How to produce a very simple GPS time information acquisition scenario

[Tassos83]

I am deploying LabVIEW 2016 with GPS ToolKit 2.0 connected to NI USRP 2920 with external oscillator for their clock input. I wish to find simple scenarios (.vi files) on how to embed niGPS session (in/out), that of course output all satellite GPS information we need, to the existing niUSRP sessions (niUSRP RX with GPS).

So in simple words I don't know how to invoke inside a ready to deploy niUSRP scenario the niGPS session via connectivity or parameters loading to output GPS time information once GPS locked.

Are there any simple such scenarios?

Thank you

[Chantastic!]

Hi Tasso,

I'm not quite sure I understand what your question is. Are you attemping to pass a niGPS session into a USRP VI? Is there a specific USRP example that you are using you wish to modify? 

[RTSLVU]

I am not sure what the GPS toolkit does but a GPS that follows the NMEA standard continuously spits out GPS "Sentences"

A sentence is a simple comma delimited ASCII text string sent at 4800 or 9600 baud (8N1)

Here is a good source for parsing GPS data http://www.gpsinformation.org/dale/nmea.htm

All you need to do is capture and parse the data.

[billko]

if you wanted to make a time server, a Raspberry Pi 2 or 3 is an excellent choice becase it has NTP built right into it.  You don't even need anything but an internet connection if you want to make it a stratum 2 time server.  You need a bit of extra hardware to make it a stratum 1 time server, of course.

I actually used LINX to deploy a little LabVIEW application that periodically queries the server to get a status and lights some LEDs in a similar manner as a cable modem so I can tell at a glance if something is wrong with the server.  (Flashing lights are a bad thing.)  I even have have a physical button that the application keeps track of to restart NTP or reboot the PI.

[Tassos83]

Hello again,

Thank you for your prompt. I am attaching the simple .vi scenario I wish to execute and of course inside it to call or invoke a niGPS session (from the GPS Toolkit). Could you help me how to introduce the GPS session inside this scenario?

Thank you very much

[Chantastic!]

Hello Tassos, 

I'm not sure if there's an easy way to utilize an niGPS session into this toolkit, as the USRP does not utilize the session based method of initializing a session to a GPS in order to generate the PPS pulse. 

Can you elaborate a little more on what application you're building that you want to do so? There may be another way to implement the desired functionality that does not require the GPS session integration. 

[Tassos83]

Hello again,

Thank you for your response. I wish to invoke the GPS Toolkit for my NI USRP-2920 device after it locks or connects to the GPS signal, in order to output info captured from satellites, like: longtitude, latitude, number of satellites locked, etc. I know that this info is provided by GPS Toolkit. So, how could I write a simple .vi script to get this data? Do you know any simple such script from the NI sources/references to utilize as instance?

Thank you,

Anastasios Bikos

[Tassos83]

I attach my .vi file to perform GPS Signal Lock/Capture/Meta Information output, i.e. satellites locked, altitude, longtitude, time of week, etc.

The problem is that although the GPS locks, I get the signal etc., I cannot receive the previous meta GPS information.

I am in kind need for comments and responses.

Thank you,

Anastasios Bikos