초록 ▼

A selective or tailored system for denying global positioning satellite (GPS) signal reception to unauthorized GPS receivers yet enabling authorized receivers to maintain access to the GPS system. The invention includes two basic units, the first being a tailored jamming unit which radiates an encod

A selective or tailored system for denying global positioning satellite (GPS) signal reception to unauthorized GPS receivers yet enabling authorized receivers to maintain access to the GPS system. The invention includes two basic units, the first being a tailored jamming unit which radiates an encoded denial or jamming waveform and the second being one or more receiver units including an interference or jamming signal suppression system which allows GPS user equipments to decode and suppress the jamming signal and receive the GPS satellite signal in the denial environment. The receiver unit decodes the encoded jamming signals. The jamming or denial signals, in its simplest form, employs a bi-polarization keying (BPK) defined as synchronously switching and radiating between two (or more) polarization states (or radiators) at a near 100-percent denial duty-cycle. The radiated signal's polarization, effective radiated power (ERP) level, noise bandwidth and density, and keying modulation (or switching rate) of the radiators are selected to provide sufficient diversity of the interference signal in victim GPS system to prevent normal C/A and/or P(Y) code receiver operation. The encoded switching modulation waveform to control switching between the denial polarization states uses a pseudo-noise encryption technique which allows asynchronous reception, decoding and synchronization for authorized users possessing essential codes, time information, and secure matched synchronization techniques implemented in an adaptive polarization feed network prior to inputting to the GPS receiver. The transmit system or network can deny GPS equipment operation over an area controlled by the effective radiated power radiation pattern of the transmit unit. The receive system or network can achieve synchronized polarization mismatch against the denial or jamming sources and also achieve suppression against other forms of interference sources.

대표청구항 ▼

[ We claim:] [1.] A system for preventing reception and recognition of global positioning satellite (GPS) signals by unauthorized receivers comprising:a jamming unit including transmitter means for transmitting plural GPS jamming signals over a geographic area, and transmitter encryption means for e

[ We claim:] [1.] A system for preventing reception and recognition of global positioning satellite (GPS) signals by unauthorized receivers comprising:a jamming unit including transmitter means for transmitting plural GPS jamming signals over a geographic area, and transmitter encryption means for enabling said transmitter means to transmit said plural GPS jamming signals in accordance with an encrypted sequence;one or more receiver units, each receiver unit including GPS jamming signal suppression means for receiving GPS jamming signals and GPS signals and for suppressing said GPS jamming signals to enable detection of the GPS signals, suppression encryption means for enabling said jamming signal suppression means to suppress each of said plural GPS jamming signals in accordance with an encrypted sequence identical to the encrypted sequence of said transmitter encryption means, and GPS signal receiving means for receiving the GPS signals detected by said GPS jamming signal suppression means.