[teqc] error in reading/using Javad JPS [SX] message

Lou Estey lou at unavco.org
Tue Apr 25 15:13:58 MDT 2017


All,

At the end of summer 2016, code for reading Javad's new [SX] message was added
to teqc, but there were two undiscovered indexing errors in the code that did
not show up in the files with [SX] supplied to me by Javad back then.  For JPS
files using [SX] these errors can result in what appears to be a correct RINEX
observation file when, in fact, it is not at all correct.  Some background:

The JPS [SX] message is Javad's GNSS-generalization of the original [SI] message,
with [SI] being used in both Javad JPS and Topcon TPS formats.  [SX] and [SI]
contain the SV listing of which SVs being tracked for that epoch.  Javad firmware
3.7.0 and later support the [SX] message.  (And note: 3.7.0 and 3.7.1 are
official releases already.)

I had hoped that correctly dealing with the JPS [SX] message would be in the
2016 Nov 7 release, but because of these errors you should not use any teqc version --
that for 2016 Nov 7 or otherwise -- unless it's an interim version of 2017 Apr 25
or later.

Based on a recent sample JPS file and after making the necessary fixes for [SX],
I do believe that handling the other new JPS GNSS-generalization messages, as
described in http://postal.unavco.org/pipermail/teqc/2016/002180.html, are fine:

[teqc version 2016 Nov 7] - has an overhaul of the parsing of Javad JPS and Topcon
TPS, making it compatible with new JPS messages (e.g. [rx], [RX], [0d], [DX], [cr])
and other changes with fw 3.6.0 and 3.7.0, including the move of Beidou B2/E5b observables
from the [*5] and [5*] messages to the [*2] and [2*] messages starting at fw 3.7.0.

The correct handing of [SX] will, of course, now be in the next official release,
along with quite a number of other improvements in teqc.

cheers,
--lou

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Louis H. Estey, Ph.D.              office:  [+001] 303-381-7456
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                                                -- Leon Lederman
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