kopia lustrzana https://github.com/inmcm/micropyGPS
Intial commit: basic stream parsing with support for RMC, VTG, and GGA sentences.
Calvin
rodzic
e4fe364be2
commit
a5ea08c5a3
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from struct import *
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# TODO:
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# GSA Sentence
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# GSV Sentence
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# Time Since First Fix
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# Time Since Last Good Fix
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# Statistics
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test_RMC = ['$GPRMC,081836,A,3751.65,S,14507.36,E,000.0,360.0,130998,011.3,E*62',
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'$GPRMC,123519,A,4807.038,N,01131.000,E,022.4,084.4,230394,003.1,W*6A',
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'$GPRMC,225446,A,4916.45,N,12311.12,W,000.5,054.7,191194,020.3,E*68',
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'$GPRMC,180041.896,A,3749.1851,N,08338.7891,W,001.9,154.9,240911,,,A*7A',
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'$GPRMC,180049.896,A,3749.1808,N,08338.7869,W,001.8,156.3,240911,,,A*70',
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'$GPRMC,092751.000,A,5321.6802,N,00630.3371,W,0.06,31.66,280511,,,A*45']
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test_VTG = ['$GPVTG,232.9,T,,M,002.3,N,004.3,K,A*01']
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test_GGA = ['$GPGGA,180050.896,3749.1802,N,08338.7865,W,1,07,1.1,397.4,M,-32.5,M,,0000*6C']
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test_GSA = ['$GPGSA,A,3,07,11,28,24,26,08,17,,,,,,2.0,1.1,1.7*37']
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test_GSV = ['$GPGSV,3,1,12,28,72,355,39,01,52,063,33,17,51,272,44,08,46,184,38*74',
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'$GPGSV,3,2,12,24,42,058,33,11,34,053,33,07,20,171,40,20,15,116,*71',
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'$GPGSV,3,3,12,04,12,204,34,27,11,324,35,32,11,089,,26,10,264,40*7B']
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class MicroGPSpy(object):
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"""GPS NMEA Sentence Parser"""
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def __init__(self, local_offset=0):
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"""Setup GPS Object Status Flags, Internal Data Registers, etc"""
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#####################
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# Object Status Flags
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self.sentence_active = False
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self.active_segment = 0
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self.process_crc = False
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self.gps_segments = []
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self.crc_xor = 0
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#####################
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# Data From Sentences
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# Time
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self.timestamp = (0, 0, 0)
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self.date = (0, 0, 0)
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self.local_offset = local_offset
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# Position/Motion
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self.latitude = (0, 0.0, 'N')
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self.longitude = (0, 0.0, 'W')
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self.speed = (0.0, 0.0, 0.0)
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self.course = 0.0
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self.altitude = 0.0
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self.geoid_height = 0.0
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# GPS Info
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self.sats_in_view = 0
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self.sats_in_use = 0
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self.hdop = 0.0
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self.pdop = 0.0
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self.vdop = 0.0
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self.valid = False
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self.fix_stat = 0
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self.fix_type = 1
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# Object Constants
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self.__hemispheres = ('N', 'S', 'E', 'W')
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# Recommended minimum specific GPS/Transit data
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def gprmc(self):
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"""Parse Recommended Minimum Specific GPS/Transit data (RMC)Sentence. Updates UTC timestamp, latitude,
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longitude, Course, Speed, and Date"""
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# UTC Timestamp
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try:
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utc_string = self.gps_segments[1]
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# Skip timestamp if receiver doesn't have one yet
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if utc_string:
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hours = int(utc_string[0:2]) + self.local_offset
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minutes = int(utc_string[2:4])
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seconds = float(utc_string[4:])
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self.timestamp = (hours, minutes, seconds)
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except ValueError:
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return False
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# Check Receiver Data Valid Flag
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if self.gps_segments[2] == 'A': # Data from Receiver is valid
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# Longitude / Latitude
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try:
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# Latitude
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l_string = self.gps_segments[3]
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lat_degs = int(l_string[0:2])
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lat_mins = float(l_string[2:])
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lat_hemi = self.gps_segments[4]
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# Longitude
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l_string = self.gps_segments[5]
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lon_degs = int(l_string[0:3])
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lon_mins = float(l_string[3:])
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lon_hemi = self.gps_segments[6]
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except ValueError:
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return False
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if lat_hemi not in self.__hemispheres:
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return False
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if lon_hemi not in self.__hemispheres:
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return False
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# Speed
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try:
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spd_knt = float(self.gps_segments[7])
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except ValueError:
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return False
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# Date
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try:
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# NOTE!!! Date string is assumed to be year >=2000,
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# Sentences recorded in 90s will display as 209X!!!
