| 1. |
- Falk, Johan, et al.
(författare)
-
Direction Finding for Electronic Warfare Systems Using the Phase of the Cross Spectral Density
- 2002
-
Ingår i: RadioVetenskap och Kommunikation (RVK). ; , s. 264-268
-
Konferensbidrag (refereegranskat)abstract
- In modern electronic warfare systems there is a need for direction-finding of transmitters using waveforms for military stealth communication. In this paper, a correlation-based method is investigated utilizing the phase of the cross spectral density to estimate the time-difference-of-arrival from a two-channel digital receiver. A least squares method is reviewed, and its performance is investigated by theoretical analysisand by Monte-Carlo simulations. Proper Cramér-Raobounds are derived. It is shown that the method is statistically efficient for flat spectrum signals. The method is found to be a promising method for use against military communication in an electronic warfare direction-finding system.
|
|
| 2. |
- Falk, Johan, et al.
(författare)
-
Effects of frequency and phase error in electronic warfare TDOA direction-finding systems
- 2003
-
Ingår i: Military Communications Conference. - : IEEE conference proceedings. - 0780381408 ; , s. 118-123
-
Konferensbidrag (refereegranskat)abstract
- Electronic warfare systems for use against military communication sources include direction-finding. The considered direction-finding electronic-warfare system usestwo intercept receivers which is eavesdropping on thetransmitted signal with no knowledge of the waveformused, or its origin. Down-conversion to baseband is required in order to digitize the received signal. This canbe done using a superheterodyne receiver where an oscillator is used to mix the signal-of-interest to baseband.Errors in frequency and phase between the oscillatorsdegrade the performance. Because of this error, the per-formance derived in previous work by the authors willnot apply since the used model no longer is applicable.The extended model presented here considers the oscil-lator errors. The performance using the extended modelis determined numerically and the result is compared tothe Cramer-Rao lower bound for the ideal system usinga typical signal waveform.
|
|
| 3. |
- Falk, Johan, et al.
(författare)
-
Multisource time delay estimation subject to receiver frequency errors
- 2003
-
Ingår i: CONFERENCE RECORD OF THE THIRTY-SEVENTH ASILOMAR CONFERENCE ON SIGNALS, SYSTEMS & COMPUTERS, VOLS 1 AND 2. - 0780381041 ; , s. 1156-1160
-
Konferensbidrag (refereegranskat)abstract
- An electronic warfare (EW) system with two spatially separated intercept receivers, targeting military communication systems is considered. The EW system estimates the direct ion-of-arrival via a correlation-based time-difference-of-arrival (TDOA) method without any prior knowledge of the signals-of-interest. An important practical consideration is the oscillator frequencies of the two intercept receivers where a difference, or error, degrades the TDOA estimator performance. A measure of this degradation, or loss in power due to the frequency error, is derived and used to describe the robustness against receiver frequency errors. In the multisource scenario, time and frequency overlapping sources can be separated using direction-filtering of the cross-correlation function between the receiver outputs with good result if one signal at a time can be selected by the direction-filter. However, the performance of the considered estimator is degraded in a multisource scenario compared to the single source case.
|
|
