MGEX DCB Products Oliver Montenbruck

Transcription

1 MGEX DCB Products Oliver Montenbruck lide DLR/GOC > 05//06

2 Products Overview DLR/GOC GP, GLO, GAL, BD All tracked signals Updated once per 3 months Weekly interval (sat-only) and daily interval (sat and sta) Zero-mean constraint per constellation within each interval Available from /03 (since /04) CA/IGG GP, GLO, GAL, BD All tracked signals Updated daily Daily interval (satellite and station biases) Zero-mean constraint per constellation within each interval Available from /03 (since 0/05) lide DLR/GOC > 05//06

3 Availability IG MGEX Product Archives ftp://cddis.gsfc.nasa.gov/pub/gps/products/mgex/dcb ftp://igs.ign.fr/pub/igs/products/mgex/dcb Coverage Period Jan 03 to now Naming (since 0/05) Info CA0MGXRAP_yyyyddd0000_0D_0D_DCB.BX.gz DLR0MGXFIN_yyyy000000_nnu_07D_DCB.BX.gz DLR0MGXFIN_yyyy000000_nnu_0D_DCB.BX.gz [IGMAIL-773] lide 3 DLR/GOC > 05//06

4 New File Naming Convention (Draft) AAAVPPPTTT_YYYYDDDHHMM_LEN_MP_CNT.FMT[.?*] 0-03 AAA 3-char AC name (here: CA for "Chinese Academy of ciences", and DLR for "German Aerospace Center") 04 V -char version/solution identifier (here: nominally 0) PPP 08-0 TTT 3-char campaign/project specification (here: "MGX") 3-char product type specification (here: RAP for "rapid", and FIN for "final") _ -5 YYYY -char separator (underline) 4-digit year of start epoch 6-8 DDD 3-digit day-of-year of start epoch 0-0 HH - MM -digit hour of start epoch (her: 00) -digit minute of start epoch (here: 00) 3 _ -char separator (underline) 4-6 LEN -digits-char intended (nominal) product period (here 0D for -day, 0Y for -year and??l for coverage interval in months) 7 _ 8-30 MP -char separator (underline) -digits-char sampling interval (here 0D for -day or 07D for 7-day averages) 3 _ 3-34 CNT -char separator (underline) 3-char content type (here: "DCB") 35. -char separator FMT 3-char format extension (here: "BX") lide 4 DLR/GOC > 05//06

5 lide 5 DCB Determination using Global Ionosphere Maps DCB from ionosphere-corrected pseudorange difference Use of known ionosphere based on global ionosphere maps IG IONEX product ingle-layer model Limited accuracy rcv sat DCB TEC 40.3 ) ( ) ( ) ( ) ( = f f ε ε M M B B I I P P ROB JPL Measured Modelled Estimated Averaged/ignored Montenbruck O., Hauschild A., teigenberger P., Differential Code Bias Estimation using Multi-GN Observations and Global Ionosphere Maps; Navigation Journal of the ION 6(3):9-0 (04). DOI 0.00/navi.64

6 Network and Receivers MGEX Network (>00 stations) tracking GP, GLO, GAL, (QZ), BD Challenge with modernized signals (GP LCL5, Galileo EE5a): Different receivers use different tracking modes Example: GP L5 pilot-only tracking or combined pilotdata tracking ampling period minute lide 6

7 Processing cheme elect signal pair (, ) Determine satellitereceiver DCB satrcv from daily mean of ionospherecorrected code difference Determine individual DCBs for each satellite and station from combined DCBs for all sites and satellites assuming DCB satrcv = DCB sat DCB rcv applying a zero-constellation-mean constraint Notes: et of contributing stations depends on selected signals Current implementation (IONDCB) enables processing of all constellations and dual-signal combinations but no combined adjustment of > signals (such as CC, CW, CW) lide 7

8 Example (Galileo E-E5 O/) Note: Daily DCB time series has been aligned across constellation changes and readjusted to global zero mean across reporting time period for plot purposes and trend analyses. lide 8 DLR/GOC > 05//06

9 Issues Differences between IG and MGEX DCBs for GP/GLO Impact of different networks (receiver types) Need to understand impact of Q and X tracking on DCBs (and possibly BOC/MBOC) Misclosure of redundant biases DCB(a-b)DCB(b-c) DCB(a-c) Needs DCB adjustment across all signal pairs Restrict DCBs to non-redundant basic DCB set No DCBs for QZ (only one satellite) Timing community deprecates zero-mean condition; prefers DCBs w.r.t. to golden receiver lide 9 DLR/GOC > 05//06