diff --git a/libraries/AP_AIS/AP_AIS.cpp b/libraries/AP_AIS/AP_AIS.cpp
index 02d1ec4e91..29bde18a8b 100644
--- a/libraries/AP_AIS/AP_AIS.cpp
+++ b/libraries/AP_AIS/AP_AIS.cpp
@@ -343,6 +343,8 @@ bool AP_AIS::payload_decode(const char *payload)
         case 2: // Position Report Class A (Assigned schedule)
         case 3: // Position Report Class A (Response to interrogation)
             return decode_position_report(payload, type);
+        case 4: // Base Station Report
+            return decode_base_station_report(payload);
         case 5: // Static and Voyage Related Data
             return decode_static_and_voyage_data(payload);
 
@@ -440,6 +442,63 @@ bool AP_AIS::decode_position_report(const char *payload, uint8_t type)
     return true;
 }
 
+bool AP_AIS::decode_base_station_report(const char *payload)
+{
+    if (strlen(payload) != 28) {
+        return false;
+    }
+
+    uint8_t repeat     = get_bits(payload, 6, 7);
+    uint32_t mmsi      = get_bits(payload, 8, 37);
+    uint16_t year      = get_bits(payload, 38, 51);
+    uint8_t month      = get_bits(payload, 52, 55);
+    uint8_t day        = get_bits(payload, 56, 60);
+    uint8_t hour       = get_bits(payload, 61, 65);
+    uint8_t minute     = get_bits(payload, 66, 71);
+    uint8_t second     = get_bits(payload, 72, 77);
+    bool fix           = get_bits(payload, 78, 78);
+    int32_t lon = get_bits_signed(payload, 79, 106)  * ((1.0f / 600000.0f)*1e7);
+    int32_t lat = get_bits_signed(payload, 107, 133) * ((1.0f / 600000.0f)*1e7);
+    uint8_t epfd       = get_bits(payload, 134, 137);
+    // 138 - 147: spare
+    bool raim          = get_bits(payload, 148, 148);
+    uint32_t radio     = get_bits(payload, 149, 167);
+
+    // log the raw infomation
+    if ((_log_options & AIS_OPTIONS_LOG_DECODED) != 0) {
+        struct log_AIS_msg4 pkt {
+            LOG_PACKET_HEADER_INIT(LOG_AIS_MSG4),
+            time_us     : AP_HAL::micros64(),
+            repeat      : repeat,
+            mmsi        : mmsi,
+            year        : year,
+            month       : month,
+            day         : day,
+            hour        : hour,
+            minute      : minute,
+            second      : second,
+            fix         : fix,
+            lon         : lon,
+            lat         : lat,
+            epfd        : epfd,
+            raim        : raim,
+            radio       : radio
+        };
+        AP::logger().WriteBlock(&pkt, sizeof(pkt));
+    }
+
+    uint16_t index;
+    if (!get_vessel_index(mmsi, index)) {
+        return true;
+    }
+
+    _list[index].info.lat = lat; // int32_t [degE7] Latitude
+    _list[index].info.lon = lon; // int32_t [degE7] Longitude
+    _list[index].last_update_ms = AP_HAL::millis();
+
+    return true;
+}
+
 bool AP_AIS::decode_static_and_voyage_data(const char *payload)
 {
     if (strlen(payload) != 71) {
diff --git a/libraries/AP_AIS/AP_AIS.h b/libraries/AP_AIS/AP_AIS.h
index 2f52a13850..a31a187988 100644
--- a/libraries/AP_AIS/AP_AIS.h
+++ b/libraries/AP_AIS/AP_AIS.h
@@ -104,6 +104,7 @@ private:
 
     // decode specific message types
     bool decode_position_report(const char *payload, uint8_t type) WARN_IF_UNUSED;
+    bool decode_base_station_report(const char *payload) WARN_IF_UNUSED;
     bool decode_static_and_voyage_data(const char *payload) WARN_IF_UNUSED;
 
     // read the specified bits from the char array each char giving 6 bits
diff --git a/libraries/AP_AIS/LogStructure.h b/libraries/AP_AIS/LogStructure.h
index 46a687acec..563a29e9c6 100644
--- a/libraries/AP_AIS/LogStructure.h
+++ b/libraries/AP_AIS/LogStructure.h
@@ -5,6 +5,7 @@
 #define LOG_IDS_FROM_AIS \
     LOG_AIS_RAW_MSG,\
     LOG_AIS_MSG1, \
+    LOG_AIS_MSG4, \
     LOG_AIS_MSG5
 
 struct PACKED log_AIS_raw {
@@ -36,6 +37,25 @@ struct PACKED log_AIS_msg1 {
     uint32_t radio;
 };
 
+struct PACKED log_AIS_msg4 {
+    LOG_PACKET_HEADER;
+    uint64_t time_us;
+    uint8_t repeat;
+    uint32_t mmsi;
+    uint16_t year;
+    uint8_t month;
+    uint8_t day;
+    uint8_t hour;
+    uint8_t minute;
+    uint8_t second;
+    uint8_t fix;
+    int32_t lon;
+    int32_t lat;
+    uint8_t epfd;
+    uint8_t raim;
+    uint32_t radio;
+};
+
 struct PACKED log_AIS_msg5 {
     LOG_PACKET_HEADER;
     uint64_t time_us;
@@ -83,6 +103,24 @@ struct PACKED log_AIS_msg5 {
 // @Field: raim: RAIM flag
 // @Field: rad: Radio status
 
+// @LoggerMessage: AIS4
+// @Description: Contents of 'Base Station Report' AIS message, see: https://gpsd.gitlab.io/gpsd/AIVDM.html#_type_4_base_station_report
+// @Field: US: Time since system startup
+// @Field: rep: Repeat Indicator
+// @Field: mmsi: MMSI
+// @Field: year: Year (UTC)
+// @Field: mth: Month (UTC)
+// @Field: day: Day (UTC)
+// @Field: h: Hour (UTC)
+// @Field: m: Minute (UTC)
+// @Field: s: Second (UTC)
+// @Field: fix: Fix quality
+// @Field: lon: Longitude
+// @Field: lat: Latitude
+// @Field: epfd: Type of EPFD
+// @Field: raim: RAIM flag
+// @Field: rad: Radio status
+
 // @LoggerMessage: AIS5
 // @Description: Contents of 'static and voyage related data' AIS message, see: https://gpsd.gitlab.io/gpsd/AIVDM.html#_type_5_static_and_voyage_related_data
 // @Field: US: Time since system startup
@@ -107,5 +145,7 @@ struct PACKED log_AIS_msg5 {
       "AISR",  "QBBBZ", "TimeUS,num,total,ID,payload", "s----", "F0000" }, \
     { LOG_AIS_MSG1, sizeof(log_AIS_msg1), \
       "AIS1",  "QBBIBbHbLLHHBBbI", "US,typ,rep,mmsi,nav,rot,sog,pos,lon,lat,cog,hed,sec,man,raim,rad", "s---------------", "F000000000000000" }, \
+    { LOG_AIS_MSG4, sizeof(log_AIS_msg4), \
+      "AIS4",  "QBIHBBBBBBLLBBI", "US,rep,mmsi,year,mth,day,h,m,s,fix,lon,lat,epfd,raim,rad", "s--------------", "F00000000000000" }, \
     { LOG_AIS_MSG5, sizeof(log_AIS_msg5), \
       "AIS5",  "QBIBINZBHHBBBBZB", "US,rep,mmsi,ver,imo,cal,nam,typ,bow,stn,prt,str,fix,dght,dst,dte", "s-------mmmm-m--", "F------------A--" }