A. de Cheveigné, "Cancellation principle", last revised: 1 Dec 2003 2 dB for a two-microphone delay-and-add beamformer). Second, jammer cancellation works well in situations where SNR is unfavorable (for which segregation is most needed). In that case estimating jammer structure is easy, whereas estimating target structure is hard. Cancellation has two weaknesses. The first is that the jammer m...

To evaluate the performance of spacecraft angle measurement in jamming, a method of TT&C (Telemetry, Tracking, and Control) monopulse system analysis is proposed in the condition that antenna keeps tracking the target. First, a geometric model of large aperture parabolic antenna is established, and the antenna patterns of sum, azimuth difference and elevation difference channel are derived thro...

Built upon a shared wireless medium, wireless sensor network is particularly vulnerable to jamming attacks. These attacks can easily be accomplished by an adversary by either bypassing MAC-layer protocols or emitting a radio signal targeted at jamming a particular channel. This paper considers a scenario where a sophisticated jammer jams an area in a multichannel wireless sensor network. The ja...

We investigate the behavior of two users and one jammer in an AWGN channel with and without fading when they participate in a zero-sum mutual information game with the sum capacity as the objective function. We assume that the jammer can eavesdrop the channel and can use the information obtained to perform correlated jamming.

By using smart radio devices, a jammer can dynamically change its jamming policy based on opposing security mechanisms; it can even induce the mobile device to enter a specific communication mode and then launch the jamming policy accordingly. On the other hand, mobile devices can exploit spread spectrum and user mobility to address both jamming and interference. In this paper, a two-dimensiona...

1. Introduction Global positioning system (GPS) employing satellite-based location techniques has been widely used in providing precision navigational capabilities for aircraft, ships, and ground traffic. Due to a large processing gain with spread spectrum techniques employed, GPS receivers can be effective in extracting the navigational information signals transmitted from satellites at a powe...

Mainbeam jamming poses a particularly difficult challenge for conventional monopulse radars. In such cases spatially adaptive processing provides some interference suppression when the target and jammer are not exactly coaligned. However, as the target angle approaches that of the jammer, mitigation performance is increasingly hampered and distortions are introduced into the resulting beam patt...

A new method is introduced for interference excision in spread spectrum communications. Time-frequency synthesis techniques are used to synthesize the nonstationary jammer from the timefrequency domain using least-squares methods. The synthesized jammer is then subtracted from the incoming data in the time domain, leading to increased signal to interference ratio at the input of the correlator....

This brief deals with the improvement of jammer suppression for adaptive broadband beamforming. The analysis is carried out with a two-microphone Griffiths–Jim Beamformer and a single jammer signal. By examining the derived optimal filter, a design strategy for the constant target-signal filter in the main channel of the adaptive beamformer is given. This leads to a substantial reduction in the...

In this paper, we propose time-frequency jammer excision techniques for direct sequence spread spectrum communications. One method is based on the estimation of the instantaneous frequency (IF) of each of the chirp jammer components using a combination of the discrete evolutionary and the Hough transforms. The second method is based in Wiener masking, and reduces the interference in a mean-squa...