CODEWITHSUNDEEP
gpsserial-port
parsecpython
parsecpython

Reputation: 615

Serial device with no documentation, GPS board

I have a GPS circuit board from china. The only information I can find on this thing is :"amoj GPS 04C www.amoj.com"

It has a serial (DB9) connection and I would like to determine how to putty into it or something.
How can I determine what the port settings that are required to access this?
Pictures below:
Photos in Dropbox

Upvotes: 1

Views: 507

Answers (3)

VLFTime
VLFTime

Reputation: 31

The Jupiter TU60 serial interface is 9600 8N1 by default. The only sentence it will output automatically is the flash checksum message about a second after power up. Google the datasheet for the device and it will let you know about this.

To have it output the position and other information, you must command it to do so. There is a default set of commands that are active after power up. They begin with @@ and are from the protocol used by Motorola. Refer to the M12+ Users Guide and Supplement (available online) for information on how to use these commands. I have been able to enter them from Realterm. The only tricky part is calculating the checksum. You can use most hex calculators to do that.

According to the datasheet, the unit goes into survey mode automatically and after about 24 hours goes into position hold. The 1PPS and 10KHz signals are valid to less than a microsecond after a few minutes after power up and to 50nS after a day. I have compared this to another standard I have to verify this. You can use the @@Ea command to get the status of the unit and the M12+ Manual will tell you how to decode it.

Upvotes: 3

user1911627
user1911627

Reputation: 1

I have the same board with the Navman jupiter T Tu60 GPS 1pps 10khz GPS Module on it. I just received my sma antenna and have hooked it up. I am using 12.6V power to the centre pin.

It outputs 1pps on the led with no signal, so that is not to be trusted. Mine is labeled 1pps and 10khz underneath the pcb but these are actually swapped! I put the 10KHz output on my dso and get a 10KHz square wave 50% duty cycle signal but there is ringing on the waveform rise so I have to set the trigger level to 0.8v to get the dso to register the 10KHz frequency. I suspect this may be because the output expects a load and is not seeing one. Now, was I using ac or dc coupling?

I too am getting nothing on the serial. I tried 9600, 4800 using putty on com1 (I have a nice old motherboard) and then tried reversing rx and tx but no luck. As of now I am checking out the serial signals with the dso to see if I can work out what is happenning. I suspect that these boards are rubbish, and useful as power supplies only.

It reads 10.0000 on my hp 5328a counter and sometimes reads 9.9999. It would be nice to be able to talk to the gps to see whether it has satellite lock.

Please let me know how you get on and if you find out any further info.

Brett VK6EZ.

Upvotes: 0

dfowler7437
dfowler7437

Reputation: 461

Look for $GP... messages at 4800 and 9600BPS as yegorich suggest. Common NMEA messages output by GPS devices are $GPGGA, $GPVTG, $GPRMC.. If you find that data coming out, use Google to look up NMEA 0183 sentence structure and you will have what you need...

Upvotes: 1

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