GNSS Simulators for Unmanned Systems
GNSS simulation is a method of testing the GNSS receiver that is used by a UAV (unmanned aerial vehicle), UGV (unmanned ground vehicle) or other robotic or autonomous system for position and navigation.
Unmanned vehicles rely on GNSS signals to carry out tasks accurately and safely, and GNSS simulation is used to characterize how their navigation systems will respond under a range of different signal conditions. This can help with a number of design aspects, such as the location of the receiver and antennas within the vehicle, and whether other sensors such as inertial navigation systems may be required.
Live Sky vs Simulation Testing
GNSS simulators provide signals that mimic those emitted by the real-world satellites overhead, and have a number of advantages over “live sky” testing that uses the actual satellite signals. It enables test conditions to be controlled exactly, enabling an extremely high degree of repeatability without needing to worry about atmospheric conditions, signal errors, or how walls and buildings at the test site may affect the signal. It may also be quicker and less costly, as the test drone or vehicle does not need to be deployed.
Single and Multi Constellation Simulators
GNSS simulators may be single-constellation or multi-constellation, providing signals that mimic one or more of the GPS, Galileo, BeiDou, GLONASS, SBAS and QZSS services. Simulators may also be multi-channel and multi-frequency, and some may provide simulation of restricted signals such as the GPS P-code used for military applications.
GPS and GNSS simulation enables the testing of a range of parameters that may affect the navigation and positioning performance of a drone or unmanned vehicle. These include time to first fix, reacquisition time, acquisition and tracking sensitivity, and navigation and timing accuracy. Simulators can also be used to test the response of a system to spoofing and jamming attacks.