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# FIXME if you want to parse old GPS logs or are time traveler
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date_string = self.gps_segments[9]
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day = date_string[0:2]
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month = date_string[2:4]
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year = date_string[4:6]
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except ValueError:
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return False
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# Course
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try:
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course = self.gps_segments[8]
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except ValueError:
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return False
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# TODO - Add Magnetic Variation
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# Update Object Data
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self.latitude = (lat_degs, lat_mins, lat_hemi)
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self.longitude = (lon_degs, lon_mins, lon_hemi)
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# Include mph and hm/h
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self.speed = (spd_knt, spd_knt * 1.151, spd_knt * 1.852)
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self.date = (day, month, year)
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self.course = course
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self.valid = True
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else:
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return False
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return True
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def gpvtg(self):
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"""Parse Track Made Good and Ground Speed (VTG) Sentence. Updates speed and course"""
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try:
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course = self.gps_segments[1]
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spd_knt = float(self.gps_segments[5])
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except ValueError:
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return False
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# Include mph and hm/h
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self.speed = (spd_knt, spd_knt * 1.151, spd_knt * 1.852)
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self.course = course
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return True
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def gpgga(self):
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"""Parse Global Positioning System Fix Data (GGA) Sentence. Updates UTC timestamp, latitude, longitude,
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fix status, satellites in use, Horizontal Dilution of Precision (HDOP), altitude, and geoid height"""
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# UTC Timestamp
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try:
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utc_string = self.gps_segments[1]
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# Skip timestamp if receiver doesn't have on yet
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if utc_string:
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hours = int(utc_string[0:2]) + self.local_offset
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minutes = int(utc_string[2:4])
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seconds = float(utc_string[4:])
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self.timestamp = (hours, minutes, seconds)
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except ValueError:
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return False
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# Number of Satellites in Use
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try:
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self.sats_in_use = int(self.gps_segments[7])
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except ValueError:
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return False
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# Horizontal Dilution of Precision
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try:
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self.hdop = float(self.gps_segments[8])
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except ValueError:
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return False
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# Get Fix Status
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try:
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self.fix_stat = int(self.gps_segments[6])
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except ValueError:
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return False
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# Process Location and Speed Data if Fix is GOOD
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if self.fix_stat:
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# Longitude / Latitude
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try:
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# Latitude
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l_string = self.gps_segments[2]
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lat_degs = int(l_string[0:2])
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lat_mins = float(l_string[2:])
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lat_hemi = self.gps_segments[3]
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# Longitude
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l_string = self.gps_segments[4]
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lon_degs = int(l_string[0:3])
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lon_mins = float(l_string[3:])
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lon_hemi = self.gps_segments[5]
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except ValueError:
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return False
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if lat_hemi not in self.__hemispheres:
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return False
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if lon_hemi not in self.__hemispheres:
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return False
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# Altitude / Height Above Geoid
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try:
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altitude = float(self.gps_segments[9])
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geoid_height = float(self.gps_segments[11])
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except ValueError:
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return False
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# Update Object Data
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self.latitude = (lat_degs, lat_mins, lat_hemi)
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self.longitude = (lon_degs, lon_mins, lon_hemi)
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self.altitude = altitude
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self.geoid_height = geoid_height
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return True
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def gpgsa(self):
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pass
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def gpgsv(self):
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pass
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def new_sentence(self):
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"""Adjust Object Flags in Preparation for a New Sentence"""
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self.gps_segments = ['']
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self.active_segment = 0
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self.crc_xor = 0
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self.sentence_active = True
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self.process_crc = True
