Merge pull request #1023 from DB8LE/testing

Filter telemetry in real-time

auto_rx/auto_rx.py

@@ -269,6 +269,8 @@ def start_decoder(freq, sonde_type, continuous=False):
             exporter=exporter_functions,
             timeout=_timeout,
             telem_filter=telemetry_filter,
+            enable_realtime_filter=config["enable_realtime_filter"],
+            max_velocity=config["max_velocity"],
             rs92_ephemeris=rs92_ephemeris,
             rs41_drift_tweak=config["rs41_drift_tweak"],
             experimental_decoder=config["experimental_decoders"][_exp_sonde_type],

auto_rx/autorx/config.py

@@ -96,6 +96,8 @@ def read_auto_rx_config(filename, no_sdr_test=False):
         "min_radius_km": 0,
         "radius_temporary_block": False,
         # "sonde_time_threshold": 3, # Commented out to ensure warning message is shown.
+        "enable_realtime_filter": True,
+        "max_velocity": 300,
         # Habitat Settings
         "habitat_uploader_callsign": "SONDE_AUTO_RX",
         "habitat_uploader_antenna": "1/4-wave",
@@ -783,6 +785,17 @@ def read_auto_rx_config(filename, no_sdr_test=False):
             )
             auto_rx_config["ozi_host"] = "<broadcast>"
             auto_rx_config["payload_summary_host"] = "<broadcast>"
+
+        # Real time filtering
+        try:
+            auto_rx_config["enable_realtime_filter"] = config.getboolean("filtering", "enable_realtime_filter")
+            auto_rx_config["max_velocity"] = config.getboolean("filtering", "max_velocity")
+        except:
+            logging.warning(
+                "Config - MIssing enable_realtime_filter or max_velocity option, using default (enabled, 300m/s)"
+            )
+            auto_rx_config["enable_realtime_filter"] = True
+            auto_rx_config["max_velocity"] = 300
             
         # If we are being called as part of a unit test, just return the config now.
         if no_sdr_test:

auto_rx/autorx/decode.py

@@ -148,6 +148,8 @@ class SondeDecoder(object):
         exporter=None,
         timeout=180,
         telem_filter=None,
+        enable_realtime_filter=True,
+        max_velocity=300,
         rs92_ephemeris=None,
         rs41_drift_tweak=False,
         experimental_decoder=False,
@@ -216,6 +218,8 @@ class SondeDecoder(object):
         self.save_decode_iq = save_decode_iq
 
         self.telem_filter = telem_filter
+        self.enable_realtime_filter = enable_realtime_filter
+        self.max_velocity = max_velocity
         self.timeout = timeout
         self.rs92_ephemeris = rs92_ephemeris
         self.rs41_drift_tweak = rs41_drift_tweak
@@ -224,6 +228,9 @@ class SondeDecoder(object):
         self.raw_file = None
         self.wideband_sondes = wideband_sondes
 
+        # Last decoded position of this sonde
+        self.last_positions = {}
+
         # Raw hex filename
         if self.save_raw_hex:
             _outfilename = f"{datetime.datetime.now(datetime.timezone.utc).strftime('%Y%m%d-%H%M%S')}_{self.sonde_type}_{int(self.sonde_freq)}.raw"
@@ -1929,6 +1936,40 @@ class SondeDecoder(object):
                 self.decoder_running = False
                 return False
 
+            # Run telemetry from DFM sondes through real-time filter
+            if self.enable_realtime_filter and (_telemetry["model"].startswith("DFM")):
+                # If sonde has already been received, calculate velocity
+                velocity = 0
+                if _telemetry["callsign"] in self.last_positions.keys():
+                    _last_position = self.last_positions[_telemetry["callsign"]]
+
+                    distance = position_info(
+                        (_last_position[0], _last_position[1], 0),
+                        (_telemetry["latitude"], _telemetry["longitude"], 0)
+                    )["great_circle_distance"] # distance is in metres
+                    time_diff = time.time() - _last_position[2] # seconds
+
+                    velocity = distance / time_diff # m/s
+
+                # Check if velocity is higher than allowed maximum
+                if velocity > self.max_velocity:
+                    _telem_ok = False
+
+                    # Reset last position to prevent an endless chain of rejecting telemetry
+                    del self.last_positions[_telemetry["callsign"]]
+                else:
+                    # Check passed, update last position and continue processing
+                    self.last_positions[_telemetry["callsign"]] = (
+                        _telemetry["latitude"],
+                        _telemetry["longitude"],
+                        time.time()
+                    )
+            
+            # Garbage collect last_positions list
+            for serial, position in self.last_positions.items():
+                # If last position packet was more than 3 hours ago, delete it from list
+                if time.time()-position[2] > 3*60*60:
+                    del self.last_positions[serial]
 
             # If the telemetry is OK, send to the exporter functions (if we have any).
             if self.exporters is None:

auto_rx/station.cfg.example

@@ -645,3 +645,13 @@ radius_temporary_block = False
 # This helps catch glitches around 00Z UTC from iMet & LMS6 sondes, and bad CRC checks from
 # DFM sondes.
 sonde_time_threshold = 3
+
+# Wether to perform real-time velocity filtering
+# This filter calculates the velocity between the previous decoded telemetry frame and
+# newly received frames, and discards them if it is faster than the velocity configured below.
+# This helps discard the frame with invalid GPS data that DFM sondes transmit once per flight.
+enable_realtime_filter = True
+
+# Maximum velocity in metres per second for sondes to be discarded in the real-time filter
+max_velocity = 300
+

auto_rx/station.cfg.example.network

@@ -644,3 +644,13 @@ radius_temporary_block = False
 # This helps catch glitches around 00Z UTC from iMet & LMS6 sondes, and bad CRC checks from
 # DFM sondes.
 sonde_time_threshold = 3
+
+# Wether to perform real-time velocity filtering
+# This filter calculates the velocity between the previous decoded telemetry frame and
+# newly received frames, and discards them if it is faster than the velocity configured below.
+# This helps discard the frame with invalid GPS data that DFM sondes transmit once per flight.
+enable_realtime_filter = True
+
+# Maximum velocity in metres per second for sondes to be discarded in the real-time filter
+max_velocity = 300
+