmitted via satellite in Satellite Based Augmentation Systems such as WAAS, which transmits it on the GPS frequency using a special pseudo-random number (PRN), so only one antenna and receiver are required.

Humidity also causes a variable delay, resulting in errors similar to ionospheric delay, but occurring in the troposphere. This effect is both more localized and changes more quickly than ionospheric effects and is not frequency dependent. These traits making precise measurement and compensation of humidity errors more difficult than ionospheric effects.

Changes in altitude also change the amount of delay due to the signal passing through less of the atmosphere at higher elevations. Since the GPS receiver computes its approximate altitude, this error is relatively simple to correct.

[edit] Multipath effects

GPS signals can also be affected by multipath issues, where the radio signals reflect off surrounding terrain; buildings, canyon walls, hard ground, etc. These delayed signals can cause inaccuracy. A variety of techniques, most notably narrow correlator spacing, have been developed to mitigate multipath errors. For long delay multipath, the receiver itself can recognize the wayward signal and discard it. To address shorter delay multipath from the signal reflecting off the ground, specialized antennas may be used to reduce the signal power as received by the antenna. Short delay reflections are harder to filter out because they interfere with the true signal, causing effects almost indistinguishable from routine fluctuations in atmospheric delay.

Multipath effects are much less severe in moving vehicles. When the GPS antenna is moving, the false solutions using reflected signals quickly fail to converge and only the direct signals result in stable solutions.

[edit] Ephemeris and clock errors

The navigation message from a satellite is sent out only every 30 seconds. In reality, the data contained in these messages tend to be “out of date” by an even larger amount. Consider the case when a GPS satellite is boosted back into a proper orbit; for some time following the maneuver, the receiver’s calculation of the satellite’s position will be incorrect until it receives another ephemeris update. The onboard clocks are extremely accurate, but they do suffer from some clock drift. This problem tends to be very small, but may add up to 2 meters (6 ft) of inaccuracy.

This class of error is more “stable” than ionospheric problems and tends to change over days or weeks rather than minutes. This makes correction fairly simple by sending out a more accurate almanac on a separate channel.

[edit] Selective availability

The GPS includes a feature called Selective Availability (SA) that introduces intentional, slowly changing random errors of up to a hundred meters (328 ft) into the publicly available navigation signals to confound, for example, guiding long range missiles to precise targets. Additional accuracy was available in the signal, but in an encrypted form that was only available to the United States military, its allies and a few others, mostly government users.

SA typically added signal errors of up to about 10 meters (32 ft) horizontally and 30 meters (98 ft) vertically. The inaccuracy of the civilian signal was deliberately encoded so as not to change very quickly, for instance the entire eastern U.S. area might read 30 m off, but 30 m off everywhere and in the same direction. To improve the usefulness of GPS for civilian navigation, Differential GPS was used by many civilian GPS receivers to greatly improve accuracy.

During the Gulf War, the shortage of military GPS units and the wide availability of civilian ones among personnel resulted in a decision to disable Selective Availability. This was ironic, as SA had been introduced specifically for these situations, allowing friendly troops to use the signal for accurate navigation, while at the same time denying it to the enemy. But since SA was also denying the same accuracy to thousands of friendly troops, turning it off or setting it to an error of zero meters (effectively the same thing) presented a clear benefit.

In the 1990s, the FAA started pressuring the military to turn off SA permanently. This would save the FAA millions of dollars every year in maintenance of their own radio navigation systems. The military resisted for most of the 1990s, and it ultimately took an executive order to have SA removed from the GPS signal. The amount of error added was “set to zero”[14] at midnight on May 1, 2000 following an announcement by U.S. President Bill Clinton, allowing users access to the error-free L1 signal. Per the directive, the induced error of SA was changed to add no error to the public signals (C/A code). Selective Availability is still a system capability of GPS, and error could, in theory, be reintroduced at any time. In practice, in view of the hazards and costs this would induce for US and foreign shipping, it is unlikely to be reintroduced, and various government agencies, including the FAA,[15] have stated that it is not intended to be reintroduced.

