global positioning system (gps) constellation status · global positioning system (gps)...
TRANSCRIPT
Global Positioning System (GPS)Constellation Status
Lieutenant Colonel Scott Shepherd, USAFJoint Staff/J6S (U.S. Department of Defense)
(703) [email protected]
JO TNI
S TAFFCH IEFS OF
JO TNI
S TA FFCH IE FS OF
30 November 2000 2
Overview
• Overall GPS Constellation Health/Status
• GPS Constellation Age
• Status of GPS Satellite Subsystems
• U.S. Launch Forecast
• Summary
JO TNI
S TA FFCH IE FS OF
30 November 2000 3
SVN 22PRN 22
SVN36PRN06
SVN 24PRN 24
SVN 51PRN 20
SVN 41PRN 14
SVN 25PRN 25
SVN 38PRN 08
SVN 27PRN 27
SVN 19PRN 19
SVN 30PRN 30
SVN 13PRN 02
SVN 35PRN 05
SVN 44 PRN 28
SVN 33PRN 03
SVN 31PRN 31
SVN 37PRN 07
SVN 46PRN 11
SVN 17 PRN 17
SVN 34PRN 04
SVN 21PRN 21
SVN 40PRN 10
SVN 23PRN 23
SVN 26PRN 26
SVN 43PRN 13
SVN 32PRN 01
A B C D E F1
2
3
4
5
SVN 39PRN 09
SVN 15PRN 15
MMD: II=9.22 yrs IIA=10.68yrs IIR=7.84yrs IIF=12.7yrs
28 Operational Satellites5- Block IIs18 -Block IIAs5- Block IIRs
Navigation Signal Availability
As of 28 November 2000
SVN 44PRN 28
SVN 29PRN 29
JO TNI
S TA FFCH IE FS OF
30 November 2000 4
Constellation StatusLaunch through MMD
131917
211523
2425
26273229223137393534
36334030
4338
465144
Jan8
9
Jan9
0
Jan9
1
Jan9
2
Jan9
3
Jan9
4
Jan9
5
Jan9
6
Jan9
7
Jan9
8
Jan9
9
Jan0
0
Jan0
1
Jan0
2
Jan0
3
Jan0
4
Jan0
5
Jan0
6
Jan0
7
Jan0
8
Jan0
9
Jan1
0
Contractual MMD Design Life New MMD New MMD to Today
Toda
y19 Past Contractual MMD15 Past Design Life 5 Past Updated MMD
Contractual MMD: 6 yrsDesign Life: 7.5 yrsBlock II MMD: 9.22 yrsBlock IIA MMD: 10.68 yrsBlock IIR MMD: 7.6 yrs
JO TNI
S TA FFCH IE FS OF
30 November 2000 5
Constellation StatusAge by Plane
-2
0
2
4
6
8
10
12
19 25 27 39 38 13 22 35 30 44 31 37 36 33 17 15 24 34 46 21 23 40 51 26 32 29 43 41
Sa
tell
ite
Ag
e,
(ye
ars
)
Past Design Life (7.5 yrs)Past Contractual MMD (6 yrs)Below Contractual MMD (6 yrs)
A Plane B Plane C Plane D Plane E Plane F Plane
JO TNI
S TA FFCH IE FS OF
30 November 2000 6
Constellation StatusSubsystem Assessment
SVN 41
SVN 44y gg gSVN 15
SVN 26
SVN 43
SVN 32
g
g
SVN 40
ySVN 34
g
y
g
g
y
g
SVN 23
g y
g
SVN 51
g g
y g
SVN 21
g
g y
SVN 24
SVN 46
SVN 36
SVN 33
SVN 31g
g
gSVN 17
SVN 22
SVN 30
SVN 13
SVN 35
F
LEGEND
SVN 25
SVN 38
SVN 27
SVN 19
A B C ED
SVN
1
2
3
4
5
g y
SVN 39g g
BU
S
NA
V
g
g
y
g
y
y
y
g
g
g
y y
g
y
y
y
y
gSVN 37
g
g
y
g y
g
g
ySVN 29
Bottom Line16 out of 28 vehicles are yellow
9 vehicles are yellow due to bus failures12 vehicles are yellow due to nav failures
>57% of constellation is degraded
JO TNI
S TA FFCH IE FS OF
30 November 2000 7
