Unmanned Systems Technology 022 | XOcean XO-450 l Radar systems l Space vehicles insight l Small Robot l BMPower FCPS l Prismatic HALE UAV l InterDrone 2018 show report l UpVision l Navigation systems

The calculations necessary for generating protection levels and figures of merit to monitor the integrity of navigation data can rarely be performed by GNSS unit processors, apart from those in heavier general aviation systems. Although some may output something like a 50% radial air probability, the density of processors and RF equipment required to match such safety standards would be too heavy and EMI-intensive for a UAS, unlike a passenger aircraft which can space the different antennas, RF front ends and computational systems dozens of metres apart. However, GNSS receivers for unmanned systems can still provide integrity monitoring. This differs from triple redundancy-type layouts, in which a UAV might integrate three systems to determine (via majority logic) what the correct readings for position, velocity or attitude are. With three of the same systems, however, it is still possible for three incorrect readings to be given if the systems all hold the same mechanical or software flaw, or if one or more satellites is outputting inaccurate navigation information. While relatively rare, a GNSS receiver designed to monitor satellite signal integrity (without overloading a small unmanned vehicle with excess RF and electronic equipment) might come with dual processors. UAV transponders might need GNSS systems capable of monitoring integrity as well as accuracy (Courtesy of uAvionix)