Move GPS leap second and UTC-to-GPS conversion

to a new GpsUtils class.

Assets/Scripts/Bridge/Cyber/CyberConversions.cs

@@ -16,8 +16,6 @@ namespace Simulator.Bridge.Cyber
 {
     static class Conversions
     {
-        static readonly DateTime GpsEpoch = new DateTime(1980, 1, 6, 0, 0, 0, DateTimeKind.Utc);
-
         static byte[] ActualBytes(byte[] array, int length)
         {
             byte[] result = new byte[length];
@@ -236,7 +234,7 @@ public static apollo.canbus.Chassis ConvertFrom(CanBusData data)
             else dir = 45 * Mathf.Round((eul.y % 360 + 360) / 45.0f);
 
             var dt = DateTimeOffset.FromUnixTimeMilliseconds((long)(data.Time * 1000.0)).UtcDateTime;
-            var measurement_time = (dt - GpsEpoch).TotalSeconds + 18.0;
+            var measurement_time = GpsUtils.UtcToGpsSeconds(dt);
             var gpsTime = DateTimeOffset.FromUnixTimeSeconds((long)measurement_time).DateTime.ToLocalTime();
 
             return new apollo.canbus.Chassis()
@@ -297,7 +295,7 @@ public static apollo.drivers.gnss.GnssBestPose ConvertFrom(GpsData data)
             double Height = 0; // sea level to WGS84 ellipsoid
 
             var dt = DateTimeOffset.FromUnixTimeMilliseconds((long)(data.Time * 1000.0)).UtcDateTime;
-            var measurement_time = (dt - GpsEpoch).TotalSeconds + 18.0;
+            var measurement_time = GpsUtils.UtcToGpsSeconds(dt);
 
             return new apollo.drivers.gnss.GnssBestPose()
             {

Assets/Scripts/Bridge/GpsUtils.cs

@@ -0,0 +1,25 @@
+/**
+* Copyright (c) 2020 LG Electronics, Inc.
+*
+* This software contains code licensed as described in LICENSE.
+*
+*/
+
+using System;
+
+namespace Simulator.Bridge
+{
+    static public class GpsUtils
+    {
+        static readonly public DateTime GpsEpoch = new DateTime(1980, 1, 6, 0, 0, 0, DateTimeKind.Utc);
+        // GPS Time requires leap seconds which is updated every several years.
+        // https://racelogic.support/01VBOX_Automotive/01General_Information/Knowledge_Base/What_are_GPS_Leap_Seconds%3F
+        // We keep a single copy of this value here for easy update later.
+        static readonly public float GpsLeapSeconds = 18.0f;
+
+        static public double UtcToGpsSeconds(DateTime utc)
+        {
+            return (utc - GpsEpoch).TotalSeconds + GpsLeapSeconds;
+        }
+    }
+}

Assets/Scripts/Bridge/Ros/RosConversions.cs

@@ -17,8 +17,6 @@ namespace Simulator.Bridge.Ros
 {
     static class Conversions
     {
-        static readonly DateTime GpsEpoch = new DateTime(1980, 1, 6, 0, 0, 0, DateTimeKind.Utc);
-
         public static CompressedImage ConvertFrom(ImageData data)
         {
             return new CompressedImage()
@@ -210,7 +208,7 @@ public static Apollo.ChassisMsg ConvertFrom(CanBusData data)
             else dir = 45 * UnityEngine.Mathf.Round((eul.y % 360 + 360) / 45.0f);
 
             var dt = DateTimeOffset.FromUnixTimeMilliseconds((long)(data.Time * 1000.0)).UtcDateTime;
-            var measurement_time = (dt - GpsEpoch).TotalSeconds + 18.0;
+            var measurement_time = GpsUtils.UtcToGpsSeconds(dt);
             var gpsTime = DateTimeOffset.FromUnixTimeSeconds((long)measurement_time).DateTime.ToLocalTime();
 
             return new Apollo.ChassisMsg()
@@ -338,7 +336,7 @@ public static Apollo.GnssBestPose ConvertFrom(GpsData data)
             double Height = 0; // sea level to WGS84 ellipsoid
 
             var dt = DateTimeOffset.FromUnixTimeMilliseconds((long)(data.Time * 1000.0)).UtcDateTime;
-            var measurement_time = (dt - GpsEpoch).TotalSeconds + 18.0;
+            var measurement_time = GpsUtils.UtcToGpsSeconds(dt);
 
             return new Apollo.GnssBestPose()
             {
@@ -462,7 +460,7 @@ public static Apollo.Gps ApolloConvertFrom(GpsOdometryData data)
             {
                 header = new Apollo.Header()
                 {
-                    timestamp_sec = (dt - GpsEpoch).TotalSeconds + 18.0,
+                    timestamp_sec = GpsUtils.UtcToGpsSeconds(dt),
                     sequence_num = data.Sequence,
                 },