check ubx send status and actually return payload

gps_ubxm8_i2c/gps.cc

@@ -34,7 +34,9 @@ const GpsUbxM8I2c::State GpsUbxM8I2c::GetState() { return _state; }
  */
 const GpsUbxM8I2c::PollResult GpsUbxM8I2c::PollUpdate() {
     if (_state == GpsUbxM8I2c::State::REQUEST_NOT_SENT) {
-        sendUBX(_ubxMessage);
+        if(!sendUBX(_ubxMessage)) {
+            return GpsUbxM8I2c::PollResult::REQUEST_SEND_FAILED;
+        }
         _state = GpsUbxM8I2c::State::POLLING_RESPONSE;
     }
 
@@ -143,6 +145,8 @@ UCIRP_GPS_PAYLOAD ConvertPayloadToECEF(UBX_NAV_PVT_PAYLOAD pvtPayload) {
     double velD = (double)pvtPayload.velD / 1000;
 
     Ned2EcefVel(lat, lon, alt, velN, velE, velD, payload.ecefVX, payload.ecefVY, payload.ecefVZ);
+
+    return payload;
 }
 
 /**

gps_ubxm8_i2c/gps.h

@@ -74,7 +74,8 @@ class GpsUbxM8I2c {
         NO_UBX_DATA,                  // data read successfully but no UBX start bytes found
         DATA_LEN_POLL_FAILED,         // there was a failure in the I2C mem read for getting the quantity of data available
         DATA_RECEIVE_I2C_FAILED,      // there was a failure in the I2C receive to read the available data from the GPS
-        DATA_RECEIVE_CHECKSUM_FAILED  // we received UBX data but the checksum didn't match the message.
+        DATA_RECEIVE_CHECKSUM_FAILED, // we received UBX data but the checksum didn't match the message.
+        REQUEST_SEND_FAILED           // the request to the GPS failed (probably i2c transmit error)
     };
     GpsUbxM8I2c(GPIO_TypeDef* gpioResetPort, uint16_t gpioResetPin, I2C_HandleTypeDef* i2c, uint8_t* ubxMessage);
     void Init();