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rinex.py
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rinex.py
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"""
module for RINEX 3.0x processing
Copyright (c) 2021 Rui Hirokawa (from CSSRLIB)
Copyright (c) 2022 Tim Everett
"""
import numpy as np
from copy import deepcopy
from rtkcmn import uGNSS, rSIG, Eph, Geph, prn2sat, gpst2time, time2gpst, Obs, \
epoch2time, timediff, timeadd, utc2gpst
import rtkcmn as gn
from ephemeris import satposs
class rnx_decode:
""" class for RINEX decoder """
MAXSAT = uGNSS.GPSMAX+uGNSS.GLOMAX+uGNSS.GALMAX+uGNSS.BDSMAX+uGNSS.QZSMAX
def __init__(self, cfg):
self.ver = -1.0
self.fobs = None
self.gnss_tbl = {'G': uGNSS.GPS, 'E': uGNSS.GAL, 'R': uGNSS.GLO, 'J': uGNSS.QZS}
self.sig_tbl = cfg.sig_tbl
self.skip_sig_tbl = cfg.skip_sig_tbl
self.nf = 4
self.sigid = np.ones((uGNSS.GNSSMAX, rSIG.SIGMAX*3), dtype=int) * rSIG.NONE
self.typeid = np.ones((uGNSS.GNSSMAX, rSIG.SIGMAX*3), dtype=int) * rSIG.NONE
self.nsig = np.zeros((uGNSS.GNSSMAX), dtype=int)
self.nband = np.zeros((uGNSS.GNSSMAX), dtype=int)
self.pos = np.array([0, 0, 0])
def flt(self, u, c=-1):
if c >= 0:
u = u[19*c+4:19*(c+1)+4]
try:
return float(u.replace("D", "E"))
except:
return 0
def adjday(self, t, t0):
"""" adjust time considering week handover """
tt = timediff(t, t0)
if tt < -43200.0:
return timeadd(t, 86400.0)
if tt > 43200.0:
return timeadd(t,-86400.0)
return t
def decode_nav(self, navfile, nav):
"""decode RINEX Navigation message from file """
nav.eph = []
nav.geph = []
with open(navfile, 'rt') as fnav:
for line in fnav:
if line[60:73] == 'END OF HEADER':
break
elif line[60:80] == 'RINEX VERSION / TYPE':
self.ver = float(line[4:10])
if self.ver < 3.02:
return -1
elif line[60:76] == 'IONOSPHERIC CORR':
if line[0:4] == 'GPSA' or line[0:4] == 'QZSA':
for k in range(4):
nav.ion[0, k] = self.flt(line[5+k*12:5+(k+1)*12])
if line[0:4] == 'GPSB' or line[0:4] == 'QZSB':
for k in range(4):
nav.ion[1, k] = self.flt(line[5+k*12:5+(k+1)*12])
for line in fnav:
if line[0] not in self.gnss_tbl:
continue
sys = self.gnss_tbl[line[0]]
prn = int(line[1:3])
if sys == uGNSS.QZS:
prn += 192
sat = prn2sat(sys, prn)
year = int(line[4:8])
month = int(line[9:11])
day = int(line[12:14])
hour = int(line[15:17])
minute = int(line[18:20])
sec = int(line[21:23])
toc = epoch2time([year, month, day, hour, minute, sec])
if sys != uGNSS.GLO:
eph = Eph(sat)
eph.toc = toc
eph.f0 = self.flt(line, 1)
eph.f1 = self.flt(line, 2)
eph.f2 = self.flt(line, 3)
line = fnav.readline() #3:6
eph.iode = int(self.flt(line, 0))
eph.crs = self.flt(line, 1)
eph.deln = self.flt(line, 2)
eph.M0 = self.flt(line, 3)
line = fnav.readline() #7:10
eph.cuc = self.flt(line, 0)
eph.e = self.flt(line, 1)
eph.cus = self.flt(line, 2)
sqrtA = self.flt(line, 3)
eph.A = sqrtA**2
line = fnav.readline() #11:14
eph.toes = int(self.flt(line, 0))
eph.cic = self.flt(line, 1)
eph.OMG0 = self.flt(line, 2)
eph.cis = self.flt(line, 3)
line = fnav.readline() #15:18
eph.i0 = self.flt(line, 0)
eph.crc = self.flt(line, 1)
eph.omg = self.flt(line, 2)
eph.OMGd = self.flt(line, 3)
line = fnav.readline() #19:22
eph.idot = self.flt(line, 0)
eph.code = int(self.flt(line, 1)) # source for GAL NAV type
eph.week = int(self.flt(line, 2))
line = fnav.readline() #23:26
eph.sva = self.flt(line, 0)
eph.svh = int(self.flt(line, 1))
tgd = np.zeros(2)
