Testing of military GNSS equipment such as receivers and antennas is a critical part of developing these systems and integrating them into vehicles such as manned and unmanned aircraft, ground vehicles, naval vessels and robotic platforms.
GNSS testing is performed in order to ensure that platforms incorporating such equipment receive the proper PNT (position, navigation and timing) data required for successful operation, as well as to characterize how equipment may perform under varied conditions. GNSS receivers and antennas may need to be tested to determine their behavior in the presence of interference as well as jamming and spoofing attacks.
Live Sky Testing
GNSS equipment can be trialed in the field, using what is known as “live sky” testing under real-world conditions. While this is a realistic form of testing and is useful for confirming laboratory and development results, it suffers from numerous disadvantages.
- It can be time-consuming and costly to repeatedly deploy equipment on actual vehicles, particularly in varied geographic locations.
- Live-sky testing is also not repeatable, and is subject to random errors and varying environmental conditions.
GNSS Signal Generators
More robust testing can be performed using GNSS signal generators, which can be used to simulate satellite signals from all constellations including GPS, Galileo, BeiDou, GLONASS, SBAS and QZSS. GNSS simulators can also be used to develop systems that utilize future GNSS frequencies before that satellites are actually launched.
GNSS simulators provide a range of options that can be used to create highly realistic and repeatable test regimes. A wide variety of satellite and environmental parameters can be simulated, including satellite positions and elevations, geographic locations, and atmospheric conditions. Specific errors can be introduced into testing in a controlled manner, and effects such as multipath and antenna patterns can be modeled.