Constellation StatusAttitude Control System
y
g
g
g
g
g
g
g
g
g
g
g
g
g
SVN 17g
g
gg g
g
g
g
g g
g
gg
gSVN 33
g gg
g
g
g
SVN 13
g g
gSVN 35
g g g
g
g
g
g
g
SVN 29
g
g gg g g
g
g
g
y
g
g g
g g
SVN 46
g
SVN 25
gy g ggg
SVN 30
g g
g g
g y
g g
g g
g
g
g
y y
g ygg
g
g
SVN 36
SVN 21
g
SVN 51 SVN 41
SVN 26
SVN 40 SVN 43
g
gW
HE
ELS
DC
EA
CS
CD
SE
NS
OR
S
WH
EE
LSS
PU
BLK IIR
SE
NS
OR
S
LEGEND BLK II/IIA
5 SVN 19 SVN 44gg
SVN 34 SVN 32g
SVN 15
g gSVN 23
F
1
C DA B ESVN 39 SVN 24SVN 22
SVN 37y
gg
g
g
SVN 31
g
g
g
4 SVN 27
g
g
2
3 SVN 38
g
Bottom Line8 vehicles with degraded attitude control3 Wheel, 2 Sensor, and 2 DCEA Failures
JO TNI
S TA FFCH IE FS OF
30 November 2000 8
Constellation StatusReaction Wheels
g gg g
g gg g
g g
g gg g
r
g gg g
g gg g
g g
g gg g
g gg g
g gg g
r
g gg g
y r
g gg gSVN 23
g gg g
g gg g
g gg g
SVN 26
SVN 39 SVN 22
g gg
g gg g
LOW-LUBE DESIGN
SVN 15 SVN 29
WH
EE
L 1
WH
EE
L 2
WH
EE
L 3
WH
EE
L 4
LEGEND SVN
5 SVN 19 SVN 44g g
g4 SVN 27 SVN 35 SVN 37g gg gg g
g
SVN 34
SVN 41
SVN 30 SVN 33
3 SVN 38 SVN 13 SVN 31g gg
SVN 17 SVN 40
BSVN 36 SVN 24 SVN 51
A
2
E F
1
C D
SVN 25 SVN 46 SVN 21
SVN 43
g
g g g g
gg g
SVN 32
Bottom Line43% of low lube vehicles with at least one
failed reaction wheel
JO TNI
S TA FFCH IE FS OF
30 November 2000 9
Constellation StatusElectrical Power System
gg g
gg g
gg gSVN 25
g
gg g
g
gg g
gg g
SVN 30
gg g
gy g
g g
gg g
gg g
gg g
g g g
gg g
SVN 33
a g
SVN 40g g
SVN 39
g g
gg g
gg ggSVN 46
AR
RA
YS
BA
TTE
RIE
S
SE
NS
OR
S
SVN 15gy gg g
LEGEND SVN
ggSVN 29
4 SVN 27 SVN 35 SVN 37 SVN 34 SVN 23 SVN 32
5 SVN 19
3 SVN 38 SVN 13 SVN 31gg g
E
SVN 43
2
gg g
gg g
g
g
g
g
SVN 17
SVN 21
g
g
g
B
g
gg
SVN 51 SVN 41
SVN 26g
SVN 44
F
1
C DASVN 36 SVN 24SVN 22
g
Bottom Line3 vehicles with degraded EPS capabilities
JO TNI
S TA FFCH IE FS OF
30 November 2000 10
Constellation StatusTelemetry, Tracking & Commanding System
SUSCEPTIBLE TO AUX LOCKOUT
g g g
g g g
g g g
g g
g g g
g g g
y g g g g g
g g g
g g g
g g g
g g gSVN 37
g
g g g
g
g g
y g
g
g g g
SVN 51
g
g g g
g g
SVN 41
SVN 25 SVN 30 SVN 33 SVN 46 SVN 21 SVN 26
SVN 39 SVN 22 SVN 36
SVN 29
SVN 34 SVN 23g
SVN 32
SVN 24
UP
LIN
K
DO
WN
LIN
K
LOC
KO
UT
SVN 15
g g
g g
LEGEND SVN
g g
SVN 17
5 SVN 19 SVN 44
y gSVN 40 SVN 43
4 SVN 27
3 SVN 38 SVN 13 SVN 31
SVN 35g
2
g g g
g g g
g g g
g
g g g
E F
1
C DA B
g g
Bottom Line3 vehicles with degraded TT&C capabilities
JO TNI
S TA FFCH IE FS OF
30 November 2000 11
Constellation StatusNavigation Payload
g g g g g g g g
y g g y
g g g g
g
g g g y
g g g g
g y
g y g gSVN 40
g g
g g g g
g
g g g g
y g
g gSVN 34
g y
g g gg g y y
g g g
g g g g
g g g y
y g g g
g
g g g y
ggg
SVN 27
SVN 43
