Multi-band jammer including airborne systems
An airborne jammer for transport by an aircraft for jamming communications in a communications system where the communications system operates with digital bursts having burst periods measured in time and occurring in a communication frequency band such as GSM having a transmit band and a receive band. The jammer includes a tone comb generator for providing repetitions of jamming signals for the communication frequency band where the jamming signals have jamming signal intervals providing frequency separation between the jamming signals. The jamming signals are generated with a dwell time substantially less than a burst period for the communications system. The jamming signals are transmitted as RF jamming signals to jam communications for mobile stations.
1. A jammer for transport by an aircraft for jamming communications in a communications system where the communications system operates with digital bursts having burst periods measured in time and occurring in a communication frequency band having a transmit band and a receive band, said jammer comprising:
an airborne tone comb generator for providing repetitions of jamming signals for the communication frequency band, said jamming signals having jamming signal frequency intervals providing frequency separation between jamming signals, said jamming signals generated with dwell times less than a burst period,
an airborne transmitter for transmitting said jamming signals as RF signals.
2. The jammer of claim 1 wherein the dwell time is approximately twenty percent or greater than the burst period.
3. The jammer of claim 1 wherein the communication band includes the entire active portion of a GSM band.
4. The jammer of claim 1 wherein the communication band includes a GSM band for base station transmitted channels.
5. The jammer of claim 1 wherein the communication band includes a GSM band for mobile station transmitted channels.
6. The jammer of claim 1 wherein the communication band includes a GSM band for base station transmitted channels and includes a GSM band for mobile station transmitted channels.
7. The jammer of claim 1 wherein the communication band corresponds to a subset of a GSM band for base station transmitted channels and corresponds to a subset of a GSM band for mobile station transmitted channels.
8. The jammer of claim 1 wherein the communication band has a plurality of channels and wherein the jamming signals dwell on each channel for a dwell period of time.
9. The jammer of claim 8 wherein communication in each channel is with TDMA bursts and wherein the jamming signals dwell on each channel at least once for each TDMA burst.
10. The jammer of claim 9 wherein the dwell period is approximately 28.8 μsec for each jamming signal.
11. The jammer of claim 1 wherein the jamming signals are provided in a set and wherein the set is repeated in frequency.
12. The jammer of claim 11 wherein the set is continuously repeated every 1.0 MHz.
13. The jammer of claim 1 wherein the jamming signal frequency interval is 0.1 MHz.
14. The jammer of claim 1 wherein the jamming signals are composite signals formed of continuous wave signals having random relative phases.
15. The jammer of claim 1 wherein said tone comb generator includes,
a binary file generator including a digital store unit having a random access memory for storing said jamming signals and for providing said jammer signals as baseband signals with said jamming signal frequency intervals,
an up-converter for converting said baseband signals to RF jammer signals.
16. The jammer of claim 15 wherein said up-converter includes a local oscillator providing an RF local oscillator signal, a mixer for multiplying the RF local oscillator signal and the baseband signals to provide lower sideband signals and upper sideband signals as said RF jammer signals.
17. The jammer of claim 16 wherein said lower sideband signals correspond to the transmit band and said upper sideband signals correspond to the receive band.
18. The jammer of claim 1 including a control unit for controlling operating parameters and wherein said operating parameters include a “look through” period when jamming signals are not transmitted.
19. The jammer of claim 1 wherein said tone comb generator generates said jamming signals using direct digital synthesis.