tgd[0] = float(self.flt(line, 2))
if sys == uGNSS.GAL:
tgd[1] = float(self.flt(line, 3))
else:
eph.iodc = int(self.flt(line, 3))
eph.tgd = tgd
line = fnav.readline() #27:30
tot = int(self.flt(line, 0))
if len(line) >= 42:
eph.fit = int(self.flt(line, 1))
eph.toe = gpst2time(eph.week, eph.toes)
eph.tot = gpst2time(eph.week, tot)
nav.eph.append(eph)
else: # GLONASS
if prn > uGNSS.GLOMAX:
print('Reject nav entry: %s' % line[:3])
break
geph = Geph(sat)
# Toc rounded by 15 min in utc
week, tow = time2gpst(toc)
toc = gpst2time(week,np.floor((tow + 450.0) / 900.0) * 900)
dow = int(np.floor(tow / 86400.0))
# time of frame in UTC
tod = self.flt(line, 2) % 86400
tof = gpst2time(week ,tod + dow * 86400.0)
tof = self.adjday(tof, toc)
geph.toe = utc2gpst(toc)
geph.tof = utc2gpst(tof)
# IODE = Tb (7bit), Tb =index of UTC+3H within current day
geph.iode = int(((tow + 10800.0) % 86400) / 900.0 + 0.5)
geph.taun = -self.flt(line, 1)
geph.gamn = self.flt(line, 2)
line = fnav.readline() #3:6
pos =np.zeros(3)
vel = np.zeros(3)
acc = np.zeros(3)
pos[0] = self.flt(line, 0)
vel[0] = self.flt(line, 1)
acc[0] = self.flt(line, 2)
geph.svh = self.flt(line, 3)
line = fnav.readline() #7:10
pos[1] = self.flt(line, 0)
vel[1] = self.flt(line, 1)
acc[1] = self.flt(line, 2)
geph.frq = self.flt(line, 3)
nav.glofrq[sat - uGNSS.GPSMAX - 1] = int(geph.frq)
line = fnav.readline() #11:14
pos[2] = self.flt(line, 0)
vel[2] = self.flt(line, 1)
acc[2] = self.flt(line, 2)
geph.age = self.flt(line, 2)
geph.pos = pos * 1000
geph.vel = vel * 1000
geph.acc = acc * 1000
nav.geph.append(geph)
#nav.eph.sort(key=lambda x: (x.sat, x.toe.time))
nav.eph.sort(key=lambda x: x.toe.time)
nav.geph.sort(key=lambda x: x.toe.time)
return nav
def decode_obsh(self, obsfile):
self.fobs = open(obsfile, 'rt')
for line in self.fobs:
if line[60:73] == 'END OF HEADER':
break
if line[60:80] == 'RINEX VERSION / TYPE':
self.ver = float(line[4:10])
if self.ver < 3.02:
return -1
elif line[60:79] == 'APPROX POSITION XYZ':
self.pos = np.array([float(line[0:14]),
float(line[14:28]),
float(line[28:42])])
elif line[60:79] == 'SYS / # / OBS TYPES':
if line[0] in self.gnss_tbl:
sys = self.gnss_tbl[line[0]]
else:
continue
self.nsig[sys] = int(line[3:6])
s = line[7:7+4*13]
if self.nsig[sys] >= 14:
line2 = self.fobs.readline()
s += line2[7:7+4*13]
for k in range(self.nsig[sys]):
sig = s[4*k:3+4*k]
if sig[1:3] not in self.sig_tbl:
continue
if self.sig_tbl[sig[1:3]] in self.skip_sig_tbl[sys]:
continue
if sig[0] == 'C':
self.typeid[sys][k] = 0
elif sig[0] == 'L':
self.typeid[sys][k] = 1
elif sig[0] == 'S':
self.typeid[sys][k] = 2
elif sig[0] == 'D':
self.typeid[sys][k] = 3
else:
continue
self.sigid[sys][k] = self.sig_tbl[sig[1:3]]
self.nband[sys] = len(np.where(self.typeid[sys]==1)[0])
return 0
def decode_obs(self, nav, maxepoch):
"""decode RINEX Observation message from file """
self.obslist = []
nepoch = 0
for line in self.fobs:
if line == '':
break
if line[0] != '>':
continue
obs = Obs()
nsat = int(line[32:35])
year = int(line[2:6])
month = int(line[7:9])
day = int(line[10:12])
hour = int(line[13:15])
minute = int(line[16:18])
sec = float(line[19:29])
obs.t = epoch2time([year, month, day, hour, minute, sec])
obs.P = np.zeros((nsat, gn.MAX_NFREQ))
obs.L = np.zeros((nsat, gn.MAX_NFREQ))
obs.D = np.zeros((nsat, gn.MAX_NFREQ))
obs.S = np.zeros((nsat, gn.MAX_NFREQ))