SVN 25 SVN 30g g y g g g
SVN 38 SVN 13 SVN 31 SVN 17
SVN 51SVN 22 SVN 36 SVN 24
SVN 33 SVN 46
gSVN 41
SVN 21 SVN 26
g g g g g g gy g g g
g y g
SVN 39
CLO
CK
SFS
UM
DU
L-B
AN
DBLK IIR
CLO
CK
SFS
DU
ND
UL-
BA
ND
LEGEND BLK II/IIA
g g g g
SVN 23 SVN 32
5 SVN 19 SVN 44 SVN 15 SVN 29
4 SVN 35 SVN 37g g g g g g g g
3
2
E F
1
A B C D
g
Bottom Line12 vehicles with degradedNav payload capabilities
3 vehicles single string in twoNav payload subsystems
JO TNI
S TA FFCH IE FS OF
30 November 2000 12
Constellation StatusClocks
g
g
y g
g g
g
r
g g
gSVN 17
g
SVN 44
g
g
g
g
SVN 33g g g g
r
g
g
gSVN 32
r
g
g
g r
y
g
y
gSVN 29
g
SVN 23
g
g
g
g
g
y
y
g
g
SVN 46
y g
SVN 15
g
g
SVN 43
gg
g g y
y
g
g
SVN 40
r
g
g
gSVN 19
r
gg
r
g
SVN 34SVN 37r y g
g
g
SVN 26
g
g
y
g g
g
g
g
ggg r g r
g y
SVN 25 SVN 30
RB
1R
B 2
CS
3C
S 4
LEGEND BLK II/IIA
g g ggg
5
3 SVN 38 SVN 13g
4 SVN 27 SVN 35
gy
2
EA B
y ySVN 39 SVN 22
g g
RB
1R
B 2
RB
3
1
C DSVN 51SVN 36 SVN 24
gg g g
g Operational Clock
FSVN 41
g
g gSVN 21
BLK IIR
SVN 31g yy
g
Bottom LineSVNs 19, 24, 32,--on last clock
JO TNI
S TA FFCH IE FS OF
30 November 2000 13
Constellation StatusBottom Line
• 19 SVs past contractual mean mission duration (6 years)• 15 SVs past design life (7.5 years)• 5 SVs past updated mean mission duration
(II--9.22, IIA--10.68, IIR--7.84)• 12 SVs one component away from navigation mission
failure• 9 SVs one component away from bus failure• No practical method to predict what component/SV will
fail next
JO TNI
S TA FFCH IE FS OF
30 November 2000 14
U.S. Launch Forecast for GPS
Programmed Launches:• FY 01: 3 IIR (9 Nov, 30 Jan, 11 Jun)• FY 02: 1 IIR (Oct)• FY 03: 4 IIR Modified• FY 04: 4 IIR Modified• FY 05: 2 IIR Modified,• FY 06: 2 IIR Modified, 1 IIF
JO TNI
S TA FFCH IE FS OF
30 November 2000 15
Summary
• GPS is an aging Constellation
• GPS Constellation produces a Healthy Navigation Signal
– 28 Operational Satellites
• Scheduled launched and upgrades will improveperformance
– Continue to support world-wide users
– Moving towards meeting future requirements
JO TNI
S TA FFCH IE FS OF
30 November 2000 16
Back-Up Slides
JO TNI
S TA FFCH IE FS OF
30 November 2000 17
Constellation Activity
• Recent constellation activity (since 18 August 2000)– SVN18 (F3) disposed due to DCEA and Wheel failure– SVN43 moved from F5 to F3– SVN16 (E5) disposed due to clock failures– SVN23 (E4) Yaw Sun Sensor (YSS) degradation– SVN21 (E2) anomaly– SVN24 (D1) last clock activated– SVN46 (D2) A2 step 3 completed but anomaly
unresolved
Constellation StatusSatellite Slot Location with 10 October 00 Vectors
JO TNI
S TA FFCH IE FS OF
30 November 2000 19
