diff --git a/main/ugv_io_gps.cc b/main/ugv_io_gps.cc
index 2652778..8517a68 100644
--- a/main/ugv_io_gps.cc
+++ b/main/ugv_io_gps.cc
@@ -37,7 +37,7 @@ const char NMEA_END_CMD[] = "\r\n";
 
 std::string st;
 
-static const char *TAG = "ugv_io";
+static const char *TAG = "ugv_io_gps";
 
 UART_GPS::UART_GPS() {}
 
@@ -122,12 +122,12 @@ void UART_GPS::ProcessLine(const char *line, size_t len) {
       }
       xSemaphoreTake(mutex_, pdMS_TO_TICKS(1000));
       data_.valid       = rmc.valid;
-      data_.latitude    = minmea_tofloat(&rmc.latitude);
-      data_.longitude   = minmea_tofloat(&rmc.longitude);
+      data_.latitude    = minmea_tocoord(&rmc.latitude);
+      data_.longitude   = minmea_tocoord(&rmc.longitude);
       data_.speed       = minmea_tofloat(&rmc.speed);
       data_.course      = minmea_tofloat(&rmc.course);
       data_.last_update = xTaskGetTickCount();
-      ESP_LOGD(TAG, "RMC: %s, (%f,%f), speed=%f, course=%f",
+      ESP_LOGV(TAG, "RMC: %s, (%f,%f), speed=%f, course=%f",
                data_.valid ? "valid" : "invalid", data_.latitude,
                data_.longitude, data_.speed, data_.course);
       xSemaphoreGive(mutex_);
@@ -143,19 +143,35 @@ void UART_GPS::ProcessLine(const char *line, size_t len) {
       xSemaphoreTake(mutex_, pdMS_TO_TICKS(1000));
       data_.fix_quality    = (GpsFixQual)gga.fix_quality;
       data_.num_satellites = gga.satellites_tracked;
-      data_.latitude       = minmea_tofloat(&gga.latitude);
-      data_.longitude      = minmea_tofloat(&gga.longitude);
+      data_.latitude       = minmea_tocoord(&gga.latitude);
+      data_.longitude      = minmea_tocoord(&gga.longitude);
       if (gga.fix_quality != 0 && gga.altitude_units != 'M') {
         ESP_LOGW(TAG, "unknown altitude units: %c", gga.altitude_units);
       }
       data_.altitude    = minmea_tofloat(&gga.altitude);
       data_.last_update = xTaskGetTickCount();
-      ESP_LOGD(TAG, "GGA: qual: %d, num_sat=%d, (%f,%f), alt=%f",
+      ESP_LOGV(TAG, "GGA: qual: %d, num_sat=%d, (%f,%f), alt=%f",
                data_.fix_quality, data_.num_satellites, data_.latitude,
                data_.longitude, data_.altitude);
       xSemaphoreGive(mutex_);
       break;
     }
+    case MINMEA_SENTENCE_GSA: {
+      minmea_sentence_gsa gsa;
+      bool                parse_success;
+      parse_success = minmea_parse_gsa(&gsa, line);
+      if (!parse_success) {
+        goto invalid;
+      }
+      xSemaphoreTake(mutex_, pdMS_TO_TICKS(1000));
+      data_.pdop    = minmea_tofloat(&gsa.pdop);
+      data_.hdop    = minmea_tofloat(&gsa.hdop);
+      data_.vdop    = minmea_tofloat(&gsa.vdop);
+      ESP_LOGV(TAG, "GSA: pdop=%f, hdop=%f, vdop=%f",
+               data_.pdop, data_.hdop, data_.vdop);
+      xSemaphoreGive(mutex_);
+      break;
+    }
     default: ESP_LOGV(TAG, "unsupported nmea sentence: %s", line);
   }
 }
@@ -184,13 +200,13 @@ void UART_GPS::DoTask() {
 
   esp_err_t ret;
   ret = WriteCommand(NMEA_OUTPUT_RMCGGA, sizeof(NMEA_OUTPUT_RMCGGA));
-  ESP_LOGI(TAG, "sent output rmc and gga: %d", ret);
+  ESP_LOGV(TAG, "sent output rmc and gga: %d", ret);
   ret = WriteCommand(NMEA_UPDATE_1HZ, sizeof(NMEA_UPDATE_1HZ));
-  ESP_LOGI(TAG, "sent update 1hz: %d", ret);
+  ESP_LOGV(TAG, "sent update 1hz: %d", ret);
 
   vTaskDelay(pdMS_TO_TICKS(100));
   ret = WriteCommand(NMEA_Q_RELEASE, sizeof(NMEA_Q_RELEASE));
-  ESP_LOGI(TAG, "sent q release: %d", ret);
+  ESP_LOGV(TAG, "sent q release: %d", ret);
 
   while (true) {
     BaseType_t pdRet = xQueueReceive(uart_queue_, &uart_event, portMAX_DELAY);
@@ -201,7 +217,7 @@ void UART_GPS::DoTask() {
       case UART_DATA: break;
       case UART_PATTERN_DET: this->HandleUartPattern(); break;
       default:
-        ESP_LOGW(TAG, "Unhandled GPS event type: %d", uart_event.type);
+        ESP_LOGW(TAG, "Unhandled UART event type: %d", uart_event.type);
         break;
     }
   }
diff --git a/main/ugv_io_gps.hh b/main/ugv_io_gps.hh
index 88cb59a..8e72ebf 100644
--- a/main/ugv_io_gps.hh
+++ b/main/ugv_io_gps.hh
@@ -31,6 +31,9 @@ struct GpsData {
   float altitude;   // meters
   float speed;      // knots
   float course;     // degrees clockwise of north
+  float pdop;
+  float hdop;
+  float vdop;
 };
 
 class UART_GPS {