316 lines
11 KiB
Python
316 lines
11 KiB
Python
#
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# Copyright 2010, 2012 Nick Foster
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#
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# This file is part of gr-air-modes
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#
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# gr-air-modes is free software; you can redistribute it and/or modify
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# it under the terms of the GNU General Public License as published by
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# the Free Software Foundation; either version 3, or (at your option)
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# any later version.
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#
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# gr-air-modes is distributed in the hope that it will be useful,
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# but WITHOUT ANY WARRANTY; without even the implied warranty of
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# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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# GNU General Public License for more details.
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#
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# You should have received a copy of the GNU General Public License
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# along with gr-air-modes; see the file COPYING. If not, write to
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# the Free Software Foundation, Inc., 51 Franklin Street,
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# Boston, MA 02110-1301, USA.
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#
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import time, os, sys
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from string import split, join
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from altitude import decode_alt
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import cpr
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import math
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from modes_exceptions import *
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#this implements a packet class which can retrieve its own fields.
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class modes_data:
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def __init__(self, data):
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self.data = data
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#this depends on packet type so we initialize it here
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#there's probably a cleaner way to do it.
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self.parity_fields = {
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"ap": (33+(self.get_numbits()-56),24),
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"pi": (33+(self.get_numbits()-56),24)
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}
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#bitfield definitions according to Mode S spec
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#(start bit, num bits)
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fields = { "df": (1,5), "vs": (6,1), "fs": (6,3), "cc": (7,1),
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"sl": (9,3), "ri": (14,4), "ac": (20,13), "dr": (9,5),
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"um": (14,6), "id": (20,13), "ca": (6,3), "aa": (9,24),
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"mv": (33,56), "me": (33,56), "mb": (33,56), "ke": (6,1),
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"nd": (7,4), "md": (11,80)
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}
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#fields in each packet type (DF value)
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types = { 0: ["df", "vs", "cc", "sl", "ri", "ac", "ap"],
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4: ["df", "fs", "dr", "um", "ac", "ap"],
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5: ["df", "fs", "dr", "um", "id", "ap"],
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11: ["df", "ca", "aa", "pi"],
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16: ["df", "vs", "sl", "ri", "ac", "mv", "ap"],
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17: ["df", "ca", "aa", "me", "pi"],
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20: ["df", "fs", "dr", "um", "ac", "mb", "ap"],
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21: ["df", "fs", "dr", "um", "id", "mb", "ap"],
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24: ["df", "ke", "nd", "md", "ap"]
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}
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#packets which are 112 bits long
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long_types = [16, 17, 20, 21, 24]
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#get a particular field from the data
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def __getitem__(self, fieldname):
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if fieldname in modes_data.types[self.get_bits(modes_data.fields["df"])]: #verify it exists in this packet type
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if fieldname in self.parity_fields:
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return self.get_bits(self.parity_fields[fieldname])
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else:
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return self.get_bits(modes_data.fields[fieldname])
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else:
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raise FieldNotInPacket(fieldname)
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#grab all the fields in the packet as a dict
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def get_fields(self):
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return {field: self[field] for field in modes_data.types[self["df"]]}
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#tell me if i'm an extended squitter or a normal Mode S reply
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def is_long(self):
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#can't use packet type because we use is_long() to get items, and
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#this causes endless recursion
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#return self["df"] in modes_data.long_types
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return self.data > (1 << 56)
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#how many bits are in the packet?
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def get_numbits(self):
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return 112 if self.is_long() else 56
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#retrieve bits from data given the offset and number of bits.
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#the offset is both left-justified (LSB) and starts at 1, to
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#correspond to the Mode S spec. Blame them.
