def read_orbits(file_object, num_of_orbits):
"""Return list of orbits read from the file.
Parameters
----------
file_object : iterable
file-like object
num_of_orbits : int
Returns
-------
orbits : list
Raises
------
RinexNavFileError
on unexpected end of the file.
"""
orbits = [None] * num_of_orbits
for i in range(num_of_orbits):
try:
line = next(file_object)
except StopIteration:
msg = 'Unexpected end of the file.'
raise RinexNavFileError(msg)
orbits[i] = line.rstrip()
return orbits
def rnx_nav(filename):
"""Возвращает объект RinexNavFile в зависимости от версии в файле.
"""
version, file_type = RinexNavFileV2.retrieve_ver_type(filename)
if version in {2.0, 2.01, 2.1, 2.11}:
return RinexNavFileV2(filename)
elif version in {3.0, 3.01, 3.02, 3.03, 3.04}:
return RinexNavFileV3(filename)
else:
msg = 'Version {} is not supported.'.format(version)
raise RinexNavFileError(msg)
def parse_epoch(file_object):
"""Returns epoch components
Parameters
----------
file_object : file-like object
Returns
-------
epoch_components : tuple
(satellite_system, satellite_number, epoch, sv_clock)
Raises
------
EOFError
on the end of the file.
RinexNavFileError
when it can't parse the epoch record.
"""
try:
line = next(file_object)
except StopIteration:
raise EOFError
system = line[0]
number = line[1:3]
# month, day, hour, min, sec; year + ...
epoch = [line[i:i + 3] for i in range(8, 23, 3)]
epoch = [line[4:9]] + epoch
sv_clock = [line[i:i + 19] for i in (23, 42, 61)]
sv_clock = [i.lower().replace('d', 'e') for i in sv_clock]
try:
number = int(number)
epoch = [int(i) for i in epoch]
epoch = validate_epoch(epoch)
sv_clock = [float(f) for f in sv_clock]
except ValueError:
msg = "Can't read epoch: {}.".format(line)
raise RinexNavFileError(msg)
return system, number, epoch, tuple(sv_clock)
def parse_orbits(self, orbits, values_per_orbit):
"""Return navigation message. Message parsed from the orbits list
according to values_per_orbit.
Parameters
----------
orbits : list
list of 'broadcast orbit' records from coordinates file
values_per_orbit : list
Returns
-------
message : tuple
Raises
------
RinexNavFileError
Can't parse the orbit record.
"""
message = []
# shortcuts
ln = self.item_len
start = self.orbit_start
end = self.orbit_end
for num, orbit in enumerate(orbits):
values = []
for i in range(start, end, ln):
value = orbit[i:i + ln].rstrip().lower().replace('d', 'e')
values.append(value)
try:
values = values[:values_per_orbit[num]]
values = [s and float(s) or 0. for s in values]
except ValueError:
msg = "Can't parse the orbit: {}".format(orbit)
raise RinexNavFileError(msg)
message += values
return tuple(message)
def parse_epoch(file_object):
"""Return satellite number, epoch and sv_clock
Raises
------
EOFError
on the end of the file.
RinexNavFileError
when it can't parse the epoch record.
"""
try:
line = next(file_object)
except StopIteration:
raise EOFError
number = line[0:2]
# year, month, day, hour, min; +sec
epoch = [line[i:i + 3] for i in range(2, 17, 3)]
sec = line[17:22]
sv_clock = [line[i:i + 19] for i in (22, 41, 60)]
sv_clock = [i.lower().replace('d', 'e') for i in sv_clock]
try:
number = int(number)
sec = sec2sec_ms(float(sec))
epoch = [int(i) for i in epoch] + list(sec)
epoch = validate_epoch(epoch)
sv_clock = [float(f) for f in sv_clock]
except ValueError:
msg = "Can't read epoch: {}.".format(line)
raise RinexNavFileError(msg)
return number, epoch, tuple(sv_clock)
def retrieve_ver_type(filename):
"""Returns RINEX version and type
Returns
-------
tuple
(float, str) -- RINEX version and type.
Raises
------
RinexNavFileError
on empty file.
"""
with open(filename) as rinex:
try:
header_line = next(rinex)
except StopIteration:
raise RinexNavFileError('Unexpected end of the file.')
else:
version = float(header_line[:9])
file_type = header_line[20]
return version, file_type
def skip_header(file_object):
"""
Skip the header of the file.
Parameters
----------
file_object : file-like object
Returns
-------
None
Raises
------
RinexNavFileError
on unexpected end of the file.
"""
line = ''
while line[60:73] != 'END OF HEADER':
try:
line = next(file_object)
except StopIteration:
msg = 'Unexpected end of the file.'
raise RinexNavFileError(msg)