Gaspare Galati

University of Rome Tor Vergata | UNIROMA2 · Dipartimento di Ingegneria Elettronica

The increasing interest in the radar detection of low-elevation and small-size targets in complicated ground environments (such as urban, suburban, and mixed country areas) calls for a precise quantification of the radar detection capabilities in those areas. Hence, a set of procedures is devised and tested, both theoretically and experimentally, u...

Forward-looking radars are essential sensors for many fast moving platforms such as fighter aircraft and missiles. Despite its multiple benefits, noise radar has not yet been used for this task because of the low Doppler tolerance of its waveform and the associated need for computational intense Doppler compensation. This Letter presents the very f...

In noise radar, digital signal processing algorithms for implementing the computation of the Cross Ambiguity Function through range correlation and Doppler compensation call for optimized solutions. In fact, to achieve a high coherent processing gain, they often compute a large amount of data beyond the maximum range and/or the maximum radial veloc...

The development of Italian space-based radars (i.e., Synthetic Aperture Radar—SAR, Radar Altimeter for remote sensing satellites—RA, and finally radar for deep space probing) has led to important international achievements and is strictly related to the history of Italian space activities. A main result is the Cosmo-SkyMed constellation of Syntheti...

Neither Christian Hülsmeyer , the “unlucky” (in the sense that his environment was not ready to accept his invention) inventor of the radar, nor the researchers and the technicians from different nations who, immediately prior to and during the Second World War, have developed the radar and made it operational, could never have imagined the present...

Industrial radar developments had some noticeable extent in Italy before September 8th, 1943 but were blocked for months after the Armistice. During W.W. II small quantities of radar equipment were produced by some factories, mainly located in northern Italy, such as SAFAR, FIVRE, Magneti Marelli, Allocchio Bacchini, San Giorgio and, last but not l...

The development of radar in Europe, particularly in the period 1937–1945, has been strongly influenced by the need for a defence against attacks from bombers, whose destructive capability greatly improved in the 1920s and 1930s, when many nations put in service acoustic detection means. The effectiveness of such “aerophones” or “sound mirrors” was...

The radar developments in Italy started in the 1930s at the Navy’s “Regio Istituto Elettrotecnico e delle Comunicazioni”, RIEC, based on the written proposal (dated April 27th, 1936) by Ugo Tiberio who is generally known as the father of Italian radar. Very clearly, after the analysis of the intensity of the back-scattered field, i.e. an early eval...

As early as in 1936, in his “Rediscovered Document” (Chap. 2) Ugo Tiberio indicated the main applications of radar techniques to military operations, including: to see enemy aircraft; to measure, from an airplane, its height from the ground; and finally, to locate a ship from an airplane for torpedoing. These are exactly the purposes for which the...

The “official” birth of radar is generally attributed to the patent by Christian Hülsmeyer from Düsseldorf, entitled “Telemobiloskop”, on April 30th, 1904. However, the invention by Hülsmeyer was not accepted, being the environment not yet ready and lacking a definite operational requirement such as the Air defense, whose need would arise only in t...

Radar was simultaneously and independently developed by many countries, and the birth of radar, as well as that of radiotelegraphy or “wireless telegraphy”, happened in Europe in a period beginning at the end of the Nineteenth Century, with Europe in peace since twenty years, whose somewhat nostalgic name was “Belle Époque”. As a matter of fact, af...

The Second World War has stimulated the search for more and more effective means to detect and locate incoming hostile aircraft and to activate a defence by fighters/interceptors or by anti-aircraft artillery (AAA of “FlaK”). So, radar technology saw an enormous advancement with the integration of search and tracking radars into the Air Defence, th...

The Spallanzani’s studies on bats and the sophisticated acoustic signals used by bats to localize their prey are a good introduction to some modern radar techniques and systems, including: pulse compression, coherent chains, phased arrays, array processing and antenna side-lobes suppression, weather monitoring, automotive and thru-the-wall applicat...

The increasing environmental consciousness and the better attention paid to the primary resources (especially oil and raw materials) is one of the main drivers of the increase in vessel traffic. In addition the sea shipping is characterized by a good delivery rate and affordable operating costs in comparison with other transport means, i.e. by road...

In many radar applications, including marine, automotive and MIMO, there is a need for orthogonal transmission from different radar sets to mitigate mutual interference; the same applies to the different channels in a MIMO radar. New techniques, belonging to the cyclic algorithm family, might be used to generate orthogonal signals with, in addition...

This book offers fascinating insights into the key technical and scientific developments in the history of radar, from the first patent, taken out by H�lsmeyer in 1904, through to the present day. Landmark events are highlighted and fascinating insights provided into the exceptional people who made possible the progress in the field, including the...

