Various SLR Observation Errors Detected in Daily Multi-Satellite Analysis Toshimichi Otsubo Kashima Space Research Center National 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 & 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 2 : Head

(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 AJI /08/17 19: ( 51 ) ( ) 47 0 / 5 AJI /08/18 18: ( 18 ) ( ) 4 1 / 6 STRL /08/19 19: ( 38 ) ( ) 37 0 / 4 AJI /08/21 18: ( 102 ) -4.7 ( 47.6 ) 38 0 / 14 STRL /08/22 19: ( 227 ) ( 45.1 ) 18 2 / 7 STRL /08/22 20: ( 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 AJI /09/17 05: ( 5 ) 6.1 ( 1.4 ) 2 0 / 16 LAG /09/18 06: ( 7 ) ( ) 4 0 / 2 AJI /09/18 07: ( 6 ) ( ) 1 0 / 3 AJI /09/18 08: ( 4 ) -1.2 ( 1.3 ) 2 0 / 23 STRL /09/19 17: ( 8 ) 1.7 ( 2.4 ) 2 0 / 13 LAG /09/19 20: ( 5 ) 3.1 ( 2.5 ) 2 0 / 13 LAG /09/19 23: ( 6 ) ( ) 8 0 / 3 LAG /09/20 00: ( 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 /07/30 05: ( 6 ) 0.1 ( 1.4 ) 8 0 / 9 STRL /07/30 07: ( 13 ) 4.8 ( 3.0 ) 4 0 / 9 AJI /07/31 22: ( 4 ) ( 1.7 ) 1 0 / 11 AJI /08/01 00: ( 21 ) ( 6.3 ) 10 0 / 26 ETA /08/01 01: ( 44 ) ( 66.9 ) 7 0 / 9 STRL /08/01 02: ( 27 ) ( 6.1 ) 5 0 / 6 AJI /08/01 02: ( 10 ) ( 7.4 ) 3 0 / 12 STEL /08/01 04: ( 10 ) ( 2.2 ) 3 0 / 14 STRL /08/01 04: ( 8 ) ( 1.8 ) 3 0 / 11 STRL /08/01 06: ( 12 ) ( 2.5 ) 3 0 / 10 STRL /08/01 07: ( 11 ) ( 2.4 ) 4 0 / 16 LAG /08/01 09: ( 8 ) ( 5.9 ) 2 0 / 13 ERS /08/01 10: ( 46 ) ( 11.6 ) 9 0 / 6 LAG /08/01 13: ( 9 ) 4.0 ( 5.2 ) 6 0 / 11 STEL /08/01 15: ( 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 LAG /08/30 23: ( 8 ) 1.2 ( 6.1 ) 8 0 / 14 LAG /08/31 02: ( 8 ) -3.4 ( 7.0 ) 4 0 / 12 LAG /08/31 21: ( 16 ) ( 10.5 ) 6 1 / 15 LAG /09/01 20: ( 9 ) 4.7 ( 6.3 ) 5 0 / 13 STRL /09/01 22: ( 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/TB Some stations tend to repeat this. (c) Wrong Sat, Wrong Date and LeapSec Wrong 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 error.