diff --git a/libraries/DataFlash/DataFlash.h b/libraries/DataFlash/DataFlash.h
index 1ceb0fb6cf..1f6448c25d 100644
--- a/libraries/DataFlash/DataFlash.h
+++ b/libraries/DataFlash/DataFlash.h
@@ -105,7 +105,7 @@ public:
     void StopLogging();
 
     void Log_Write_Parameter(const char *name, float value);
-    void Log_Write_GPS(const AP_GPS &gps, uint8_t instance, int32_t relative_alt);
+    void Log_Write_GPS(const AP_GPS &gps, uint8_t instance);
     void Log_Write_RFND(const RangeFinder &rangefinder);
     void Log_Write_IMU(const AP_InertialSensor &ins);
     void Log_Write_IMUDT(const AP_InertialSensor &ins);
diff --git a/libraries/DataFlash/LogFile.cpp b/libraries/DataFlash/LogFile.cpp
index 8f22db7f89..9dc5fa77ee 100644
--- a/libraries/DataFlash/LogFile.cpp
+++ b/libraries/DataFlash/LogFile.cpp
@@ -707,7 +707,7 @@ bool DataFlash_Backend::Log_Write_Parameter(const AP_Param *ap,
 }
 
 // Write an GPS packet
-void DataFlash_Class::Log_Write_GPS(const AP_GPS &gps, uint8_t i, int32_t relative_alt)
+void DataFlash_Class::Log_Write_GPS(const AP_GPS &gps, uint8_t i)
 {
     const struct Location &loc = gps.location(i);
     struct log_GPS pkt = {
@@ -720,7 +720,6 @@ void DataFlash_Class::Log_Write_GPS(const AP_GPS &gps, uint8_t i, int32_t relati
         hdop          : gps.get_hdop(i),
         latitude      : loc.lat,
         longitude     : loc.lng,
-        rel_altitude  : relative_alt,
         altitude      : loc.alt,
         ground_speed  : (uint32_t)(gps.ground_speed(i) * 100),
         ground_course : gps.ground_course_cd(i),
diff --git a/libraries/DataFlash/LogStructure.h b/libraries/DataFlash/LogStructure.h
index e0564a4099..fd77d6bbc5 100644
--- a/libraries/DataFlash/LogStructure.h
+++ b/libraries/DataFlash/LogStructure.h
@@ -51,7 +51,6 @@ struct PACKED log_GPS {
     uint16_t hdop;
     int32_t  latitude;
     int32_t  longitude;
-    int32_t  rel_altitude;
     int32_t  altitude;
     uint32_t ground_speed;
     int32_t  ground_course;
@@ -714,9 +713,9 @@ Format characters in the format string for binary log messages
     { LOG_PARAMETER_MSG, sizeof(log_Parameter), \
       "PARM", "QNf",        "TimeUS,Name,Value" },    \
     { LOG_GPS_MSG, sizeof(log_GPS), \
-      "GPS",  "QBIHBcLLeeEefB", "TimeUS,Status,GMS,GWk,NSats,HDop,Lat,Lng,RAlt,Alt,Spd,GCrs,VZ,U" }, \
+      "GPS",  "QBIHBcLLeEefB", "TimeUS,Status,GMS,GWk,NSats,HDop,Lat,Lng,Alt,Spd,GCrs,VZ,U" }, \
     { LOG_GPS2_MSG, sizeof(log_GPS), \
-      "GPS2", "QBIHBcLLeeEefB", "TimeUS,Status,GMS,GWk,NSats,HDop,Lat,Lng,RAlt,Alt,Spd,GCrs,VZ,U" }, \
+      "GPS2", "QBIHBcLLeEefB", "TimeUS,Status,GMS,GWk,NSats,HDop,Lat,Lng,Alt,Spd,GCrs,VZ,U" }, \
     { LOG_GPA_MSG,  sizeof(log_GPA), \
       "GPA",  "QCCCC", "TimeUS,VDop,HAcc,VAcc,SAcc" }, \
     { LOG_GPA2_MSG, sizeof(log_GPA), \