GX450 GPS at 1Hz?

AirLink Routers AirLink routers
1

I have a GX450 configured to send GPS to a remote server with a 1 second interval. The server is receiving data once every 2 seconds. Same results with a local server configured.

Is 1 second a best effort?

Any other settings I need to make to get 1 Hz?

Here’s the config:

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I flashed the firmware to 4.9.4p09 and reset all setting to factory defaults, then configured the GPS remote server.

Thanks for any help.

  • Patrick
2

Hi @pejackson

Note: Your cellular carrier may impose a minimum transmit time.
Location Report Time Interval
The amount of time between location reports (in seconds)
Options are:
• 1– 65535
• 0 = Disables location reporting based on a time interval (default)
With this option disabled, you can still receive reports based on distance traveled or
the vehicle being stationary for a configured time. (See Report Interval Distance
(meters) on page 247 and Stationary Vehicle Timer (minutes) on page 248.)

Please refer to page 247 in software configuration guide document for more details.

Yes, it is.

You can configure location reports via a serial connection, generally using either NMEA or TAIP. To configure serial streaming for DB-9 (RS-232) ports and/or USB Serial ports, go to Location > Local/
Streaming.
I can receive NMEA reports every once second from DB-9 (RS-232) ports.

Please refer to page 257 in software configuration guide document for more details.

You can get this document at here:
https://source.sierrawireless.com/resources/airlink/software_reference_docs/airlink-aleos-configuration-guide-for-gx450/#sthash.Dvjxq1Ub.dpbs

Please help to mark “Solution” if your question is answered. So the community could easily find the solution for their problems.

3

Thanks @Donald

I have read the relevant pages from the software configuration guide. The only mention of limitation I could find was the one you noted: “Your cellular carrier may impose a minimum transmit time.”. I’m actually sending to the LAN side of my GX450. I’m using the remote server configuration (rather than Local IP) because I have multiple devices DHCPing addresses from the router, and I need to ensure the reports go to a specific device.

As a test, I disabled the remote server and used the Local IP configuration and got the same results (1 sample every 2 seconds).

Thanks for clarifying that the 1 second interval setting is best-effort. Unfortunately, our requirements are 1) 1Hz samples and 2) Send to a remote server over IP (e.g. no serial port connection). I’m evaluating different routers and so far we like the Airlink the best, but this is definitely a con.

I just really want to make sure there isn’t something simple I’m missing, as the setting range includes 1 second intervals certainly seems to imply that 1Hz is supported, if not limited by the cellular carrier.

So just to confirm: Do you know that 1/2 Hz is actual limit for a remote server? Or does it just seem a reasonable conclusion based on the configuration I posted?

Thanks again for your time.

4

Hi @pejackson,

It is a actual limit for a remote server and Local IP report.

Note: If the Local Reporting Time Interval is set to 1 second, there may be some variation in the report interval, with the report interval sometimes being less than 1 second and sometimes more than 1 second.

Please refer to page 260 in software configuration guide document for reference.

Please help to mark “Solution” if your question is answered. So the community could easily find the solution for their problems.

5

Thanks for the clarification. I read that as “expect network jitter”, but I think it also can be interpreted as “you might get less than 1Hz”. But that still seems strange to me that anything besides the jitter would not be deterministic, especially if updates on the serial port can be 1Hz.