The US military has developed the ability to locally deny GPS (and other navigation services) to hostile forces in a specific area of crisis without affecting the rest of the world or its own military systems.[14]

One interesting side effect of the Selective Availability hardware is the capability to correct the frequency of the GPS caesium and rubidium atomic clocks to an accuracy of approximately 2 × 10-13 (one in five trillion). This represented a significant improvement over the raw accuracy of the clocks.[citation needed]

On 19 September 2007, the United States Department of Defense announced that they would not procure any more satellites capable of implementing SA. [16]

[edit] Relativity

According to the theory of relativity, due to their constant movement and height relative to the Earth-centered inertial reference frame, the clocks on the satellites are affected by their speed (special relativity) as well as their gravitational potential (general relativity). For the GPS satellites, general relativity predicts that the atomic clocks at GPS orbital altitudes will tick more rapidly, by about 45,900 nanoseconds (ns) per day, because they are in a weaker gravitational field than atomic clocks on Earth’s surface. Special relativity predicts that atomic clocks moving at GPS orbital speeds will tick more slowly than stationary ground clocks by about 7,200 ns per day. When combined, the discrepancy is 38 microseconds per day; a difference of 4.465 parts in 1010.[17]. To account for this, the frequency standard onboard each satellite is given a rate offset prior to launch, making it run slightly slower than the desired frequency on Earth; specifically, at 10.22999999543 MHz instead of 10.23 MHz.[18]

GPS observation processing must also compensate for another relativistic effect, the Sagnac effect. The GPS time scale is defined in an inertial system but observations are processed in an Earth-centered, Earth-fixed (co-rotating) system, a system in which simultaneity is not uniquely defined. The Lorentz transformation between the two systems modifies the signal run time, a correction having opposite algebraic signs for satellites in the Eastern and Western celestial hemispheres. Ignoring this effect will produce an east-west error on the order of hundreds of nanoseconds, or tens of meters in position.[19]

The atomic clocks on board the GPS satellites are precisely tuned, making the system a practical engineering application of the scientific theory of relativity in a real-world environment.

[edit] GPS interference and jamming

Since GPS signals at terrestrial receivers tend to be relatively weak, it is easy for other sources of electromagnetic radiation to desensitize the receiver, making acquiring and tracking the satellite signals difficult or impossible.

Solar flares are one such naturally occurring emission with the potential to degrade GPS reception, and their impact can affect reception over the half of the Earth facing the sun. GPS signals can also be interfered with by naturally occurring geomagnetic storms, predominantly found near the poles of the Earth’s magnetic field.[20] Another source of problems is the metal embedded in some car windscreens to prevent icing, degrading reception just inside the car.

Man-made interference can also disrupt, or jam, GPS signals. In one well documented case, an entire harbor was unable to receive GPS signals due to unintentional jamming caused by a malfunctioning TV antenna preamplifier.[21] Intentional jamming is also possible. Generally, stronger signals can interfere with GPS receivers when they are within radio range, or line of sight. In 2002, a detailed description of how to build a short range GPS L1 C/A jammer was published in the online magazine Phrack.[22]

The U.S. government believes that such jammers were used occasionally during the 2001 war in Afghanistan and the U.S. military claimed to destroy a GPS jammer with a GPS-guided bomb during the Iraq War.[23] Such a jammer is relatively easy to detect and locate, making it an attractive target for anti-radiation missiles. The UK Ministry of Defence tested a jamming system in the UK’s West Country on 7 and 8 June 2007. [24]

Some countries allow the use of GPS repeaters to allow for the reception of GPS signals indoors and in obscured locations, however, under EU and UK laws, the use of these is prohibited as the signals can cause interference to other GPS receivers that may receive data from both GPS satellites and the repeater.

