GPS OperationsCGSIC Brief

15 September 08

Lt Joe Riedesel2d Space Operations Squadron This briefing is UNCLASSIFIED

1UNCLASSIFIED

Overview

• Navigation and Timing Performance– Navigation Performance– Time Transfer Performance

• Constellation Status

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3UNCLASSIFIED

-10-505

1015

117

127

137

147

157

167

177

187

197

207

217

NAN

OSE

CO

ND

S

JDAY

RMSAvg

UTC TIME TRANSFERSpecification 28ns

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5

GPS Space and ControlClock and Reaction Wheel Performance Status

Wheelfunctionalwatch listdeadunused

2 3 41SVN (PRN)

2 3 41Clock*Wheel* II/IIA = Rb, Rb, Cs, Cs IIR = Rb, Rb, RbDiagonal Line = Unhealthy

launchdate Clock

meets specwatch list

deadunused

in use

Watch List

39A (09) 06/93

52M (31) 9/06

1

2

SLOT

3

4

5

PLANE A C D E F

38A (08) 11/97

56R (16) 1/03

33A (03) 03/96

59R (19) 03/04

46R (11) 10/99

51R (20) 05/00

40A (10) 07/96

43R (13) 07/97

36A (06) 03/94

41R (14) 11/00

44R (28) 07/00

48M (07) 03/08

35A (05) 08/93

37A (**) 05/93

34A (04) 10/93

54R (18) 01/01

32A (**) 11/92

26A (26) 07/92

45R (21) 03/03

6

47R (22) 12/03

30A (30) 9/96

B

60R (23) 06/04

61R (2) 10/99

53M (17) 09/05

25A (25) 02/92

24A (24) 07/91

58M (12) 11/06

23A (32) 11/90

55M (15) 10/07

57M (29) 12/07

27A (27) 09/92

19 (+0) SVs past design life 15 (+0) SVs past pre-launch mean life estimate (MLE) 18 (+0) SVs one component away from nav mission failure 8 (+0) SVs one component away from bus failure Anomaly Summary

• SVN 25 set unhealthy• SVN 35 set unhealthy

Constellation Status Summary

Changes Since Last Update

Total SVs in Category

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7

IIA Vehicles On Last Clock

• SVN 36: has a higher likelihood of failing due to its Rb clock being turned on with over 8 years of on-orbit storage

• SVN-37: being stored as on-orbit spare in LADO• SVN-32: being stored as on-orbit spare in LADO

SVN Slot 1st Clock Last Clock

Storage time for current

clock (Years)

Clock operating time (Years)

Operational Clock

Clocks Remaining

Current Age of Vehicle (Years)

23 5-Dec-90 1-Jan-04 13.1 4.7 Rb #2 None 17.824 13-Jul-91 7-Sep-00 9.2 8.0 Cs #4 None 17.225 15-Mar-92 25-Dec-05 13.8 2.7 Rb #1 None 16.527 A4 24-Sep-92 20-May-05 12.7 3.3 Cs #4 None 16.030 B2 27-Sep-96 2-Jun-06 9.7 2.3 Cs #3 None 12.032 5-Dec-92 19-Aug-96 3.7 12.1 Cs #3 None 15.833 C2 3-Apr-96 1-Jan-07 10.8 1.7 Cs#4 None 12.435 21-Sep-93 8-Sep-05 12.0 3.0 Rb #1 None 15.036 18-Mar-94 19-Mar-04 10.0 4.5 Rb #1 None 14.537 20-May-93 21-Aug-07 14.3 1.1 Rb #2 None 15.340 E3 1-Aug-96 25-Mar-08 11.7 0.5 Cs #3 None 12.1

Bottom Line: 11 of 15 IIAs left are on their last clock

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IIR/IIR(M) Clock Status No IIR/IIR(M) clock failures to date

SVN 43: First IIR launch, AFS 3 on for test purposes only

SVN 44:

AFS 1 had a baseplate heater failure Clock is assessed as viable Performance could be slightly degraded during eclipse season

SVN 61:AFS 3 clock failureSwitched to AFS 1

SVN Clock Status Date Active Total Years in Use

41 AFS 1 On 15-Nov-00 7.83AFS 1 On 13-Aug-97 11.09AFS 3 Off 7-Jul-98 0.87AFS 1 Off 10-Aug-00 0.06AFS 2 On 14-Aug-00 8.08

45 AFS 3 On 4-Apr-03 5.4446 AFS 1 On 21-Dec-99 8.7347 AFS 3 On 24-Dec-03 4.7248 AFS 3 On 19-Mar-08 0.4851 AFS 1 On 17-May-00 8.3352 AFS 3 On 29-Sep-06 1.9553 AFS 3 On 29-Sep-05 2.9554 AFS 1 On 7-Feb-01 7.6055 AFS 3 On 22-Oct-07 0.8956 AFS 3 On 6-Feb-03 5.6057 AFS 3 On 23-Dec-07 0.7258 AFS 3 On 21-Nov-06 1.8159 AFS 3 On 24-Mar-04 4.4760 AFS 2 On 28-Jun-04 4.21

AFS 1 On 27-Apr-08 0.38AFS 3 Off 10-Nov-04 3.47

ALL 89.68

43

44

61

9

A CB ED F

80

100

120

160

180

0

20

40

60

GLAN(deg)

A338

A139

B156

B344

D434

D246

E340

E454

F343

F141

D345

E151

E247

C359

F460

D161

35

A427

36

25 24

GPS Locations

C453

140

37

B230

A252

Watch List

Block IIABlock IIRBlock IIR-M

Block IIA reserve

58 B4

23

C233

C157

F25526

IIR-20(M)

48

32

SVN-27 Rephase Start Nov ’08 to b/u SVN-39 SVN-26 Rephase to F5 t/b Complete Apr ’09

Geographic Longitude of Ascending Node(GLAN)

0

100

120

AA CCBB EEDD FF

60

80

180

140

20

40

160F3 43

26

51

40

54

46

34

3530

56

44

39

25

38 27

F2

F1

F4

E1

E3

E4

E2

D2

D4

D1

D3

B4

A1 B2

B1

B3

A2

A4

A3

C1

C2C3

4547

60

6153C4

NOTE: Chart reflects status of bus & navigation payload only (not NDS payload status).

FMC

PMC

NMCInactiveManeuver

OPSCAP

3359

52

Block SVNs ( # )IIA 22-40 (14)IIR/IIR-M 41-61 (18)Current IIR-M’s (48, 52, 53, 55, 57, 58)

5823

24

4132

36

57

55

37

48

Summary

• Navigation and Timing Performance– Navigation Performance– Time Transfer Performance

• Constellation Status

• Questions…

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