Marc Lesturgie

Dual function radar communication Time-modulated array

This paper introduces the use of Time-modulated array methods to realize a dual function array. It is able to do a radar function in the mainlobe, while realizing a communication in the side lobe.

Applications of passive surveillance radar system using cell phone base station illuminators

The networks of cell phone base stations not only provide continuous service for mobile communications users but also offer abundant illuminator resources for passive surveillance radar systems. This extensively explores the potential applications of passive surveillance radar using cell phone base station signals for various scenarios such as ground traffic monitoring, coastal and air surveillance, and through-the-wall motion detections. These promising experimental results demonstrated that such systems can be an attractive, low-cost alternative solution for various applications and prospectively as a complement to traditional active radar systems.

A Coherent Model of Forest Propagation— Application to Detection and Localization of Targets Using the DORT Method

We study the propagation of electromagnetic fields in forest media in a frequency band between 100 and 300 MHz. We develop an exact coherent model in order to compute the electromagnetic field of a received wave after multiple scattering from the elements of the medium, in and outside the forest. We propose simplifications for the model of the forest and approximations for the electromagnetic method to reduce the computing time. We use and simulate a DORT based method to detect and locate a hidden target in the medium. We develop this method to adapt it to a real configuration and we apply it to measurements in anechoic chamber.

Analysis and comparison of MIMO radar waveforms

Choosing a proper waveform is a critical task for the implementation of multiple-input multiple-output (MIMO) radars. In addition to the general requirements for radar waveforms such as good resolution, low sidelobes, etc, MIMO radar waveforms also should possess good orthogonality. In this paper we give a brief overview of MIMO radar waveforms, which are classified into four categories: (1) time division multiple access (TDMA), (2) frequency division multiple access (FDMA), (3) Doppler division multiple access (DDMA), and (4) code division multiple access (CDMA). A special circulating MIMO waveform is also addressed The properties as well as application limitations of different waveforms are analyzed and compared. Some simulations results are also presented to illustrate the respective performance of different waveforms.

Target detection performance analysis for airborne passive bistatic radar

For a ground-based/airborne passive bistatic radar, its performance is dependent on the geometrical configuration and the passive transmit signal attributes. Theoretical power budget and ambiguity function analysis using a ground-based non-cooperative transmitter of opportunity with a passive bistatic radar being airborne but stationary (airship, etc.) had shown that target detection performance is limited by the strong direct path coupling signal. In comparison, the bistatic ground clutter power is significantly lower and even more so for noise power. For the passive radar to perform satisfactorily, sufficient attenuation must be provided for the direct path and strong ground clutter signals, corresponding to increasing the height of the target peak on the ambiguity function pedestal. In addition, performance could also be improved by increasing the time-bandwidth product (assuming no target migration issues), which lowers the pedestal of the ambiguity function of the strong direct path interfering signal.

Adaptive MIMO radar detection in non-Gaussian and heterogeneous clutter considering fluctuating targets

Previously, the Generalized Likelihood Ratio Test - Linear Quadratic (GLRT-LQ) has been extended to the Multiple-Input Multiple-Output (MIMO) case where all transmit-receive subarrays are considered jointly as a system such that only one detection threshold is used. The new MIMO detector is Constant False Alarm Rate (CFAR) with respect to the clutter power fluctuations. In this paper, the adaptive version of this detector is considered, as well as a fluctuating target model similar to that of the Swerling Target. The degradation of the detection performance due to the estimation of the covariance matrix and the fluctuation of the target is studied through simulations for both the well-known Optimum Gaussian Detector (OGD) and the new MIMO detector under Gaussian and non-Gaussian clutter.

Use of STAP techniques to enhance the detection of slow targets in shipborne HFSWR

This paper addresses the detection of low velocity targets from a shipborne HFSWR (high frequency surface waves radar). In a shipborne configuration, as a consequence of the ship motion, the first order of Bragg lines is spread in the useful Doppler interval where detections of a ship target are expected to appear. Space time techniques like STAP, usually studied for airborne radar purposes, are candidates to reduce the effect of ship motion. The influence of pitch and roll components is also discussed. Simulations of STAP techniques are given, based on a conventional architecture of processing. Estimation of the clutter covariance matrix is studied with respect to the characteristics of the radar waveform. Interleaving between the classical HFSWR waveform and a wide band learning waveform is proposed, to enable the covariance estimation.

Automatic Target Recognition for Passive Radar

Air-traffic controllers cannot identify air vehicles flying with a defective or nonexistent transponder. Primary radar does not help, because it cannot classify air vehicles from echoes. Passive radar offers a potential solution, the main difficulty lying in the analysis of the data. We present a novel, automatic object-target recognition system capable of classifying air vehicles observed with passive radar. We describe the testbed we deployed near Orly Airport, and the data it provided over 10 days. A preliminary experiment involving three broad classes, and using a grid of parallel classifiers, gives a promising correct recognition rate of 71%.

Robust MIMO radar detection for correlated subarrays

Previously, the well-known Optimum Gaussian Detector (OGD) has been extended to the Multiple-Input Multiple-Output (MIMO) case where all transmit-receive subarrays are considered jointly as a system such that only one detection threshold is used [1, 2]. In this extension, all subarrays have been assumed to be widely separated and the transmitted waveforms are assumed to be orthogonal. However, the necessary separation needed for each subarray to be uncorrelated depends on several factors and it might not be possible to ensure that this condition is always respected, especially in the case of moving platforms. Moreover, perfectly orthogonal waveforms do not exist. Hence, we consider in this paper, a new robust MIMO detector that is able to maintain the same Probability of False Alarm (Pfa) irregardless of the correlation between the subarrays.

Automatic real-time collection of RCS of airplanes in a real bistatic low-frequency configuration using a software defined passive radar based on illuminators of opportunity

In this paper, a novel method of measurement of the real RCS of various airplanes in real conditions, in bistatic mode, and at low frequency is derived. The presence of an airplane is detected by the use of an ADS-B receiver. The RCS of an airplane is derived thanks to the ratio of the power of the received echo signal to the power of the received direct path signal. In practical experiments, a VOR transmitter is used as illuminator of opportunity, and a software-defined radio is used as receiver. The measured RCS will later be used to classify airplanes, in the context of ATR.