Garmin GPS16x HVS

The Garmin GPS16x HVS (27) was selected as it is IPX7 rated and has a built-in antenna. The device is interfaced with messages that follows the NMEA0183 protocol. Baud rate is not defined in the NMEA standard. The baud rate can be set to 4800, 9600, 19200 or 38400. Lower baud rate increases immunity against radio frequency interference (RFI) but requires more time for transfer. 38400 was selected and tested. The device follows RS-232 defined voltage levels but also supports TTL voltage levels. The device does not support polling but outputs the selected messages at a frequency of 1 Hz. The user can enable or disable the different available messages. The available NMEA-approved output sentences are: GPALM, GPGGA, GPGLL, GPGSA, GPGSV, GPRMC, GPVTG. In addition, the device can provide the following Garmin proprietary sentences: PGRMB, PGRME, PGRMF, PGRMM, PGRMT, and PGRMV. In order to be able to meet system requirement A.REQ.2.06.4, GPRMC was enabled. GPRMC provides SOG, COG, and position. The GPGGA message enabled in addition because it provides the following useful information: Signal quality, number of satellites with fix and horizontal accuracy of position.