How to enable RTCM in LIV4F

[kolee]

Hi,

I have a EVB-LIV4F. I would like to know how to enable RTCM message. I would like to extract the following raw measurements from RTCM:

1) the time of the measurement

2) satellite pseudoranges measured between the satellite and GNSS receiver

3) their standard deviations

4) carrier phase

5) Doppler shifts

Thanks.

[rvl]

To get the raw measurements you need the ME (Measurement Engine) version of the firmware. Have you loaded that to your module? I'm not familiar with the details beyond that. There used to be a dedicated Teseo-LIV4FM for this, but it was discontinued before we could actually order it. Not sure if there were any further documentation specific for that module, before it was removed from the ST website?

I'm also interested to test raw measurements with LIV4F, but do not have the hardware ready yet. Not 100% optimistic in what to expect in performance with regards to noise and cycle slips, but we'll see when we get there. Obviously also interested to hear what you (and others) experience.

[Francesco Virlinzi]

Teseo-LIV4FM will not be produced any more and all the Teseo-LIV4FM features have been moved on Teseo-LIV4F using dedicated firmware

To get raw measurement data in RTCM format you have to install the _ME_ firmware available for free @ https://www.st.com/en/embedded-software/teseo-liv4fsw.html  (Edit: fixed from 3F to 4F)

In the package there are 4 firmware:

 - Standard PVT (the default one installed in production)

- PVT with IRSS support

 - PVT with MSM1 decoder

 - PVT and ME (the one you are looking for)

You can download and install the ME firmware in the module and get the raw measurement data you need.

Regards

[kolee]

Thanks Francesco. I download the ME firmware to EVB-LIV4F. The RTCM monitoring reports MSM7 message (msg id 1077, 1097). How do I access those messages to retrieve raw measurement.

Also, with the ME firmware, I don't receive GxGST message. How do I activate GST message in ME firmware?

Thanks.

[patrikpordi]

@kolee 

Where did you find the ME firmware? The link that was provided above does not point me to that.

Thanks!

[kolee]

Teseo-LIV4FSW - Firmware for Teseo-LIV4F tiny dual-bands GNSS module - STMicroelectronics

[Tesla DeLorean]

Thanks, I fixed the link in the earlier post to reflect where the firmware is really situated

[kolee]

Hi,

I would appreciate if someone can give me insight. As I said in my earlier post, I load the ME firmware to EVB-LIV4F. However, I don't know how to retrieve raw measurement. I got some special characters.

==============================

$BDGSV,2,1,08,44,,,40,22,,,34,12,,,28,21,,,,1*77
▒
e▒W▒▒
▒h-▒9▒▒▒]M▒Pݡ
Jie▒▒|▒▒'▒▒▒N&Y:▒▒_▒o&▒▒PCR▒a▒▒R▒▒ z:RH▒▒▒▒N!▒▒▒▒▒Q]▒▒r▒▒x7R?(g▒▒▒▒ɱ>▒▒yǷn@▒▒D▒▒a▒▒R▒E▒E2▒a▒▒R▒▒
tt▒▒▒▒|$▒▒▒▒r▒;`▒c▒▒
▒▒8K▒▒P
▒▒▒^e7

$GNRMC,180334.507,V,,,,,,,010824,,,N,V*29

==============================

Please help.

Thanks.

[patrikpordi]

Below you can find a basic python script to see the data, once you have the messages based on the definitions 
you can write your own decoder or use a software that can use RTCM directly. I am trying to make it work with RTKLIB navi, I am able to retrieve the messages. did not make the RTK corrections work yet
```

import serial

# Function to read data from a serial port
def read_serial_data(port, baudrate):
try:
with serial.Serial(port, baudrate, timeout=1) as ser:
while True:
data = ser.readline().decode('ascii', errors='ignore').strip()
if data:
print(data)
except serial.SerialException as e:
print(f"Error: {e}")
except KeyboardInterrupt:
print("Exiting...")

# Usage
if __name__ == "__main__":
port = "/dev/ttyACM1" # Replace with your serial port
baudrate = 9600 # Set the baud rate to match your device
read_serial_data(port, baudrate)

```

[Tesla DeLorean]

Can you record this to a file, ie binary bytes / uint8_t, rather than cut-n-paste from a terminal console?

https://github.com/cturvey/RandomNinjaChef/blob/main/RTCM3Test.c

https://github.com/cturvey/RandomNinjaChef/blob/main/RTCM3Wrapper.c