gprmc.cpp

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#include <septentrio_gnss_driver/parsers/nmea_parsers/gprmc.hpp>
 
const std::string GprmcParser::MESSAGE_ID = "$GPRMC";
 
const std::string GprmcParser::getMessageID() const
{
    return GprmcParser::MESSAGE_ID;
}
 
GprmcMsg GprmcParser::parseASCII(const NMEASentence& sentence,
                                 const std::string& frame_id, bool use_gnss_time,
                                 Timestamp time_obj) noexcept(false)
{
 
    // Checking the length first, it should be between 13 and 14 elements
    const size_t LEN_MIN = 13;
    const size_t LEN_MAX = 14;
 
    if (sentence.get_body().size() > LEN_MAX || sentence.get_body().size() < LEN_MIN)
    {
        std::stringstream error;
        error << "Expected GPRMC length is between " << LEN_MIN << " and " << LEN_MAX
              << ". The actual length is " << sentence.get_body().size();
        throw ParseException(error.str());
    }
 
    GprmcMsg msg;
 
    msg.header.frame_id = frame_id;
 
    msg.message_id = sentence.get_body()[0];
 
    if (sentence.get_body()[1].empty() || sentence.get_body()[1] == "0")
    {
        msg.utc_seconds = 0;
    } else
    {
        double utc_double;
        if (string_utilities::toDouble(sentence.get_body()[1], utc_double))
        {
            msg.utc_seconds =
                parsing_utilities::convertUTCDoubleToSeconds(utc_double);
            if (use_gnss_time)
            {
                // The Header's Unix Epoch time stamp
                time_t unix_time_seconds =
                    parsing_utilities::convertUTCtoUnix(utc_double);
                // The following assumes that there are two digits after the decimal
                // point in utc_double, i.e. in the NMEA UTC time.
                Timestamp unix_time_nanoseconds =
                    unix_time_seconds * 1000000000 +
                    (static_cast<Timestamp>(utc_double * 100) % 100) * 10000;
                msg.header.stamp = timestampToRos(unix_time_nanoseconds);
            } else
            {
                msg.header.stamp = timestampToRos(time_obj);
            }
        } else
        {
            throw ParseException(
                "Error parsing UTC seconds in GPRMC"); // E.g. if one of the fields
                                                       // of the NMEA UTC string is
                                                       // empty
        }
    }
    bool valid = true;
    bool to_be_ignored = false;
 
    msg.position_status = sentence.get_body()[2];
    // Check to see whether this message should be ignored
    to_be_ignored &= !(sentence.get_body()[2].compare("A") ==
                       0); // 0 : if both strings are equal.
    to_be_ignored &=
        (sentence.get_body()[3].empty() || sentence.get_body()[5].empty());
 
    double latitude = 0.0;
    valid =
        valid && parsing_utilities::parseDouble(sentence.get_body()[3], latitude);
    msg.lat = parsing_utilities::convertDMSToDegrees(latitude);
 
    double longitude = 0.0;
    valid =
        valid && parsing_utilities::parseDouble(sentence.get_body()[5], longitude);
    msg.lon = parsing_utilities::convertDMSToDegrees(longitude);
 
    msg.lat_dir = sentence.get_body()[4];
    msg.lon_dir = sentence.get_body()[6];
 
    valid =
        valid && parsing_utilities::parseFloat(sentence.get_body()[7], msg.speed);
    msg.speed *= KNOTS_TO_MPS;
 
    valid =
        valid && parsing_utilities::parseFloat(sentence.get_body()[8], msg.track);
 
    std::string date_str = sentence.get_body()[9];
    if (!date_str.empty())
    {
        msg.date = std::string("20") + date_str.substr(4, 2) + std::string("-") +
                   date_str.substr(2, 2) + std::string("-") + date_str.substr(0, 2);
    }
    valid =
        valid && parsing_utilities::parseFloat(sentence.get_body()[10], msg.mag_var);
    msg.mag_var_direction = sentence.get_body()[11];
    if (sentence.get_body().size() == LEN_MAX)
    {
        msg.mode_indicator = sentence.get_body()[12];
    }
 
    if (!valid)
    {
        was_last_gprmc_valid_ = false;
        throw ParseException("Error parsing GPRMC message.");
    }
 
    was_last_gprmc_valid_ = !to_be_ignored;
 
    return msg;
}
 
bool GprmcParser::wasLastGPRMCValid() const { return was_last_gprmc_valid_; }