initial commit for v2.0

README.rst

@@ -1,5 +1,5 @@
-The Python Mode-S Decoder
+The Python Mode-S Decoder (2.0-Dev branch)
-=========================
+==========================================
 
 Python library for Mode-S message decoding. Support Downlink Formats (DF) are:
 
@@ -28,6 +28,13 @@ Detailed manual on Mode-S decoding is published by the author, at:
 http://adsb-decode-guide.readthedocs.io
 
 
+New features in v2.0
+---------------------
+- ADS-B and EHS data streaming
+- Active aircraft viewing (in terminal)
+- More advanced BDS identification in Enhanced Mode-S
+
+
 Source code
 -----------
 Checkout and contribute to this open source project at:

pyModeS/__init__.py

@@ -1,6 +1,8 @@
 from __future__ import absolute_import, print_function, division
 
-from .util import *
+from .decoder.util import *
-from . import adsb
+from .decoder import adsb
-from . import ehs
+from .decoder import ehs
-from . import els
+from .decoder import els
+from .decoder import util
+from .decoder import modes_common

pyModeS/decoder/__init__.py

@@ -0,0 +1 @@
+from __future__ import absolute_import, print_function, division

pyModeS/streamer/aero.py

@@ -0,0 +1,178 @@
+"""
+Functions for aeronautics in this module
+    - physical quantities always in SI units
+    - lat,lon,course and heading in degrees
+
+International Standard Atmosphere
+    p,rho,T = atmos(H)    # atmos as function of geopotential altitude H [m]
+    a = vsound(H)         # speed of sound [m/s] as function of H[m]
+    p = pressure(H)       # calls atmos but retruns only pressure [Pa]
+    T = temperature(H)    # calculates temperature [K]
+    rho = density(H)      # calls atmos but retruns only pressure [Pa]
+
+Speed conversion at altitude H[m] in ISA:
+    Mach   = tas2mach(Vtas,H)  # true airspeed (Vtas) to mach number conversion
+    Vtas = mach2tas(Mach,H)    # true airspeed (Vtas) to mach number conversion
+    Vtas = eas2tas(Veas,H)   # equivalent airspeed to true airspeed, H in [m]
+    Veas = tas2eas(Vtas,H)   # true airspeed to equivent airspeed, H in [m]
+    Vtas = cas2tas(Vcas,H)   # Vcas  to Vtas conversion both m/s, H in [m]
+    Vcas = tas2cas(Vtas,H)   # Vtas to Vcas conversion both m/s, H in [m]
+    Vcas = mach2cas(Mach,H)    # Mach to Vcas conversion Vcas in m/s, H in [m]
+    Mach   = cas2mach(Vcas,H)  # Vcas to mach copnversion Vcas in m/s, H in [m]
+"""
+
+import numpy as np
+
+"""Aero and geo Constants """
+kts = 0.514444      # knot -> m/s
+ft = 0.3048         # ft -> m
+fpm = 0.00508       # ft/min -> m/s
+inch = 0.0254       # inch -> m
+sqft = 0.09290304   # 1 square foot
+nm = 1852.          # nautical mile -> m
+lbs = 0.453592      # pound -> kg
+g0 = 9.80665        # m/s2, Sea level gravity constant
+R = 287.05287       # m2/(s2 x K), gas constant, sea level ISA
+p0 = 101325.        # Pa, air pressure, sea level ISA
+rho0 = 1.225        # kg/m3, air density, sea level ISA
+T0 = 288.15         # K, temperature, sea level ISA
+gamma = 1.40        # cp/cv for air
+gamma1 = 0.2        # (gamma-1)/2 for air
+gamma2 = 3.5        # gamma/(gamma-1) for air
+beta = -0.0065      # [K/m] ISA temp gradient below tropopause
+r_earth = 6371000.  # m, average earth radius
+a0 = 340.293988     # m/s, sea level speed of sound ISA, sqrt(gamma*R*T0)