Due to the potential for both natural and man-made noise, numerous techniques continue to be developed to deal with the interference. The first is to not rely on GPS as a sole source. According to John Ruley, “IFR pilots should have a fallback plan in case of a GPS malfunction”.[25] Receiver Autonomous Integrity Monitoring (RAIM) is a feature now included in some receivers, which is designed to provide a warning to the user if jamming or another problem is detected. The U.S. military has also deployed their Selective Availability / Anti-Spoofing Module (SAASM) in the Defense Advanced GPS Receiver (DAGR). In demonstration videos, the DAGR is able to detect jamming and maintain its lock on the encrypted GPS signals during interference which causes civilian receivers to lose lock.[26]

[edit] Techniques to improve accuracy

[edit] Augmentation

Main article: GNSS Augmentation

Augmentation methods of improving accuracy rely on external information being integrated into the calculation process. There are many such systems in place and they are generally named or described based on how the GPS sensor receives the information. Some systems transmit additional information about sources of error (such as clock drift, ephemeris, or ionospheric delay), others provide direct measurements of how much the signal was off in the past, while a third group provide additional navigational or vehicle information to be integrated in the calculation process.

Examples of augmentation systems include the Wide Area Augmentation System, Differential GPS, Inertial Navigation Systems and Assisted GPS.

[edit] Precise monitoring

The accuracy of a calculation can also be improved through precise monitoring and measuring of the existing GPS signals in additional or alternate ways.

After SA, which has been turned off, the largest error in GPS is usually the unpredictable delay through the ionosphere. The spacecraft broadcast ionospheric model parameters, but errors remain. This is one reason the GPS spacecraft transmit on at least two frequencies, L1 and L2. Ionospheric delay is a well-defined function of frequency and the total electron content (TEC) along the path, so measuring the arrival time difference between the frequencies determines TEC and thus the precise ionospheric delay at each frequency.

Receivers with decryption keys can decode the P(Y)-code transmitted on both L1 and L2. However, these keys are reserved for the military and “authorized” agencies and are not available to the public. Without keys, it is still possible to use a codeless technique to compare the P(Y) codes on L1 and L2 to gain much of the same error information. However, this technique is slow, so it is currently limited to specialized surveying equipment. In the future, additional civilian codes are expected to be transmitted on the L2 and L5 frequencies (see GPS modernization, below). Then all users will be able to perform dual-frequency measurements and directly compute ionospheric delay errors.

A second form of precise monitoring is called Carrier-Phase Enhancement (CPGPS). The error, which this corrects, arises because the pulse transition of the PRN is not instantaneous, and thus the correlation (satellite-receiver sequence matching) operation is imperfect. The CPGPS approach utilizes the L1 carrier wave, which has a period 1000 times smaller than that of the C/A bit period, to act as an additional clock signal and resolve the uncertainty. The phase difference error in the normal GPS amounts to between 2 and 3 meters (6 to 10 ft) of ambiguity. CPGPS working to within 1% of perfect transition reduces this error to 3 centimeters (1 inch) of ambiguity. By eliminating this source of error, CPGPS coupled with DGPS normally realizes between 20 and 30 centimeters (8 to 12 inches) of absolute accuracy.

Relative Kinematic Positioning (RKP) is another approach for a precise GPS-based positioning system. In this approach, determination of range signal can be resolved to an accuracy of less than 10 centimeters (4 in). This is done by resolving the number of cycles in which the signal is transmitted and received by the receiver. This can be accomplished by using a combination of differential GPS (DGPS) correction data, transmitting GPS signal phase information and ambiguity resolution techniques via statistical tests—possibly with processing in real-time (real-time kinematic positioning, RTK).