Within the frame of the Eurad-2014 Special Session «110 years of radar developments in Europe after Hülsmeyer's Telemobiloskop» this introductory paper contains (i) a retrospective analysis of the present literature and of its missing elements and (ii) a kind of presentation of this Special Session and its rationale.

The Italian contribution to radar is little knows due to scarce and sometimes imprecise literature. This paper aims to cover naval and coastal radar developments in Italy from the beginning (1935) to the halt due to the Armistice of September 8th, 1943, mostly due to Ugo Tiberio and Nello Carrara.

Noise Radar Technology (NRT) is nowadays a promising technology to achieve robustness against external interference, lack of ambiguities and high resolution. This paper is devoted to some possible applications of NRT in civil field, in particular, for the surface surveillance in airports and in sea, showing its advantages versus the more classical...

A new version of an open form localisation algorithm, called regularised location estimator (RLE), for time difference of arrival (TDOA) multilateration systems is proposed. This algorithm is based on Tikhonov regularisation and on maximum-likelihood estimation. It is aimed to solve the localisation problem for both well-conditioned and ill-conditi...

The present invention relates to a system for locating non-cooperating objects by means of a random or pseudo-random noisy type waveform generator, an amplifier, of said waveforms and an antenna which radiates them towards the object, which object generates an electromagnetic echo which is detected by a passive subsystem of antennas and receivers....

One of the main focus of the research in modern radar systems, as MIMO (Multiple Input Multiple Output) radar and multifunction/multistatic radar, is the waveforms design and optimization in order to get a low degradation in the main lobe (low Signal to Noise Ratio loss), a low Peak Side-Lobe Ratio (PSLR) and good orthogonality properties. In MIMO...

This study deals with a specific aspect of the well-known problem of the variation of the radar cross section of complex targets with the transmitted frequency. In particular, it considers pairs of modified Golay codes and demonstrates that—even with a modest variation of the transmitted frequency—the square complementary properties of radar return...

In this paper, an effective procedure to emplace standard and enhanced mode-S multilateration stations for airport surveillance is studied and developed. This procedure is based on meta-heuristic optimization techniques, such as genetic algorithm (GA), and is intended to obtain useful parameters for an optimal system configuration that provides acc...

In this paper, the use of regularization methods to solve the location problem in multilateration systems, using Mode-S signals, is studied, evaluated, and developed. The Tikhonov method has been implemented as a first application to solve the classical system of hyperbolic equations in multilateration systems. Some simulations are obtained and the...

The aim of this study is to analyse the accuracy of passive location systems by using the CraméŕRao lower bound (CRLB). The study is focused on sensor networks derived from the well-known Multilateration (MLAT) systems, used for aircraft and vehicle surveillance. The measurement used in the standard MLAT configuration is the Time Difference Of Arri...

Modern radar include more and more multiple functions and multiple channels as in the case of MPAR (Multifunction Phased Array Radar) and MIMO (Multiple Input Multiple Output) radar. In this context sophisticated waveforms and related processing (pulse compression, extraction of information) are needed. Moreover, to avoid changes in target RCS and...

An array system solution is adopted in the paper to face the problem of separation of superimposed signals by performing blind source separation. A five channels receiving station has been implemented to provide a large dynamic range, wide bandwidth and fast sampling, with a proper array of six independent antenna elements properly designed to give...

The Transponder Data Recorder is an experimental 1090 MHz signal acquisition system designed by the Radar and Navigation group at Tor Vergata University to record the signals in the Secondary Surveillance Radar band, centered at 1090 MHz. The peculiarity of the receiver is that it is based on five receiving chains (4 linear chains with large dynami...

In this work the potential usage of ADS-B and Wide Area Multilateration (WAM) Surveillance with High Altitude Platform Systems (HAPS) is considered. The paper investigates the possible configuration of the system, the link budget, the geometry and the limitation due to the random access to the channel by the Mode S Signals (capacity). The surveilla...

An integrated target/weather surveillance at medium range, i.e. for the Terminal Manoeuvre Area (TMA) in the frame of Air Traffic Control (ATC) and regional weather monitoring, is made possible by MPAR (Multifunction Phased Array Radar) techniques, allowing a single technology to satisfy different requirements. The guidelines for system design, nee...

By means of Active Phased Array techniques, an integrated target/weather surveillance at medium range, i.e. for Terminal Manoeuvre Area in the frame of ATC and regional weather monitoring, is possible and affordable provided that cost reduction for Transmit/Receive modules makes phased array radar affordable to civilian users. The MPAR (Multifuncti...

Wide Area Multilateration is a form of Cooperative Independent Surveillance, used in Air Traffic Control Systems, based on the principle of hyperbolic localization of targets that emit SSR Mode S signals that is received from a group of ground based stations. The accuracy of WAM systems is strongly dependent by the Time Stamp assigned by each recei...

