gr-air-modes/python/modes_parse.py

#
# Copyright 2010 Nick Foster
# 
# This file is part of gr-air-modes
# 
# gr-air-modes is free software; you can redistribute it and/or modify
# it under the terms of the GNU General Public License as published by
# the Free Software Foundation; either version 3, or (at your option)
# any later version.
# 
# gr-air-modes is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
# GNU General Public License for more details.
# 
# You should have received a copy of the GNU General Public License
# along with gr-air-modes; see the file COPYING.  If not, write to
# the Free Software Foundation, Inc., 51 Franklin Street,
# Boston, MA 02110-1301, USA.
# 


import time, os, sys
from string import split, join
from altitude import decode_alt
from cpr import cpr_decode
import math

class modes_parse:
  def __init__(self, mypos):
      self.my_location = mypos
      self.cpr_decoder = cpr_decoder(self.my_location)
    
  def parse0(self, shortdata, parity, ecc):
#	shortdata = long(shortdata, 16)
    #parity = long(parity)

    vs = bool(shortdata >> 26 & 0x1)    #ground sensor -- airborne when 0
    cc = bool(shortdata >> 25 & 0x1)    #crosslink capability, binary
    sl = shortdata >> 21 & 0x07  #operating sensitivity of onboard TCAS system. 0 means no TCAS sensitivity reported, 1-7 give TCAS sensitivity
    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,
								  #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

    altitude = decode_alt(shortdata & 0x1FFF, True) #bit 13 is set for type 0

    return [vs, cc, sl, ri, altitude]

  def parse4(self, shortdata, parity, ecc):
#	shortdata = long(shortdata, 16)
    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
    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,
								#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
    um = shortdata >> 13 & 0x3F #transponder status readouts, no decoding information available

    altitude = decode_alt(shortdata & 0x1FFF, True)

    return [fs, dr, um, altitude]



  def parse5(self, shortdata, parity, ecc):
#	shortdata = long(shortdata, 16)
    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
    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,
								#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
    um = shortdata >> 13 & 0x3F #transponder status readouts, no decoding information available

    return [fs, dr, um]

  def parse11(self, shortdata, parity, ecc):
#	shortdata = long(shortdata, 16)
    interrogator = ecc & 0x0F
	
    ca = shortdata >> 13 & 0x3F #capability
    icao24 = shortdata & 0xFFFFFF
    
    return [icao24, interrogator, ca]

#def parse17(self, shortdata, longdata, parity, ecc):
#	shortdata = long(shortdata, 16)
#	longdata = long(longdata, 16)
#	parity = long(parity, 16)
#	ecc = long(ecc, 16)

#	subtype = (longdata >> 51) & 0x1F;

	#the subtypes are:
	#0: No position information
	#1: Identification (Category set D)
	#2: Identification (Category set C)
	#3: "" (B)
	#4: "" (A)
	#5: Surface position accurate to 7.5m
	#6: "" to 25m
	#7: "" to 185.2m (0.1nm)
	#8: "" above 185.2m
	#9: Airborne position to 7.5m
	#10-18: Same with less accuracy
	#19: Airborne velocity
	#20: Airborne position w/GNSS height above earth
	#21: same to 25m
	#22: same above 25m
	#23: Reserved
	#24: Reserved for surface system status
	#25-27: Reserved
	#28: Extended squitter aircraft status
	#29: Current/next trajectory change point
	#30: Aircraft operational coordination
	#31: Aircraft operational status


#	if subtype == 4:
#		retstr = parseBDS08(shortdata, longdata, parity, ecc)
#	elif subtype >= 9 and subtype <= 18:
#		retstr = parseBDS05(shortdata, longdata, parity, ecc)
#	elif subtype == 19:
#		subsubtype = (longdata >> 48) & 0x07
#		if subsubtype == 0:
#			retstr = parseBDS09_0(shortdata, longdata, parity, ecc)
#		elif subsubtype == 1:
#			retstr = parseBDS09_1(shortdata, longdata, parity, ecc)
#		else:
#			retstr = "BDS09 subtype " + str(subsubtype) + " not implemented"
#	else:
#		retstr = "Type 17, subtype " + str(subtype) + " not implemented"

#	return retstr

  def parseBDS08(self, shortdata, longdata, parity, ecc):
    icao24 = shortdata & 0xFFFFFF

    msg = ""
    for i in range(0, 8):
      msg += self.charmap( longdata >> (42-6*i) & 0x3F)