+
+
+def atmos(H):
+    # H in metres
+    T = np.maximum(288.15 - 0.0065 * H, 216.65)
+    rhotrop = 1.225 * (T / 288.15)**4.256848030018761
+    dhstrat = np.maximum(0., H - 11000.0)
+    rho = rhotrop * np.exp(-dhstrat / 6341.552161)
+    p = rho * R * T
+    return p, rho, T
+
+
+def temperature(H):
+    p, r, T = atmos(H)
+    return T
+
+
+def pressure(H):
+    p, r, T = atmos(H)
+    return p
+
+
+def density(H):
+    p, r, T = atmos(H)
+    return r
+
+
+def vsound(H):
+    """Speed of sound"""
+    T = temperature(H)
+    a = np.sqrt(gamma * R * T)
+    return a
+
+
+def distance(lat1, lon1, lat2, lon2, H=0):
+    """
+    Compute spherical distance from spherical coordinates.
+
+    For two locations in spherical coordinates
+    (1, theta, phi) and (1, theta', phi')
+    cosine( arc length ) =
+       sin phi sin phi' cos(theta-theta') + cos phi cos phi'
+    distance = rho * arc length
+    """
+
+    # phi = 90 - latitude
+    phi1 = np.radians(90.0 - lat1)
+    phi2 = np.radians(90.0 - lat2)
+
+    # theta = longitude
+    theta1 = np.radians(lon1)
+    theta2 = np.radians(lon2)
+
+    cos = np.sin(phi1) * np.sin(phi2) * np.cos(theta1 - theta2) \
+        + np.cos(phi1) * np.cos(phi2)
+
+    arc = np.arccos(cos)
+    dist = arc * (r_earth + H)   # meters, radius of earth
+    return dist
+
+
+def bearing(lat1, lon1, lat2, lon2):
+    lat1 = np.radians(lat1)
+    lon1 = np.radians(lon1)
+    lat2 = np.radians(lat2)
+    lon2 = np.radians(lon2)
+    x = np.sin(lon2-lon1) * np.cos(lat2)
+    y = np.cos(lat1) * np.sin(lat2) \
+        - np.sin(lat1) * np.cos(lat2) * np.cos(lon2-lon1)
+    initial_bearing = np.arctan2(x, y)
+    initial_bearing = np.degrees(initial_bearing)
+    bearing = (initial_bearing + 360) % 360
+    return bearing
+
+
+# -----------------------------------------------------
+# Speed conversions, altitude H all in meters
+# -----------------------------------------------------
+def tas2mach(Vtas, H):
+    """True Airspeed to Mach number"""
+    a = vsound(H)
+    Mach = Vtas/a
+    return Mach
+
+
+def mach2tas(Mach, H):
+    """Mach number to True Airspeed"""
+    a = vsound(H)
+    Vtas = Mach*a
+    return Vtas
+
+
+def eas2tas(Veas, H):
+    """Equivalent Airspeed to True Airspeed"""
+    rho = density(H)
+    Vtas = Veas * np.sqrt(rho0/rho)
+    return Vtas
+
+
+def tas2eas(Vtas, H):
+    """True Airspeed to Equivalent Airspeed"""
+    rho = density(H)
+    Veas = Vtas * np.sqrt(rho/rho0)
+    return Veas
+
+
+def cas2tas(Vcas, H):
+    """Calibrated Airspeed to True Airspeed"""
+    p, rho, T = atmos(H)
+    qdyn = p0*((1.+rho0*Vcas*Vcas/(7.*p0))**3.5-1.)
+    Vtas = np.sqrt(7.*p/rho*((1.+qdyn/p)**(2./7.)-1.))
+    return Vtas
+
+
+def tas2cas(Vtas, H):
+    """True Airspeed to Calibrated Airspeed"""
+    p, rho, T = atmos(H)
+    qdyn = p*((1.+rho*Vtas*Vtas/(7.*p))**3.5-1.)
+    Vcas = np.sqrt(7.*p0/rho0*((qdyn/p0+1.)**(2./7.)-1.))
+    return Vcas
+
+
+def mach2cas(Mach, H):
+    """Mach number to Calibrated Airspeed"""
+    Vtas = mach2tas(Mach, H)
+    Vcas = tas2cas(Vtas, H)
+    return Vcas
+
+
+def cas2mach(Vcas, H):
+    """Calibrated Airspeed to Mach number"""
+    Vtas = cas2tas(Vcas, H)
+    Mach = tas2mach(Vtas, H)
+    return Mach