The aim of this work is to discriminate and separate overlapped downlink SSR signals received by a multilateration (MLAT) station in a crowded environment. As a typical MLAT receiver station is equipped with an omni directional antenna, the probability of multiple receptions increases as a function of the traffic density. The proposed algorithm is...

Cost reduction for transmit/receive modules makes phased array radar of potential interest to civilian users. An integrated target/weather surveillance at medium range, i.e. for terminal manoeuvre area in the frame of ATC and regional weather monitoring, is made possible by MPAR (multifunction phased array radar) techniques, allowing a single techn...

Multilateration (MLAT) is an increasingly important location and identification system for surface traffic surveillance, is in use in large airports such as London-Heathrow, Frankfurt/Main and Rome-Fiumicino. Target location can be extended to approach and terminal area surveillance (wide area multilateration, WAM), with a system coverage to some h...

Location and identification of cooperating aircraft in the airport area (and beyond) may be implemented by multilateration (MLAT) systems using the secondary surveillance radar (SSR) mode S signals. Most of these signals, spontaneously emitted from on-board mode S transponders at a fixed carrier frequency, arrive randomly at the receiving station,...

Two localization algorithms for multilateration systems are derived and analyzed. Instead of the classical time difference of arrival (TDOA), a direct use of the time of arrival (TOA) is made. The algorithms work for arbitrary spatial dimensions and overdetermined systems. These derivations are tested in a real-case implementation with simulated da...

The aims of this work is to analyse the Cramer Rao lower bound (CRLB) for passive location of radio sources, as in multilateration (MLAT) systems and in their wide area version. The CRLB is used, in this paper, as the analysis method for the accuracy of position estimation using different measurements, related in a non-linear way to the target kine...

Secondary surveillance radar (SSR) was originated in the 40's as an Identification Friend or Foe (IFF) system and, starting from the psila50 and psila60, provided the air traffic control (ATC) with identity and altitude data for the aircraft under coverage, implementing a rough form of cooperative independent surveillance, complementing the non-coo...

Secondary surveillance radar (SSR) based on multilateration principle and omni-directional antennae are operational today [1], [2]. We proposed several new algorithms to separate a mixture of overlapping SSR replies on a M-elements antenna in previous works [3], [4], [5], [6], other solutions were also proposed in the literature [7], [8], [9]. Unfo...

Traditional millimeter-wave surface movement radar (SMR) has been designed and tested. A novel concept for the design of a new SMR is suggested based on synthetic aperture antenna and noise radar technology. It enables designing SMR without mechanical rotation of an antenna, but applying several nonmoving synthetic aperture antennas instead. Applic...

Two new closed form localization algorithms for multilateration systems are derived and analyzed. The derivation neglects the time difference of arrival in favor of the direct use of the time of arrival (TOA). The algorithms work for arbitrary spatial dimensions and overdetermined systems. A strategy for quick rejection of obviously false time meas...

arget position integrity is very important when this information is used for surveillance and safety purposes as in a Multilateration System (MLAT). In this paper some of the classical Satellite Navigation algorithms are modified to be applied to the MLAT environmental and one of the big limitations of these algorithms i.e. the single fault hypothe...

This paper is focused on the 1090 MHz SSR channel capacity increase by innovative transmission and decoding techniques. A lot of Air traffic control systems use the 1090 MHz channel: SSR downlink (on-board transponders), ADS-B messages, TIS-B, FIS-B. We focus the attention on the MLAT (multilateration) system, useful to localize and identify transp...

Noise Radar Technology (NRT) uses noise waveforms (continuous or pulsed) as a radar signal and correlation processing of the returns for their optimal reception. This paper is devoted to some possible applications of NRT in civil field, in particular to millimetre-wave radars, with comparison of the use of Noise W-band radar versus the more classic...

This paper presents an effective algorithm to discriminate and separate superimposed SSR (secondary surveillance radar) mode S signals. The algorithm is an adaptation of the PA (projection algorithm) [1,3,4] that perform a blind separation of the multiple SSR sources using a single channel receiver. As present-days SSR stations only have a single-c...

Grouping of a set of SSR Mode S stations into functional entities called clusters has significant operational facets; it calls for a constrained optimization, an important significant constraint being the scarcity of Interrogation Identifier codes. This problem can be approached by two ways, i.e., integer programming methods and heuristic approache...

This paper presents a novel, effective algorithm to discriminate and separate super-imposed SSR (Secondary Surveillance Radar) Mode S signals. Our goal is a blind separation of multiple SSR sources using a single channel receiver. Other algorithms perform sources separation exploiting space diversity or statistical properties, but with the practica...

