Real-Time Orbit And Clock Estimation Using PANDA Software Shi C, Lou YD, Zhao QL, Liu JN GNSS...
-
Upload
cori-owens -
Category
Documents
-
view
214 -
download
0
Transcript of Real-Time Orbit And Clock Estimation Using PANDA Software Shi C, Lou YD, Zhao QL, Liu JN GNSS...
![Page 1: Real-Time Orbit And Clock Estimation Using PANDA Software Shi C, Lou YD, Zhao QL, Liu JN GNSS Research Center, Wuhan University, China IGS Analysis Center.](https://reader035.fdocuments.us/reader035/viewer/2022062516/56649d8d5503460f94a76191/html5/thumbnails/1.jpg)
Real-Time Orbit And Clock Estimation Using PANDA
Software
Shi C, Lou YD, Zhao QL, Liu JNGNSS Research Center, Wuhan University, China
IGS Analysis Center Workshop 2008 2-6, June 2008, Miami, Florida, USA
![Page 2: Real-Time Orbit And Clock Estimation Using PANDA Software Shi C, Lou YD, Zhao QL, Liu JN GNSS Research Center, Wuhan University, China IGS Analysis Center.](https://reader035.fdocuments.us/reader035/viewer/2022062516/56649d8d5503460f94a76191/html5/thumbnails/2.jpg)
Contents
• Introduction of PANDA software
• Strategy for Real-time POD• Strategy for Real-time Clock• Preliminary Results• Summary
![Page 3: Real-Time Orbit And Clock Estimation Using PANDA Software Shi C, Lou YD, Zhao QL, Liu JN GNSS Research Center, Wuhan University, China IGS Analysis Center.](https://reader035.fdocuments.us/reader035/viewer/2022062516/56649d8d5503460f94a76191/html5/thumbnails/3.jpg)
Introduction of PANDA
PANDA : Positioning And Navigation Data Analyst
• To derive possible information from GNSS/SLR/ VLBI data in real-time and post-mission
• Developed at Wuhan University since 2001• Current Applications
– POD of GNSS&GEO (COMPASS, GPS)– POD of LEOs, CHAMP GRACE (Delft University), COSMIC
(JiaoTong Uni. Taiwan)– Huge Network (NEIS)
– PPP+Ambiguity-Fixing(GFZ, Nottingham Uni) – …..
![Page 4: Real-Time Orbit And Clock Estimation Using PANDA Software Shi C, Lou YD, Zhao QL, Liu JN GNSS Research Center, Wuhan University, China IGS Analysis Center.](https://reader035.fdocuments.us/reader035/viewer/2022062516/56649d8d5503460f94a76191/html5/thumbnails/4.jpg)
PANDA System Structure
![Page 5: Real-Time Orbit And Clock Estimation Using PANDA Software Shi C, Lou YD, Zhao QL, Liu JN GNSS Research Center, Wuhan University, China IGS Analysis Center.](https://reader035.fdocuments.us/reader035/viewer/2022062516/56649d8d5503460f94a76191/html5/thumbnails/5.jpg)
New Development: Real-Time
• PPP Based Positioning Service System– Real-time GPS orbits– Real-time GPS Satellite Clock Offsets– Precise Point Positioning
• Funded by – the Program 973 (No:2006CB701301)the Program 973 (No:2006CB701301)– Real-time Precise Positioning Service Prototype Real-time Precise Positioning Service Prototype
System (863)System (863)– Real-time POD for LEOs (863) Real-time POD for LEOs (863)
![Page 6: Real-Time Orbit And Clock Estimation Using PANDA Software Shi C, Lou YD, Zhao QL, Liu JN GNSS Research Center, Wuhan University, China IGS Analysis Center.](https://reader035.fdocuments.us/reader035/viewer/2022062516/56649d8d5503460f94a76191/html5/thumbnails/6.jpg)