pyModeS/streamer/client.py

@@ -0,0 +1,163 @@
+'''
+Stream beast raw data from a TCP server, convert to mode-s messages
+'''
+from __future__ import print_function, division
+import sys
+import socket
+import time
+from threading import Thread
+
+if (sys.version_info > (3, 0)):
+    PY_VERSION = 3
+else:
+    PY_VERSION = 2
+
+class BaseClient(Thread):
+    def __init__(self, host, port):
+        Thread.__init__(self)
+        self.host = host
+        self.port = port
+        self.buffer = []
+
+
+    def connect(self):
+        while True:
+            try:
+                s = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
+                s.settimeout(10)    # 10 second timeout
+                s.connect((self.host, self.port))
+                print("Server connected - %s:%s" % (self.host, self.port))
+                print("collecting ADS-B messages...")
+                return s
+            except socket.error as err:
+                print("Socket connection error: %s. reconnecting..." % err)
+                time.sleep(3)
+
+    def read_beast_buffer(self):
+        '''
+        <esc> "1" : 6 byte MLAT timestamp, 1 byte signal level,
+            2 byte Mode-AC
+        <esc> "2" : 6 byte MLAT timestamp, 1 byte signal level,
+            7 byte Mode-S short frame
+        <esc> "3" : 6 byte MLAT timestamp, 1 byte signal level,
+            14 byte Mode-S long frame
+        <esc> "4" : 6 byte MLAT timestamp, status data, DIP switch
+            configuration settings (not on Mode-S Beast classic)
+        <esc><esc>: true 0x1a
+        <esc> is 0x1a, and "1", "2" and "3" are 0x31, 0x32 and 0x33
+
+        timestamp:
+        wiki.modesbeast.com/Radarcape:Firmware_Versions#The_GPS_timestamp
+        '''
+
+        messages_mlat = []
+        msg = []
+        i = 0
+
+        # process the buffer until the last divider <esc> 0x1a
+        # then, reset the self.buffer with the remainder
+
+        while i < len(self.buffer):
+            if (self.buffer[i:i+2] == [0x1a, 0x1a]):
+                msg.append(0x1a)
+                i += 1
+            elif (i == len(self.buffer) - 1) and (self.buffer[i] == 0x1a):
+                # special case where the last bit is 0x1a
+                msg.append(0x1a)
+            elif self.buffer[i] == 0x1a:
+                if i == len(self.buffer) - 1:
+                    # special case where the last bit is 0x1a
+                    msg.append(0x1a)
+                elif len(msg) > 0:
+                    messages_mlat.append(msg)
+                    msg = []
+            else:
+                msg.append(self.buffer[i])
+            i += 1
+
+        # save the reminder for next reading cycle, if not empty
+        if len(msg) > 0:
+            reminder = []
+            for i, m in enumerate(msg):
+                if (m == 0x1a) and (i < len(msg)-1):
+                    # rewind 0x1a, except when it is at the last bit
+                    reminder.extend([m, m])
+                else:
+                    reminder.append(m)
+            self.buffer = [0x1a] + msg
+        else:
+            self.buffer = []
+
+        # extract messages
+        messages = []
+        for mm in messages_mlat:
+            msgtype = mm[0]
+            # print(''.join('%02X' % i for i in mm))
+
+            if msgtype == 0x32:
+                # Mode-S Short Message, 7 byte, 14-len hexstr
+                msg = ''.join('%02X' % i for i in mm[8:15])
+            elif msgtype == 0x33:
+                # Mode-S Long Message, 14 byte, 28-len hexstr
+                msg = ''.join('%02X' % i for i in mm[8:22])
+            else:
+                # Other message tupe
+                continue
+
+            if len(msg) not in [14, 28]:
+                # incomplete message
+                continue
+
+            ts = time.time()
+
+            messages.append([msg, ts])
+        return messages
+
+    def handle_messages(self, messages):
+        """re-implement this method to handle the messages"""
+        for msg, t in messages:
+            print("%f %s" % (t, msg))
+
+    def run(self):
+        sock = self.connect()
+
+        while True:
+            try:
+                received = sock.recv(1024)
+
+                if PY_VERSION == 2:
+                    received = [ord(i) for i in received]
+
+                self.buffer.extend(received)
+                # print(''.join(x.encode('hex') for x in self.buffer))
+
+                # process self.buffer when it is longer enough
+                # if len(self.buffer) < 2048:
+                #     continue
+                # -- Removed!! Cause delay in low data rate scenario --
+
+                messages = self.read_beast_buffer()
+
+                if not messages:
+                    continue
+                else:
+                    self.handle_messages(messages)
+
+                time.sleep(0.001)
+            except Exception as e:
+                print("Unexpected Error:", e)
+
+                try:
+                    sock = self.connect()
+                except Exception as e:
+                    print("Unexpected Error:", e)
+
+
+
+if __name__ == '__main__':
+    # for testing purpose only
+    host = sys.argv[1]
+    port = int(sys.argv[2])
+    client = BaseClient(host=host, port=port)
+    client.daemon = True
+    client.run()

