Constrained optimal design of automotive radar arrays using the Weiss-Weinstein Bound

We propose a design strategy for optimizing antenna positions in linear arrays for far-field Direction of Arrival (DoA) estimation of narrow-band sources in collocated MIMO radar. Our methodology allows to consider any spatial constraints and number of antennas, using as optimization function the Weiss- Weinstein bound formulated for an observation model with random target phase and known SNR, over a pre-determined Field-of-View (FoV). Optimized arrays are calculated for the typical case of a 77GHz MIMO radar of 3Tx and 4Rx channels. Simulations demonstrate a performance improvement of the proposed arrays compared to the corresponding uniform and minimum redundancy arrays for a wide regime of SNR values.Comment: 2018 IEEE MTT-S International Conference on Microwaves for Intelligent Mobility (ICMIM

Contributions aux bornes inférieures de l’erreur quadratique moyenne en traitement du signal

A l’aide des bornes inférieures de l’erreur quadratique moyenne, la caractérisation du décrochement des estimateurs, l’analyse de la position optimale des capteurs dans un réseau ainsi que les limites de résolution statistiques sont étudiées dans le contexte du traitement d’antenne et du radar

Spatio-Temporal Analysis of Spontaneous Speech with Microphone Arrays

Accurate detection, localization and tracking of multiple moving speakers permits a wide spectrum of applications. Techniques are required that are versatile, robust to environmental variations, and not constraining for non-technical end-users. Based on distant recording of spontaneous multiparty conversations, this thesis focuses on the use of microphone arrays to address the question Who spoke where and when?. The speed, the versatility and the robustness of the proposed techniques are tested on a variety of real indoor recordings, including multiple moving speakers as well as seated speakers in meetings. Optimized implementations are provided in most cases. We propose to discretize the physical space into a few sectors, and for each time frame, to determine which sectors contain active acoustic sources (Where? When?). A topological interpretation of beamforming is proposed, which permits both to evaluate the average acoustic energy in a sector for a negligible cost, and to locate precisely a speaker within an active sector. One additional contribution that goes beyond the eld of microphone arrays is a generic, automatic threshold selection method, which does not require any training data. On the speaker detection task, the new approach is dramatically superior to the more classical approach where a threshold is set on training data. We use the new approach into an integrated system for multispeaker detection-localization. Another generic contribution is a principled, threshold-free, framework for short-term clustering of multispeaker location estimates, which also permits to detect where and when multiple trajectories intersect. On multi-party meeting recordings, using distant microphones only, short-term clustering yields a speaker segmentation performance similar to that of close-talking microphones. The resulting short speech segments are then grouped into speaker clusters (Who?), through an extension of the Bayesian Information Criterion to merge multiple modalities. On meeting recordings, the speaker clustering performance is signicantly improved by merging the classical mel-cepstrum information with the short-term speaker location information. Finally, a close analysis of the speaker clustering results suggests that future research should investigate the effect of human acoustic radiation characteristics on the overall transmission channel, when a speaker is a few meters away from a microphone

Weiss-Weinstein bound for MIMO radar with colocated linear arrays for SNR threshold prediction

International audienceSeveral works have suggested that a multi-input multi-output (MIMO) radar system offers improvement in terms of performance in comparison with classical phased-array radar. However, under the widely spread assumption of a uniform a priori distribution for one parameter of interest, there is no result concerning lower bounds on the mean-square error in the case of a Gaussian observation model with parameterized mean. This Fast Communication fills this lack by using the Weiss-Weinstein bound (WWB) which can be calculated under this difficult scenario. As we will show, the proposed bound for MIMO Radar with colocated linear arrays has no closed-form expression. To solve this problem, we propose a closed-form approximation that, as we will show by simulations, is close to the actual bound. This approximated bound is then analyzed for a design purpose in terms of array geometry. Simulations confirm the good ability of the proposed bound to predict the mean square error (MSE) of the maximum a posteriori (MAP) in all ranges of SNR. Particularly, the tightness of the bound to predict the SNR threshold effect is shown