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Conformal arrays, distributed processors and bistatic architectures allow us to develop more and more effective phased array multifunction radars. In particular, conical (as well as cylindrical) arrays permit to avoid scan angle losses, and multiple sub-arrays with digital beamforming enhance the time-energy efficiency by executing in parallel the various radar tasks. A system architecture, now under...
Conformal arrays, distributed processors and bistatic architectures allow us to develop more and more effective phased array multifunction radars. In particular, conical (as well as cylindrical) arrays permit to avoid scan angle losses, and multiple sub-arrays with digital beamforming enhance the time-energy efficiency by executing in parallel the various radar tasks. A system architecture, now under...
Multilateration (MLAT) and Automatic Dependent Surveillance — Broadcast (ADS-B) systems exploiting the Secondary Surveillance Radar (SSR) channel suffer from garbling. This means that if two or more mode S signals impinge on the receiver at the same or very near time they could not be decoded. To alleviate this problem, many solutions have been proposed, one in particular [1] is effective for a large...
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 a sufficiently wide covering pattern. The source...
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 dynamic range and one with a logarithmic receiver) connected...
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 (Multifunction Phased Array Radar) architecture allows a single...
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 technology to satisfy different requirements. The main...
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 conceived for a multi channel receiver with garbled...
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 hundred kilometers around the airport. Practically...
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 measurements based on coding theory is also proposed.
Traditional millimeter wave Surface Movement Radar (SMR) have been designed and tested. A novel concept for the design of a new SMR is suggested based upon Synthetic Aperture Antenna and Noise Radar Technology. It enables designing of SMR without mechanical rotation of an antenna, but applying several nonmoving Synthetic Aperture Antennas instead. Application of Noise Radar Technology is also considered...
Target 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 hypothesis is removed. Simulated tests in a real scenario...
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]. Unfortunately, a rare event, but important, has not yet...
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 transponder-equipped targets (aircraft and vehicles). Today...
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-cooperative surveillance of the primary radar and very...
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 classical FM-CW or pulse compression solutions.
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 kinematics . The basic measurement is the classical TDOA...
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 approaches. The definition of a general, usable decision support...
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-channel receiver, the proposed algorithm is operatively...
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 practical inconvenience of the need for a multi-channel receiver...
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