[edit] GPS time and date

While most clocks are synchronized to Coordinated Universal Time (UTC), the Atomic clocks on the satellites are set to GPS time. The difference is that GPS time is not corrected to match the rotation of the Earth, so it does not contain leap seconds or other corrections which are periodically added to UTC. GPS time was set to match Coordinated Universal Time (UTC) in 1980, but has since diverged. The lack of corrections means that GPS time remains at a constant offset (19 seconds) with International Atomic Time (TAI). Periodic corrections are performed on the on-board clocks to correct relativistic effects and keep them synchronized with ground clocks.

The GPS navigation message includes the difference between GPS time and UTC, which as of 2006 is 14 seconds. Receivers subtract this offset from GPS time to calculate UTC and specific timezone values. New GPS units may not show the correct UTC time until after receiving the UTC offset message. The GPS-UTC offset field can accommodate 255 leap seconds (eight bits) which, at the current rate of change of the Earth’s rotation, is sufficient to last until the year 2330.

As opposed to the year, month, and day format of the Julian calendar, the GPS date is expressed as a week number and a day-of-week number. The week number is transmitted as a ten-bit field in the C/A and P(Y) navigation messages, and so it becomes zero again every 1,024 weeks (19.6 years). GPS week zero started at 00:00:00 UTC (00:00:19 TAI) on January 6, 1980 and the week number became zero again for the first time at 23:59:47 UTC on August 21, 1999 (00:00:19 TAI on August 22, 1999). To determine the current Gregorian date, a GPS receiver must be provided with the approximate date (to within 3,584 days) to correctly translate the GPS date signal. To address this concern the modernized GPS navigation messages use a 13-bit field, which only repeats every 8,192 weeks (157 years), and will not return to zero until near the year 2137.

[edit] GPS modernization

Main article: GPS modernization

Having reached the program’s requirements for Full Operational Capability (FOC) on July 17, 1995,[27] the GPS completed its original design goals. However, additional advances in technology and new demands on the existing system led to the effort to modernize the GPS system. Announcements from the Vice President and the White House in 1998 initiated these changes, and in 2000 the U.S. Congress authorized the effort, referring to it as GPS III.

The project aims to improve the accuracy and availability for all users and involves new ground stations, new satellites, and four additional navigation signals. New civilian signals are called L2C, L5 and L1C; the new military code is called M-Code. Initial Operational Capability (IOC) of the L2C code is expected in 2008.[28] A goal of 2013 has been established for the entire program, with incentives offered to the contractors if they can complete it by 2011.

[edit] Applications

The Global Positioning System, while originally a military project, is considered a dual-use technology, meaning it has significant applications for both the military and the civilian industry.

[edit] Military

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The military use GPS for the following purposes:

[edit] Navigation

GPS allows soldiers to find objectives in the dark or in unfamiliar territory, and to coordinate the movement of troops and supplies.

[edit] Target tracking

Various military weapons systems use GPS to track potential ground and air targets before they are flagged as hostile. These weapons systems pass GPS co-ordinates of targets to precision-guided munitions to allow them to engage the targets accurately.

Military aircraft, particularly those used in air-to-ground roles use GPS to find targets (for example, gun camera video from AH-1 Cobras in Iraq show GPS co-ordinates that can be looked up in Google Earth).

[edit] Missile and projectile guidance

GPS allows accurate targeting of various military weapons including ICBMs, cruise missiles and precision-guided munitions.

Artillery projectiles with embedded GPS receivers able to withstand forces of 12,000G have been developed for use in 155 mm howitzers.[29]

[edit] Search and Rescue

Downed pilots can be located faster if they have a GPS receiver.

[edit] Reconnaissance and Map Creation

The military use GPS extensively to aid mapping and reconnaissance.

[edit] Other

The GPS satellites also carry nuclear detonation detectors, which form a major portion of the United States Nuclear Detonation Detection System.[30]

[edit] Civilian

See also: GPS applications

This antenna is mounted on the roof of a hut containing a scientific experiment needing precise timing.

This antenna is mounted on the roof of a hut containing a scientific experiment needing precise timing.

