GNSS for unmanned and autonomous vehicles and drones
Many unmanned systems such as UAVs, UGVs and AUVs require the use of GPS/GNSS to provide them with a high degree of positioning accuracy for applications such as mapping, surveying, precision agriculture and search & rescue. A GNSS antenna is mounted somewhere on the vehicle, and satellite data is then usually fed into the avionics, autopilot or navigation systems.
In addition to navigation, unmanned vehicles may use GNSS to georeference gathered data, avoid collisions, or provide tracking capabilities. The GNSS data provides inputs to the control loop of a drone or other autonomous vehicle, allowing it to maintain position, return to home or follow a series of preset waypoints. This is particularly important for waterborne robots such as AUVs and ROVs whose positions can be significantly affected by tidal activity.
NovAtel SPAN on FlexPak6 GNSS INS Receiver
GNSS faces the limitation of needing to be within line of sight of at least four satellites in order to provide reliable navigation. In poor signal environments it can be advantageous to couple the GNSS with an Inertial Navigation System (INS), which uses rotation and acceleration information to calculate a relative position that can be used for navigation during loss of GNSS signal. In turn the GNSS can provide an external reference to the INS that helps reduce the effect of bias errors.
GNSS/INS receivers for UAVs and unmanned vehicles are particularly useful for urban or heavily wooded environments, or for missions where the vehicle is likely to traverse through tunnels or other GNSS signal obstructions.