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Permalink Reply by Chris on May 12, 2008 at 1:20pm

The internal Nomad GPS is not intended for survey-grade accuracy.

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Permalink Reply by Alex Mahrou on May 14, 2008 at 8:02pm

What kind of survey receiver are you using? You can hook it up to arcpad using NMEA.

If you are trying to achieve submeter with the Nomad, forget it. I'm pretty sure that you can't hook up an external antenna to the nomad; at least Trimble or TDS does not make one.

The measurements collected with a nomad, are really not designed to be post-processed, even though Pathfinder office allows for it. I've heard this from Trimble directly. It is a sirf chip receiver, meant to be usefull where you would favor just a "fix" over precision. The best you can get with a nomad, is to turn on SBAS, and hope you can get it where you can.

Since you're a surveyor, I would hook up your survey receiver via bt or serial to the Nomad and use that in arcpad.

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Permalink Reply by Paul on May 15, 2008 at 6:14am

Thanks for the reply Alex.

Just to explain why I'm trying this setup. I have 3 great tools that I use individually and would like to merge them all together.
1. TDS Nomad (Surveying Data Collector)
2. Leica SmartRover RTK GPS (Centimeter Accuracy)
3. ESRI ArcPad 7.1 (Mobile GIS software)

I use the Leica SmartRover GPS unit which has an ATX1230 GPS antenna. I have setup the bluetooth connection between the Nomad & ATX1230. But when I go into ArcPad and use NMEA 0183 settings, I get an error message that the GPS data is invalid.

I have contacted both TDS & Leica technical support. TDS told me that everything is good with my setup but Leica said their antenna doesn't transmit NMEA data. I will keep trying to get this to work. Maybe the people at Leica, TDS & ESRI will hopefully get there excellent products to work together.

Thanks.

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Permalink Reply by Alex Mahrou on May 15, 2008 at 4:59pm

That worries me that leica told you that. here is the datasheet for your system. It states that your reciever can output NMEA 0183 V2.20 and Leica proprietary. I would maybe check to see that your reciever is outputing the standard NMEA messages.

Did you create an outgoing serial port under your bluetooth connection settings on the Nomad after you created a partnership with the ATX?

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Permalink Reply by Paul on May 16, 2008 at 7:43am

Alex,

Do you mind if I add you to my friends list?

I emailed Leica tech. support and they said that my current configuration (Leica + NMEA) wouldn't work because the GPS corrections are being done on their RX1250 data collector.
That seems to be a "cop out" because I'm not looking for GPS corrections that are centimeter accuracy. I'm just looking for sub-meter which I think the receiver should put out automatically with NMEA.

Thanks for the link to Leica's datasheet. I'll keep trying to get an answer from Leica. Sometimes when it's not a direct issue with their equipment or your trying to use a third party setup, they aren't to helpful.

Also, yes I did create an ouput serial port #8 with the bluetooth connection between the Nomad & Leica ATX1230. The bluetooth connection seems to be working fine.

Thanks.

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Permalink Reply by Alex Mahrou on May 20, 2008 at 7:19pm

Sure, you can add me... But I really think that this can be done. Oh well. I would get your partnership going between the nomad and the gps and use Franson GPS Gate on the Nomad to see if you are getting NMEA messages. Download it here. GPSGate will scan to see which port your nmea messages are coming from, and then re-broadcast them to virtual ports. There is a chance that it will recognize the nmea messages off of the survey receiver, and then you could connect arcpad to one of these virtual ports. I have found that this sometimes works when I have an application that won't use the regular nmea messages off of the receiver.

Having said that...
I am 100% confident that you will not get sub-meter with the Nomad, even whilst connecting to Real-Time SBAS. The nomad rarely will pick up SBAS anyways, due to the level of noise onboard with this device. The best that you will see, is 2-5 meters with SBAS or Post-Processed.

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Permalink Reply by Paul on May 28, 2008 at 1:08pm

Alex,
I downloaded and installed GPSGate on the Nomad. I configured it to the Input Port: Com3 which is connected to Com8, where the GPS hardware port resides. I also configured the Output Port (Virtual Port-NMEA) to Com4.
I got it to connect to the Leica ATX1230 via Bluetooth. It says "running o.k." but it told me that "no data is coming in". The Virtual Port 4 says "Running OK".
I then went into ArcPad and set it up for the same settings;
Com4-Franson, 4800 Baud etc. but it still isn't receiving any data.
If you think I'm doing something wrong, please let me know. If not, thanks for all of your help. It was a good experience to play around with the Nomad's GPS settings. I hope in the future TDS will think about including a "Survey Grade" GPS module in the Nomad.
Thanks again.

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