CGSIC HONORRESPECTDEVOTION TO DUTY Navstar GPS Constellation Status

CGSIC HONOR-RESPECT-DEVOTION TO DUTY Navstar GPS Constellation Status Doug Louden Chief, GPS Liaison, USCG HQ AF Space Command GPSOC, Civil Analyst Colorado Springs, CO. Peterson AFB (719) 554 -3582 Schriever AFB (719) 567 -5093 23 May 2006 1

Outline n Launch recommendations n Constellation Health Assessment n Nav Coverage n NAVCEN and Interference Reporting Procedures n Constellation Performance and Summary 2

IIR-(M) Launch Considerations n So far, launch considerations: n n C 4 (SVN 53), A 2 (next launch, SVN 58) Can re-phase to desired location if launch is within plane 3

GPS IIR/MLV Launch Window Opening Time - 2006 (Descending/Ascending Node Injection) IIR-15(M) Weather unstable at Cape during Sept 06 launch window for IIR-15(M) 4

IIR-15(M) - Eclipse window -Recommended launch window SVN 25 (A 2) eclipse season no factor for Sep 06 launch 5

Weather/Eclipse Season n IIR-15(M) launch in Sep 06 to replace SVN 25 at A 2 Weather unstable at Cape in Sep 06 for launch to A 2 n Multiple weather delays with IIR-12 (Jul 04) and IIR-13 (Nov 04) n SVN 25 at A 2 has next eclipse season: mid-June to mid-July 06 n SVN 25 will go through eclipse before replacement n SVN 25 eclipse season poses no problem for a Sep 06 launch n 6

Launch Recommendations n Launch IIR-15(M) to A 2 in Sep 06 to replace SVN 25 n n No need to decommission an SV, 29 PRNs in use, 1 is available Launch IIR-16(M) NET Apr 07 Determine IIR-16(M) plane/slot at future date n Determine a vehicle to remove from service for PRN prior to IIR 16(M) launch n 7

Glossary Cross-plane back-up: A satellite in the 6 n Expanded slot: An expandable slot in the Expandable 24 constellation that has been plane constellation providing back-up augmented by an additional satellite and navigation coverage for a failed satellite in has been slightly rephased so that the new an adjacent plane thereby minimizing the close pair of satellites straddle the original impact of the failure. location. n Close/Distant pairs: The GPS Optimized 24 constellation is a non-symmetric 6 plane n Optimized 24 Constellation: The nonsymmetric six plane GPS constellation as constellation. Each plane in the Optimized documented in the currently approved SPS 24 constellation has four satellites grouped PS. This structure has four satellites per as a close pair (separated by about 30 deg plane grouped as a close pair and a distant Argument of Latitude) and a distant pair. Also referred to as the “Baseline 24” (separated by about 130 deg Argument of constellation. Latitude). n On-orbit storage: The time between when n Expandable 24 Constellation: The Optimized 24 Constellation with three a satellite or component is launched and expandable baseline slots defined in the B, when it is initialized and operated. D, and F planes to create an additional n Expandable slot: The B 1, D 2 or F 2 slots of close pair. Also referred to as the Expandable 24 constellation which, “Optimized 27” constellation. when “expanded”, forms a “fore” and “aft” slot, straddling the original baseline slot, thus providing an additional close pair and better constellation performance than the 24 + 3. n 8

GPS Locations 1 Apr 06 (GLAN) 37 Rephase 1 deg day drift 180 36 160 35 140 GLAN (deg) 39 120 100 80 IIR-15(M) 30 56 B 1 25 20 38 A A 4 44 B 2 33 C 2 59 C 3 24 46 D 2 29 C 4 61 B 3 D 1 D 41 F 1 54 E 4 32 D 3 60 F 4 15 C F 2 D 4 47 E 2 A 3 26 40 E 3 45 B 51 E 1 37 in April 34 53 27 B 4 A 2 60 40 0 A 1 43 F 3 C 1 E F Empty Slot Block IIA Block IIR-M 9

Constellation Status Health Total SVs in Category Changes Since Last Year n n n 17 (-1) SVs past design life 12 (-1) SVs past pre-launch mean life estimate (MLE) 14 (-1, +1) SVs one component away from nav mission failure 9 (+0) SVs one component away from bus failure Anomaly Summary n SVN 39 (C 5) Clock swap X 2 n SVN 25 (A 2) Clock swap (on last clock) n SVN 30 (B 2) Clock swap SVN 31 disposal 15 Dec 05 SVN 25 last clock 10

Constellation Assessment A Design Life: II/IIA - 7. 5 yrs IIR - 10 yrs IIF - 15 yrs MLE: II= 12. 05 IIA= 13. 03 IIR= 14. 18 IIR-M=8. 60 yrs MMD: IIF= 11. 0 yrs Vehicle count: 29 total 1 IIs 15 IIAs 13 IIRs (includes 1 st IIR-M) IIRs : only 3 Rb clocks C D E F 1 SVN 39 PRN 09 SVN 56 PRN 16 SVN 36 PRN 06 SVN 61 PRN 02 SVN 51 PRN 20 SVN 41 PRN 14 2 SVN 25 PRN 25 SVN 30 PRN 30 SVN 33 PRN 03 SVN 46 PRN 11 SVN 47 PRN 22 SVN 26 PRN 26 3 4 SVN 38 PRN 08 SVN 44 PRN 28 SVN 59 PRN 19 SVN 45 PRN 21 SVN 40 PRN 10 SVN 43 PRN 13 SVN 27 PRN 27 SVN 35 PRN 05 SVN 53 PRN 17 M SVN 34 PRN 04 SVN 54 PRN 18 SVN 60 PRN 23 SVN PRN SVN 37 PRN 07 SVN 15 PRN 15 SVN PRN SVN 29 PRN 29 SVN PRN SVN 24 PRN 24 SVN PRN SVN 32 PRN 01 SVN PRN Clocks NAV BUS Good Clock Status = Dead SVN 00 Suspect PRN 00 Unused 1 2 Rubidium 3 4 Cesium B As Of 1 Apr 06 N: /Althouse/GPS-/Program Summary/Problem Vehicle Listing 11

