This is a collection of all the metrics collected by **gpsdMeasurement.py** script. # Table of contents * [gps_fix](#gps_fix) * [mode](#mode) * [lat](#lat) * [lon](#lon) * [alt](#alt) * [alt_msl](#alt_msl) * [alt_hae](#alt_hae) * [speed](#speed) * [climb](#climb) * [track](#track) * [magtrack](#magtrack) * [magvar](#magvar) * [ept](#ept) * [epx](#epx) * [epy](#epy) * [epv](#epv) * [eph](#eph) * [sep](#sep) * [ecefpAcc](#ecefpacc) * [ecefvAcc](#ecefvacc) * [leapseconds](#leapseconds) * [fix_valid](#fix_valid) * [fix_3d](#fix_3d) * [gps_sky](#gps_sky) * [nSat](#nsat) * [uSat](#usat) * [sat_used_ratio](#sat_used_ratio) * [gdop](#gdop) * [hdop](#hdop) * [pdop](#pdop) * [tdop](#tdop) * [vdop](#vdop) * [xdop](#xdop) * [ydop](#ydop) * [gps_visible](#gps_visible) * [gps_used](#gps_used) * [sbas_visible](#sbas_visible) * [sbas_used](#sbas_used) * [galileo_visible](#galileo_visible) * [galileo_used](#galileo_used) * [beidou_visible](#beidou_visible) * [beidou_used](#beidou_used) * [qzss_visible](#qzss_visible) * [qzss_used](#qzss_used) * [glonass_visible](#glonass_visible) * [glonass_used](#glonass_used) * [unknown_visible](#unknown_visible) * [unknown_used](#unknown_used) * [avg_signal_visible](#avg_signal_visible) * [avg_signal_used](#avg_signal_used) * [max_signal](#max_signal) * [gps_pps](#gps_pps) * [offset_ns](#offset_ns) * [precision_exp](#precision_exp) * [present](#present) ## gps_fix This measurement is the current navigation solution from the latest TPV message. Basically: where am I, what kind of fix do I have, and how confident is the receiver? ### mode Fix type. Usually: 1 = no fix 2 = 2D fix 3 = 3D fix ### lat Latitude in decimal degrees. ### lon Longitude in decimal degrees. ### alt Altitude in meters.This is effectively the same as mean sea level altitude. ### alt_msl Altitude above mean sea level, in meters. ### alt_hae Altitude above the ellipsoid, in meters. ### speed Current ground speed, in meters per second. ### climb Vertical speed, in meters per second. Positive means climbing, negative means descending. ### track Course over ground in degrees. ### magtrack Magnetic course over ground in degrees. ### magvar Magnetic variation in degrees. ### ept Estimated timestamp error, in seconds. This is gpsd estimate of uncertainty for the reported time. ### epx Estimated longitude-related horizontal uncertainty, in meters. ### epy Estimated latitude-related horizontal uncertainty, in meters. ### epv Estimated vertical uncertainty, in meters. ### eph Estimated horizontal position uncertainty, in meters. ### sep Estimated spherical error or 3D position uncertainty, in meters. ### ecefpAcc Estimated ECEF position accuracy, in meters. ### ecefvAcc Estimated ECEF velocity accuracy, in meters per second. ### leapseconds Current leap-second offset between GPS time and UTC. ### fix_valid Boolean derived by the script. true if mode >= 2. ### fix_3d Boolean derived by the script. true if mode == 3. ## gps_sky This measurement comes from the latest SKY message. It says: how good is the sky view, how many satellites are visible and used, and how good is the geometry? ### nSat Number of satellites visible or reported. ### uSat Number of satellites currently used in the navigation solution. ### sat_used_ratio Derived value: uSat / nSat. Shows how many visible satellites are actually being used. ### gdop Geometric dilution of precision. Overall combined geometry quality. Lower is better. ### hdop Horizontal dilution of precision. Lower is better. ### pdop Position dilution of precision. Lower is better. ### tdop Time dilution of precision. Lower is better. ### vdop Vertical dilution of precision. Lower is better. ### xdop Dilution of precision in the X direction. Lower is better. ### ydop Dilution of precision in the Y direction. Lower is better. ### gps_visible How many GPS satellites were listed. ### gps_used How many GPS satellites were actually used in the fix. ### sbas_visible How many SBAS satellites were listed. ### sbas_used How many SBAS satellites were used in the fix. ### galileo_visible How many Galileo satellites were listed. ### galileo_used How many Galileo satellites were used in the fix. ### beidou_visible How many BeiDou satellites were listed. ### beidou_used How many BeiDou satellites were used in the fix. ### qzss_visible How many QZSS satellites were listed. ### qzss_used How many QZSS satellites were used in the fix. ### glonass_visible How many GLONASS satellites were listed. ### glonass_used How many GLONASS satellites were used in the fix. ### unknown_visible How many satellites had an unknown gnssid. ### unknown_used How many unknown-constellation satellites were used. ### avg_signal_visible Average signal strength across all visible satellites, based on ss. ### avg_signal_used Average signal strength across satellites actually used in the fix. ### max_signal Maximum ss value seen among visible satellites. ## gps_pps This measurement comes from the latest PPS message. What is says: is PPS present, and what is the current timing offset between the PPS event and the host clock timestamp? ### offset_ns Derived value in nanoseconds. Calculated by the script as: (clock_sec * 1e9 + clock_nsec) - (real_sec * 1e9 + real_nsec) The difference between the kernel or host timestamp and the PPS event timestamp. A negative value means the host timestamp is slightly earlier than the PPS reference. A positive value means it is slightly later. ### precision_exp Precision exponent reported by gpsd for the PPS source. ### present Boolean derived by the script. Always true when a PPS message was received and exported.