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def update(self, new_char):
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"""Process a new input char and updates GPS object if necessary based on special characters ('$', ',', '*')
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Function builds a list of received string that are validate by CRC prior to parsing by the appropriate
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sentence function. Returns sentence type on successful parse, None otherwise"""
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valid_sentence = False
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# Validate new_char is a printable char
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ascii_char = ord(new_char)
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if 33 <= ascii_char <= 126:
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# Check if a new string is starting ($)
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if new_char == '$':
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self.new_sentence()
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return False
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# Check if sentence is ending (*)
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elif new_char == '*':
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self.process_crc = False
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self.active_segment += 1
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self.gps_segments.append('')
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return False
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# Check if a section is ended (,), Create a new substring to feed
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# characters to
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elif new_char == ',':
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self.active_segment += 1
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self.gps_segments.append('')
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# Store All Other printable character and check CRC when ready
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else:
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if self.sentence_active:
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self.gps_segments[self.active_segment] += new_char
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# When CRC input is disabled, sentence is nearly complete
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if not self.process_crc:
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if len(self.gps_segments[self.active_segment]) == 2:
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try:
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final_crc = int(self.gps_segments[self.active_segment], 16)
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if self.crc_xor == final_crc:
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valid_sentence = True
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except ValueError:
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pass # CRC Value was deformed and could not have been correct
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# Update CRC
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if self.process_crc:
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self.crc_xor ^= ascii_char
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# If a Valid Sentence Was received and it's a supported sentence, then
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# parse it!!
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if valid_sentence and self.gps_segments[0] in self.supported_sentences:
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# Clear Active Processing Flag
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self.sentence_active = False
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# parse the Sentence Based on the message type, return True if
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# parse is clean
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if self.supported_sentences[self.gps_segments[0]](self):
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# Let host know that the GPS object was updated by returning
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# parsed sentence type
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return self.gps_segments[0]
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# Tell Host no new sentence was parsed
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return None
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# All the currently supported NMEA sentences
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supported_sentences = {'GPRMC': gprmc, 'GPGGA': gpgga, 'GPVTG': gpvtg, 'GPGSA': gpgsa, 'GPGSV': gpgsv}
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if __name__ == "__main__":
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my_gps = MicroGPSpy()
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sentence = ''
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for RMC_sentence in test_RMC:
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for y in RMC_sentence:
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sentence = my_gps.update(y)
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print('Parsed a', sentence, 'Sentence')
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print('Parsed Strings:', my_gps.gps_segments)
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print('Sentence CRC Value:', hex(my_gps.crc_xor))
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print('Longitude:', my_gps.longitude)
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print('Latitude', my_gps.latitude)
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print('UTC Timestamp:', my_gps.timestamp)
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print('Speed:', my_gps.speed)
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print('Date Stamp:', my_gps.date)
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print('Course', my_gps.course)
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print('Data is Valid', my_gps.valid)
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print('')
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for VTG_sentence in test_VTG:
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for y in VTG_sentence:
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sentence = my_gps.update(y)
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print('Parsed a', sentence, 'Sentence')
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print('Parsed Strings', my_gps.gps_segments)
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print('Sentence CRC Value:', hex(my_gps.crc_xor))
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print('Speed:', my_gps.speed)
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print('Course', my_gps.course)
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print('')
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for GGA_sentence in test_GGA:
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for y in GGA_sentence:
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sentence = my_gps.update(y)
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print('Parsed a', sentence, 'Sentence')
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print('Parsed Strings', my_gps.gps_segments)
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print('Sentence CRC Value:', hex(my_gps.crc_xor))
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print('Longitude', my_gps.longitude)
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print('Latitude', my_gps.latitude)
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print('UTC Timestamp:', my_gps.timestamp)
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print('Fix Status:', my_gps.fix_stat)
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print('Altitude:', my_gps.altitude)
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print('Height Above Geoid:', my_gps.geoid_height)
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print('Horizontal Dilution of Precision:', my_gps.hdop)
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print('Satellites in Use by Receiver:', my_gps.sats_in_use)
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