diff --git a/libraries/AP_GPS/AP_GPS.cpp b/libraries/AP_GPS/AP_GPS.cpp
index 6f0b6c90e4..1e94fa810c 100644
--- a/libraries/AP_GPS/AP_GPS.cpp
+++ b/libraries/AP_GPS/AP_GPS.cpp
@@ -1584,6 +1584,7 @@ void AP_GPS::handle_gps_rtcm_fragment(uint8_t flags, const uint8_t *data, uint8_
         // we have one or more partial fragments already received
         // which conflict with the new fragment, discard previous fragments
         rtcm_buffer->fragment_count = 0;
+        rtcm_stats.fragments_discarded += rtcm_buffer->fragments_received;
         rtcm_buffer->fragments_received = 0;
     }
 
@@ -1612,6 +1613,7 @@ void AP_GPS::handle_gps_rtcm_fragment(uint8_t flags, const uint8_t *data, uint8_
     if (rtcm_buffer->fragment_count != 0 &&
         rtcm_buffer->fragments_received == (1U << rtcm_buffer->fragment_count) - 1) {
         // we have them all, inject
+        rtcm_stats.fragments_used += rtcm_buffer->fragments_received;
         inject_data(rtcm_buffer->buffer, rtcm_buffer->total_length);
         rtcm_buffer->fragment_count = 0;
         rtcm_buffer->fragments_received = 0;
@@ -2252,6 +2254,8 @@ void AP_GPS::Write_GPS(uint8_t i)
         sample_ms     : last_message_time_ms(i),
         delta_ms      : last_message_delta_time_ms(i),
         undulation    : undulation,
+        rtcm_fragments_used: rtcm_stats.fragments_used,
+        rtcm_fragments_discarded: rtcm_stats.fragments_discarded
     };
     AP::logger().WriteBlock(&pkt2, sizeof(pkt2));
 }
diff --git a/libraries/AP_GPS/AP_GPS.h b/libraries/AP_GPS/AP_GPS.h
index 73cb0836bf..41ae0c35fa 100644
--- a/libraries/AP_GPS/AP_GPS.h
+++ b/libraries/AP_GPS/AP_GPS.h
@@ -717,6 +717,11 @@ private:
         uint8_t buffer[MAVLINK_MSG_GPS_RTCM_DATA_FIELD_DATA_LEN*4];
     } *rtcm_buffer;
 
+    struct {
+        uint16_t fragments_used;
+        uint16_t fragments_discarded;
+    } rtcm_stats;
+
     // re-assemble GPS_RTCM_DATA message
     void handle_gps_rtcm_data(const mavlink_message_t &msg);
     void handle_gps_inject(const mavlink_message_t &msg);
diff --git a/libraries/AP_GPS/LogStructure.h b/libraries/AP_GPS/LogStructure.h
index e34bed923f..ffdbd73db5 100644
--- a/libraries/AP_GPS/LogStructure.h
+++ b/libraries/AP_GPS/LogStructure.h
@@ -63,6 +63,8 @@ struct PACKED log_GPS {
 // @Field: SMS: time since system startup this sample was taken
 // @Field: Delta: system time delta between the last two reported positions
 // @Field: Und: Undulation
+// @Field: RTCMFU: RTCM fragments used
+// @Field: RTCMFD: RTCM fragments discarded
 struct PACKED log_GPA {
     LOG_PACKET_HEADER;
     uint64_t time_us;
@@ -76,6 +78,8 @@ struct PACKED log_GPA {
     uint32_t sample_ms;
     uint16_t delta_ms;
     float undulation;
+    uint16_t rtcm_fragments_used;
+    uint16_t rtcm_fragments_discarded;
 };
 
 /*
@@ -202,7 +206,7 @@ struct PACKED log_GPS_RAWS {
     { LOG_GPS_MSG, sizeof(log_GPS), \
       "GPS",  "QBBIHBcLLeffffB", "TimeUS,I,Status,GMS,GWk,NSats,HDop,Lat,Lng,Alt,Spd,GCrs,VZ,Yaw,U", "s#---SmDUmnhnh-", "F----0BGGB000--" , true }, \
     { LOG_GPA_MSG,  sizeof(log_GPA), \
-      "GPA",  "QBCCCCfBIHf", "TimeUS,I,VDop,HAcc,VAcc,SAcc,YAcc,VV,SMS,Delta,Und", "s#mmmnd-ssm", "F-BBBB0-CC0" , true }, \
+      "GPA",  "QBCCCCfBIHfHH", "TimeUS,I,VDop,HAcc,VAcc,SAcc,YAcc,VV,SMS,Delta,Und,RTCMFU,RTCMFD", "s#mmmnd-ssm--", "F-BBBB0-CC0--" , true }, \
     { LOG_GPS_UBX1_MSG, sizeof(log_Ubx1), \
       "UBX1", "QBHBBHI",  "TimeUS,Instance,noisePerMS,jamInd,aPower,agcCnt,config", "s#-----", "F------"  , true }, \
     { LOG_GPS_UBX2_MSG, sizeof(log_Ubx2), \