Added normalized_quality calculation

ogn/parser/parse.py

@@ -1,7 +1,7 @@
 import re
 from datetime import datetime
 
-from ogn.parser.utils import createTimestamp, parseAngle, KNOTS_TO_MS, KPH_TO_MS, FEETS_TO_METER, fahrenheit_to_celsius, CheapRuler
+from ogn.parser.utils import createTimestamp, parseAngle, KNOTS_TO_MS, KPH_TO_MS, FEETS_TO_METER, fahrenheit_to_celsius, CheapRuler, normalized_quality
 from ogn.parser.pattern import PATTERN_APRS, PATTERN_APRS_POSITION, PATTERN_APRS_POSITION_WEATHER, PATTERN_APRS_STATUS, PATTERN_SERVER
 from ogn.parser.exceptions import AprsParseError
 
@@ -39,6 +39,7 @@ def parse(aprs_message, reference_timestamp=None, calculate_relations=False):
             cheap_ruler = CheapRuler((message['latitude'] + positions[message['receiver_name']][1]) / 2.0)
             message['distance'] = cheap_ruler.distance((message['longitude'], message['latitude']), positions[message['receiver_name']])
             message['bearing'] = cheap_ruler.bearing((message['longitude'], message['latitude']), positions[message['receiver_name']])
+            message['normalized_quality'] = normalized_quality(message['distance'], message['signal_quality']) if 'signal_quality' in message else None
 
     return message
 

ogn/parser/utils.py

@@ -87,3 +87,9 @@ class CheapRuler():
             return 0
         result = math.atan2(-dy, dx) * 180 / MATH_PI + 90
         return result if result >= 0 else result + 360
+
+
+def normalized_quality(distance, signal_quality):
+    """Signal quality normalized to 10km."""
+
+    return signal_quality + 20.0 * math.log10(distance / 10000.0) if distance > 0 else None

tests/parser/test_utils.py

@@ -1,7 +1,7 @@
 import unittest
 from datetime import datetime, timezone
 
-from ogn.parser.utils import parseAngle, createTimestamp, CheapRuler
+from ogn.parser.utils import parseAngle, createTimestamp, CheapRuler, normalized_quality
 
 
 class TestStringMethods(unittest.TestCase):
@@ -56,6 +56,11 @@ class TestStringMethods(unittest.TestCase):
         bearing = cheap_ruler.bearing(koenigsdf, hochkoenig)
         self.assertAlmostEqual(bearing, 110.761300063515)
 
+    def test_normalized_quality(self):
+        self.assertAlmostEqual(normalized_quality(10000, 1), 1)
+        self.assertAlmostEqual(normalized_quality(20000, 10), 16.020599913279625)
+        self.assertAlmostEqual(normalized_quality(5000, 5), -1.0205999132796242)
+
 
 if __name__ == '__main__':
     unittest.main()