SVN 39 and 53 out 6 N 128. 7 E PDOPmax = 10. 33 12

SVN 25 Status n Age = 14 years n Single String in Nav n n n Single String in Bus n n NDU power supply failed 23 Dec 05 Rubidium 1 (last clock) selected 25 Dec 05, performance variable Operating on three wheels Wheel #3 electronics failed in 2003 Double lubed wheels additional failures unlikely n Solar array degradation n Currently being power managed n n High constellation coverage value n n SVN 32 and SVN 37 will provide cross plane backup SVN 25 recommended for replacement by IIR-15(M) 13

SVN 25 and 39 Out 64 S 95. 8 E PDOPmax = 11. 65 14

GPS On-orbit Satellite Predicted Life Remaining (Oct 05 Reliability) Decommissioned/Out-of-Service 15

GPS Satellite Age (as of: 1 Apr 06) 16 Blk II Block II & IIA MLE 12 Blk IIR 10 Blk IIR-M 8 Deactivated 6 4 Operational for 4. 5 yrs – Used for Test & Checkout Blk IIA Block IIR MLE Design Life: II/IIA IIRM IIF - 7. 5 yrs 10 yrs 8. 5 yrs 15 yrs Block IIR-M MLE 14 Years 2 Satellite Vehicle 15 24 25 28 26 27 32 29 37 39 35 34 36 33 40 30 38 43 46 51 44 41 54 56 45 47 59 60 61 53 16

Accuracy Equation Accuracy = Statistical Conversion * DOP * URE 2 + UEE 2 Accuracy; DOP is a big part of the accuracy equation Poor HDOP Good DOP Poor VDOP URE True Range Nav Message Good UEE Moderate Poor DOP GA MCS MS 50% (CEP) ~68% (~DRMS) ~95% (~2 DRMS) 0 1 2 3 4 5 6 17

SPS PS Requirements n Sec 3. 2, table 3 -2: PDOP Availability Standard ≥ 98% global Position Dilution of Precision (PDOP) of 6 or less ≥ 88% worst site PDOP of 6 or less n Conditions and Constraints Defined for position solution meeting the representative user conditions and operating within the service volume over any 24 -hour interval. n Based on using only satellites transmitting standard code and indicating “healthy” in the broadcast navigation message (sub-frame 1). n Sec 3. 2, paragraph 2: n In support of the service availability standard, 24 operational satellites must be available on orbit with 0. 95 probability (averaged over any day). 18

NAVCEN & Data Broadcasts Subscription services that deliver Operational Advisory Broadcast (GPS Status Messages) and/or the Notice Advisory to NAVSTAR Users (NANU) via List servers. 1. 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. 2. 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. 3. CGSIC List server: This service provides the subscriber with an e-mail containing GPS and CGSIC announcements. 19

Interference Reporting The Navigation Center appreciates your reports regarding service degradations, outages, or other incidents. n Please report problems via our GPS Problem Report Page. n After a GPS user completes these forms, they are sent to a database for tracking, analysis, and resolution. n Reports may be received via phone/fax. n 20

Interference Reporting Process User contacted for additional information, if necessary. n If the report is aviation related it will be directed to the FAA for tracking, analysis, and resolution. n Maritime and terrestrial related reports will be processed simultaneously by the USCG GPS Liaison to the GPS Operations Center at Schriever AFB and NIS personnel for resolution. n Ø Ø Check for constellation events during reported outage period by using NANU. Perform analysis of constellation activity during reported outage times. 21

Interference Reporting Process 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. n 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. n Focus is on Customer Service and Satisfaction. n 22

n n n Navigation Information Service http: //www. navcen. uscg. gov http: //www. navcenter. org (mirror site) E-mail: TIS-PF-NISWS@uscg. mil Phone: +1 703 313 5900 Fax: +1 703 313 5920 23

Constellation Summary n 29 satellites on-orbit n 29 satellites set healthy to users 0 satellites launched(2006) n 1 satellites decommissioned n 1 satellite disposed (SVN 31) n Component changes since Oct 2005 n SVN 39 Clock swap: Cs to Rb to Cs n SVN 25 Clock swap: (Cs to last Rb) and NDU power supply failure n SVN 30 Clock swap: (Rb to Rb) n n Constellation changes since Oct 2005 SVN 53 operational 16 Dec 05 n SVN 37 rephase started Jan 06 arrived target GLAN 27 April n 24

Summary and GPS Future Recommendations n Launch IIR-15(M) to A 2 in Sep 06 to replace SVN 25 n n No need to decommission an SV, 29 PRNs in use, 1 is available (PRN 31) Launch IIR-16(M) NET Apr 07 Determine IIR-16(M) plane/slot in future n Determine a vehicle to remove from service for PRN prior to IIR 16(M) COMPAT test at a future date n 25

CGSIC GPS Constellation Status Thank you Doug Louden Chief, GPS Liaison, USCG 07 May 2006 26