Many civilian applications benefit from GPS signals, using one or more of three basic components of the GPS; absolute location, relative movement, time transfer.

The ability to determine the receiver’s absolute location allows GPS receivers to perform as a surveying tool or as an aid to navigation. The capacity to determine relative movement enables a receiver to calculate local velocity and orientation, useful in vessels or observations of the Earth. Being able to synchronize clocks to exacting standards enables time transfer, which is critical in large communication and observation systems. An example is CDMA digital cellular. Each base station has a GPS timing receiver to synchronize its spreading codes with other base stations to facilitate inter-cell hand off and support hybrid GPS/CDMA positioning of mobiles for emergency calls and other applications.

Finally, GPS enables researchers to explore the Earth environment including the atmosphere, ionosphere and gravity field. GPS survey equipment has revolutionized tectonics by directly measuring the motion of faults in earthquakes.

To help prevent civilian GPS guidance from being used in an enemy’s military or improvised weaponry, the US Government controls the export of civilian receivers. A US-based manufacturer cannot generally export a GPS receiver unless the receiver contains limits restricting it from functioning when it is simultaneously (1) at an altitude above 18 kilometers (60,000 ft) and (2) traveling at over 515 m/s (1,000 knots).[31]

[edit] History

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The design of GPS is based partly on the similar ground-based radio navigation systems, such as LORAN and the Decca Navigator developed in the early 1940s, and used during World War II. Additional inspiration for the GPS system came when the Soviet Union launched the first Sputnik in 1957. A team of U.S. scientists led by Dr. Richard B. Kershner were monitoring Sputnik’s radio transmissions. They discovered that, because of the Doppler effect, the frequency of the signal being transmitted by Sputnik was higher as the satellite approached, and lower as it continued away from them. They realized that since they knew their exact location on the globe, they could pinpoint where the satellite was along its orbit by measuring the Doppler distortion.

The first satellite navigation system, Transit, used by the United States Navy, was first successfully tested in 1960. Using a constellation of five satellites, it could provide a navigational fix approximately once per hour. In 1967, the U.S. Navy developed the Timation satellite which proved the ability to place accurate clocks in space, a technology the GPS system relies upon. In the 1970s, the ground-based Omega Navigation System, based on signal phase comparison, became the first world-wide radio navigation system.

The first experimental Block-I GPS satellite was launched in February 1978.[28] The GPS satellites were initially manufactured by Rockwell International and are now manufactured by Lockheed Martin.

[edit] Timeline

* In 1972, the US Air Force Central Inertial Guidance Test Facility (Holloman AFB) conducted developmental fight tests of two prototype GPS receivers over White Sands Missile Range, using ground-based pseudo-satellites.

* In 1978 the first experimental Block-I GPS satellite was launched.

* In 1983, after Soviet interceptor aircraft shot down the civilian airliner KAL 007 in restricted Soviet airspace, killing all 269 people on board, U.S. President Ronald Reagan announced that the GPS system would be made available for civilian uses once it was completed.

* By 1985, ten more experimental Block-I satellites had been launched to validate the concept.

* On February 14, 1989, the first modern Block-II satellite was launched.

* In 1992, the 2nd Space Wing, which originally managed the system, was de-activated and replaced by the 50th Space Wing.

* By December 1993 the GPS system achieved initial operational capability[32]

* By January 17, 1994 a complete constellation of 24 satellites was in orbit.

* Full Operational Capability was declared by NAVSTAR in April 1995.

* In 1996, recognizing the importance of GPS to civilian users as well as military users, U.S. President Bill Clinton issued a policy directive[33] declaring GPS to be a dual-use system and establishing an Interagency GPS Executive Board to manage it as a national asset.

* In 1998, U.S. Vice President Al Gore announced plans to upgrade GPS with two new civilian signals for enhanced user accuracy and reliability, particularly with respect to aviation safety.

