I am attempting to use a GlobalSat MR-350P-S4 gps receiver with PPS to synchronize the system clocks of various instruments.
I have previously been able to get data off of the gps using both gpsd (viewed data through gpspipe -r and cgps -s) and gpsmon on a Debian operating system. All had been working well for the past week, however, for some reason everything has stopped working today. When running gpspipe -r to see if it is collecting any NMEA packages, I get no results following its typical startuo information:
{"class":"DEVICES","devices":[{"class":"DEVICE","path":"/dev/ttyUSB0","activated":"2023-07-11T16:25:12.592Z","native":0,"bps":9600,"parity":"N","stopbits":1,"cycle":1.00},{"class":"DEVICE","path":"/dev/pps0","driver":"PPS","activated":"2023-07-11T16:25:12.594Z"}]} {"class":"WATCH","enable":true,"json":false,"nmea":true,"raw":0,"scaled":false,"timing":false,"split24":false,"pps":false}`
when running gpsd -N -D3 /dev/ttyUSB0 /dev/pps0 I get the following errors:
gpsd:INFO: KPPS:/dev/ttyUSB0 kernel PPS timeout unknown error gpsd:INFO: KPPS:/dev/pps0 kernel PPS timeout unknown error
gpsd:WARN: PPS:/dev/pps0 unchanged state, ppsmonitor sleeps 10 gpsd:WARN: PPS:/dev/ttyUSB0 unchanged state, ppsmonitor sleeps 10
(where /dev/ttyUSB0 is the serial port that my gps receiver is connected to and /dev/pps0 is the pps device)
I have also tried just running gpsmon /dev/ttyUSB0 and this has shown no data.
I have used systemctl stop gpsd gpsd.socket gpsd.service and manually restarted them, with no change to the output. I have checked all of the wiring several times - including using a DMM to check the output voltage of the power cable (5 V as expected). Dmesg shows that the proper pps and tty devices are being used.
I am really at a loss for what to do. I am unfortunately pretty new to both Linux and gpsd so this may have a simple solution, but I have been unable to figure it out. Any advice would be appreciated. Thank you!