Julien Le Kernec

Assessment of Sochacki lenses for autonomous maritime patrol FLAR

Initial numerical and experimental results are given for minimal layer lens antennas for Forward Looking Airborne Radar as the primary sensor onboard small Unmanned Aerial Vehicles adapted for fully autonomous long distance maritime patrol. 27dBi was achieved by a single material lens that is dimensionally compatible with the fuselage of a 6-meter class Unmanned Aerial Vehicle. Numerical results for 2 and 3 layer lenses up to 38dBi directivity were given, been comparable to the reflector antennas presently used in P-3C and P-8A manned maritime patrol aircraft.

Multitones’ Performance for Ultra Wideband Software Defined Radar

This chapter proposes and tests an approach for an unbiased study of radar waveforms’ performances. Through an empirical performance analysis, the performances of Chirp and Multitones are compared with both simulations and measurements. An ultra wideband software defined radar prototype was designed and the prototype has performances comparable to the state of the art in software defined radar. The study looks at peak-to-mean-envelope power ratio, spectrum efficiency, and pulse compression as independent waveform criteria. The experimental results are consistent with the simulations. The study shows that a minimum of 10 bits resolution for the AD/DA converters is required to obtain near-optimum performances.

A self-sufficient digitally controlled ring oscillator compensated for supply voltage variation

A self-sufficient Giga-Hertz digitally controlled ring oscillator for clock distribution network is presented in this paper. It features a high supply insensitivity in order to mitigate the additional jitter due to supply noise. This is achieved by inducing a mutual compensation between the oscillation frequency parameters that are affected by the supply voltage variations. The proposed method can be easily implemented and takes advantage of the deep sub-micrometer effects peculiar to topical CMOS technologies. We demonstrate by simulations that this approach remains efficient over process variations despite the reliability issue of short channel MOS transistors.

Multisensor data fusion for human activities classification and fall detection

Significant research exists on the use of wearable sensors in the context of assisted living for activities recognition and fall detection, whereas radar sensors have been studied only recently in this domain. This paper approaches the performance limitation of using individual sensors, especially for classification of similar activities, by implementing information fusion of features extracted from experimental data collected by different sensors, namely a tri-axial accelerometer, a micro-Doppler radar, and a depth camera. Preliminary results confirm that combining information from heterogeneous sensors improves the overall performance of the system. The classification accuracy attained by means of this fusion approach improves by 11.2% compared to radar-only use, and by 16.9% compared to the accelerometer. Furthermore, adding features extracted from a RGB-D Kinect sensor, the overall classification accuracy increases up to 91.3%.

Performances of Multitones for Ultra-Wideband Software-Defined Radar

From the literature review, it is apparent that there is a gap in quantifying the performances of multitone waveforms specifically for radar applications and experimental results not commonly found. This paper focuses on the radar performance analysis of multitones with P3 phase-codes in simulation and experimentally to determine the effect of hardware on radar performances. For this purpose, a software-defined radar (SDR) approach has been used, including a digital core with hardware in-the-loop controlled by MATLAB and an analog front end that uses bandpass sampling and a reference channel. The proposed radar setup with processing algorithm has been evaluated in terms of processing time, showing that a real-time implementation on the latest field programmable gate array chipsets is feasible. This approach is flexible and entirely arbitrary waveforms can be generated with an instantaneous bandwidth up to 800 MHz. All the experimental results presented in Section IV are beyond the state of the art and bring novel insight into the impairment of SDR.

Inter-range-cell interference free compression algorithm: Performance in operational conditions

The analysis of the performance of a novel algorithm found in the literature, the inter-range cell interference (IRCI) free compression algorithm, is presented in this paper. The algorithm presents a Dirac response in distance compression with a pedestal error at −350 dB. These performances would be very valuable for the radar field. The robustness of the performances for the IRCI free compression algorithm and matched filtering (MF) compression algorithm are explored first in simulations with point targets. Their sensitivity to bit resolution is also assessed. Both algorithms are then tested with measured signals from a wireless test performed using an ultra-wide band software defined radar platform with 800 MHz instantaneous bandwidth in X-band on a trihedral corner reflector. For an orthogonal frequency division multiplexing signal with N carriers, the results show that IRCi free compression algorithm offers an extra 2 dB in contrast for this measurement with an added processing cost of at least 4N real multiplications when compared to MF compression algorithm.

A constrained hybrid Cramér-Rao bound for parameter estimation

In statistical signal processing, hybrid parameter estimation refers to the case where the parameters vector to estimate contains both non-random and random parameters. Numerous works have shown the versatility of deterministic constrained Cramér-Rao bound for estimation performance analysis and design of a system of measurement. However in many systems both random and non-random parameters may occur simultaneously. In this communication, we propose a constrained hybrid lower bound which take into account of equality constraint on deterministic parameters. The usefulness of the proposed bound is illustrated with an application to radar Doppler estimation.