pyModeS/streamer/pmstream.py

@@ -0,0 +1,95 @@
+from __future__ import print_function, division
+import os
+import sys
+import curses
+import numpy as np
+import time
+import pyModeS as pms
+from threading import Lock
+from client import BaseClient
+from stream import Stream
+from screen import Screen
+
+LOCK = Lock()
+ADSB_MSG = []
+ADSB_TS = []
+EHS_MSG = []
+EHS_TS = []
+
+HOST = 'sil.lr.tudelft.nl'
+PORT = 30334
+
+LAT0 = 51.9899
+LON0 = 4.3754
+
+class ModesClient(BaseClient):
+    def __init__(self, host, port):
+        super(ModesClient, self).__init__(host, port)
+
+    def handle_messages(self, messages):
+        local_buffer_adsb_msg = []
+        local_buffer_adsb_ts = []
+        local_buffer_ehs_msg = []
+        local_buffer_ehs_ts = []
+
+        for msg, t in messages:
+            if len(msg) < 28:           # only process long messages
+                continue
+
+            df = pms.df(msg)
+
+            if df == 17 or df == 18:
+                local_buffer_adsb_msg.append(msg)
+                local_buffer_adsb_ts.append(t)
+            elif df == 20 or df == 21:
+                local_buffer_ehs_msg.append(msg)
+                local_buffer_ehs_ts.append(t)
+            else:
+                continue
+
+
+        LOCK.acquire()
+        ADSB_MSG.extend(local_buffer_adsb_msg)
+        ADSB_TS.extend(local_buffer_adsb_ts)
+        EHS_MSG.extend(local_buffer_ehs_msg)
+        EHS_TS.extend(local_buffer_ehs_ts)
+        LOCK.release()
+
+
+sys.stdout = open(os.devnull, 'w')
+
+client = ModesClient(host=HOST, port=PORT)
+client.daemon = True
+client.start()
+
+stream = Stream(lat0=LAT0, lon0=LON0)
+
+try:
+    screen = Screen()
+    screen.daemon = True
+    screen.start()
+
+    while True:
+        if len(ADSB_MSG) > 200:
+            LOCK.acquire()
+            stream.process_raw(ADSB_TS, ADSB_MSG, EHS_TS, EHS_MSG)
+            ADSB_MSG = []
+            ADSB_TS = []
+            EHS_MSG = []
+            EHS_TS = []
+            LOCK.release()
+
+        acs = stream.get_aircraft()
+        # try:
+        screen.update_data(acs)
+        screen.update()
+        # except KeyboardInterrupt:
+        #     raise
+        # except:
+        #     continue
+
+except KeyboardInterrupt:
+    sys.exit(0)
+
+finally:
+    curses.endwin()

