Zero Velocity Input; Nmea Input; Nmea Output - Advanced Navigation Spatial Dual Reference Manual

Parameter
Trigger
Maximum Frequency
Maximum Pulse Rate
Table 21: Odometer Specifications
12.3.4

Zero Velocity Input

When using this function, a high state indicates to Spatial Dual that it is stationary. The
low state indicates that the vehicle is not stationary. Use of this function can
significantly improve drift performance when a GNSS signal is not available.
12.3.5

NMEA Input

This function accepts external data in the NMEA format. Advanced Navigation
recommends against using NMEA where possible due to the inefficiency, inaccuracy
and poor error checking of the format. All NMEA messages received must have a valid
checksum. Supported messages are listed below. The recommended combination of
messages are GPGGA, GPVTG and GPZDA with optional messages GPGSV and GPGSA.
Message ID
GPGGA
GNGGA
GPGLL
GNGLL
GPRMC
GNRMC
GPVTG
GNVTG
GPHDT
GNHDT
HEHDT
GPGSV
GNGSV
GPGSA
GNGSA
GPZDA
GNZDA
Table 22: Supported NMEA messages
12.3.6

NMEA Output

This function outputs a configurable combination of the NMEA messages GPZDA,
GPGGA, GPVTG, GPRMC, GPHDT and PASHR at up to 20 Hz. The messages output and
3D position
2D position
2D position, 2D velocity and coarse time
2D velocity
Heading
Satellites
Dilution of Position
Time
Spatial Dual Reference Manual
Page 83 of 137
Version 2.3
12/04/2016
Value
Low → High
600Khz
4294967 pulses/metre
Description