The Strategy For RT-POD
Two Steps: Generate NEQs of short ARCsCombine NEQs to estiamte orbits
NTRIP Data Cleaning
Last hourly NEQ
SRIF
Comb. NEQs for the last 1-N hours
Updated orbit and predicted orbit
Epoch-wise orbit update
Least Square Combinatio
Key Issues: Ambiguity-FixingWeight of predicted orbitsConstrained Parameter:
Orbit boundariesAmbiguitiesZTD, ERP
![Page 7: Real-Time Orbit And Clock Estimation Using PANDA Software Shi C, Lou YD, Zhao QL, Liu JN GNSS Research Center, Wuhan University, China IGS Analysis Center.](https://reader035.fdocuments.us/reader035/viewer/2022062516/56649d8d5503460f94a76191/html5/thumbnails/7.jpg)
Parallel Combination
1h 2h 3h 12h Combined
Last hourly NEQ
Hourly NEQ
Combined NEQ
12h112h2h 12h 12h
1h 2h 3h 11h Combined 12h Combined 13h Combined
Last hourly NEQ
Hourly NEQ
Combined NEQ < 12h
Combined NEQ for orbits
Combine hourly NEQs Time-Consuming1. Save the combined NEQs of the last n-1,n-2, …,1 hours
2. Combined the last hourly NEQ with the saved combined NEQs
3. Only one combination (red) must be done in real-time
• Time-Saving• Fast restart with saved
(combined) NEQ
![Page 8: Real-Time Orbit And Clock Estimation Using PANDA Software Shi C, Lou YD, Zhao QL, Liu JN GNSS Research Center, Wuhan University, China IGS Analysis Center.](https://reader035.fdocuments.us/reader035/viewer/2022062516/56649d8d5503460f94a76191/html5/thumbnails/8.jpg)
Orbital Boundary Constraints
1, 1, 1,1, 1( )k k k k k k
w k k k k w wv t t x x l P
kt 1kt 2kt
1 1 1
1 1 1
1 1 1
( ) ( )
( ) ( )
( ) ( )
k k k k
k k k k
k k k k
r t r t
r t r t
q t q t
1 1 0 1,( ) ( ) ( )k k k k k k kX t X t t t x
1 1 1 1 0 1( ) ( )k k k k kX t X t I x 1 1 1
! 1 11( , )
0 0
k k k
k k
k k kk k
k k
r r r
r r q
r r rt t
r r q
I
Juncture
Connected 1,k kwP
Not connected1, 0k kwP
Osculating orbital elements
![Page 9: Real-Time Orbit And Clock Estimation Using PANDA Software Shi C, Lou YD, Zhao QL, Liu JN GNSS Research Center, Wuhan University, China IGS Analysis Center.](https://reader035.fdocuments.us/reader035/viewer/2022062516/56649d8d5503460f94a76191/html5/thumbnails/9.jpg)
1, 1, 1,1, 1( )k k k k k k
w k k k k w wv t t x x l P
, ,
1, 1 1 1, 1
k k k k k
k k k k k
N x W
N x W
NEQs:
Juncture constraint:
1 1 1( ) minT T Tk k k k k k w w wJ x v p v v p v v p v
1, 1, 1, 1,, 1, 1, 1, , 1
1, 1, 1, 1,11, 1, 1 1, 1
T k k T k k T k k k kkk k k k w k k k k w k k k w w
k k k k k k k kkw k k k k w k k w w
xN P P W P l
xP N P W P l
Solution with the Constraints
![Page 10: Real-Time Orbit And Clock Estimation Using PANDA Software Shi C, Lou YD, Zhao QL, Liu JN GNSS Research Center, Wuhan University, China IGS Analysis Center.](https://reader035.fdocuments.us/reader035/viewer/2022062516/56649d8d5503460f94a76191/html5/thumbnails/10.jpg)
Stratgy For RT Clocks
Two approaches are developed:• Estimate SatClock Epoch-by-
Epoch(1hz)• Estimate SatClock Difference
between Epoch
![Page 11: Real-Time Orbit And Clock Estimation Using PANDA Software Shi C, Lou YD, Zhao QL, Liu JN GNSS Research Center, Wuhan University, China IGS Analysis Center.](https://reader035.fdocuments.us/reader035/viewer/2022062516/56649d8d5503460f94a76191/html5/thumbnails/11.jpg)
