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#2287 Resolves Motorola P25P1 LC GPS parsing issue. (#2293)

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Co-authored-by: denny <dennis.sheirer@gmail.com>
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Denny Sheirer
2025-11-15 07:35:18 -05:00
committed by GitHub
parent c4d9d58a5d
commit 48202da9e4
1 changed files with 23 additions and 11 deletions
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34
src/main/java/io/github/dsheirer/module/decode/p25/phase1/message/lc/motorola/LCMotorolaUnitGPS.java
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@@ -1,6 +1,6 @@
/*
* *****************************************************************************
* Copyright (C) 2014-2024 Dennis Sheirer
* Copyright (C) 2014-2025 Dennis Sheirer
*
* This program is free software: you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
@@ -35,14 +35,10 @@ public class LCMotorolaUnitGPS extends LinkControlWord
{
private static final double LATITUDE_MULTIPLIER = 90.0 / 0x7FFFFF;
private static final double LONGITUDE_MULTIPLIER = 180.0 / 0x7FFFFF;
private static final int LATITUDE_SIGN = 24;
private static final FragmentedIntField LATITUDE = FragmentedIntField.of(25, 26, 27, 28, 29, 30, 31, 32, 33,
34, 35, 36, 37, 38, 39, 40, 41, 42, 43, 44, 45, 46, 47);
private static final int LONGITUDE_SIGN = 48;
private static final FragmentedIntField LONGITUDE = FragmentedIntField.of(49, 50, 51, 52, 53, 54, 55, 56,
57, 58, 59, 60, 61, 62, 63, 64, 65, 66, 67, 68, 69, 70, 71);
private static final FragmentedIntField LATITUDE_TWOS_COMPLEMENT = FragmentedIntField.of(24, 25, 26, 27, 28,
29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40, 41, 42, 43, 44, 45, 46, 47);
private static final FragmentedIntField LONGITUDE_TWOS_COMPLEMENT = FragmentedIntField.of(48, 49, 50, 51,
52, 53, 54, 55, 56, 57, 58, 59, 60, 61, 62, 63, 64, 65, 66, 67, 68, 69, 70, 71);
private P25Location mLocation;
private GeoPosition mGeoPosition;
private List<Identifier> mIdentifiers;
@@ -98,7 +94,7 @@ public class LCMotorolaUnitGPS extends LinkControlWord
*/
public double getLatitude()
{
return getInt(LATITUDE) * LATITUDE_MULTIPLIER * (getMessage().get(LATITUDE_SIGN) ? -1 : 1);
return parse24BitInteger(getInt(LATITUDE_TWOS_COMPLEMENT)) * LATITUDE_MULTIPLIER;
}
/**
@@ -107,7 +103,7 @@ public class LCMotorolaUnitGPS extends LinkControlWord
*/
public double getLongitude()
{
return getInt(LONGITUDE) * LONGITUDE_MULTIPLIER * (getMessage().get(LONGITUDE_SIGN) ? -1 : 1);
return parse24BitInteger(getInt(LONGITUDE_TWOS_COMPLEMENT)) * LONGITUDE_MULTIPLIER;
}
/**
@@ -124,4 +120,20 @@ public class LCMotorolaUnitGPS extends LinkControlWord
return mIdentifiers;
}
/**
* Parses a 24-bit two-complement number to a signed integer.
* @param value with 24 bits
* @return signed integer value.
*/
public static int parse24BitInteger(int value)
{
//If high-order bit is set, perform sign extension setting the 8x high order bits as a signed 32-bit integer
if((value & 0x800000) == 0x800000)
{
value |= 0xFF000000;
}
return value;
}
}