Gnss Fix Output; Odometer Input; Zero Velocity Input; Pitot Tube Input - Advanced Navigation Spatial FOG Dual Reference Manual

12.4.2

GNSS Fix Output

In this function, the pin is low when there is no GNSS fix or a 2D fix and high when
there is a 3D, SBAS, Differential or RTK GNSS fix.
12.4.3

Odometer Input

This function is designed for low resolution vehicle speed sensors and odometers. It
expects a normally low input with a high state for the trigger. If the pulse length is
more than 0.1 metres this odometer input function should be used, if it is less than 0.1
metres the wheel speed sensor function should be used. Please contact Advanced
Navigation support for help integrating with your speed sensor.
Parameter
Trigger
Maximum Frequency
Maximum Pulse Rate
Table 20: Odometer Specifications
12.4.4

Zero Velocity Input

When using this function, a high state indicates to Spatial FOG 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.
12.4.5

Pitot Tube Input

This function is designed for fixed wing aircraft to enhance navigation through the use
of a pitot tube to measure airspeed. It requires a differential pressure sensor that has a
frequency output such as the Kavlico P992 (frequency output option) or the
Paroscientific series 5300. Please contact Advanced Navigation support for help
integrating with a pitot tube.
12.4.6

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.
Spatial FOG Dual Reference Manual
Page 81 of 138
Version 1.0
26/06/2015
Value
Low → High
600Khz
4294967 pulses/metre