****************************************************************************** IGS-ACS Mail 10 Feb 06:33:51 PST 2009 Message Number 138 ****************************************************************************** Dear colleagues, I prepared "pre-2000" GPS P1-C1 bias files, synchronized and cross- checked various receiver name lists, and took steps for handling of AS-free periods in 1994/1995/1997. "Pre-2000" GPS P1-C1 bias files ------------------------------- Monthly P1-C1 bias averages that were computed on the basis of TUM daily reprocessing results are made available back to January 1996. For the years 1994 and 1995, yearly averaged bias values were computed on the basis of 1996 monthly mean values (as pre-1996 bias retrievals turned out to be very noisy). By this, bias values for three previous PRN numbers (namely G12, G13, G28), or 31 satellite-months remain "undefined" (indicated with 0.000): P1C19401.DCB:G12 0.000 0.000 P1C19401.DCB:G13 0.000 0.000 P1C19401.DCB:G28 0.000 0.000 P1C19402.DCB:G12 0.000 0.000 P1C19402.DCB:G13 0.000 0.000 P1C19402.DCB:G28 0.000 0.000 P1C19403.DCB:G13 0.000 0.000 P1C19403.DCB:G28 0.000 0.000 P1C19404.DCB:G13 0.000 0.000 P1C19404.DCB:G28 0.000 0.000 P1C19405.DCB:G28 0.000 0.000 P1C19406.DCB:G28 0.000 0.000 P1C19407.DCB:G12 0.000 0.000 P1C19407.DCB:G28 0.000 0.000 P1C19408.DCB:G28 0.000 0.000 P1C19409.DCB:G28 0.000 0.000 P1C19410.DCB:G28 0.000 0.000 P1C19411.DCB:G28 0.000 0.000 P1C19412.DCB:G28 0.000 0.000 P1C19501.DCB:G28 0.000 0.000 P1C19502.DCB:G28 0.000 0.000 P1C19504.DCB:G12 0.000 0.000 P1C19504.DCB:G28 0.000 0.000 P1C19505.DCB:G12 0.000 0.000 P1C19505.DCB:G28 0.000 0.000 P1C19506.DCB:G12 0.000 0.000 P1C19506.DCB:G28 0.000 0.000 P1C19507.DCB:G12 0.000 0.000 P1C19507.DCB:G28 0.000 0.000 P1C19510.DCB:G12 0.000 0.000 P1C19510.DCB:G28 0.000 0.000 The introduced bias results may be found at ftp://ftp.unibe.ch/aiub/CODE/1994/P1C19401.DCB.Z ftp://ftp.unibe.ch/aiub/CODE/1994/P1C19402.DCB.Z ftp://ftp.unibe.ch/aiub/CODE/1994/P1C19403.DCB.Z ... ftp://ftp.unibe.ch/aiub/CODE/1996/P1C19601.DCB.Z ftp://ftp.unibe.ch/aiub/CODE/1996/P1C19602.DCB.Z ftp://ftp.unibe.ch/aiub/CODE/1996/P1C19603.DCB.Z ... or ftp://ftp.unibe.ch/aiub/CODE/1994/P1C19401.F.Z ftp://ftp.unibe.ch/aiub/CODE/1994/P1C19402.F.Z ftp://ftp.unibe.ch/aiub/CODE/1994/P1C19403.F.Z ... ftp://ftp.unibe.ch/aiub/CODE/1996/P1C19601.F.Z ftp://ftp.unibe.ch/aiub/CODE/1996/P1C19602.F.Z ftp://ftp.unibe.ch/aiub/CODE/1996/P1C19603.F.Z ... or, in a compiled, cc2noncc-compatible form, in ftp://ftp.unibe.ch/aiub/bcwg/cc2noncc/p1c1bias.1994 ftp://ftp.unibe.ch/aiub/bcwg/cc2noncc/p1c1bias.1994p ftp://ftp.unibe.ch/aiub/bcwg/cc2noncc/p1c1bias.1996 ftp://ftp.unibe.ch/aiub/bcwg/cc2noncc/p1c1bias.1996p Note 1: Each file contains monthly sets of bias values for the entire history starting with the year specified by the file name extension. Note 2: Bias files indicated with a "p" (for plus) at the end of the file name extension are files that include in addition a set of latest bias values updated daily from a sliding 30-day combination. Receiver name lists ------------------- An automatic procedure for comparison of various lists of receiver names has been set up. The output of this comparison is posted regularly to: ftp://ftp.unibe.ch/aiub/bcwg/cc2noncc/receiver_p1c1bias.lis An essential data source in this regard is CODE's receiver information file: ftp://ftp.unibe.ch/aiub/bcwg/cc2noncc/receiver_bernese.lis ftp://ftp.unibe.ch/aiub/BSWUSER50/GEN/RECEIVER. It is worth mentioning that this receiver list includes all receiver names (including verified receiver class) that are relevant for the reprocessing at TUM as well as those used for the operational analysis at CODE. The mentioned comparison file (receiver_p1c1bias.lis) includes in addition the following information: - Is RINEX data for a particular receiver type available in CODE's "1994-now" RINEX datapool? - Are all known "C1/X2" and "C1/P2" receiver models included in the updated p1c1bias. files? Remark: A missing entry would be indicated with a "0". - Is a particular receiver name included in rcvr_ant.tab? - Is a particular receiver name included in igs.snx, sio.snx? - Is a particular receiver name included in other receiver lists? Is the given receiver class consistent with that specified in CODE's reference list? Remark: A corresponding comparison is done with respect to the GAMIT rcvant.dat file. Further receiver lists could be easily added for cross-checking. Please let me know. AS-free periods --------------- The necessary software change for adequate handling of AS-free periods in 1994/1995/1997 was implemented into AIUB's development version of the Bernese Software (and into the distributed Version 5.0 of the Bernese Software, cf. B_151 improvement). For ACs relying on the cc2noncc RINEX conversion tool, the AS-free periods are included with "zero values" blocks in the introduced p1c1bias. files (in order to suppress correction of the P2 observable). A cross-correlation (CC) receiver (providing C1 and X2=C1+(P2-P1) under AS conditions) is expected to provide C1, P1, P2 when AS is switched off. It is obvious that the proposed workaround does work only if the (thus uncorrected!) C1 observable remains unconsidered and the P1 observable is used instead (by the analysis software emplyoed at the AC). Feedback in this context is welcome. ACs doing the P1-C1 data correction in their own analysis software are advised to suppress the P1-C1 data correction of the P2 observable in case of CC receiver models during AS-free periods. Start and end dates of such periods (given in MJD) may be gathered from our F90 module "AS mode": ftp://ftp.unibe.ch/aiub/bcwg/cc2noncc/as-free_periods/ASMODE.f90 Upload of data samples and bias results --------------------------------------- Finally, let me mention that RINEX data samples for receiver types to be classified may be uploaded to: ftp://ftp.unibe.ch/incoming/bcwg/ The same ftp address may be used for upload of (highly desired) pre-1996 P1-C1 bias results from other analysis groups. Best regards, Stefan From: Stefan Schaer