I am using a L76-L on Pytrack to track a location. I am looking for a location update every second. I am getting enough messages to update every second, but the NMEA messages are already delayed by 5-6 seconds when read from the I2C bus. I have tried many many different configurations, e.g. upping the baudrate, using only GPS or GPS+GLONASS. The delay was always the same.
E.g. i get an RMC message with timestamp 12:02:30 and the actual time is already 35 seconds. I have tested this in the field and the timestamps are correct for the coordinates, but 5-6 seconds old.
Please try to connect wires to the module, in order to read NMEA message directly form the module’s UART port. And adding timestamp( both I2C and UART ) for comparison. This operation aims to find out whether the module itself is faulted or not.
Please provide the firmware version by sending command : $PQVERNO,R3F
you will get response like:
Hi, I tried it with 3 different pytracks/Quectel modules, but unfortunately I cannot do the comparison of UART/I2C at the moment.
Might it be connected with the DGPS modes? I noticed that the delay seems to be longer when a lot of movement (aprupt changes) or fast movement is happening.
Also the Buffer seems to be huge, when I read out the buffer I get very old timestamps. > than 40 seconds old. But even with fast enough buffer emptying and reducing the messages to only RMC I get a delay of 1-6 seconds.
That would be $PQVERNO,R,L76LNR02A01SC,2018/07/23,08:35*65
Please try to upgrade the latest f/m version, and check whether delay extinct or not.
L76LNR03A01S.zip (2.0 MB)