On the Challenges for Autonomous Multi-Static Cooperative Airborne Radars

A multi-static radar system consists of an RF transmitter, which may be detectable by a third-party system, and one or more receivers that provide detection and geolocation of targets discreetly. Such an airborne system allows long-range detection of low-altitude targets. The system discussed here is cooperative: the waveforms used by the system are knowledgeable by all the nodes and we do not use opportunistic transmissions unlike PCL systems. As this system is intended to operate in adverse conditions, it must be autonomous: it do not rely for its synchronization on third-party signals like those from GNSS, which may be unusable (absent, jammed or spoofed). This paper addresses three main challenges to overcome to operate such a system effectively: -the synchronization of the oscillators, -that of the waveforms as well as the multiple beams digitally formed at reception allowing the search and tracking functions.