Question

Hi,

We try to use RUTX11 (FW version RUTX_R_00.02.06.1) to get GPS position in real time.

We observe that GPS movement is sometime late (up to 25 seconds) with respect to real antenna movement (given by another separate movement sensor).

The received nmea sentences contains :

• correct UTC time (contains the exact current second)
• latitude/longitude late with respect to real antenna movement

In other term, if we move the antenna of 10 meters between 12:00:00 and 12:00:10, the nmea messages say that we move between 12:00:25 and 12:00:35 for example (while the nmea sentence received at 12:00:00 contains the correct UTC time 12:00:00).

Is it a known problem ?

How to solve it ?

Thank you for for help

For info we use following GPS configuration :

* GPS Configuration :

- Enabled : on

* Satellite configuration :

- Galileo NMEA support : enabled

- Glonass NMEA support : enabled

- BeiDou NMEA support : enabled

* NMEA forwarding :

- Enabled : on

- Hostname : 192.168.1.10 (our correct IP)

- Protocol : TCP

- Port 8500

* NMEA forwarding cache

- Save cache in RAM

- Maximum sentence : 1

* NMEA Collecting

- Enabled : on

- Location : /mnt/gps.txt

* NMEA sentence settings

- GPGGA : on, forwarding interval 1s, collecting on, collecting interval 1s

- (everything else disabled)

Answer 1

Hi,

GPS of RUTX11, unfortunately, won't do what you expect it to do in real-time and it is not "right on that metre" accurate.

Mostly our GPS is used with geofencing or just to send NMEA data to other servers that collect information and it could be a lot of things why you're getting late information:

1. Buffer on RUTX11 (too often messages).

2. Buffer on your other device that is getting the messages.

3. Internet connection is too slow to send that many messages.

4. Service that writes/saves the messages somewhere is working slower with information that it's gaining.

In any case, we do not state that RUTX11 can get its GPS location in real-time and there are other devices for that very reason.

https://teltonika-gps.com/products/

EB.

Comments

Is there any chance you could let us know which third party GPS is integrated in RUTX11 and whether it is possible to configure it bypassing the RUTX11 system? How is it connected to the linux system?

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Hi,

GPS functionality comes from the RUTX11 modem - Quectel EG06.

EB.

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I don't understand this statement:

In any case, we do not state that RUTX11 can get its GPS location in real-time and there are other devices for that very reason.

 Since when is GPS not realtime? Since when does one buy a GPS capable device without the expectation of realtime? Can you give me and example of one single GPS capable device who's use case isn't realtime GPS? Teltonika, you're breaking me heart...

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@remip: Have you tried Modbus? Is there also a delay? Entering gpsctl -seix in the command line always gives me the exact time on the second. Of course saving data to disk to relay it is going to take longer. But 2x seconds? I have to test this...