pyModeS/streamer/screen.py

@@ -0,0 +1,133 @@
+from __future__ import print_function, division
+import curses
+import numpy as np
+import time
+from threading import Thread
+
+COLUMNS = ['lat', 'lon', 'alt', 'gs', 'tas', 'ias', 'mach', 'roc', 'trk', 'hdg', 't']
+
+class Screen(Thread):
+    def __init__(self):
+        Thread.__init__(self)
+        self.screen = curses.initscr()
+        curses.noecho()
+        self.screen.keypad(True)
+        self.y = 3
+        self.x = 1
+        self.offset = 0
+        self.acs = {}
+        self.lock_icao = None
+
+
+    def reset_cursor_pos(self):
+        self.screen.move(self.y, self.x)
+
+    def update_data(self, acs):
+        self.acs = acs
+
+    def draw_frame(self):
+        self.screen.border(0)
+        self.screen.addstr(0, 2, "Online aircraft ('crtl+c' to exit, 'enter' to select)")
+
+    def update(self):
+        if len(self.acs) == 0:
+            return
+
+        resized = curses.is_term_resized(self.scr_h, self.scr_w)
+        if resized is True:
+            self.scr_h, self.scr_w = self.screen.getmaxyx()
+            self.screen.clear()
+            curses.resizeterm(self.scr_h, self.scr_w)
+
+        self.screen.refresh()
+        self.draw_frame()
+
+        row = 1
+
+        header = 'icao'
+        for c in COLUMNS:
+            c = 'updated' if c=='t' else  c
+            header += '%10s' % c
+
+        if len(header) > self.scr_w - 2:
+            header = header[:self.scr_w-3] + '>'
+
+        self.screen.addstr(row, 1, header)
+
+        row +=1
+        self.screen.addstr(row, 1, '-'*(self.scr_w-2))
+
+        icaos = np.array(list(self.acs.keys()))
+        icaos = np.sort(icaos)
+
+        for row in range(3, self.scr_h - 3):
+            idx = row + self.offset
+
+            if idx > len(icaos) - 1:
+                line = ' '*(self.scr_w-2)
+
+            else:
+                line = ''
+
+                icao = icaos[idx]
+                ac = self.acs[icao]
+
+                line += icao
+
+                for c in COLUMNS:
+
+                    if c == 't':
+                        val = str(int(ac[c]))
+                        line += '%12s' % val
+                    else:
+                        val = '' if ac[c] is None else ac[c]
+                        line += '%10s' % val
+
+                if len(line) > self.scr_w - 2:
+                    line = line[:self.scr_w-3] + '>'
+
+            if self.lock_icao == icao:
+                self.screen.addstr(row, 1, line, curses.A_STANDOUT)
+            elif row == self.y:
+                self.screen.addstr(row, 1, line, curses.A_BOLD)
+            else:
+                self.screen.addstr(row, 1, line)
+
+        self.screen.addstr(self.scr_h-3, 1, '-'*(self.scr_w-2))
+
+        total_page = len(icaos) // (self.scr_h - 4) + 1
+        current_page = self.offset // (self.scr_h - 4) + 1
+        self.screen.addstr(self.scr_h-2, 1, '(%d / %d)' % (current_page, total_page))
+
+        self.reset_cursor_pos()
+
+    def run(self):
+        self.draw_frame()
+        self.scr_h, self.scr_w = self.screen.getmaxyx()
+
+        while True:
+            c = self.screen.getch()
+
+            if c == curses.KEY_HOME:
+                self.x = 1
+                self.y = 1
+            elif c == curses.KEY_NPAGE:
+                offset_intent = self.offset + (self.scr_h - 4)
+                if offset_intent < len(self.acs) - 5:
+                    self.offset = offset_intent
+            elif c == curses.KEY_PPAGE:
+                offset_intent = self.offset - (self.scr_h - 4)
+                if offset_intent > 0:
+                    self.offset = offset_intent
+                else:
+                    self.offset = 0
+            elif c == curses.KEY_DOWN :
+                y_intent = self.y + 1
+                if y_intent < self.scr_h - 3:
+                    self.y = y_intent
+            elif c == curses.KEY_UP:
+                y_intent = self.y - 1
+                if y_intent > 2:
+                    self.y = y_intent
+            elif c == curses.KEY_ENTER or c == 10 or c == 13:
+                self.lock_icao = (self.screen.instr(self.y, 1, 6)).decode()

