NMEA-0183 message: MSS
The NMEA MSS message is supported by Trimble receivers capable of MSK (Beacon) reception.
Signal-to-noise ratio, signal strength, frequency, and bit rate from a MSK (Beacon) receiver
The format of the MSS message is:
$‐‐MSS, x.x,x.x,x.x,x.x,x*hh<CR><LF>
                                                            
An example of the MSS message from a dual‐channel DGNSS receiver is:
$GPMSS,26.4,7.2,283.5,200,2*61
                                                            
MSS message fields
| Field | Meaning | 
|---|---|
| 0 | Message ID $--MSS | 
| 1 | Signal strength (SS), dB re: 1 uV/m | 
| 2 | Signal-to-noise ratio (SNR), dB | 
| 3 | Beacon frequency, 283.5 to 325.0 kHz | 
| 4 | Beacon bit rate (25, 50, 100, 200) bits per second | 
| 5 | Channel number (set equal to "1" or null for single-channel receivers) | 
| 6 | The checksum data, always begins with * |