Riccardo Palama

Statistical analysis of bistatic and monostatic sea clutter

In this work, we analyze the sea clutter data collected simultaneously by the bistatic and monostatic nodes of an S-band netted radar system under different out-of-plane geometries. The empirical distribution of sea clutter data are fitted to some known heavy-tailed distributions, and the sea spikes statistics are examined. Our analyses show that spikiness is higher for small bistatic angles and that bistatic data are sometimes less spiky than monostatic ones only for horizontal polarization.

Multistatic CFAR detection in non-Gaussian clutter

This work deals with a target detection algorithm for multistatic and multiple input - multiple output radars. The adopted algorithm is able to keep the false alarm rate constant, if the disturbance samples associated to each receiver-transmitter pair are distributed according to a Compound-Gaussian model. In particular, we analyze the performance of the adopted detection algorithm, in order to evaluate the impact of clutter diversity on the detection performance. To this aim, we simulated the clutter samples by varying the shape parameter of the clutter distribution associated to each receiver-transmitter pair. The results highlight that clutter diversity has a strong impact on the detection performance. In the case of two channels, i.e. two receiver-transmitter pairs, a significant result is that the same value of the probability of the detection is obtained for different couples of the shape parameters associated to the two channels.

First measurements with NeXtRAD, a polarimetric X/L Band radar network

NeXtRAD is a fully polarimetric, X/L Band radar network. It is a development of the older NetRAD system and builds on the experience gained with extensive deployments of NetRAD for sea clutter and target measurements. In this paper we will report on the first measurements with NeXtRAD, looking primarily at sea clutter and some targets, as well as early attempts at calibration using corner reflectors, and an assessment of the polarimetric response of the system. We also highlight innovations allowing for efficient data manipulation post measurement campaigns, as well as the plans for the coming years with this system.

Correlation analysis of simultaneously collected bistatic and monostatic sea clutter

In this work we analyse the correlation properties of simultaneous bistatic and monostatic polarimetric sea clutter data, collected by the NetRAD multistatic radar system. In particular, we study the temporal autocorrelation and cross-correlation functions of the texture and speckle samples, as a function of the system geometry and of the polarization of the transmitter and receiver antennas. These features can vary significantly as a function of bistatic angle and the goal of this paper is to quantify these variations and extract any trends that are observed.

A radar architecture for joint dynamic spectrum access and target-matched illumination

In this study, we address a simple cognitive architecture to design a radar waveform that fills the gaps in the radio-frequency spectrum and matches the target scattering properties. The metric used to calculate the radar waveform is the Mutual Information between the received signal and the target impulse response. Particular attention is paid to analyse the impact of the properties of the communication signals on the chosen metric, for both ideal and non-ideal cases.

Copolar calibration of multistatic radar in the presence of multipath

This paper addresses the Polarimetric calibration of the nodes of a multistatic radar system, by using a reference object with known scattering matrix, such as a metallic sphere. A calibration technique is proposed and its experimental validation performed in a realistic scenario, by accounting also for the multipath effect. The intensity of the signal scattered by a metallic sphere and received by the monostatic and bistatic nodes of the NetRAD system is measured, by varying the antenna height, the object range and the bistatic angle. The adopted calibration technique shows a quite good accuracy, as the calibrated values of the radar cross section of the reference object are close to the theoretical ones, after the compensation of the multipath effect.