gnsstoolbox 1.2.12

Python GNSS processing package

GnssToolbox - Python package for GNSS learning

Installation

This package requires Python 3

Required packages :

• gpsdatetime - https://pypi.org/project/gpsdatetime/ (J. Beilin - ENSG)
• re
• math
• numpy
• copy
• time
• os
• json
• from operator import attrgetter

Installation is accomplished from the command line.

• From pypi

user@desktop$pip3 install pygnsstoolbox

• From package source directory

user@desktop$~/gnsstoolbox$ python3 setup.py install

For usage see gnsstoolbox cheatsheet and beamer slides shipped with the package.

Import modules

""" Ephemerides management """
import gnsstoolbox.orbits as orb

""" GNSS data (rinex "o" files) """ 
import gnsstoolbox.rinex_o as rx

""" Processing tools (rotations, coordinate conversions...) """
import gnsstoolbox.gnsstools as tools

""" Code processing """
import gnsstoolbox.gnss_process as proc

""" Constantes utiles """
import gnsstoolbox.gnss_const as const

""" Corrections (troposphere, antennas...) """
import gnsstoolbox.gnss_corr as corr

gnss_const

Constant	Description	Unit
c	celerity	299792458.0 m/s
f1	frequency L1 gps	1.57542 GHz
f2	frequency L2 gps	1.22760 GHz
f5	frequency L5 gps	1.17645 GHz

orbits

Structure

Orbit class contains all orbits informations :

• NAV_dataG : GPS navigation message
• NAV_dataE : Galileo navigation message
• NAV_dataR : Glonass navigation message
• G : GPS precise orbits
• E : Galileo precise orbits
• R : Glonass precise orbits

Data loading

• Broadcast ephemerides loading (*.yyn ou *.yyg)

Orb = orbits.orbit()
Orb.loadRinexN('brdm1500.13p')  

• Precise ephemerides loading (*.sp3)

Orb = orbits.orbit()
Orb.loadSp3(['igs17424.sp3','igl17424.sp3','grm17424.sp3'])

or

Orb.loadSp3('igs17424.sp3') 

Data access

• Get broadcast ephemerides for a satellite at an instant mjd

Eph = Orb.getEphemeris(constellation,PRN,mjd)
try:
	print("TOC : ",Eph.tgps.st_iso_epoch())
except:
	print("Unable to find satellite")	

• Get all precise ephemerides for a satellite

(orb,nl) = Orb.getSp3('G',5) 

# Satellite GPS, PRN 5
# 'G' : GPS, 'E' : Galileo, 'R' : Glonass

X = orb[:,1] # X coordinates at all sp3 epochs
Y = orb[:,2]
Z = orb[:,3]

Satellite coordinates processing

Process of ECEF coordinates and clock error (dte) for a satellite given by its constellation ('G','E','R'), its PRN, an instant mjd and et possibly a degree for Lagrange processing (precise orbits).

X, Y, Z, dte = Orb.calcSatCoord(const,PRN,mjd,degree)

A debug class object is implemented during coordinate processing. It contains all intermediaries results.

In order to get its attributes :

print(Orb.debug.__dict__)

Module Rinex_o

Data loading

Loading observation Rinex file (*.yyo)

Rnx = rx.rinex_o()
Rnx.loadRinexO('smne1500.13o') 

Data access

• Get epoch object for a given MJD :

t=gpst.gpsdatetime()
t.rinex_t('13  5 30  1  0 30.0000000')
Ep = Rnx.getEpochByMjd(t.mjd)

• Get header object for a given MJD :

Hd = Rnx.getHeaderByMjd(t.mjd)

• Get attribute from any header

X0 = Hd.X

• Print all header or epoch informations

print(Hd)
print(Ep)

• Get any observable from an epoch :

C1 = Ep.getObs("C1","G", 31)

or

S = Ep.getSat("G", 31)
C1 = S.getObs("C1")

or (only for C/A code)

C1 = Ep.getSat("G", 31).C1

• Get all common data for 2 datasets at a given MJD

Ep_base,Ep_rover = rinex_base.getCommonEpochs(rinex_rover, 56442)

gnsstools

• toolGeoCartGRS80 : geographic to cartesian coordinates conversion. All angles should be given in radians.

X,Y,Z = tools.toolGeoCartGRS80(lon,lat,h)

• toolCartGeoGRS80 : cartesian to geographic coordinates conversion. All angles are given in radians.

lon,lat,h = tools.toolCartGeoGRS80(X,Y,Z)

• toolCartLocGRS80 : cartesian to topocentric coordinates conversion.

x, y, z = tools.toolCartLocGRS80(X0,Y0,Z0,X,Y,Z)

• toolAzEle : azimut and elevation (radians) for one or several satellites Xs,Ys,Zs (scalar or vector) seen from a point with X,Y,Z coordinates.

Az, Ele = tools.toolAzEle(X,Y,Z,Xs,Ys,Zs)

• toolRotX, toolRotY, toolRotZ : alpha radians rotation around X, Y ou Z axis.

X,Y,Z =  tools.toolRotX(X,Y,Z,alpha)

gnss_process

• TrilatGps : trilateration wtih 4 parameters (X,Y,Z,cdtr)

X,Y,Z,cdtr,sigma0_2,V,Qxx = trilatGps(PosSat,Dobs,X0)

• TrilatGnss : trilateration à 4,5 ou 6 parameters (X,Y,Z,cdtr,[cGGTO,cGPGL])

X,Y,Z,cdtr,cGGTO,cGPGL,sigma0_2,V,Qxx =  trilatGnss(PosSat,Dobs,X0,sat_index)

• TrilatGnssPonderationElev : trilateration à 4,5 ou 6 parameters (X,Y,Z,cdtr,[cGGTO,cGPGL]) avec with weighting given from elevation of each satellite.

X,Y,Z,cdtr,cGGTO,cGPGL,sigma0_2,V,Qxx =  trilatGnssPonderationElev(PosSat,Dobs,X0,sat_index,ElevSat)

Licence

Copyright (C) 2014-2023, Jacques Beilin - ENSG-Geomatics

Distributed under terms of the CECILL-C licence.