I’ve acquired a late model (Ashtech-Thales) G-12 OEM Board. I’ve got it up and running on the bench and receiving DGPS. It looks like I’m in business again because it puts out the NMEA RMC sentence which I need for the marine chartplotter and NMEA data logger.

So far I’ve only used a stationary antenna and have observed NMEA/DGPS accuracy to be similar to a SCA12 unit when the PSM filtering option is set for kinematic (walking mode) - That is around 1.8 meters at 95% assurance and 0.9 meters at 50% assurance or CEP.

It does make quite a difference when the PSM option is set for static filtering. With static filtering the receiver drift is less than one meter per minute. If I start recording when it is already near the reference point I have observed 95% accuracy over a period of several hours at less than 0.8 meters and CEP at around 0.5 meters which is near the advertised specs.

Soon I’ll get everything assembled in a project box so I take it out on the road for some real world testing of the NMEA output.

At this point I’m still looking for a way to get suitable carrier phase data out. The DOS datalogger software reports that it can’t open the COM port. Remote32 and GBSS demo software from the FTP site appear to require passwords or have expired.

How does one get carrier phase data suitable for post processing out of an OEM board? Do I have to use TEQC conversion of raw data? I assume the AC12 and GG14 work the same as the G12.

Modified By L.A. Johnson on 3/27/2007 at 11:40 PM

a question


what dgps are you observing with the board?

what dgps were you referencing with the sca12 unit?


do I need to dig the sca 12 out of the closet?

G12 is a good choice for your combination use requirements. I have an older model CSI GBX-Pro with that board in it that is getting a little finicky for real-time DGPS, so I am using it as a base station at my office for the time being.

Turn off all other windows comm programs, ESPECIALLY MS Activesync! (Wcescomm.exe is the executable you need to end).

Once you have done that you need to use RCS or Remote.exe (dos) to give the board commands to output the correct data. Datalogr.exe is my choice to log raw b and e files.

You can also set the unit up to stream the binary data directly using RCS or Remote.exe and then use TEQC's streaming Ashtech binary converter (-s) option to get a b file out of it...

JD, those puppies never left my neck of the woods. I just spent yesterday working with a SCA12 and a CSI MBX beacon receiver doing real-time DGPS work with Carlson SurvCE. Yes, its' bigger than a mobile mapper. So am I!
Modified By Robert Bills on 3/28/2007 at 12:46 AM

I am fortunate to have a coast guard transmitting station within about 20 miles from my home base. We have a few different DGPS receiver options- all are EOL and all seem to work about the same if they are set up right.

One important thing that I did not mention above. I had to turn off the option for hardware data checking for the COM port I/O on the G-12 to get the external devices to recognize the input.

It sounds like I’m going to have to keep working to get carrier phase from the G-12. It's really more of an academic exercise at this point because the main use will be the NMEA data, but I would like to have the option to hook up a 12 volt mini- computer and log carrier phase for some situations

RCS software is a new one for me and I’ll give it a try. What Com port settings and raw data options should I turn on?

Robert, Are you then saying that DOS datalogger will start working and quit complaining about not receiving communication from the COM port if I get things set up right? I am using an old Win98 computer for my test bed and it will be the same OS or maybe just DOS for any mobile system.

I have tried turning on the MBN binary message using Evaluate and switching the receiver from 9600 to 38400 baud but datalogger always refuses to start.

I like the idea of streaming raw data to a rinex converter as a base station, but that will be for another day. I’ve already have suitable rinex base stations.


One final question. Does anyone know if it helps to run a high gain antenna (greater than about 22 DB gain) on the G-12 or a SCA12 to try to reduce the effects of multipath? I have already been impressed with the DGPS realtime accuracy of the sca12 under multipath conditions from moderate winter time deciduous tree cover using a 24 DB gain antenna with some cable and connector loss.