Not sure if this may help you at all. Firstly, I'm a novice at GPS time and chrony. I've messed around a bit with it recently and appear to have some success.
I'm using a cheap no-name (u-blox?) GPS receiver to which I've added a connection for the PPS signal.
I'm running a Pi Zero 2W with 64-bit bookworm, fully updated.
I probably need more configuration. cgps -s shows a 3D FIX, not a 3D DGPS FIX.
I don't think my GPS source is being used, but the PPS seems good, so I'll concentrate on what I did for that.Notes:
I didn't need to change the permissions on /dev/pps0In config.txt I haveThe pps-gpio module doesn't show in dmesg, but it is loadedI haven't done anything with AppArmor.
As I said, I don't know if that helps at all. I'm just dabbling with this stuff and have been struggling to find a guide that just works.
I'm using a cheap no-name (u-blox?) GPS receiver to which I've added a connection for the PPS signal.
I'm running a Pi Zero 2W with 64-bit bookworm, fully updated.
I probably need more configuration. cgps -s shows a 3D FIX, not a 3D DGPS FIX.
I don't think my GPS source is being used, but the PPS seems good, so I'll concentrate on what I did for that.
Code:
MS Name/IP address Stratum Poll Reach LastRx Last sample ===============================================================================#x NMEA 0 0 377 0 +243ms[ +243ms] +/- 1000us#* PPS 0 3 377 4 +327ns[ +342ns] +/- 269nsI didn't need to change the permissions on /dev/pps0
Code:
rpdom@cam2:~ $ ls -l /dev/pps0 crw-rw---- 1 root root 250, 0 Jun 10 11:40 /dev/pps0Code:
# For GPSDdtoverlay=pps-gpio,gpiopin=17enable_uart=1init_uart_baud=9600Code:
rpdom@cam2:~ $ dmesg | grep gpio[ 1.263161] pinctrl-bcm2835 3f200000.gpio: GPIO_OUT persistence: yes[ 7.274736] rpi-gpiomem 3f200000.gpiomem: window base 0x3f200000 size 0x00001000[ 7.275325] rpi-gpiomem 3f200000.gpiomem: initialised 1 regions as /dev/gpiomemrpdom@cam2:~ $ lsmod | grep ppspps_gpio 12288 0As I said, I don't know if that helps at all. I'm just dabbling with this stuff and have been struggling to find a guide that just works.
Statistics: Posted by rpdom — Fri Jun 20, 2025 10:49 am