* On May 2, 2000 “Selective Availability” was discontinued as a result of the 1996 executive order, allowing users to receive a non-degraded signal globally.

* In 2004, the United States Government signed a historic agreement with the European Community establishing cooperation related to GPS and Europe’s planned Galileo system.

* In 2004, U.S. President George W. Bush updated the national policy, replacing the executive board with the National Space-Based Positioning, Navigation, and Timing Executive Committee.

* November 2004, QUALCOMM announced successful tests of Assisted-GPS system for mobile phones.[3]

* In 2005, the first modernized GPS satellite was launched and began transmitting a second civilian signal (L2C) for enhanced user performance.

* The most recent launch was on 17 November 2006. The oldest GPS satellite still in operation was launched in August 1991.

* On September 14, 2007, the aging mainframe-based Ground Segment Control System was transitioned to the new Architecture Evolution Plan. [4]

[edit] Satellite numbers

Name Launch Period No of satellites launched, inc. launch failures Currently in service

Block I 1978-1985 11 0

Block II 1985-1990 9 0

Block IIA 1990-1997 19 15+11

Block IIR 1997-2004 12 12

Block IIR-M 2005- 3 3

Total 54 (plus one not launched) 30+1

1One test satellite

[edit] Awards

Two GPS developers have received the National Academy of Engineering Charles Stark Draper prize year 2003:

* Ivan Getting, emeritus president of The Aerospace Corporation and engineer at the Massachusetts Institute of Technology, established the basis for GPS, improving on the World War II land-based radio system called LORAN (Long-range Radio Aid to Navigation).

* Bradford Parkinson, professor of aeronautics and astronautics at Stanford University, conceived the present satellite-based system in the early 1960s and developed it in conjunction with the U.S. Air Force.

One GPS developer, Roger L. Easton, received the National Medal of Technology on February 13, 2006 at the White House.[34]

On February 10, 1993, the National Aeronautic Association selected the Global Positioning System Team as winners of the 1992 Robert J. Collier Trophy, the most prestigious aviation award in the United States. This team consists of researchers from the Naval Research Laboratory, the U.S. Air Force, the Aerospace Corporation, Rockwell International Corporation, and IBM Federal Systems Company. The citation accompanying the presentation of the trophy honors the GPS Team “for the most significant development for safe and efficient navigation and surveillance of air and spacecraft since the introduction of radio navigation 50 years ago.”

[edit] Other systems

Main article: Global Navigation Satellite System

Other satellite navigation systems in use or various states of development include:

* Beidou — China’s regional system that China has proposed to expand into a global system named COMPASS.

* Galileo — a proposed global system being developed by the European Union, joined by China, Israel, India, Morocco, Saudi Arabia and South Korea, Ukraine planned to be operational by 2011–12.

* GLONASS — Russia’s global system which is being restored to full availability in partnership with India.

* Indian Regional Navigational Satellite System (IRNSS) — India’s proposed regional system.

* QZSS – Japanese proposed regional system, adding better coverage to the Japanese islands.

[edit] See also

Satellite navigation systems Portal

Nautical Portal



* radio navigation

* High Sensitivity GPS

* Degree Confluence Project Use GPS to visit integral degrees of latitude and longitude.

* Exif, GPS data transfer.

* Geotagging

* Geocaching

* NaviTraveler.com, – a GPS point sharing community.

* GPS Drawing Digital mapping and drawing with GPS tracks.

* GPS tracking


* Assisted GPS

* GPX (XML schema for interchange of waypoints)

* ID Sniper rifle

* OpenStreetMap, free content maps and street pictures (GFDL)

* Telematics: Many telematics devices use GPS to determine the location of mobile equipment.

* The American Practical Navigator—Chapter 11 “Satellite Navigation”

* Point of Interest

* Automotive navigation system

* NextGen

[edit] Notes

1. ^ Parkinson, B.W. (1996), Global Positioning System: Theory and Applications, chap. 1: Introduction and Heritage of NAVSTAR, the Global Positioning System. pp. 3-28, American Institute of Aeronautics and Astronautics, Washington, D.C.

