You can not select more than 25 topics
Topics must start with a letter or number, can include dashes ('-') and can be up to 35 characters long.
84 lines
2.7 KiB
84 lines
2.7 KiB
from datetime import datetime
|
|
from .constants import SECS_IN_HR, SECS_IN_WEEK, \
|
|
SPEED_OF_LIGHT, GPS_L1, GPS_L2
|
|
from .gps_time import GPSTime
|
|
from .helpers import get_constellation
|
|
import warnings
|
|
|
|
|
|
class DCB:
|
|
def __init__(self, prn, data):
|
|
self.max_time_diff = 2*SECS_IN_WEEK
|
|
self.prn = prn
|
|
self.epoch = data['epoch']
|
|
self.healthy = True
|
|
if 'C1W_C2W' in data:
|
|
self.C1W_C2W = data['C1W_C2W']
|
|
elif 'C1P_C2P' in data:
|
|
self.C1W_C2W = data['C1P_C2P']
|
|
else:
|
|
self.healthy = False
|
|
if 'C1C_C1W' in data:
|
|
self.C1C_C1W = data['C1C_C1W']
|
|
elif 'C1C_C1P' in data:
|
|
self.C1C_C1W = data['C1C_C1P']
|
|
else:
|
|
self.healthy = False
|
|
|
|
def valid(self, time):
|
|
return abs(time - self.epoch) <= self.max_time_diff and self.healthy
|
|
|
|
def get_delay(self, signal):
|
|
if signal == 'C1C':
|
|
return (- SPEED_OF_LIGHT*1e-9*self.C1W_C2W*GPS_L2**2/(GPS_L1**2 - GPS_L2**2)
|
|
+ SPEED_OF_LIGHT*1e-9*self.C1C_C1W)
|
|
if signal == 'C2P':
|
|
return (- SPEED_OF_LIGHT*1e-9*self.C1W_C2W*GPS_L1**2/(GPS_L1**2 - GPS_L2**2))
|
|
if signal == 'C1P':
|
|
return (SPEED_OF_LIGHT*1e-9*self.C1C_C1W)
|
|
## Todo: update dcb database and get delay to include additional signals
|
|
if signal == 'C2C':
|
|
warnings.warn("Differential code bias not implemented for signal C2C", UserWarning)
|
|
return 0
|
|
if signal == 'C5C':
|
|
warnings.warn("Differential code bias not implemented for signal C5C", UserWarning)
|
|
return 0
|
|
if signal == 'C6C':
|
|
warnings.warn("Differential code bias not implemented for signal C6C", UserWarning)
|
|
return 0
|
|
if signal == 'C7C':
|
|
warnings.warn("Differential code bias not implemented for signal C7C", UserWarning)
|
|
return 0
|
|
if signal == 'C8C':
|
|
warnings.warn("Differential code bias not implemented for signal C8C", UserWarning)
|
|
return 0
|
|
|
|
|
|
def parse_dcbs(file_name, SUPPORTED_CONSTELLATIONS):
|
|
with open(file_name, 'r+') as DCB_file:
|
|
contents = DCB_file.readlines()
|
|
data_started = False
|
|
dcbs_dict = {}
|
|
for line in contents:
|
|
if not data_started:
|
|
if line[1:4] == 'DSB':
|
|
data_started = True
|
|
else:
|
|
continue
|
|
line_components = line.split()
|
|
if len(line_components[2]) < 3:
|
|
break
|
|
prn = line_components[2]
|
|
if get_constellation(prn) not in SUPPORTED_CONSTELLATIONS:
|
|
continue
|
|
dcb_type = line_components[3] + '_' + line_components[4]
|
|
epoch = GPSTime.from_datetime(datetime.strptime(line_components[5], '%Y:%j:%f')) + 12*SECS_IN_HR
|
|
if prn not in dcbs_dict:
|
|
dcbs_dict[prn] = {}
|
|
dcbs_dict[prn][dcb_type] = float(line_components[8])
|
|
dcbs_dict[prn]['epoch'] = epoch
|
|
|
|
dcbs = []
|
|
for prn in dcbs_dict:
|
|
dcbs.append(DCB(prn, dcbs_dict[prn]))
|
|
return dcbs
|
|
|