Various SLR Observation Errors Detected in Daily Multi-Satellite

Analysis

Toshimichi Otsubo

Kashima Space Research CenterNational Institute of Information and Communications Technology

ILRS Fall 2005 Workshop, 4 Oct 2005

Upgraded QC analysis at NICT

• More frequent!– Daily analysis (used to be weekly) – Daily webpage updates & email AIUB, weekly SLReport.

• More satellites!– 16 Sats at maximum. Typ. 11 to 14.

• More accurate!– ‘concerto v4’ – IERS Conventions 2003 compatible

Various SLR Errors Seen in Post-fit Residuals

(Type a) Spikes

(Type b) Constant RB or TB

(Type c) Wrong Satellites, Wrong Year/Day or LeapSec

(Type d) Unexplainable

(a) Spikes - Pattern 1 : Tail

(a) Spikes - Pattern 1 : Tail

(a) Spikes - Pattern 1 : Tail

(a) Spikes - Pattern 1 : Tail

(a) Spikes - Pattern 2 : Head

(a) Spikes - Pattern 3 : Middle

(a) Spikes - Pattern 3 : Middle

(a) Spikes - Pattern 3 : Middle

(a) Spikes - Pattern 3 : Middle

(b) Constant - Pattern 1 : Range Bias

## 1893 = KATZIVELY# sat site date time dur rb mm error tb us error prec bad total AJI1 1893 2005/08/17 19:42 1 -30 ( 51 ) -------.- ( ----.- ) 47 0 / 5 AJI1 1893 2005/08/18 18:42 2 -3809 ( 18 ) -------.- ( ----.- ) 4 1 / 6 STRL 1893 2005/08/19 19:56 1 35 ( 38 ) -------.- ( ----.- ) 37 0 / 4 AJI1 1893 2005/08/21 18:03 6 -3800 ( 102 ) -4.7 ( 47.6 ) 38 0 / 14 STRL 1893 2005/08/22 19:08 3 267 ( 227 ) -44.8 ( 45.1 ) 18 2 / 7 STRL 1893 2005/08/22 20:53 4 -14 ( 32 ) 1.8 ( 14.9 ) 6 4 / 8

(b) Constant - Pattern 1 : Range Bias

## 7941 = MATERA# sat site date time dur rb mm error tb us error prec bad total AJI1 7941 2005/09/17 05:43 9 2 ( 5 ) 6.1 ( 1.4 ) 2 0 / 16 LAG2 7941 2005/09/18 06:46 2 5 ( 7 ) -------.- ( ----.- ) 4 0 / 2 AJI1 7941 2005/09/18 07:03 0 2 ( 6 ) -------.- ( ----.- ) 1 0 / 3 AJI1 7941 2005/09/18 08:55 10 6 ( 4 ) -1.2 ( 1.3 ) 2 0 / 23 STRL 7941 2005/09/19 17:09 5 1872 ( 8 ) 1.7 ( 2.4 ) 2 0 / 13 LAG1 7941 2005/09/19 20:36 39 1866 ( 5 ) 3.1 ( 2.5 ) 2 0 / 13 LAG2 7941 2005/09/19 23:09 3 -14 ( 6 ) -------.- ( ----.- ) 8 0 / 3 LAG1 7941 2005/09/20 00:13 12 -4 ( 3 ) 6.0 ( 4.6 ) 2 0 / 8

(b) Constant - Pattern 2 : Time Bias

## 8834 = WETTZELL# sat site date time dur rb mm error tb us error prec bad total STRL 8834 2005/07/30 05:28 4 2 ( 6 ) 0.1 ( 1.4 ) 8 0 / 9 STRL 8834 2005/07/30 07:16 3 30 ( 13 ) 4.8 ( 3.0 ) 4 0 / 9 AJI1 8834 2005/07/31 22:43 5 16 ( 4 ) 202.8 ( 1.7 ) 1 0 / 11 AJI1 8834 2005/08/01 00:43 12 -1 ( 21 ) 198.4 ( 6.3 ) 10 0 / 26 ETA2 8834 2005/08/01 01:09 161 -16 ( 44 ) 205.9 ( 66.9 ) 7 0 / 9 STRL 8834 2005/08/01 02:28 7 -17 ( 27 ) 198.9 ( 6.1 ) 5 0 / 6 AJI1 8834 2005/08/01 02:45 6 -28 ( 10 ) 196.9 ( 7.4 ) 3 0 / 12 STEL 8834 2005/08/01 04:10 6 46 ( 10 ) 204.6 ( 2.2 ) 3 0 / 14 STRL 8834 2005/08/01 04:18 5 2 ( 8 ) 229.2 ( 1.8 ) 3 0 / 11 STRL 8834 2005/08/01 06:05 5 4 ( 12 ) 273.2 ( 2.5 ) 3 0 / 10 STRL 8834 2005/08/01 07:56 7 8 ( 11 ) 267.1 ( 2.4 ) 4 0 / 16 LAG2 8834 2005/08/01 09:17 26 7 ( 8 ) 273.9 ( 5.9 ) 2 0 / 13 ERS2 8834 2005/08/01 10:18 3 -47 ( 46 ) 287.5 ( 11.6 ) 9 0 / 6 LAG2 8834 2005/08/01 13:19 20 7 ( 9 ) 4.0 ( 5.2 ) 6 0 / 11 STEL 8834 2005/08/01 15:31 7 -7 ( 6 ) 2.7 ( 1.3 ) 4 0 / 13

(b) Constant - Pattern 2 : Time Bias

## 7811 = BOROWIEC# sat site date time dur rb mm error tb us error prec bad total LAG1 7811 2005/08/30 23:11 24 20 ( 8 ) 1.2 ( 6.1 ) 8 0 / 14 LAG1 7811 2005/08/31 02:39 21 34 ( 8 ) -3.4 ( 7.0 ) 4 0 / 12 LAG1 7811 2005/08/31 21:47 33 29 ( 16 ) -35998.4 ( 10.5 ) 6 1 / 15 LAG1 7811 2005/09/01 20:35 22 25 ( 9 ) 4.7 ( 6.3 ) 5 0 / 13 STRL 7811 2005/09/01 22:13 5 1 ( 5 ) 0.5 ( 2.0 ) 6 0 / 12

(c) Wrong sat? Wrong date?

(d) Unexplainable

Discussions

Looked into the post-fit residuals just in the last two months:(a) Spikes

1-return NP: Handle with care (how NASA overcame this?) Reconsider the fitting function?

(b) Constant RB/TBSome stations tend to repeat this.

(c) Wrong Sat, Wrong Date and LeapSecWrong year: seen every Jan. Leap Second on 1 Jan 2006!

(d) Unexplainable??? (e) More?

Important: What we saw are mostly innocent for analysts. 3 cm error (hidden) is more guilty than 3 metre erro

r.