pyModeS/streamer/stream.py

@@ -0,0 +1,169 @@
+from __future__ import print_function, division
+import numpy as np
+import time
+import pyModeS as pms
+
+
+class Stream():
+    def __init__(self, lat0, lon0):
+
+        self.acs = dict()
+
+        self.cache_new_acs = False
+        self.__new_acs = set()
+
+        self.lat0 = lat0
+        self.lon0 = lon0
+
+        self.t = 0
+        self.cache_timeout = 60     # seconds
+
+
+    def process_raw(self, adsb_ts, adsb_msgs, ehs_ts, ehs_msgs, tnow=None):
+        """process a chunk of adsb and ehs messages recieved in the same
+        time period.
+        """
+        if tnow is None:
+            tnow = time.time()
+
+        self.t = tnow
+
+        local_updated_acs_buffer = []
+
+        # process adsb message
+        for t, msg in zip(adsb_ts, adsb_msgs):
+            icao = pms.adsb.icao(msg)
+            tc = pms.adsb.typecode(msg)
+
+            if icao not in self.acs:
+                self.acs[icao] = {
+                    'lat': None,
+                    'lon': None,
+                    'alt': None,
+                    'gs': None,
+                    'trk': None,
+                    'roc': None,
+                    'tas': None,
+                    'ias': None,
+                    'mach': None,
+                    'hdg': None,
+                }
+
+            self.acs[icao]['t'] = t
+
+            if 1 <= tc <= 4:
+                self.acs[icao]['callsign'] = pms.adsb.callsign(msg)
+
+            if (5 <= tc <= 8) or (tc == 19):
+                vdata = pms.adsb.velocity(msg)
+                if vdata is None:
+                    continue
+
+                spd, trk, roc, tag = vdata
+                if tag != 'GS':
+                    continue
+
+                self.acs[icao]['gs'] = spd
+                self.acs[icao]['trk'] = trk
+                self.acs[icao]['roc'] = roc
+                self.acs[icao]['tv'] = t
+
+            if (5 <= tc <= 18):
+                oe = pms.adsb.oe_flag(msg)
+                self.acs[icao][oe] = msg
+                self.acs[icao]['t'+str(oe)] = t
+
+                if ('tpos' in self.acs[icao]) and (t - self.acs[icao]['tpos'] < 180):
+                    # use single message decoding
+                    rlat = self.acs[icao]['lat']
+                    rlon = self.acs[icao]['lon']
+                    latlon = pms.adsb.position_with_ref(msg, rlat, rlon)
+                elif ('t0' in self.acs[icao]) and ('t1' in self.acs[icao]) and \
+                     (abs(self.acs[icao]['t0'] - self.acs[icao]['t1']) < 10):
+                    # use multi message decoding
+                    try:
+                        latlon = pms.adsb.position(
+                            self.acs[icao][0],
+                            self.acs[icao][1],
+                            self.acs[icao]['t0'],
+                            self.acs[icao]['t1'],
+                            self.lat0, self.lon0
+                            )
+                    except:
+                        # mix of surface and airborne position message
+                        continue
+                else:
+                    latlon = None
+
+                if latlon is not None:
+                    self.acs[icao]['tpos'] = t
+                    self.acs[icao]['lat'] = latlon[0]
+                    self.acs[icao]['lon'] = latlon[1]
+                    self.acs[icao]['alt'] = pms.adsb.altitude(msg)
+                    local_updated_acs_buffer.append(icao)
+
+        # process ehs message
+        for t, msg in zip(ehs_ts, ehs_msgs):
+            icao = pms.ehs.icao(msg)
+
+            if icao not in self.acs:
+                continue
+
+            bds = pms.ehs.BDS(msg)
+
+            if bds == 'BDS50':
+                tas = pms.ehs.tas50(msg)
+
+                if tas:
+                    self.acs[icao]['t50'] = t
+                    self.acs[icao]['tas'] = tas
+
+            elif bds == 'BDS60':
+                ias = pms.ehs.ias60(msg)
+                hdg = pms.ehs.hdg60(msg)
+                mach = pms.ehs.mach60(msg)
+
+                if ias or hdg or mach:
+                    self.acs[icao]['t60'] = t
+                if ias:
+                    self.acs[icao]['ias'] = ias
+                if hdg:
+                    self.acs[icao]['hdg'] = hdg
+                if mach:
+                    self.acs[icao]['mach'] = mach
+
+        # clear up old data
+        for icao in list(self.acs.keys()):
+            if self.t - self.acs[icao]['t'] > self.cache_timeout:
+                del self.acs[icao]
+                continue
+
+        if self.cache_new_acs:
+            self.add_new_aircraft(local_updated_acs_buffer)
+
+        return
+
+    def get_aircraft(self):
+        """all aircraft that are stored in memeory"""
+        acs = self.acs
+        icaos = list(acs.keys())
+        for icao in icaos:
+            if acs[icao]['lat'] is None:
+                acs.pop(icao)
+        return acs
+
+    def add_new_aircraft(self, acs):
+        """add new aircraft to the list"""
+        self.__new_acs.update(acs)
+        return
+
+    def get_new_aircraft(self):
+        """update aircraft from last iteration"""
+        newacs = dict()
+        for ac in self.__new_acs:
+            newacs[ac] = self.acs[ac]
+        return newacs
+
+    def reset_new_aircraft(self):
+        """reset the updated icao buffer once been read"""
+        self.__new_acs = set()

setup.py

@@ -30,7 +30,7 @@ setup(
     # Versions should comply with PEP440.  For a discussion on single-sourcing
     # the version across setup.py and the project code, see
     # https://packaging.python.org/en/latest/single_source_version.html
-    version='1.2.0',
+    version='2.0-dev',
 
     description='Python Mode-S Decoder',
     long_description=long_description,
@@ -63,7 +63,6 @@ setup(
         # Specify the Python versions you support here. In particular, ensure
         # that you indicate whether you support Python 2, Python 3 or both.
         'Programming Language :: Python :: 2',
-        'Programming Language :: Python :: 2.6',
         'Programming Language :: Python :: 2.7',
         'Programming Language :: Python :: 3',
         'Programming Language :: Python :: 3.3',

tox.ini

@@ -1,6 +1,6 @@
 [tox]
 toxworkdir=/tmp/tox
-envlist = py26,py27,py35
+envlist = py27,py35
 [testenv]
 deps=pytest
 commands=py.test