obs.lli = np.zeros((nsat, gn.MAX_NFREQ), dtype=int)
obs.Pstd = np.zeros((nsat, gn.MAX_NFREQ), dtype=int)
obs.Lstd = np.zeros((nsat, gn.MAX_NFREQ), dtype=int)
obs.mag = np.zeros((nsat, gn.MAX_NFREQ))
obs.sat = np.zeros(nsat, dtype=int)
n = 0
for k in range(nsat):
line = self.fobs.readline()
if line[0] not in self.gnss_tbl:
continue
sys = self.gnss_tbl[line[0]]
if sys not in nav.gnss_t:
continue
prn = int(line[1:3])
if sys == uGNSS.QZS:
prn += 192
obs.sat[n] = prn2sat(sys, prn)
if obs.sat[n] == 0:
continue
nsig_max = (len(line) - 4 + 2) // 16
for i in range(self.nsig[sys]):
if i >= nsig_max:
break
obs_ = line[16*i+4:16*i+17].strip()
if obs_ == '' or self.sigid[sys][i] == 0:
continue
try:
obsval = float(obs_)
except:
obsval = 0
f = i // (self.nsig[sys] // self.nband[sys])
if f >= gn.MAX_NFREQ:
print('Obs file too complex, please use RTKCONV to remove unused signals')
raise SystemExit
if self.typeid[sys][i] == 0: # code
obs.P[n, f] = obsval
Pstd = line[16*i+18]
obs.Pstd[n, f] = int(Pstd) if Pstd != " " else 0
elif self.typeid[sys][i] == 1: # carrier
obs.L[n, f] = float(obs_)
lli = line[16*i+17]
obs.lli[n, f] = int(lli) if lli != " " else 0
Lstd = line[16*i+18]
obs.Lstd[n, f] = int(Lstd) if Lstd != " " else 0
elif self.typeid[sys][i] == 2: # C/No
obs.S[n, f] = obsval
elif self.typeid[sys][i] == 3: # Doppler
obs.D[n, f] = obsval
n += 1
obs.P = obs.P[:n, :]
obs.L = obs.L[:n, :]
obs.Pstd = obs.Pstd[:n, :]
obs.Lstd = obs.Lstd[:n, :]
obs.D = obs.D[:n, :]
obs.S = obs.S[:n, :]
obs.lli = obs.lli[:n, :]
obs.mag = obs.mag[:n, :]
obs.sat = obs.sat[:n]
self.obslist.append(obs)
nepoch += 1
if maxepoch != None and nepoch >= maxepoch:
break
self.index = 0
self.fobs.close()
def decode_obsfile(self, nav, obsfile, maxepoch):
self.decode_obsh(obsfile)
self.decode_obs(nav, maxepoch)
def first_obs(nav, rov, base, dir):
if dir == 1: # forward solution
rov.index = base.index = 0
else: # backward solution
rov.index = len(rov.obslist) - 1
base.index = len(base.obslist) - 1
# sync base and rover, step one obs to sync
_, _ =next_obs(nav, rov, base, dir)
# step back to first obs
obsr, obsb = next_obs(nav, rov, base, -dir)
return obsr, obsb
def next_obs(nav, rov, base, dir):
""" sync observations between rover and base """
rov.index += dir # 1=forward, -1=backward
if abs(dir) != 1 or rov.index < 0 or rov.index >= len(rov.obslist):
return [], []
obsr, obsb = rov.obslist[rov.index], base.obslist[base.index]
dt = timediff(obsr.t, obsb.t)
baseChange = False
ixb = base.index + dir
while True:
if ixb < 0 or ixb >= len(base.obslist):
ixb -= dir
dt_next = dt
break # hit end of obs list
dt_next = timediff(obsr.t, base.obslist[ixb].t)
if abs(dt_next) >= abs(dt):
break # next base obs is not closer
else:
base.index = ixb
ixb += dir
baseChange = True
dt = dt_next
if baseChange and nav.interp_base and len(nav.sol) > 0:
# save base residuals for next epoch
nav.obsb = deepcopy(obsb)
nav.rsb, nav.varb, nav.dtsb, nav.svhb = satposs(obsb, nav)
obsb = base.obslist[base.index]
return obsr, obsb
def rcvstds(nav, obs):
""" decode receiver stdevs from rinex fields """
# skip if weighting factor is zero
if nav.err[5] == 0:
return
for i in np.argsort(obs.sat):
for f in range(nav.nf):
s = obs.sat[i] - 1
# decode receiver stdevs,
# Lstd: 0.004 cycles -> m
nav.rcvstd[s,f] = obs.Lstd[i,f] * 0.004 * 0.2
# Pstd: 0.01*2^(n+5)
nav.rcvstd[s,f+nav.nf] = 0.01 * (1 << (obs.Pstd[i,f] + 5))