M. Fossi

Simultaneous scattering matrix measurement through signal coding

A method making use of signal coding for simultaneous measurement of all four elements of a target scattering matrix with a polarimetric radar is studied. The method is based on a simultaneous transmission of two orthogonal signals on two orthogonal polarization channels. The four elements of the scattering matrix are retrieved on reception by correlating the signal on each polarization channel with both orthogonal signals. Although the method increases the radar system complexity, it potentially overcomes the limitations of the measurement accuracy introduced by the fast polarization switch and may also improve both polarization and Doppler processing of radar signals.<<ETX>>

An Efficient Subcarrier Allocation Method for AeroMACS-Based Communication Systems

The work presented here deals with an IEEE 802.16e-based system for airport surface communications, named AeroMACS. Such a system has been proposed as a possible solution to satisfy the growing demand of new communication services and needs of next generation air traffic management (ATM) systems. By focusing on a specific airport environment, a resource allocation algorithm is proposed that allows the communication system capacity to be increased by exploiting the tap correlation related to each user communication channel. Optimal resource allocation using tap correlation has been previously shown to have a significant gain with respect to different alternatives, but also suffers from severe computational complexity. In order to relax this drawback, a novel suboptimal method is proposed that allows the implementation complexity to be lowered and the derivation of channel parameters to be made affordable, in particular in the case of fast varying propagation conditions or high estimation latency. The performance of the proposed algorithm is validated by comparisons with those achieved by the optimal approach and alternative solutions under different application conditions and users speed values. The final result shown here is a significant performance improvement for the proposed algorithm with respect to standard alternatives.

Performance Analysis of a Dwell-Time Processor for Monopulse Beacon Radars

Performance of a monopulse air traffic control radar beacon system (ATCRBS) target data extractor is analyzed via an analytical approach. Results refer to a statistical analysis of the section of the receiver which associates replies sent by the desired aircraft during the antenna dwell-time. Some numerical results are reported which refer to the ATCRBS section to be devised in the discrete address beacon system (DABS).

OFDM radar signals for both surveillance and navigation aids to landing aircrafts

In the Air Traffic Control domain, currently the airport primary radar performs surveillance function, while dedicated radio channels in the VHF band allow ground-air voice communications, which notify information about ground conditions. It is believed of interest in increasing security in the most sensitive phases of landing, to explore the possibility to combine the traditional tracking function performed by airport primary radar (radar function) with a broadcast communication function. This function simultaneously and automatically provides aircrafts, monitored near real-time, with a series of particularly useful data, such as local air-meteorological conditions and management of airport runways. This information is integrated in the waveform emitted by the radar, thus implementing a broadcast transmission channel, whose content can be automatically decoded by the aircraft equipped with an appropriate receiving system. This paper illustrates a preliminary feasibility analysis of using radar&communication techniques in this particular application, and consequent parameters setting.

Reply Correlation Test Analysis in Monopulse Beacon Radars

The statistical behavior of the position data furnished by single air traffic control radar beacon system (ATCRBS) reports is analyzed. Some statistical models are correspondingly derived in order to be employed for the performance evaluation of the dwell-time section of the ATCRBS monopulse receiver. The expression of the failure probability is derived for the range and azimuth tests performed by the association algorithms operating in the monopulse ATCRBS target data extractor. Some numerical results are reported referring to the evaluation of the above failure probabilities in different conditions.

Preliminary Waveform Analysis for a New Concept of ATC Radar

The expected growth of air traffic in national and international airports requires the development of new, efficient air traffic management systems. A key objective is to develop new technologies for maximizing airspace and airport capacity and safety. The availability of accurate ground condition information, regardless of the information independently acquired by the aircraft or that provided by the controller via voice channel, is believed to be of considerable interest in increasing landing security. Currently, the radar surveillance function and the communication function toward approaching aircrafts are carried out separately: the airports primary surveillance radar performs surveillance, while dedicated radio channels in the VHF band allow air-ground voice communications. In this context, this paper explores the possibility of combining the traditional tracking function performed by radar with the communication function, which automatically provides aircrafts, monitored near real time, with a series of data particularly useful for the final landing. The data at issue are typically those related to airport ground conditions, such as local air-meteorological conditions and airport runway management. This information is integrated into the waveform emitted by the radar, thus implementing a broadcast transmission channel, whose content can be automatically decoded by an aircraft equipped with an appropriate receiving system. The proposed study is a preliminary analysis of the topic, with the main purpose of assessing the feasibility of using radar and communication techniques in this particular application.