gps time synchronization with pps?

asked 2017-03-21 16:56:07 -0500

lucasw gravatar image

updated 2017-03-21 17:00:43 -0500

I'd like to receive a GPS time message and be able to convert any ros time stamp into GPS time for consumption by other systems that have GPS receivers but aren't synchronized to my ros system clock.

It sounds like I would also want to make use of a gps receiver that sends a pulse when it sends the message with the timestamp, so that latency with receiving the serial message can be eliminated, and the timestamp could be made good to within a few milliseconds.

Is there software available for this, and perhaps recommended hardware for receiving the sync pulse? I can imagine having a microcontroller that receives the sync and the gps message while doing something ntp like to figure out what the ros time conversion is for the host computer (or eliminate the mcu and connect the pulse to audio input and low latency audio drivers?), but naturally would prefer to use something available rather than make this from scratch.

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Comments

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If you have a serial port and a GPS with PPS and RS-232 outputs, you can use gpsd and chrony to synchronize your system clock to GPS time.

ahendrix gravatar imageahendrix ( 2017-03-21 18:08:12 -0500 )edit

It looks like there is a USB solution (I'd like it to work with a modern laptop) with more latency but still good enough for me, the pps is routed to a usb signal that gets polled 1024Hz, the problem then is actually locating one of these for purchase, that answer probably lies in another forum..

lucasw gravatar imagelucasw ( 2017-03-21 18:13:14 -0500 )edit