2. ^ a b GPS Overview from the NAVSTAR Joint Program Office. Accessed December 15, 2006.

3. ^ HowStuffWorks. How GPS Receivers Work. Accessed May 14, 2006.

4. ^ globalsecurity.org [1].

5. ^ Dana, Peter H. GPS Orbital Planes. August 8, 1996.

6. ^ What the Global Positioning System Tells Us about Relativity. Accessed January 2, 2007.

7. ^ USCG Navcen: GPS Frequently Asked Questions. Accessed January 3, 2007.

8. ^ Massatt, Paul and Brady, Wayne. “Optimizing performance through constellation management”, Crosslink, Summer 2002, pages 17-21.

9. ^ US Coast Guard General GPS News 9-9-05

10. ^ USNO. NAVSTAR Global Positioning System. Accessed May 14, 2006.

11. ^ NMEA NMEA 2000

12. ^ http://gge.unb.ca/Resources/HowDoesGPSWork.html

13. ^ AN02 Network Assistance (HTML). Retrieved on 2007-09-10.

14. ^ a b Office of Science and Technology Policy. Presidential statement to stop degrading GPS. May 1, 2000.

15. ^ FAA, Selective Availability. Retrieved Jan. 6, 2007.

16. ^ http://www.defenselink.mil/releases/release.aspx?releaseid=11335

17. ^ Rizos, Chris. University of New South Wales. GPS Satellite Signals. 1999.

18. ^ The Global Positioning System by Robert A. Nelson Via Satellite, November 1999

19. ^ Ashby, Neil Relativity and GPS. Physics Today, May 2002.

20. ^ Space Environment Center. SEC Navigation Systems GPS Page. August 26, 1996.

21. ^ The hunt for an unintentional GPS jammer. GPS World. January 1, 2003.

22. ^ Low Cost and Portable GPS Jammer. Phrack issue 0x3c (60), article 13]. Published December 28, 2002.

23. ^ American Forces Press Service. CENTCOM charts progress. March 25, 2003.

24. ^ [2]

25. ^ Ruley, John. AVweb. GPS jamming. February 12, 2003.

26. ^ Commercial GPS Receivers: Facts for the Warfighter. Hosted at the Joint Chiefs website, linked by the USAF’s GPS Wing DAGR program website. Accessed on 10 April, 2007

27. ^ US Coast Guard news release. Global Positioning System Fully Operational

28. ^ a b Hydrographic Society Journal. Developments in Global Navigation Satellite Systems. Issue #104, April 2002. Accessed April 5, 2007.

29. ^ XM982 Excalibur Precision Guided Extended Range Artillery Projectile. GlobalSecurity.org (2007-05-29). Retrieved on 2007-09-26.

30. ^ Sandia National Laboratory’s Nonproliferation programs and arms control technology.

31. ^ Arms Control Association. Missile Technology Control Regime. Accessed May 17, 2006.

32. ^ United States Department of Defense. Announcement of Initial Operational Capability. December 8, 1993.

33. ^ National Archives and Records Administration. U.S. GLOBAL POSITIONING SYSTEM POLICY. March 29, 1996.

34. ^ United States Naval Research Laboratory. National Medal of Technology for GPS. November 21, 2005

[edit] External links

Wikimedia Commons has media related to:

Global Positioning System

Government links

* GPS.gov—General public education website created by the U.S. Government

* National Space-Based PNT Executive Committee—Established in 2004 to oversee management of GPS and GPS augmentations at a national level.

* USCG Navigation Center—Status of the GPS constellation, government policy, and links to other references. Also includes satellite almanac data.

* The GPS Joint Program Office (GPS JPO)—Responsible for designing and acquiring the system on behalf of the US Government.

