Here is a list of all documented struct and union fields with links to the struct/union documentation for each field:

• altitude : nmea_sentence_gga
• altitude_units : nmea_sentence_gga
• dgps_age : nmea_sentence_gga
• fix_quality : nmea_sentence_gga
• hdop : nmea_sentence_gga
• heading : gps_data , nmea_sentence_rmc
• height : nmea_sentence_gga
• height_units : nmea_sentence_gga
• latitude : gps_data , nmea_sentence_gga , nmea_sentence_rmc
• longitude : gps_data , nmea_sentence_gga , nmea_sentence_rmc
• satellites_tracked : nmea_sentence_gga
• speed : gps_data , nmea_sentence_rmc
• valid : nmea_sentence_rmc