Spatial FOG Reference ManualPage 84 of 144Version 2.303/05/201812 Interfacing12.1 CommunicationCommunication with Spatial FOG is over the primary RS422 or RS232 interface in theAdvanced Navigation Packet Protocol (ANPP). The RS422 or RS232 format is fixed at 1start bit, 8 data bits, 1 stop bit and no parity. See section 13 for details on the protocol.12.1.1 Baud RateThe default baud rate of Spatial FOG is 115,200. The baud rate can be set anywherefrom 1,200 to 10,000,000 baud and can be modified using the Spatial FOG Managersoftware or the baud rate packet, see section 13.10.3. It is important to select a baudrate that is capable of carrying the amount of data that Spatial FOG is set to send. Seepacket rates in section 13.5 for more details on data output calculation. The data ratein bytes per second can be calculated by dividing the baud rate by 10. For example ifthe baud rate is 115,200, then the data rate is 11,520 bytes per second.12.2 External DataExternal sources of position, velocity and/or heading can be integrated into SpatialFOG's filter solution. The data can be sent to Spatial FOG in the ANPP format over theprimary port or through one of the GPIO pins in a number of diferent formats. If usingthe ANPP, please use Table 17 below to find the relevant section. If using the GPIOs,please see section 12.3.Packet SectionExternal Position and Velocity 13.9.25External Position 13.9.26External Velocity 13.9.27External Body Velocity 13.9.28External Heading 13.9.29External Time 13.9.33External Depth 13.9.34External Pitot Pressure 13.9.37External Odometer 13.9.43External Air Data 13.9.44Table 17: ANPP external data reference12.3 GPIO Pins and Auxiliary RS232Spatial FOG contains two general purpose input output pins and one auxiliary RS232port on the main connector. These pins are multi function and can be used to extendSpatial FOG with additional peripherals, sensors and data formats. The GPIO pins have