Constellation StatusProblem Vehicles Summary
RED: lost redundancy incomponent required for
MISSIONBLUE: lost redundancy incomponent required for
DISPOSAL
Plane # SV SVN ProblemsA 5 19 Clocks, Reaction Wheels
25 NDU27 L Band
B 5 13 L Band, EPS, Yaw Sun Sensor, TTC22 TTC, FSDU30 NDU
C 4 31 NDU, L Band37 Control System Command Decoder
D 5 15 Reaction Wheels, Arrays, TTC24 Reaction Wheels, L Band, Clocks
E 4 21 L band23 Yaw Sun Sensor, Solar Array Drives, Power Level40 FSDU
F 4 26 Digital Control Electronics Assembly, L Band29 Digital Control Electronics Assembly, L Band32 Clocks, L Band
JO TNI
S TA FFCH IE FS OF
30 November 2000 20
Current Disposal Metric(NDS Ratings not Included)
0
50
100
150
200
250
300
350
400
450
NDS 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0
Nav 350 36 350 233 70 10 198 126 9 18 117 67 70 70 58 27 18 0 0 0 0 9 0 0
Work 13 19 3 12 4 7 1 2 47 12 4 5 3 2 3 2 0 13 13 13 13 3 4 3
TTC 0 187 0 0 187 187 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0
EPS 5 10 0 0 0 10 0 13 117 0 0 0 5 0 5 0 0 0 0 0 0 0 5 5
AVCS 58 117 0 58 0 6 0 58 6 117 0 6 0 0 0 6 0 0 0 0 0 0 6 0
24D1
15D5
32F4
19A5
22B1
13B3
31C3
26F2
23E4
29F1
27A4
21E2
40E3
30B2
25A2
37C4
34D4
44B5
46D2
51E1
43F3
36C1
17D3
33C2
JO TNI
S TA FFCH IE FS OF
30 November 2000 21
Current Disposal Metric by Plane(NDS Ratings not Included)
0
50
100
150
200
250
300
350
400
450
NDS 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0
Nav 0 58 0 117 233 70 70 10 0 0 9 0 198 27 350 0 0 18 36 0 67 70 9 18
Work 2 3 3 4 12 4 2 7 4 13 3 3 1 2 13 13 4 0 19 13 5 3 47 12
TTC 0 0 0 0 0 187 0 187 0 0 0 0 0 0 0 0 0 0 187 0 0 0 0 0
EPS 0 5 0 0 0 0 0 10 0 0 0 5 0 0 5 0 5 0 10 0 0 5 117 0
AVCS 0 0 0 0 58 0 0 6 0 0 0 0 0 6 58 0 6 0 117 0 6 0 6 117
39A1
25A2
38A3
27A4
19A5
22B1
30B2
13B3
35B4
44B5
36C1
33C2
31C3
37C4
24D1
46D2
17D3
34D4
15D5
51E1
21E2
40E3
23E4
29F1
JO TNI
S TA FFCH IE FS OF
30 November 2000 22
Special Topics
• Special Consideration Satellites
– SVN 19
– SVN 23
– SVN 29
JO TNI
S TA FFCH IE FS OF
30 November 2000 23
SVN 19 Clock Status
CFS#3 is SVN19’s last usable clockWhat is the status of CFS#3?• CFS #3 - Operational from 11/1/89 - 1/2/92 (2.17 Years)
– Deactivated originally due to frequency stepping– Reactivated on 9/23/99
• One Day Stability ≅ 2.1E-13, Specification = 2.0 E -13– Equates to very marginal clock performance– Averaging 2.25 navigation uploads per day– Stability will only get worse, not better
• Beam Current = 1.39 nanoamperes– Typically, any beam current less than 2 nA is reason for concern– Beam current will continue to decrease
JO TNI
S TA FFCH IE FS OF
30 November 2000 24
