How can i connect directly to the GPS receiver if I run my program?

[jtc]

I am using LabVIEW 7.1 and using a Novatel GPS. I placed the program I created on the Windows Start-up Menu. I want to create a program that when it runs it will automatically read GPS data via RS232 port. I already created a sample program and i also looked on all the samples but still I cant make it read GPS log data automatically.  

What happening is, if I log-on to the GPS Receiver using the GPS Utility Software first, then closes this software, and then RUN my program, that is the time it will get GPS data. Otherwise it will not.

Any advise i would greatly appreciate.

Best regards,

[Brian_Beal]

This sounds like a com port configuration problem.  Be sure that you configure the com port the way that the Novatel requires, including termination character.  The GPS should be ready to receive commands, or automatically output data, on power-up.

[jtc]

Thank you for the reply Mr Brian Beal. I really appreciate your kind advise.

I have checked and configured all the requirements from Novatel but I still fail. The required ASCII syntax is

COM [port] bps [parity[databits[stopbits[handshake[echo[break]]]]]]

I always have to logged the following to the Novatel Software (everytime it is turned on) in order for my program to read GPS data.

      - COM COM1 57600 N 8 1 N OFF ON

      - log com1 gpgga ontime 1

      - saveconfig

Without logging on the GPS receiver using the Novatel Software, my application will not show the GPS log data that i am requesting. However, once I logged on the GPS receiver and run my application, I will see the real time GPS log data that i need.

Do you think my application is wrong?

[Brian_Beal]

Are you using Labview?  How are you initializing the com port on your computer?

[aartjan]

I have used labview with Novatel GPS and can tell you this:

You need to configure its output (as you described) in order to get output. Depending on the GPS card (OEM3 / OEM4) you will get a acknoledgement "com1>" or ">" (I believe) or an error. If you want to initialize the Novatel with Labview, I would read back the response to make sure the command is acknowledged.

You can also make commands persistent (using "saveconfig"), such that the GPS will start streaming data right at power on.

Therefore: you should be able to easily do everything with Labview without the need of external programs.

Aart-Jan

[jtc]

Yes, i am using LabVIEW 7.1. I am making the COM configuration using a VISA function. In this function i will be able to set all the parameters needed like baudrate, parity, databits, handshake.

Baudrate - 57600

Parity - none

Databits - 8

Stop bits - 1

Handshake - none

Whats odd is i am also trying successful LabVIEW sample programs but i am getting same results.

[jtc]

I made some test today and documented them so you can see my problem. I am using a Novatel OEM4 (Propak) GPS Receiver. Everytime I issue a command or instruction i will get acknowledgement as <ok  [com1]. Likewise, when i issue SAVECONFIG i will get the same acknowledgement.

Thank you very much for your advises.

Best regards,

Bong

[jtc]

To Bryan and Aartjan

I was able to fix the problem. My application can now connect to the GPS receiver without any error. There was no problem on my program rather on the configuration of the GPS receiver. I issued the ccommand "unlogall" to the GPS receiver which cleared all the previous commands saved on the GPS receiver.

Thanks.

[azimuth]

 Hello, I am trying to figure out how to write a VI to talk to a Propak V3 through LabVIEW. Do you think you can send me the code to look at? Is it a generic NMEA parser, or does it function differently?

Thank you very much

azimuthny@yahoo.com

Igor Labutov 

[RTSLVU]

Here is  some good information on decoding NEMA GPS data.

http://www.gpsinformation.org/dale/nmea.htm