provided is a bistatic and multistatic system for detecting and identifying a target in close proximity to an orbiting satellite . an electromagnetic fence is established to surround the satellite , using a ground - based communication uplink from a gateway antenna . a contact or breach of the electromagnetic fence by the target is detected by the satellite , or at other sensor locations , and an exact position , range and isar image of the target is calculated using scattered rf energy from the fence . identification data is transmitted to satellite system monitors , whereby the data is used to decide on a corrective course of action .