Gnss Fix Output; Odometer Input; Stationary Input; Pitot Tube Input - Advanced Navigation Spatial OEM Reference Manual

second. The 1PPS line starts pulsing approximately 100 milliseconds after power up and always
fires irrespective of whether Spatial has accurate time or not. It is important to note that when
Spatial acquires time corrections from it's GNSS receiver, the 1PPS signal may fire at an interval of
less than 1 second. This typically only occurs the first time the GNSS receiver obtains a fix after
startup. The time initialised status flag can be used to determine whether the time and 1PPS line is
accurate or not.
8.3.2

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.
8.3.3

Odometer Input

This function is designed for wheel speed sensors and vehicle speed sensors. It expects a
normally low input with a transition from low to high for the trigger. Please contact Advanced
Navigation support for help integrating with your speed sensor.
Parameter
Voltage Level
Trigger
Maximum Frequency
Maximum Pulse Rate
Table 10: Odometer Specifications
8.3.4

Stationary Input

In this function, a high state indicates to Spatial that the vehicle is stationary. The low state
indicates that the vehicle could be moving. This can significantly improve performance when a
GNSS signal is not available.
8.3.5

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.
8.3.6

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.
Spatial OEM Reference Manual
Page 44 of 88
Version 2.7
Value
0 – 5V
Low → High
600 Khz
4,000,000 pulses/metre