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def get_bits(self, arg):
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(offset, num) = arg
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return (self.data >> (self.get_numbits() - offset - num + 1)) & ((1 << num) - 1)
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class modes_parse:
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def __init__(self, mypos):
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self.my_location = mypos
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self.cpr = cpr.cpr_decoder(self.my_location)
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def parse0(self, shortdata):
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vs = bool(shortdata >> 26 & 0x1) #ground sensor -- airborne when 0
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cc = bool(shortdata >> 25 & 0x1) #crosslink capability, binary
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sl = shortdata >> 21 & 0x07 #operating sensitivity of onboard TCAS system. 0 means no TCAS sensitivity reported, 1-7 give TCAS sensitivity
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ri = shortdata >> 15 & 0x0F #speed coding: 0 = no onboard TCAS, 1 = NA, 2 = TCAS w/inhib res, 3 = TCAS w/vert only, 4 = TCAS w/vert+horiz, 5-7 = NA, 8 = no max A/S avail,
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#9 = A/S <= 75kt, 10 = A/S (75-150]kt, 11 = (150-300]kt, 12 = (300-600]kt, 13 = (600-1200]kt, 14 = >1200kt, 15 = NA
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altitude = decode_alt(shortdata & 0x1FFF, True) #bit 13 is set for type 0
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return [vs, cc, sl, ri, altitude]
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def parse4(self, shortdata):
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fs = shortdata >> 24 & 0x07 #flight status: 0 is airborne normal, 1 is ground normal, 2 is airborne alert, 3 is ground alert, 4 is alert SPI, 5 is normal SPI
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dr = shortdata >> 19 & 0x1F #downlink request: 0 means no req, bit 0 is Comm-B msg rdy bit, bit 1 is TCAS info msg rdy, bit 2 is Comm-B bcast #1 msg rdy, bit2+bit0 is Comm-B bcast #2 msg rdy,
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#bit2+bit1 is TCAS info and Comm-B bcast #1 msg rdy, bit2+bit1+bit0 is TCAS info and Comm-B bcast #2 msg rdy, 8-15 N/A, 16-31 req to send N-15 segments
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um = shortdata >> 13 & 0x3F #transponder status readouts, no decoding information available
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altitude = decode_alt(shortdata & 0x1FFF, True)
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return [fs, dr, um, altitude]
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def parse5(self, shortdata):
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fs = shortdata >> 24 & 0x07 #flight status: 0 is airborne normal, 1 is ground normal, 2 is airborne alert, 3 is ground alert, 4 is alert SPI, 5 is normal SPI
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dr = shortdata >> 19 & 0x1F #downlink request: 0 means no req, bit 0 is Comm-B msg rdy bit, bit 1 is TCAS info msg rdy, bit 2 is Comm-B bcast #1 msg rdy, bit2+bit0 is Comm-B bcast #2 msg rdy,
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#bit2+bit1 is TCAS info and Comm-B bcast #1 msg rdy, bit2+bit1+bit0 is TCAS info and Comm-B bcast #2 msg rdy, 8-15 N/A, 16-31 req to send N-15 segments
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um = shortdata >> 13 & 0x3F #transponder status readouts, no decoding information available
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ident = shortdata & 0x1FFF
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return [fs, dr, um, ident]
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def parse11(self, shortdata, ecc):
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interrogator = ecc & 0x0F
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ca = shortdata >> 13 & 0x3F #capability
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icao24 = shortdata & 0xFFFFFF
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return [icao24, interrogator, ca]
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#the Type 17 subtypes are:
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#0: No position information
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#1: Identification (Category set D)
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#2: Identification (Category set C)
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#3: "" (B)
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#4: "" (A)
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#5: Surface position accurate to 7.5m
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#6: "" to 25m
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#7: "" to 185.2m (0.1nm)
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#8: "" above 185.2m
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#9: Airborne position to 7.5m
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#10-18: Same with less accuracy
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#19: Airborne velocity
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#20: Airborne position w/GNSS height above earth
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#21: same to 25m
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#22: same above 25m
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#23: Reserved
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#24: Reserved for surface system status
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#25-27: Reserved
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#28: Extended squitter aircraft status
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#29: Current/next trajectory change point
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#30: Aircraft operational coordination
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#31: Aircraft operational status
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categories = [["NO INFO", "RESERVED", "RESERVED", "RESERVED", "RESERVED", "RESERVED", "RESERVED", "RESERVED"],\
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["NO INFO", "SURFACE EMERGENCY VEHICLE", "SURFACE SERVICE VEHICLE", "FIXED OBSTRUCTION", "RESERVED", "RESERVED", "RESERVED"],\
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["NO INFO", "GLIDER", "BALLOON/BLIMP", "PARACHUTE", "ULTRALIGHT", "RESERVED", "UAV", "SPACECRAFT"],\
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["NO INFO", "LIGHT", "SMALL", "LARGE", "LARGE HIGH VORTEX", "HEAVY", "HIGH PERFORMANCE", "ROTORCRAFT"]]
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def parseBDS08(self, shortdata, longdata):
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icao24 = shortdata & 0xFFFFFF
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subtype = (longdata >> 51) & 0x1F
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category = (longdata >> 48) & 0x07
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catstring = self.categories[subtype-1][category]
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msg = ""
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for i in range(0, 8):
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msg += self.charmap( longdata >> (42-6*i) & 0x3F)
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return (msg, catstring)
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def charmap(self, d):
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if d > 0 and d < 27:
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retval = chr(ord("A")+d-1)
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elif d == 32:
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retval = " "
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elif d > 47 and d < 58:
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retval = chr(ord("0")+d-48)
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else:
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retval = " "
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return retval
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def parseBDS05(self, shortdata, longdata):
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icao24 = shortdata & 0xFFFFFF
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encoded_lon = longdata & 0x1FFFF
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encoded_lat = (longdata >> 17) & 0x1FFFF
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cpr_format = (longdata >> 34) & 1
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enc_alt = (longdata >> 36) & 0x0FFF
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altitude = decode_alt(enc_alt, False)
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[decoded_lat, decoded_lon, rnge, bearing] = self.cpr.decode(icao24, encoded_lat, encoded_lon, cpr_format, 0)
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return [altitude, decoded_lat, decoded_lon, rnge, bearing]
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#welp turns out it looks like there's only 17 bits in the BDS0,6 ground packet after all.