SVN 19CFS#3 Prognosis
What can be expected from CFS#3?
• Optimistically, CFS#3 may live another 2-3 months– The problem is that its performance will continue to degrade
• If CFS #3 does live another 2-3 months:– Stability will degrade beyond specification– The number of contingency uploads needed will increase– It may be very difficult, if not impossible, to maintain SVN19’s accuracy
within the current accepted tolerance
• Anticipated loss drove SVN 44’s orbital location
Bottom Line: The future performance of SVN 19’s CFS is very uncertain and anyperformance expectations beyond a few months are extremely unwarranted
JO TNI
S TA FFCH IE FS OF
30 November 2000 25
SVN 23 Status
• 9.9 years on-orbit– Past contractual MMD (6 years) and design life (7.5 years)– 0.3 years short of updated Block IIA MMD (10.22 years)
• September loss of yaw led to discovery of sensor degradation– This eliminates scissoring as an option– Minimum of four critical supports per day for remainder of on orbit life
• Eclipse season from 3 Nov 2000 through 16 Dec 2000– Expect positive power balance problems– Battery reconditioning impossible due to orbital geometry– Ability to make it through this eclipse season without disabling secondary
payloads is unpredictable– Workload increases to > 6 critical supports per day during eclipse
Bottom Line: SVN 23 continued operations is dependent on disablingpart of the secondary payload.
JO TNI
S TA FFCH IE FS OF
30 November 2000 26
SVN 29 Status
• SVN29 nodal position can not be controlled• Vehicle will occupy F1 node from 1 Dec 2000 to 2 April 2001• Following the 2 April exit, SVN29 will not be in a primary node
until it reaches the F4 slot (SVN32) in Nov 2003• SVN29 time on orbit = 7.9 years• Options for attempting a delta V
– Following nodal exit in 2001– As required by failures of other vehicles in the plane (SVN32
or SVN26)– Following a failure of SVN29
Recommendation: Delay decision until a time closer to nodal exit to gainbetter picture of entire constellation status
JO TNI
S TA FFCH IE FS OF
30 November 2000
Current Transition Plan
– Upgrade Dedicated Monitor Stations and Ground Antennas withNew Digital Receivers and Computers
– Replace Existing Master Control Station Mainframe ComputerWith a Distributed Architecture
– Add Accuracy Improvement Initiative, Air Force SatelliteControl Network Interface with MCS
– Build Fully Mission Capable Alternate Master Control Station(AMCS) at Vandenberg Tracking Station
– Add IIF Command and Control Functionality
2-Step Plan: Replace Existing Mainframe With DistributedArchitecture Then Add Block IIF Functionality