* U.S. Naval Observatory’s GPS constellation status

* U.S. Army Corps of Engineers manual: NAVSTAR HTML and PDF (22.6 MB, 328 pages)

* PNT Selective Availability Announcements

* GPS SPS Signal Specification, 2nd Edition—The official Standard Positioning Signal specification.

* Federal Aviation Administration’s GPS FAQ

Introductory / tutorial links

* How does GPS work? TomTom explains GPS, navigation, and digital maps

* GPS Academy Garmin interactive video web site explaing what exactly GPS is and what it can do for you

* HowStuffWorks’ Simplified explanation of GPS and video about how GPS works.

* Trimble’s Online GPS Tutorial Tutorial designed to introduce you to the principles behind GPS

* GPS and GLONASS Simulation(Java applet) Simulation and graphical depiction of space vehicle motion including computation of dilution of precision (DOP)

Technical, historical, and ancillary topics links

* Dana, Peter H. “Global Positioning System Overview”

* Satellite Navigation: GPS & Galileo (PDF)—16-page paper about the history and working of GPS, touching on the upcoming Galileo

* History of GPS, including information about each satellite’s configuration and launch.

* Chadha, Kanwar. “The Global Positioning System: Challenges in Bringing GPS to Mainstream Consumers” Technical Article (1998)

* GPS Weapon Guidance Techniques

* RAND history of the GPS system (PDF)

* GPS Anti-Jam Protection Techniques

* Crosslink Summer 2002 issue by The Aerospace Corporation on satellite navigation.

* Improved weather predictions from COSMIC GPS satellite signal occultation data.

* David L. Wilson’s GPS Accuracy Web Page A thorough analysis of the accuracy of GPS.

* Innovation: Spacecraft Navigator, Autonomous GPS Positioning at High Earth Orbits Example of GPS receiver designed for high altitude spaceflight.

* The Navigator GPS Receiver GSFC’s Navigator spaceflight receiver.

* Neil Ashby’s Relativity in the Global Positioning System


v • d • e

Satellite navigation systems

Historical Flag of the United States Transit

Operational Flag of the Soviet Union / Flag of Russia GLONASS · Flag of the United States GPS

Developmental Flag of the People’s Republic of China Beidou/COMPASS · Flag of Europe Galileo · Flag of India IRNSS · Flag of Japan QZSS

Related topics EGNOS · GAGAN · GPS·C · LAAS · MSAS · WAAS


v • d • e

Time signal stations

Longwave DCF77 · HBG · JJY · MSF · TDF · WWVB

Shortwave BPM · CHU · RWM · WWV · WWVH · YVTO

GNSS time transfer Beidou · Galileo · GLONASS · GPS · IRNSS

Defunct time stations OMA · VNG


v • d • e

Global structure in Systems, Systems sciences and Systems scientists

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Systems Biological system · Complex system · Complex adaptive system · Conceptual system · Cultural system · Dynamical system · Economic system · Ecosystem · Formal system · Global Positioning System · Human organ systems · Information systems · Legal system · Metric system · Nervous system · Non-linear system · Operating system · Physical system · Political system · Sensory system · Social system · Solar System · System · Systems of measurement

Fields of theory Chaos theory · Complex systems · Control theory · Cybernetics · Holism in science · Sociotechnical systems theory · Systems biology · System dynamics · Systems ecology · Systems engineering · Systems theory · Systems science

Systems scientists Russell L. Ackoff · William Ross Ashby · Gregory Bateson · Ludwig von Bertalanffy · Kenneth E. Boulding · Peter Checkland · C. West Churchman · Heinz von Foerster · Charles François · Jay Wright Forrester · Ralph W. Gerard · Debora Hammond · George Klir · Niklas Luhmann · Humberto Maturana · Donella Meadows · Mihajlo D. Mesarovic · Howard T. Odum · Talcott Parsons · Ilya Prigogine · Anatol Rapoport · Francisco Varela · John N. Warfield · Norbert Wiener

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