Preliminary Results
The distribution of the 70 IGS stations for Real time satellite orbit determination (70stations)
Rinex data are inputted as stream through simulated real-time model
Test Network
![Page 12: Real-Time Orbit And Clock Estimation Using PANDA Software Shi C, Lou YD, Zhao QL, Liu JN GNSS Research Center, Wuhan University, China IGS Analysis Center.](https://reader035.fdocuments.us/reader035/viewer/2022062516/56649d8d5503460f94a76191/html5/thumbnails/12.jpg)
Result of RT-POD vs IGS Finals
Max ( cm) Min ( cm) Mean ( cm)Radial 6.0 2.7 4.1
Cross 6.5 3.1 4.0
Along 10.6 4.6 7.3
Mean 7.5 3.6 5.4
![Page 13: Real-Time Orbit And Clock Estimation Using PANDA Software Shi C, Lou YD, Zhao QL, Liu JN GNSS Research Center, Wuhan University, China IGS Analysis Center.](https://reader035.fdocuments.us/reader035/viewer/2022062516/56649d8d5503460f94a76191/html5/thumbnails/13.jpg)
Result of RT-POD
Difference between calculated real-time orbits (Hourly predicted orbits) and IGS final products
![Page 14: Real-Time Orbit And Clock Estimation Using PANDA Software Shi C, Lou YD, Zhao QL, Liu JN GNSS Research Center, Wuhan University, China IGS Analysis Center.](https://reader035.fdocuments.us/reader035/viewer/2022062516/56649d8d5503460f94a76191/html5/thumbnails/14.jpg)
Result of RT-CLK vs IGS Finals
Statistics of the RMS values
max(ns) min(ns) mean(ns)
198 0.30 0.04 0.13
199 0.36 0.10 0.22
200 0.38 0.07 0.16
201 0.31 0.07 0.18
202 0.30 0.12 0.19
203 0.41 0.07 0.21
mean 0.18CPUT per epoch on IBM T60 notebook
RMS values of the difference between the calculated SatClock and IGS final products over the period day 198-203 of year 2006
![Page 15: Real-Time Orbit And Clock Estimation Using PANDA Software Shi C, Lou YD, Zhao QL, Liu JN GNSS Research Center, Wuhan University, China IGS Analysis Center.](https://reader035.fdocuments.us/reader035/viewer/2022062516/56649d8d5503460f94a76191/html5/thumbnails/15.jpg)
Performance of the RT Production
Quality of the Real-time SatClock and SatOrbit for the day of year 2006
![Page 16: Real-Time Orbit And Clock Estimation Using PANDA Software Shi C, Lou YD, Zhao QL, Liu JN GNSS Research Center, Wuhan University, China IGS Analysis Center.](https://reader035.fdocuments.us/reader035/viewer/2022062516/56649d8d5503460f94a76191/html5/thumbnails/16.jpg)
PPP Based on the RT Production
Epoch by Epoch
WUHN Station
RMS:
N: 2.87cm
E: 3.23cm
U: 7.96cm
![Page 17: Real-Time Orbit And Clock Estimation Using PANDA Software Shi C, Lou YD, Zhao QL, Liu JN GNSS Research Center, Wuhan University, China IGS Analysis Center.](https://reader035.fdocuments.us/reader035/viewer/2022062516/56649d8d5503460f94a76191/html5/thumbnails/17.jpg)
• Real-time POD, 5cm• Real-time Clock, 0.18ns• PPP with the Products, 5, 10
cm
Summary
![Page 18: Real-Time Orbit And Clock Estimation Using PANDA Software Shi C, Lou YD, Zhao QL, Liu JN GNSS Research Center, Wuhan University, China IGS Analysis Center.](https://reader035.fdocuments.us/reader035/viewer/2022062516/56649d8d5503460f94a76191/html5/thumbnails/18.jpg)
Thanks For Your Attention !