Two-layer particle filter for multiple target detection and tracking

This paper deals with the detection and tracking of an unknown number of targets using a Bayesian hierarchical model with target labels. To approximate the posterior probability density function, we develop a two-layer particle filter. One deals with track initiation, and the other with track maintenance. In addition, the parallel partition method is proposed to sample the states of the surviving targets

Virtual MIMO RADAR using OFDM-CDM Waveforms

This paper addresses a new perspective on the exploitation ofdiversity resembling recent seminal proposals with multiple antennas known as MIMO radar. Our focus pursues similar advantages as spatial MIMO systems but intending to achieve the desired resistance over fading or/and SNR increase without relying on multiple antennas. We design an OFDM-CDM waveform well inspired in modern communications systems that creates a virtual MIMO system operating on the artificial 2D domain formed by a set ofwell separated carriers (OFDM) and several OFDM symbols each one modulated by orthogonal codes (CDM). We consider the most general scenario with moving targets and large size targets originating an equivalent time variant andfrequency selective channel model. Our proposal proceeds in two steps, a first one to reorthogonalize the transmitted set of OFDMsignal by proper time andfrequency synchronization (this stage provides range and velocity estimators), and a second one based on Neyman Pearson detection improved by the diversity gain

Implementing FFT-based digital channelized receivers on FPGA platforms

This paper presents an in-depth study of the implementation and characterization of fast Fourier transform (FFT) pipelined architectures suitable for broadband digital channelized receivers. When implementing the FFT algorithm on field-programmable gate array (FPGA) platforms, the primary goal is to maximize throughput and minimize area. Feedback and feedforward architectures have been analyzed regarding key design parameters: radix, bitwidth, number of points and stage scaling. Moreover, a simplification of the FFT algorithm, the monobit FFT, has been implemented in order to achieve faster real time performance in broadband digital receivers. The influence of the hardware implementation on the performance of digital channelized receivers has been analyzed in depth, revealing interesting implementation trade-offs which should be taken into account when designing this kind of signal processing systems on FPGA platforms

Particle filter for extracting target label information when targets move in close proximity

This paper addresses the problem of approximating the posterior probability density function of two targets after a crossing from the Bayesian perspective such that the information about target labels is not lost. To this end, we develop a particle filter that is able to maintain the inherent multimodality of the posterior after the targets have moved in close proximity. Having this approximation available, we are able to extract information about target labels even when the measurements do not provide information about target's identities. In addition, due to the structure of our particle filter, we are able to use an estimator that provides lower optimal subpattern assignment (OSPA) errors than usual estimators

An Assessment of Available Models for the Design of Schottky-Based Multipliers Up to THz Frequencies

[EN]This paper evaluates the ranges of application and physical limitations of lumped equivalent circuits and drift-diffusion models for the design of THz circuits. The predictions of these models have been compared with aMonte Carlo model, which was considered as a reference, and with measurements from doublers and triplers designed and fabricated by the Jet Propulsion Laboratory. Additionally, the usefulness of Schottky diodes as frequency multipliers above 3 THz is analyzed with the Monte Carlo model.European Commision (EC). Funding FP7/SP1/SPA. Project Code: 242334European Commision (EC). Funding FP7/SP1/ICT. Project Code: 24384

Nonlinear filtering update phase via the Single Point Truncated Unscented Kalman filter

A fast algorithm to approximate the first two moments of the posterior probability density function (pdf) in nonlinear non-Gaussian Bayesian filtering is proposed. If the pdf of the measurement noise has a bounded support and the measurement function is continuous and bijective, we can use a modified prior pdf that meets Bayes' rule exactly. The central idea of this paper is that a Kalman filter applied to a modified prior distribution can improve the estimate given by the conventional Kalman filter. In practice, bounded support is not required and the modification of the prior is accounted for by adding an extra-point to the set of sigma-points used by the unscented Kalman filter

Low-cost CW-LFM radar sensor at 100 GHz

This paper presents a W-band high-resolution radar sensor for short-range applications. Low-cost technologies have been properly selected in order to implement a versatile and easily scalable radar system. A large operational bandwidth of 9 GHz, required for obtaining high-range resolution, is attained by means of a frequency multiplication-based architecture. The system characterization to identify the performance-limiting stages and the subsequent design optimization are presented. The assessment of system performance for several representative applications has been carried out

Analysis of nonharmonic oscillations in Schottky diodes

[EN]We investigate damped nonharmonic oscillations at terahertz frequencies observed in the current response of Schottky diodes simulated with the Monte Carlo method under applied signals of a few hundred GHz. From Monte Carlo simulations of different diode structures, two kinds of nonharmonic oscillations have been identified. The first kind of oscillations is due to the coupling of the nonlinear performance of the Schottky junction with the inertial motion of the carriers in the non-depleted region of the epilayer. The second kind of oscillations is due to the modulation of the n+–n junction when high electric fields are induced in the non-depleted region of the epilayer. These oscillations constitute a promising mechanism for THz signal generation.ROOTHz (FP7-243845

Real Time FPGA Implementation of an Modulation Classifier for Electronic Warfare Applications

This paper presents an automatic modulation classifier for electronic warfare applications. It is a pattern recognition modulation classifier based on statistical features of the phase and instantaneous frequency. This classifier runs in a real time operation mode with sampling rates in excess of 1 Gsample/s. The hardware platform for this application is a Field Programmable Gate Array (FPGA). This AMC is subsidiary of a digital channelised receiver also implemented in the same platform

Estimation of atmospheric attenuation at 99 GHz using a total power radiometer

A total power radiometer operating at 99 GHz was implemented for a propagation experiment aimed to estimate attenuation along a slant path, in Madrid. Valuable data was collected during a measurement campaign in mid-april of 2012. The retrieved time series of radiometric attenuation allow the use of this technique at this frequency to be validated, under clear sky and cloudy conditions, using a low cost instrument calibrated with simple procedures. In spite of some hardware limitations, this experiment shows an interesting application of radiometric technique in order to study atmospheric propagation at 99 GHz