A multistatic electronic sensing system (e.g., radar or sonar) has at least one transmitting and at least one receiving antenna, the number of antennas in the system being greater than two. The antennas are usually separated by some number of wavelengths. At least some electronics will be at each location, although the signals are usually sent to a processing system, at another location(s).
There must be excellent time synchronization among the system components. If the system uses frequency agility, spread spectrum, or combination techniques of electronic protection/electronic counter-countermeasures (ECCM), the components also must know the frequencies in use.
Multistatic radars also can help detect stealth aircraft. One of the principles of stealth is that it reflects little or no signal in the direction of the transmitting antenna. If the receivers are in a different location than the transmitter, however, it may receive a stronger return than if the transmitting and receiving antennas were colocated. A set of weak returns on several antennas can be used to triangulate the target position.
Passive radar is a special case of multistatic radar, where the transmitter function is not part of the radar system, but of another high-power radio wave transmitter, such as a television broadcast station.
Multistatic radar, with a large number of transmitters, is also much more survivable than conventional radar. If a suppression of enemy air defense (SEAD) mission attacks and destroys one or more transmitters, it does not necessarily break the entire radar system.