[python] get air traffic from opensky-network and display in GCS (#2259)

conf/control_panel_example.xml

@@ -65,6 +65,7 @@
     <program name="ADS-B Intruders receiver" command="sw/ground_segment/misc/sbs2ivy">
       <arg flag="--ac" constant="@AC_ID"/>
     </program>
+    <program name="OpenSky-Network Intruders" command="sw/ground_segment/python/opensky-network/opensky.py"/>
     <program name="SVInfo" command="sw/ground_segment/python/svinfo/svinfo.py"/>
     <program name="IridiumDialer" command="sw/tools/iridium/iridium_link.py"/>
     <program name="PayloadForward" command="sw/ground_segment/python/payload_forward/payload.py"/>

sw/ground_segment/cockpit/intruders.ml

@@ -51,11 +51,11 @@ let update_intruder = fun id wgs84 heading alt speed climb time ->
 let intruder_exist = fun id ->
   Hashtbl.mem intruders id
 
-(* remove old intruders after 10s *)
+(* remove old intruders after 20s *)
 let remove_old_intruders = fun () ->
   Hashtbl.iter
     (fun id i ->
-      if (Unix.gettimeofday () -. i.last_update) > 10.0 then
+      if (Unix.gettimeofday () -. i.last_update) > 20.0 then
         remove_intruder id
     ) intruders
 

sw/ground_segment/python/opensky-network/opensky.py

@@ -0,0 +1,176 @@
+#!/usr/bin/env python
+#
+# Copyright (C) 2018 Gautier Hattenberger <gautier.hattenberger@enac.fr>
+#
+# This file is part of paparazzi.
+#
+# paparazzi 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 2, or (at your option)
+# any later version.
+#
+# paparazzi 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 paparazzi; see the file COPYING.  If not, see
+# <http://www.gnu.org/licenses/>.
+#
+
+'''
+Get air traffic information from the opensky-network system (https://opensky-network.org/)
+
+The python API is required and should be installed using the instruction
+from https://github.com/openskynetwork/opensky-api
+
+Positions of the UAVs are used to request for the surrounding aircraft
+and INTRUDER messages are sent to the IVY bus for display in the GCS
+'''
+
+
+from __future__ import print_function
+
+import sys
+from os import path, getenv
+from time import sleep, time
+
+from opensky_api import OpenSkyApi
+
+# if PAPARAZZI_HOME not set, then assume the tree containing this
+# file is a reasonable substitute
+PPRZ_HOME = getenv("PAPARAZZI_HOME", path.normpath(path.join(path.dirname(path.abspath(__file__)), '../../../..')))
+sys.path.append(PPRZ_HOME + "/var/lib/python")
+
+from pprzlink.ivy import IvyMessagesInterface
+from pprzlink.message import PprzMessage
+
+
+class OpenSkyTraffic(object):
+    def __init__(self, period=10., margin=1., timeout=60., verbose=False):
+        self.period = period
+        self.margin = margin
+        self.timeout = timeout
+        self.last_receive = time()
+        self.verbose = verbose
+        self._interface = IvyMessagesInterface("OpenSkyTraffic")
+        self._opensky = OpenSkyApi()
+        self.ac_list = {}
+        self.intruder_list = {}
+        self.running = False
+        if self.verbose:
+            print("Starting opensky interface...")
+        
+        # subscribe to FLIGHT_PARAM ground message
+        self._interface.subscribe(self.update_ac, PprzMessage("ground", "FLIGHT_PARAM"))
+
+    def stop(self):
+        if self.verbose:
+            print("Shutting down opensky interface...")
+        self.running = False
+        if self._interface is not None:
+            self._interface.shutdown()
+
+    def __del__(self):
+        self.stop()
+
+    def update_ac(self, ac_id, msg):
+        # update A/C info
+        self.last_receive = time()
+        self.ac_list[ac_id] = (self.last_receive, float(msg['lat']), float(msg['long']))
+
+    def filter_ac(self):
+        # purge timeout A/C
+        timeout = time() - self.timeout
+        for ac, (t, lat, lon) in self.ac_list.items():
+            if t < timeout:
+                del self.ac_list[ac]
+
+    def compute_bbox_list(self):
+        bbox = []
+        # for now assume that all UAVs are close enough, so merge all boxes into one
+        # future improvement could handle groups of UAVs far appart
+        lat_min, lat_max, lon_min, lon_max = None, None, None, None
+        for ac, (t, lat, lon) in self.ac_list.items():
+            if lat_min is None:
+                lat_min = lat
+                lat_max = lat
+                lon_min = lon
+                lon_max = lon
+            else:
+                lat_min = min(lat, lat_min)
+                lat_max = max(lat, lat_max)
+                lon_min = min(lon, lon_min)
+                lon_max = max(lon, lon_max)
+
+        if lat_min is not None:
+            bbox.append((lat_min-self.margin, lat_max+self.margin, lon_min-self.margin, lon_max+self.margin))
+        return bbox
+
+    def get_intruders(self):
+        self.filter_ac()
+        bbox = self.compute_bbox_list()
+        # request surounding aircraft to opensky-network
+        self.intruder_list = {}
+        for bb in bbox:
+            states = self._opensky.get_states(bbox=bb)
+            if states is not None:
+                for s in states.states:
+                    self.intruder_list[s.callsign] = s
+
+    def send_intruder_msgs(self):
+        self.get_intruders()
+        def val_or_default(val, default):
+            if val is None:
+                return default
+            else:
+                return val
+        for i in self.intruder_list:
+            intruder = self.intruder_list[i]
+            if intruder.callsign is not None and len(intruder.callsign) > 0:
+                msg = PprzMessage("ground", "INTRUDER")
+                msg['id'] = intruder.icao24
+                msg['name'] = intruder.callsign.replace(" ", "")
+                msg['lat'] = int(intruder.latitude * 1e7)
+                msg['lon'] = int(intruder.longitude * 1e7)
+                msg['alt'] = int(val_or_default(intruder.geo_altitude, 0.) * 1000.)
+                msg['course'] = val_or_default(intruder.heading, 0.)
+                msg['speed'] = val_or_default(intruder.velocity, 0.)
+                msg['climb'] = val_or_default(intruder.vertical_rate, 0.)
+                msg['itow'] = intruder.time_position
+                if self.verbose:
+                    print(msg)
+                self._interface.send(msg)
+
+    def run(self):
+        try:
+            self.running = True
+            t = 0.
+            while self.running:
+                t = t + 0.1 # increment timer until next update time is reach
+                if t > self.period:
+                    self.send_intruder_msgs()
+                    t = 0.
+                sleep(0.1) # wait a short time
+        except KeyboardInterrupt:
+            self.stop()
+        except Exception as e:
+            print("Failing with: "+str(e))
+            self.stop()
+
+
+
+if __name__ == '__main__':
+    import argparse
+
+    parser = argparse.ArgumentParser(description="OpenSky-Network traffic information")
+    parser.add_argument('-p', '--period', dest='period', default=10., type=float, help="update period")
+    parser.add_argument('-m', '--margin', dest='margin', default=1., type=float, help="margin in degree to define the bounding box")
+    parser.add_argument('-t', '--timeout', dest='timeout', default=60., type=float, help="timeout to remove A/C")
+    parser.add_argument('-v', '--verbose', dest='verbose', default=False, action='store_true', help="display debug messages")
+    args = parser.parse_args()
+
+    osn = OpenSkyTraffic(args.period, args.margin, args.timeout, args.verbose)
+    osn.run()
+