A. Borgia

High resolution software defined radar system for target detection

The Universal Software Radio Peripheral USRP NI2920, a software defined transceiver so far mainly used in Software Defined Radio applications, is adopted in this work to design a high resolution L-Band Software Defined Radar system. The enhanced available bandwidth, due to the Gigabit Ethernet interface, is exploited to obtain a higher slant-range resolution with respect to the existing Software Defined Radar implementations. A specific Lab VIEW application, performing radar operations, is discussed, and successful validations are presented to demonstrate the accurate target detection capability of the proposed software radar architecture. In particular, outdoor and indoor test are performed by adopting a metal plate as reference structure located at different distances from the designed radar system, and results obtained from the measured echo are successfully processed to accurately reveal the correct target position, with the predicted slant-range resolution equal to 6m.

POTENTIALITIES OF USRP-BASED SOFTWARE DEFINED RADAR SYSTEMS

Software Deflned Radar is the latest trend in radar development. To handle enhanced radar signal processing techniques, advanced radars need to be able of generating various types of waveforms, such as frequency modulated or phase coded, and to perform multiple functions. The adoption of a Software Deflned Radio system makes easier all these abilities. In this work, the implementation of a Software Deflned Radar system for target tracking using the Universal Software Radio Peripheral platform is discussed. For the flrst time, an experimental characterization in terms of radar application is performed on the latest Universal Software Radio Peripheral NI2920, demonstrating a strongly improved target resolution with respect to the flrst generation platform.

Radar array diagnosis from undersampled data using a compressed sensing/sparse recovery technique

A Compressed Sensing/Sparse Recovery approach is adopted in this paper for the accurate diagnosis of fault array elements from undersampled data. Experimental validations on a slotted waveguide test array are discussed to demonstrate the effectiveness of the proposed procedure in the failures retrieval froma small set of measurements with respect to the number of radiating elements. Due to the sparsity feature of the proposed formulation, the method is particularly appealing for the diagnostics of large arrays, typically adopted for radar applications.

Software defined radar: synchronization issues and practical implementation

The present work is focused on Software Defined Radar - (SDR) paradigm, which gives a more versatile solution when compared to classical radar systems. Thanks to this new system model, most of the fundamental operations, such as signal generation, filtering, up and down conversion, are easily implemented via software. The objective of this paper is to show the main issues related to the design of an effective Software Defined Radar device. Specifically, we will discuss and face the synchronization issues existing between a received and a transmitted signal when an open source hardware, namely the Universal Software Radio Peripheral (USRP), is considered.

Beam-Scanning Reflectarray Based on a Single Varactor-Tuned Element

A single varactor-tuned element is investigated as effective solution for the realization of reconfigurable reflectarray antennas. The proposed configuration is successfully implemented for the design of an X-band reflectarray prototype of 3×15 radiators. A dedicated electronic control board is designed as an integral part of the antenna. Good performances in terms of beam-scanning capabilities are obtained from measurements.

Software-Defined Radar System for Landslides Monitoring

An integrated system for landslides early warning, based on a flexible network architecture and including different sensors, is described to monitoring landslides evolution in critical scenarios. Particular focus is devoted on the experimental assessment of an L-band Software Defined Radar sensor, specifically designed for the application, by discussing the measurement results obtained on a real landslide scenario located on the A3 highway in Calabria (Italy). In particular, a mathematical estimator useful for the proper detection of landslide movements is defined and applied to the measured range profiles, thus demonstrating the usefulness of the proposed radar monitoring approach.

Low-Cost Radars Integrated into a Landslide Early Warning System

Radar activities performed at University of Calabria in the framework of a national project on “Landslides Early Warning” are described in this contribution. After a brief outline of the whole Landslides Early Warning Integrated System, two compact and low-cost radar configurations, the first one based on the adoption of a software radio platform, the second one using a compact Vector Network Analyzer as SFCW scatterometer module, are deeply described. Experimental results are discussed as validation tests to demonstrate the radars range detection capabilities.

Multimode/multifrequency low frequency airborne radar design

This work deals with the design of multimode/multifrequency airborne radar suitable for imaging and subsurface sounding. The system operates at relatively low frequencies in the band ranging from VHF to UHF. It is able to work in two different modalities: (i) nadir-looking sounder in the VHF band (163MHz) and (ii) side-looking imager (SAR) in the UHF band with two channels at 450MHz and 860MHz. The radar has been completely designed by CO. Ri. S. T. A. for what concerns the RF and the electronic aspect, and by the University of Calabria for what concerns the design, realization, and test of SAR antennas. The radar has been installed on a civil helicopter and its operation has been validated in flight in both sounder and imager modality. Preliminary surveys have been carried out over different areas of Campania region, South Italy.

Environmental Effects on the Performances of a UHF Passive Tag-Based Commercial RFID System

A simple setup for the evaluation of the environmental effects on the performance of a passive tags-based commercial RFID system is described in this work. A standard classroom/office room is assumed as test scenario, and the evaluation of field emission as well as the minimum power threshold required for an accurate detection in the presence of obstacles is performed. This preliminary measurement campaign can be helpfully applied to properly highlight the potentialities as well as the limitations of the RFID systems when applied for the accurate tracking of items located into a real noisy scenario.

Fractal Reflectarray Antennas: State of Art and New Opportunities

Fractal geometries are appealing in all applications where miniaturization capabilities are required, ranging from antennas to frequency selective surfaces (FSS) design. Recently, some fractal patches configurations, giving low losses, reduced size, and quite good phase ranges, have been proposed for the design of reflectarray unit cells. This paper reviews existing fractal-based reflectarrays, highlighting their benefits and limitations. Furthermore, a comprehensive analysis of an innovative reflectarray unit cell, using a fractal-shaped fixed-size patch, is presented. The miniaturization capabilities of the Minkowski fractal shape are fully exploited to obtain a compact cell offering quite good phase agility, by leaving unchanged the patch size and acting only on the fractal scaling factor. Experimental validations are fully discussed on a realized 10 GHz cell. This is subsequently adopted to synthesize various reflectarray prototypes offering single or multiple-beam capabilities over a quite large angular region (up to 50 degrees). Finally, experimental validations on a realized elements prototype are presented to demonstrate the wide angle beam-pointing capabilities as well as a quite large bandwidth of about 6%.