constants module
Constants for GPS navigation and coordinate transforms.
Based on the UIUC ECE 456 implementation [1].
References
- constants.A = 6378137.0
Semi-major axis (radius) of the Earth [m].
- Type:
float
- constants.B = 6356752.3145
Semi-minor axis (radius) of the Earth [m].
- Type:
float
- constants.C = 299792458.0
Speed of light [m/s].
- Type:
float
- constants.CODE_TYPE_ANDROID = {'beidou': {'I': 'b1', 'X': 'l5'}, 'galileo': {'C': 'e1', 'Q': 'e5a', 'X': 'e5a'}, 'glonass': {'C': 'l1'}, 'gps': {'C': 'l1', 'Q': 'l5', 'X': 'l5'}, 'qzss': {'C': 'l1', 'X': 'l5'}}
GNSS code type identifier from GnssMeasurement specification [4].
- Type:
dict
- constants.CONSTELLATION_ANDROID = {0: 'unknown', 1: 'gps', 2: 'sbas', 3: 'glonass', 4: 'qzss', 5: 'beidou', 6: 'galileo', 7: 'irnss'}
Satellite System identifier from GNSSStatus specification [3].
- Type:
dict
- constants.CONSTELLATION_CHARS = {'C': 'beidou', 'E': 'galileo', 'G': 'gps', 'I': 'irnss', 'J': 'qzss', 'R': 'glonass', 'S': 'sbas'}
Satellite System identifier from Rinex specification p13 in [2].
- Type:
dict
- constants.E = 0.08181919035595996
Eccentricity of the shape (not orbit) of the Earth.
- Type:
float
- constants.E1SQ = 0.00669437999014
First esscentricity squared of Earth (not orbit).
- Type:
float
- constants.E2SQ = 0.00673949674228
Second eccentricity squared of Earth (not orbit).
- Type:
float
- constants.F = -4.442807633e-10
Relativistic correction term [s/m^(1/2)].
- Type:
float
- constants.F1 = 1575420000.0
GPS L1 frequency [Hz].
- Type:
float
- constants.F2 = 1227600000.0
GPS L2 frequency [Hz].
- Type:
float
- constants.GPS_EPOCH_0 = datetime.datetime(1980, 1, 6, 0, 0, tzinfo=datetime.timezone.utc)
Starting time for GPS epoch
- Type:
datetime.datetime
- constants.GRAV = -9.80665
Acceleration due to gravity ENU frame of reference [m/s].
- Type:
float
- constants.LAT_ACC_THRESH = 1.57e-06
10 meter latitude accuracy.
- Type:
float
- constants.MU_EARTH = 398600500000000.0
\(G*M_E\), the “gravitational constant” for orbital motion about the Earth [m^3/s^2].
- Type:
float
- constants.OMEGA_E_DOT = 7.2921151467e-05
The sidereal rotation rate of the Earth (WGS-84) [rad/s].
- Type:
float
- constants.QZSS_PRN_SVN = {193: 1, 194: 2, 195: 4, 196: 5, 199: 3}
Translation from PRN to SVN for the QZSS constellation [5].
- Type:
dict
- constants.TROPO_DELAY_C1 = 2.47
First coefficient of simplified tropospheric delay model developed in [1].
- Type:
float
- constants.TROPO_DELAY_C2 = 0.0121
Second coefficient of simplified tropospheric delay model developed in [1].
- Type:
float
- constants.TROPO_DELAY_C3 = 0.000133
Third coefficient of simplified tropospheric delay model developed in [1].
- Type:
float
- constants.T_TRANS = 0.07
Average time taken for signal transmission from GPS sats to receivers.
- Type:
float
- constants.WEEKSEC = 604800
Number of seconds in a week [s].
- Type:
int