Sylphase SDGPS
The software-defined GPS(/GNSS) toolkit

Type signature: (solution->solution)



shift-gnss-time [OPTION]...

Allowed options:

Option Description
--help produce help message
--offset OFFSET add OFFSET to all packets' GNSS times
--start-at START_TIME offset all packets' GNSS times so that the first packet with GNSS time has it equal to START_TIME
--start-now --start-at, but calculate START_TIME to be the value sampled from the system's CLOCK_REALTIME clock, sampled at the instant the packet passes through this node, converted from UTC to GNSS time, and snapped to the nearest multiple of SNAP_PERIOD
--start-now-coordinated-via FILENAME --start-now, but allow for synchronizing multiple shift-gnss-time nodes; synchronization is coordinated via the provided FILENAME, which must initially either not exist or be empty

Startup process:
1. The first shift-gnss-time node to start up will atomically write its START_TIME to FILENAME
2. Additional shift-gnss-time nodes will read their START_TIME from FILENAME
--snap-start-time SNAP_PERIOD (=1) snap START_TIME to the nearest multiple of SNAP_PERIOD (units: seconds); useful for e.g. aligning the second boundaries of stream time to the second boundaries of GNSS time in order to generate a PPS signal aligned to GNSS time
* Note: only used for --start-now and --start-now-coordinated-via
--display-offset-relative-to-real-time display offset of output packet's GNSS time relative to CLOCK_REALTIME (converted from UTC to GNSS time) in console status line (also enables output of "Offset (seconds)/shift-gnss-time packet.time-CLOCK_REALTIME" statlog variable)