slv.measurements.mobile.gps

GPS records for the mobile platforms and the observation/GPS merge.

Two GPS sources exist for the TRAX trains:

• lin-group (air-trend) GPS, 1 s, Dec 2014 on, in the UATAQ pipeline (qaqc/final levels; final is what observations are merged with). Speed and RMC status come from GPRMC, which was not logged Dec 2015 – 19 Jan 2018. Records only while the Pi has train power.

• horel-group CR1000 logger, 5 s from 19 Nov 2018 (pilot files before that are 1-min and unusable for classification), with battery voltage and roof T/RH; runs on its own battery so it keeps recording when train power is off.

read_trax_gps() picks by era; merge_with_gps() attaches positions to an observation frame (the pipeline’s final GPS on the Pi clock).

Attributes

GPS_NUMERIC	GPS columns forced to float64 on read.
ALTITUDE_RANGE_MSL	the Great Salt Lake shore is ~1280 m and the highest paved roads in reach (the Uinta passes on the Mirror Lake Highway, ~3290 m; Guardsman Pass ~2980 m) stay under the top.
HOREL_POST_PILOT	Post-pilot start of the horel logger (5-s GPS with speed and RMC status).
LIN_GPS_DROP_FLAGS	bad fix quality, < 4 satellites, invalid RMC status, pi-clock overlap.

Functions

clock_checked_days	Days whose Pi clock can be trusted to max_clock_offset_s.
fill_gps_gaps_with_horel	Georeference the rows the lin GPS could not, using the horel logger's 5-s fixes.
lin_clock_offset_by_day	Median GPS-minus-Pi clock offset (s) per UTC day, from a lin GPS frame.
merge_with_gps	Attach GPS positions to a mobile site's concentration records.
read_horel_cr1000	Horel-group CR1000 logger record (5 s): GPS + battery voltage + roof T/RH.
read_lin_gps	Lin-group (air-trend) GPS at 1 s from the pipeline qaqc level, Dec 2014 on.
read_trax_gps	Best GPS source for classifying, by era: lin-group GPS before HOREL_POST_PILOT, horel logger (with battery/T/RH) after.