Autosync GPS/GNSS Output

A Transmitter with autosync installed will automatically forward (“re-tweet”) all GPS/GNSS sentences from the GNSS receiver to the main interface. Thus, it can be simultaneously used as a GPS unit on the ROV. Due to this feature, Transmitters with autosync default to 9600 baud (Obsolete Mk II non-autosync transmitters default to 115,200 baud). This is to better emulate a GPS receiver. Mk III transponders are always set to 115,200 baud since they cannot have an autosync option installed.

Most users don't bother to connect the transmitter or transponder serial input and output to anything as the system will work fine without looking at the transmitter/transponder data. Using the GPS/GNSS re-tweet would be one exception to this rule.

A Receiver with autosync installed can be commanded to forward all GPS/GNSS sentences from the GNSS receiver to the main interface (see “V3” and “V0” commands). Since the receiver must be submerged in normal operation (and thus the GPS lock is lost during operation), we do not provide a method for using the ROVL RX GNSS as a substitute for a topside GPS.

The forwarded/re-tweeted GPS sentences from the ROVL units may include:

$GPGSA and/or $GNGSA - GPS dilution of position and active satellites

$GPGSV - Number of SVs in view, PRN, elevation, azimuth, and SNR

$GPVTG and/or $GNVTG - Actual track made good and speed over ground

$GPGGA and/or $GNGGA - Time, position, and fix related data

$GPGLL and/or $GNGLL - Position data: position fix, time of position fix, and status

$GPTXT - Free text, manufacturer defined

$GPRMC and/or $GNRMC - Minimum recommended Position, Velocity, and Time