	#retstr = "Type 17 subtype 04 (ident) from " + "%x" % icao24 + " with data " + msg

    return msg

  def charmap(self, d):
    if d > 0 and d < 27:
      retval = chr(ord("A")+d-1)
    elif d == 32:
      retval = " "
    elif d > 47 and d < 58:
      retval = chr(ord("0")+d-48)
    else:
      retval = " "

    return retval

  def parseBDS05(self, shortdata, longdata, parity, ecc):
    icao24 = shortdata & 0xFFFFFF

    encoded_lon = longdata & 0x1FFFF
    encoded_lat = (longdata >> 17) & 0x1FFFF
    cpr_format = (longdata >> 34) & 1

    enc_alt = (longdata >> 36) & 0x0FFF

    altitude = decode_alt(enc_alt, False)

    [decoded_lat, decoded_lon, rnge, bearing] = cpr_decoder.decode(icao24, encoded_lat, encoded_lon, cpr_format, 0)

    return [altitude, decoded_lat, decoded_lon, rnge, bearing]


#welp turns out it looks like there's only 17 bits in the BDS0,6 ground packet after all. fuck.
  def parseBDS06(self, shortdata, longdata, parity, ecc):
    icao24 = shortdata & 0xFFFFFF

    encoded_lon = longdata & 0x1FFFF
    encoded_lat = (longdata >> 17) & 0x1FFFF
    cpr_format = (longdata >> 34) & 1

#	enc_alt = (longdata >> 36) & 0x0FFF

    altitude = 0

    [decoded_lat, decoded_lon, rnge, bearing] = cpr_decoder.decode(icao24, encoded_lat, encoded_lon, cpr_format, 1)

    return [altitude, decoded_lat, decoded_lon, rnge, bearing]

  def parseBDS09_0(self, shortdata, longdata, parity, ecc):
    icao24 = shortdata & 0xFFFFFF
    vert_spd = ((longdata >> 6) & 0x1FF) * 32
    ud = bool((longdata >> 15) & 1)
    if ud:
      vert_spd = 0 - vert_spd
    turn_rate = (longdata >> 16) & 0x3F
    turn_rate = turn_rate * 15/62
    rl = bool((longdata >> 22) & 1)
    if rl:
      turn_rate = 0 - turn_rate
    ns_vel = (longdata >> 23) & 0x7FF - 1
    ns = bool((longdata >> 34) & 1)
    ew_vel = (longdata >> 35) & 0x7FF - 1
    ew = bool((longdata >> 46) & 1)
    subtype = (longdata >> 48) & 0x07

    velocity = math.hypot(ns_vel, ew_vel)
    if ew:
      ew_vel = 0 - ew_vel
    if ns:
      ns_vel = 0 - ns_vel
    heading = math.atan2(ew_vel, ns_vel) * (180.0 / math.pi)
    if heading < 0:
      heading += 360

	#retstr = "Type 17 subtype 09-0 (track report) from " + "%x" % icao24 + " with velocity " + "%.0f" % velocity + "kt heading " + "%.0f" % heading + " VS " + "%.0f" % vert_spd

    return [velocity, heading, vert_spd]

  def parseBDS09_1(self, shortdata, longdata, parity, ecc):
    icao24 = shortdata & 0xFFFFFF
    alt_geo_diff = longdata & 0x7F - 1
    above_below = bool((longdata >> 7) & 1)
    if above_below:
      alt_geo_diff = 0 - alt_geo_diff;
    vert_spd = float((longdata >> 10) & 0x1FF - 1)
    ud = bool((longdata >> 19) & 1)
    if ud:
      vert_spd = 0 - vert_spd
    vert_src = bool((longdata >> 20) & 1)
    ns_vel = float((longdata >> 21) & 0x3FF - 1)
    ns = bool((longdata >> 31) & 1)
    ew_vel = float((longdata >> 32) & 0x3FF - 1)
    ew = bool((longdata >> 42) & 1)
    subtype = (longdata >> 48) & 0x07


    if subtype == 0x02:
      ns_vel *= 4
      ew_vel *= 4


    vert_spd *= 64
    alt_geo_diff *= 25
	
    velocity = math.hypot(ns_vel, ew_vel)
    if ew:
      ew_vel = 0 - ew_vel
	
    if ns_vel == 0:
      heading = 0
    else:
      heading = math.atan(float(ew_vel) / float(ns_vel)) * (180.0 / math.pi)
    if ns:
      heading = 180 - heading
    if heading < 0:
      heading += 360

    #retstr = "Type 17 subtype 09-1 (track report) from " + "%x" % icao24 + " with velocity " + "%.0f" % velocity + "kt heading " + "%.0f" % heading + " VS " + "%.0f" % vert_spd

    return [velocity, heading, vert_spd]