Titelmaster. Geometrical and Kinematical Precise Orbit Determination of GOCE

Transcription

1 Titelmaster Gemetrical and Kinematical Precise Orbit Determinatin f GOCE Akbar Shabanlui Institute f Gedesy and Geinfrmatin, University f Bnn 7th Octber 2010 Clgne, Germany

2 Outline Precise Orbit Determinatin (POD) principle Gemetrical Precise Orbit Determinatin (GPOD) Kinematical Precise Orbit Determinatin (KPOD) 2 GOCE Lagrange receiver (clck) Zer difference estimatin prcedure Results Cnclusins

3 Precise Orbit Determinatin (POD) 3 Credit by ESA

4 Precise Orbit Determinatin (POD) methds 4 POD

5 Gemetrical Precise Orbit Determinatin (GPOD) 5

6 Precise Orbit Determinatin (POD) methds 6 POD

7 Kinematical Precise Orbit Determinatin (KPOD) 7

8 Precise Orbit Determinatin (POD) methds Gemetrical POD : pint-wise, psitins!= KPOD, e.g. Bern Kinematical POD : cntinus, psitins, velcities and acceleratins 8 Dynamical POD : cntinus, psitins, velcities and acceleratins based n frce functin infrmatin POD

9 GPS LAGRANGE receiver nbard GOCE 9 Credit by ESA

10 GNSS receiver n-bard GOCE 10 Credit by ESA

11 GNSS receiver n-bard GOCE LAGRANGE (Laben GNSS Receiver fr Advanced Navigatin, Gedesy and Experiments) 12 chanels, dual frequency (L1 and L2) GPS/GLONASS The clck f the GOCE LAGRANAGE receiver is nt steered t integer secnds (free clck system) Interplatin f SST bservatins (Data Screening with triple differenced methd) Interplatin f GPS rbits (Zer differenced) 11

12 GNSS receiver n-bard GOCE (Rinex SST) Clck is nt steerd t be integer 12

13 Clck jumps f receiver (Nv. 2009) 13 GPS LAGRANGE receiver clck behavir!

14 Clck behavir f receiver (Nv. 2009) ms Clck jumps f 20 ms at ~27 hurs can be seen

15 GPS visibility nbard GOCE (Nv. 2009) 15 7 < Number f GPS satellites (PRNs) < 12

16 GPS visibility nbard GOCE (Nv. 2009) 16 7 < Number f GPS satellites (PRNs) < 12

17 Zer differenced GPOD 17 Credite by ESA

18 Zer differenced GPOD Zer Difference Only cnnectin between LEO satellite and GPS satellites, Gemetrical Only pure gemetrical relatins between LEO and the GPS satellites have t be used, n frce mdels and n cnstraints, 18 Precise Cnsideratin all effects n GPS-SST bservatins and using precise GNSS satellites ephemerides.

19 Prcessing cncept Cde measurements Phase measurements Zer differencing prcedure (ZD) 19 GPOD

20 Precise Orbit Determinatin (POD) Φ () t = ρ () t + cδt () t I () t s s s ri, r r r s1 s1 s1 s1 + T () t + λ A + e () t + ε () t r i ri, ri, ri, N trpsphere effect at GOCE altitude (~250 km) First rder inspheric effect eliminated with In-free linear cmbinatin Ambiguity term cannt be slved as Integer (real)! 20 GPS precise rbits (at 15 minutes) and clcks at 30 sec

21 GPS Antenna ffsets 21

22 GPS antenna ffsets GPS receiver ffset with respect t GOCE reference frame is cnstant L1 and L2 (L3) Phase Center Offsets (PCO) are derived frm IGS ANTEX (ANTenna Exchange frmat) Phase Center Variatin (PCV) can be empirical estimated based n carrier phase residuals! (r ANTEX?) 22 Offset with respect t center f mass (COM) is slwly varing!

23 Gemetrical POD hl-sst s1 s1 Φ ri, () t = s ρr () t + cδtr() t + 1 s1 Φ ri, () t = a s x () t x 1 s1 s1 s + λiari, + eri, () t + εri, () t 1 s 1 s2 s2 Φ ΦΦ ri, () ri =, () = At ρ x, a () t r () t x+ C cφ δtr() t + s s 2 2 s 2 Φ Φ Φ ( t ri, 1() ) t = ri, () ta s2 s2 s2 + = r λia a ( t1 ) () t x, x CΦ( t x ri, + eri, () 1) t + εri, () t s3 s3 Φ s3 s3 Φ ri, () ri t, () t = = ρr () t a + () c t x, C x δtr() t + Φ t s 4 s s 3 43 ΦΦ x=n Φ ( ri t, () t s3 s3 s3 + ri, () t = λi a () t 2) = A Φ, C r( tx Φ ri, + 2 ) C x eri, () x, NC t + ε Φ xˆ ri, () ( t2 ) s5 s5 ri, () t () t Φ ( T 1 N= AC a ) x s Φ A 4 s4 Φ ri, () t s= ρr () t + cδtr() t + 4 s4 Φ ri, () t = ax () t x Φ( tn) = A s4 s4 s4 + λi r( t ri, + n) x, C eri, () t + εφ( ri, () t n t) s5 s5 Φ ri, () t = ρr () t + cδtr() t + 1 x ˆ = x 0 + x, C s5 s xˆ = N 5 Φ ri, () t = s a () 5 x st x 5 s5 + λ A + e () t + ε () t 1 T 1 1 ˆ = i ri, ri, ri, () 23

24 Grund tracks f GPS, GOCE (2 Nv. 1 Rev.) 24

25 Shrt arc f GOCE (02 Nv. 2 Rev.) minutes shrt arc ( )

26 GPOD GOCE results 26 Estimated gemetrical 3D Ps. - PSO

27 Kinematical POD 27

28 Shrt arc representatin LEO rbit can be represented as: Gibbs effect! r r( τ) = r( τ) + d( τ) = r( τ) + dυ sin( υπτ) n υ= 1 Precisin! 28 J r( τ) = r( τ) + d( τ) = r( τ) + e E ( τ) + b B ( τ) 2 j 2 j 2 j+ 1 2 j+ 1 j= 1 j= 1 J J n r( τ) = r( τ) + d ( τ) + d ( τ) Slutin? P F fast cnvergence! J J n r( τ ) = r( τ ) + e E ( τ ) + b B ( τ ) + dυ sin( υπτ ) 2 j 2 j 2 j+ 1 2 j+ 1 j= 1 j= 1 υ= 1

29 Determinatin f Euler-Bernulli cefficients A satellite shrt arc can be represented with the Euler- Bernulli term up t degree J as: J r( τ) r( τ) = d( τ) e2 je2 j( τ) + b2 j 1B2 j 1( τ) j= 1 j= 1 J Reference mtin ra Euler-Bernulli rb

30 KPOD GOCE results 30 Estimated kinematical Ps. (J=4) PSO (Furier index 30 and 40)

31 Cnclusins and recmmendatins GNSS-GOCE satellites cnfiguratin and gemetrical strength play an imprtant rle in POD. Estimated Gemetrical Precise Orbit can be used t estimate kinematical POD f GOCE. 31 Kinematical POD can be used t recver the Earth s gravity field mdel based n the hl-sst methds, (GOCE SST mdel). N gravity field and n frce mdels have been used in the Gemetrical and Kinematical mdes (advantage). Empirical PCV results shuld imprve POD f GOCE!

32 Thank yu fr yur attentin!