Multilateration systems based on secondary surveillance radar (SSR) systems and omnidirectional antennae are operational today (Bezousek, 1998 and Galat, 2004). Assuming the replacement of the single-element antenna by an array, we proposed new algorithms to discriminate overlapped signals in previous works (Petrochilos et al., 2002, 2004 and 2007)...

The "multilateration" (MLAT) system is a surveillance and identification element of the A-SMGCS using the SSR transponder (Mode S or even A/C) reply/squitter as signals received by fixed stations where the time-of-arrival (TOA) is measured. In a central processing unit, the target position is estimated by the TDOA technique (time difference of arri...

This paper is focused on the implementation of an innovative vehicles surveillance system using the 1090 MHz channel. SSR (secondary surveillance radar) mode S (selective) exploitation in high traffic environment calls for enhancing communication capacity. In the multilateration and ADS-B applications, the presence of both SSR mode S replies and sq...

secondary surveillance radar (SSR) based on multilateration principle and omni-directional antennae are operational today. We proposed new algorithms to separate a mixture of overlapping SSR replies on a M-elements antenna in previous works, other solutions were also proposed in the literature. Unfortunately, all have either some shortcomings, or a...

Fog is a significant factor affecting the Air Traffic Control (ATC). Significant limitations of the airport capacity are due to fog that causes the reduction of the visibility (Runway Visual Range, RVR). Today METAR (Meteorological Aviation Report) and forecasts TAF (Terminal Aerodrome Forecast) are only available to estimate the visibility variati...

GNSS systems use frequency band close to that of L-band primary surveillance radar for Air Traffic Contro, i.e. 1250-1350 MHz, and of some Wind Profiler Radar (1290 MHz). According to the World Radio Communication Conference 2003 (WRC-03) resolution, in order to protect Aeronautic Radio Navigation System (ARNS) systems, Radio Navigation Satellite S...

Multilateration systems based on secondary surveillance radar (SSR) and omni-directional antennae are operational today (P. Bezousek, 1998) with expected capacity limitations due to the increase of the air traffic. Assuming the replacement of the omni-directional antenna by an array, we proposed new algorithms in previous works (N. Petrochilos, Jul...

SSR (secondary surveillance radar) exploitation in high traffic environment calls for enhancing surveillance and communication capacity. In the multilateration applications, the use of omni directional (or, anyway, wide beam) antennas and the presence of both SSR Mode S replies and squitter make the superimposition of 1090 MHz signals probable, wit...

There is an increasing interest on the various applications of the SSR Mode S (secondary surveillance radar - mode selective) for air traffic and airport traffic management. This paper discusses the applications of ICAO standard Mode S signals, in particular in the down link channel around 1090 MHz, to locate and identify cooperating targets in the...

A new method for SSR (secondary surveillance radar) signal analysis, in particular SSR Mode S replies, can be obtained exploiting the super resolution algorithms capability to discriminate signals in the frequency domain. This work summarises the results obtained by the application of Tufts-Kumaresan, Music, Esprit and Unitary Esprit algorithms to...

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High resolution requirements for airport surface traffic monitoring with lightweight, small, all-weather sensors call for the use of a network of millimetre-wave radars to perform the surveillance function in the surface movement control and guidance system. In this paper a W-band radar employed as the basic sensor is described. Some results of rec...

The paper addresses the problem of the reconstruction of the rainfall field using weather radar observables. It is well known that at the C band and especially at the X band the reconstruction of the rainfall rate profile along the range using absolute (ZH) and differential (ZDR) reflectivity measurements is significantly affected by the attenuatio...

A distributed system based on a network of short-range (1.5-3 km) radars, operating in the W-band (93-95 GHz), is proposed for the ground surveillance of airports. Both the architecture and the main features of each subsystem are described. The system can boast very high resolution, the elimination of shadowing, and the inclusion of image processin...

There is a recent interest in X-band weather radar due to the high sensitivity and to the cheap microwave hardware. However, the attenuation due to the precipitation itself makes it difficult to estimate the rainrate unless this phenomena is of limited extent, as for insulated phenomena and/or short range operation (e.g. for valleys, urban basin hy...

The effectiveness of an attenuation correction procedure on the error structure of a C-band radar rainfall estimation is studied theoretically and by computer simulation. The iterative procedure to correct the radar observables affected by attenuation is based on the best-fit relationships between the absolute and differential reflectivity and the...

The Global Navigation Satellite System (GNSS) is strongly dependent on the choice of the satellite constellation. At the present time, the GNSS space segment is made by the following satellite constellations: GPS, GLONASS and a set of geostationary satellites. In a medium-long term future, a new GNSS could substitute the existing satellite navigati...

This chapter analyzes the performance of a new processor, based on the use of clutter maps, to be used in millimeter-wave radar for the surveillance of airport surface movements. The design of the radar signal processor to perform the detection function represents a challenging task. Some of the reasons are: the disturbance background is generally...