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def parseBDS06(self, shortdata, longdata):
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icao24 = shortdata & 0xFFFFFF
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encoded_lon = longdata & 0x1FFFF
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encoded_lat = (longdata >> 17) & 0x1FFFF
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cpr_format = (longdata >> 34) & 1
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altitude = 0
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[decoded_lat, decoded_lon, rnge, bearing] = self.cpr.decode(icao24, encoded_lat, encoded_lon, cpr_format, 1)
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return [altitude, decoded_lat, decoded_lon, rnge, bearing]
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def parseBDS09_0(self, shortdata, longdata):
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icao24 = shortdata & 0xFFFFFF
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vert_spd = ((longdata >> 6) & 0x1FF) * 32
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ud = bool((longdata >> 15) & 1)
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if ud:
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vert_spd = 0 - vert_spd
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turn_rate = (longdata >> 16) & 0x3F
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turn_rate = turn_rate * 15/62
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rl = bool((longdata >> 22) & 1)
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if rl:
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turn_rate = 0 - turn_rate
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ns_vel = (longdata >> 23) & 0x7FF - 1
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ns = bool((longdata >> 34) & 1)
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ew_vel = (longdata >> 35) & 0x7FF - 1
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ew = bool((longdata >> 46) & 1)
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subtype = (longdata >> 48) & 0x07
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velocity = math.hypot(ns_vel, ew_vel)
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if ew:
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ew_vel = 0 - ew_vel
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if ns:
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ns_vel = 0 - ns_vel
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heading = math.atan2(ew_vel, ns_vel) * (180.0 / math.pi)
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if heading < 0:
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heading += 360
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return [velocity, heading, vert_spd, turn_rate]
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def parseBDS09_1(self, shortdata, longdata):
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icao24 = shortdata & 0xFFFFFF
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alt_geo_diff = longdata & 0x7F - 1
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above_below = bool((longdata >> 7) & 1)
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if above_below:
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alt_geo_diff = 0 - alt_geo_diff;
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vert_spd = float((longdata >> 10) & 0x1FF - 1)
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ud = bool((longdata >> 19) & 1)
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if ud:
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vert_spd = 0 - vert_spd
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vert_src = bool((longdata >> 20) & 1)
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ns_vel = float((longdata >> 21) & 0x3FF - 1)
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ns = bool((longdata >> 31) & 1)
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ew_vel = float((longdata >> 32) & 0x3FF - 1)
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ew = bool((longdata >> 42) & 1)
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subtype = (longdata >> 48) & 0x07
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if subtype == 0x02:
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ns_vel *= 4
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ew_vel *= 4
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vert_spd *= 64
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alt_geo_diff *= 25
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velocity = math.hypot(ns_vel, ew_vel)
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if ew:
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ew_vel = 0 - ew_vel
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if ns_vel == 0:
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heading = 0
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else:
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heading = math.atan(float(ew_vel) / float(ns_vel)) * (180.0 / math.pi)
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if ns:
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heading = 180 - heading
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if heading < 0:
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heading += 360
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return [velocity, heading, vert_spd]
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def parse20(self, shortdata, longdata):
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[fs, dr, um, alt] = self.parse4(shortdata)
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#BDS defines TCAS reply type and is the first 8 bits
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#BDS1 is first four, BDS2 is bits 5-8
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bds1 = longdata_bits(longdata, 33, 4)
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bds2 = longdata_bits(longdata, 37, 4)
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#bds2 != 0 defines extended TCAS capabilities, not in spec
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return [fs, dr, um, alt, bds1, bds2]
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def parseMB_commB(self, longdata): #bds1, bds2 == 0
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raise NoHandlerError
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def parseMB_caps(self, longdata): #bds1 == 1, bds2 == 0
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#cfs, acs, bcs
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raise NoHandlerError
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def parseMB_id(self, longdata): #bds1 == 2, bds2 == 0
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msg = ""
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for i in range(0, 8):
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msg += self.charmap( longdata >> (42-6*i) & 0x3F)
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return (msg)
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def parseMB_TCASRA(self, longdata): #bds1 == 3, bds2 == 0
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#ara[41-54],rac[55-58],rat[59],mte[60],tti[61-62],tida[63-75],tidr[76-82],tidb[83-88]
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raise NoHandlerError
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