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USCG NAVIGATION CENTER

Learn about GPS satellite constellation status, clock and wheel performance, and interference reporting at the 2005 meeting in Prague, Czech Republic. Includes key data and resolution processes.

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USCG NAVIGATION CENTER

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  1. USCG NAVIGATION CENTER NAVCEN and GPS CGSIC IISC European Meeting Prague, Czech Republic 14 March 2005 Rebecca M. Casswell Chief, GPS Branch

  2. Topics • Constellation Status • Interference Reporting • NAVCEN Mirror Site • U.S. NDGPS

  3. Constellation SummarySince 1 Jan 04 • 28 operational on-orbit satellites • 3 satellites launched • SVN59(PRN19): 20 Mar 04 • SVN60(PRN23): 23 Jun 04 • SVN61(PRN02): 6 Nov 04 • Next launch- May 2005

  4. Clock meets spec watch list dead unused in use Wheel functional watch list dead launch date SVN (PRN) Clock* Wheel 1 2 3 4 1 2 3 4 * II/IIA = Rb, Rb, Cs, Cs IIR = Rb, Rb, Rb Diagonal Line = Unhealthy PLANE A C D E F B 61R (02) 11/04 56R (16) 1/03 24A (24) 07/91 36A (06) 03/94 51R (20) 05/00 39A (09) 06/93 41R (14) 11/00 1 SLOT 33A (03) 03/96 25A (25) 02/92 46R (11) 10/99 30A (30) 9/96 47R (22) 12/03 26A (26) 07/92 2 59R (19) 03/04 45R (21) 03/03 40A (10) 07/96 38A (08) 11/97 43R (13) 07/97 44R (28) 07/00 3 27A (27) 09/92 37A (07) 05/93 54R (18) 01/01 60R (23) 06/04 34A (04) 10/93 35A (05) 08/93 4 31A (31) 03/93 29A (29) 12/92 15 (15) 10/90 5 32A (01) 11/92 17 (17) 12/89 6 7 GPS Space and ControlClock and Reaction Wheel Performance Status(as of 22 Nov 2004)

  5. GPS Positions22 November 04 30 B2 34 25 A2 D4 32 160 61 Arg. of Latitude (deg) D1 60 IIR-14 F4 24 120 36 C1 43 F3 17 56 B1 80 40 E3 27 A4 45 40 D3 29 33 38 A3 C2 0 Equator EPOCH 1 Jul 93 15 54 F2 59 E4 26 C3 320 44 B3 47 E2 Block II 280 39 31 46 A1 D2 Block IIA 37 41 F1 240 C4 Block IIR 35 IIR-15 51 E1 200 B4 A B C D E F

  6. Constellation Performance • PDOP Availability: • Requirement - PDOP of 6 or Less, 98% of the Time or Better • Actual - 99.98495% • Horizontal Service Availability • Requirement - 95% Threshold of 36 meters, 99% of the Time or Better • Actual – 2.75 meters • Vertical Service Availability • Requirement - 95% Threshold of 77 meters, 99% of the Time or Better • Actual – 3.98 meters • User Range Error • Requirement - 6 meters or Less, Constellation Average • Actual - 1.12 meters (excluding SVN23 anomaly, 1 Jan 04) All Errors Based on Dual Frequency, Signal in Space Only. Information Presented Reflects Data Collected During the Period from January 1, 2004 to August 31, 2004. Thresholds Provided Reflect Average Location Requirements from SPS Signal Specification Dated October, 2001.

  7. Subscription services that deliver Operational Advisory Broadcast (GPS Status Messages) and/or the Notice Advisory to NAVSTAR Users (NANU) via List servers. GPS Status List server:This service provides the subscriber with an e-mail containing the newly updated Status Message that is sent by the NAVCEN within 60 minutes of notification by the Air Force of a change to the GPS Constellation. NANU List server: This service provides the subscriber with an e-mail containing the NANU that is sent by NAVCEN within 60 minutes of notification by the Air Force of a change to the GPS Constellation. CGSIC List server: This service provides the subscriber with an e-mail containing GPS and CGSIC announcements. Data Broadcasts

  8. The Navigation Center appreciates your reports regarding service degradations, outages, or other incidents or anomalies. Please report problems via ourGPS Problem Report Page After a GPS user completes these forms, they are sent to a database for tracking, analysis, and resolution. Reports may be received via phone/fax. Interference Reporting

  9. User contacted for additional information, if necessary. The report contains specific data regarding the observed outage, degradation, incident or anomaly. If the report is aviation related it will be directed to the FAA for tracking, analysis, and resolution. Maritime and terrestrial related reports will be simultaneously processed by the USCG GPS Liaison to the GPS Operations Center at Schriever AFB and NIS personnel for resolution. Interference Reporting Process

  10. Check for constellation events during reported outage period by using NANU. Check Post Assessment PDOP Charts at GPS Operations Center website. Check DGPS logs for GPS signal anomalies (high pseudo range residual, high position error, high range rate correction, various types of dilution of position, high pseudo range noise) during reported outage times. GSC Liaison checks for reports from military users during same time period of civilian report. Perform analysis of constellation activity during reported outage times. USCG/USAF Resolution Process

  11. Upon finding a resolution, the NIS will notify the user; if the report is not resolved for 30 days, the user will be notified of the situation. 30 days after reporting findings to the user, the NIS will again contact the user to assess the situation and submit a new report if necessary. Focus is on Customer Service and Satisfaction. Interference Reporting Process

  12. NAVCEN Web Site

  13. 1. http://www.navcenter.org 2. Maintained to disseminate information for GPS, DGPS, and Loran radio navigation systems in the event our main site is unavailable. 3. Fully redundant information - all information and functions that are available on the primary site is available on the mirror site. 4. Hosted off-site with remote access capabilities. NAVCEN Mirror Site

  14. DGPS

  15. Current NDGPS Coverage In the lower 48, approximately 87% has single coverage and 55% has dual coverage.

  16. International Standard • NDGPS is designed to an international, non-proprietary standard • Compliant with RTCM SC-104 and ITU-R M.823 • Increases market for manufacturers • Enhances Global interoperability • Signal is free to all users • 47 other countries operate systems compatible to ours • Resulting in a seamless international navigation system

  17. Acceptance of the international standard is leading to a seamless worldwide service.

  18. High Accuracy NDGPS NDGPS (1 to 3 meters) HA-NDGPS Dynamic (0.1 meters) GPS (16-24 meters)

  19. High Accuracy NDGPSProgram Objectives • Develop a nationwide 3-D dynamic positioning service that has an accuracy of less than 15 centimeter and time to alarm integrity of less than 2 seconds • Coexist with existing NDGPS infrastructure • Do not degrade existing NDGPS • Minimize deployment costs

  20. Navigation Information Service http://www.navcen.uscg.gov http://www.navcenter.org (mirror site) E-mail: nisws@navcen.uscg.mil Phone: +1 703 313 5900 Fax: +1 703 313 5920

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