[FOSS-GPS] High accuracy positioning with low cost GPSdevices:aFOSS project

[Tomoji Takasu]

Hello, Stephan

> I ve sent you an RTCM-log from that WTZR0-station.

I checked your RTCM log of station WTZR0.

All of the type 1014 message header field "Synchronous GNSS
Flag" of WTZR0 are set to "1" as follows (sync=?).

1 decode_type1004:nsat=11 sync=1
3 decode_rtcm3: len=125 type=1012
3 decode_rtcm3: len=183 type=1004
1 decode_type1004:nsat=11 sync=1
3 decode_rtcm3: len=125 type=1012
3 decode_rtcm3: len=183 type=1004
1 decode_type1004:nsat=11 sync=1
3 decode_rtcm3: len=125 type=1012
3 decode_rtcm3: len= 64 type=1019
...

RTCM 3.0 or 3.1 defines "Synchronous GNSS Flag" as

"... If it is set to "1", it means that the next message will
contain observables of another GNSS source referenced
to the same Epoch Time."

RTKLIB recognizes that another observation data exists
with the flag and waits next data, but no next data comes
and it is discarded. In this case, "Synchronus GNSS Flag"
must be 0 to complete the processing of the epoch.

It might be due to the bug of the receiver or the server of
NRTK. So I do not provide the patch for RTKLIB 2.2.1.

If you want to avoid the problem. Please add the line:

sync=0;

after the line 473 of rtklib_2.2.1/src/rtcm.c and rebuild
RTKNAVI (and RTKPOST, RTKCONV).

Please refer the following "How to apply a patch" for the
build procedure.

http://gpspp.sakura.ne.jp/rtklib/rtklib_support.htm

Best Regards,


Tomoji TAKASU


----- Original Message ----- 
From: "stefans" <stefans_htd at yahoo.de>
To: <foss-gps at lists.osgeo.org>
Sent: Monday, May 18, 2009 4:37 PM
Subject: Re: [FOSS-GPS] High accuracy positioning with low cost 
GPSdevices:aFOSS project


>
> Hello ttakasu,
>
>
>
> this is a strange thing:
> Some RTCM3.0/3.1-Streams are processed correctly, for some, the Obs data 
> are
> missing.
>
> I ve sent you an RTCM-log from that WTZR0-station.
>
>
>
>
> Stefan
>
>
>
> -- 
> View this message in context: 
> http://n2.nabble.com/High-accuracy-positioning-with-low-cost-GPS-devices%3A-a-FOSS-project-tp1312818p2931210.html
> Sent from the Open Source GPS-related discussion and support mailing list 
> archive at Nabble.com.
>
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