uataq.instruments.GPS.read_data#

GPS.read_data(group, lvl=None, time_range=None, num_processes=1, file_pattern=None, estimate_motion=True)[source]#

Read GPS data, with speed in m/s and course in degrees.

Extends Instrument.read_data(). Recorded speed is Speed_m_s (lin’s files hold NMEA knots, converted here; horel’s are already m/s), and course is Course_deg.

horel data is indexed by the CR1000 logger’s clock, which runs ahead of GPS time by a drifting 1-20 s. Where the receiver’s time of day was logged (Instrument_Time, horel’s raw GTIM), the true time of each fix is added as GPS_Time_UTC. lin’s Time_UTC is already GPS time.

Receivers logging only GPGGA sentences record neither, in which case both are estimated from the positions (see uataq.gps.estimate_speed_course()) and the boolean columns Speed_Estimated / Course_Estimated mark every value that came from positions rather than from the receiver. Recorded values are never overwritten.

Parameters:: estimate_motion (bool) – Fill missing speed and course from the positions. Default True. Only reachable through the instrument object – uataq.read_data() does not forward it.
Return type:: DataFrame