Correction of systematic errors in Wide Area Multilateration

This work presents a method to estimate and correct slow time-dependent position errors due to non perfect ground station synchronization and tropospheric propagation. It uses opportunity traffic emissions, i.e. signals transmitted from the aircrafts within the coverage zone. This method is used to overcome the difficulty of installing reference beacons simultaneously visible by all the base stations in a given Wide Area Multilateration (WAM) system

Trajectory Reconstruction Techniques for Evaluation of ATC Systems

This paper is focused on trajectory reconstruction techniques for evaluating ATC systems, using real data of recorded opportunity traffic. We analyze different alternatives for this problem, from traditional interpolation approaches based on curve fitting to our proposed schemes based on modeling regular motion patterns with optimal smoothers. The extraction of trajectory features such as motion type (or mode of flight), maneuvers profile, geometric parameters, etc., allows a more accurate computation of the curve and the detailed evaluation of the data processors used in the ATC centre. Different alternatives will be compared with some performance results obtained with simulated and real data sets

Simulation Model for Sea Clutter in Airborne Radars

This paper presents the architecture and the methods used to dynamically simulate the sea backscatter of an airborne radar operating in a medium repetition frequency mode (MPRF). It offers a method of generating a sea backscatter signal which fulfills the intensity statistics of real clutter in time domain, spatial correlation and local Doppler spectrum of real data. Three antenna channels (sum, guard and difference) and their cross-correlation properties are simulated. The objective of this clutter generator is to serve as the signal source for the simulation of complex airborne pulsed radar signal processor

Automatic Adaptation of Airport Surface Surveillance to Sensor Quality

This paper describes a novel method to enhance current airport surveillance systems used in Advanced Surveillance Monitoring Guidance and Control Systems (A-SMGCS). The proposed method allows for the automatic calibration of measurement models and enhanced detection of nonideal situations, increasing surveillance products integrity. It is based on the definition of a set of observables from the surveillance processing chain and a rule based expert system aimed to change the data processing method

Experimentel ADS-B based surveillance

This paper describes an ADS-B implementation in air-to-air and ground based experimental surveillance within a prototype ATM system. The relations between airborne and ground systems related to surveillance are detailed, and the prototype surveillance systems and their algorithms described. Their performance is analysed, based both on simulated and real data

Generic multisensor multitarget bias estimation architecture

Current bias estimation algorithms for air traffic control (ATC) surveillance are focused on radar sensors, but the integration of new sensors (especially automatic dependent surveillance-broadcast and wide area multilateration) demands the extension of traditional procedures. This study describes a generic architecture for bias estimation applicable to multisensor multitarget surveillance systems. It consists on first performing bias estimations using measurements from each target, of a subset of sensors, assumed to be reliable, forming track bias estimations. All track bias estimations are combined to obtain, for each of those sensors, the corresponding sensor bias. Then, sensor bias terms are corrected, to subsequently calculate the target or sensor-target pair specific biases. Once these target-specific biases are corrected, the process is repeated recursively for other sets of less reliable sensors, assuming bias corrected measures from previous iterations are unbiased. This study describes the architecture and outlines the methodology for the estimation and the bias estimation design processes. Then the approach is validated through simulation, and compared with previous methods in the literature. Finally, the study describes the application of the methodology to the design of the bias estimation procedures for a modern ATC surveillance application, specifically for off-line assessment of ATC surveillance performance

Bias Estimation for Evaluation of ATC surveillance systems

This paper describes an off-line bias estimation and correction system for air traffic control related sensors, used in a newly developed Eurocontrol tool for the assessment of ATC surveillance systems. Current bias estimation algorithms are mainly focused in radar sensors, but the installation of new sensors (especially automatic dependent surveillance-broadcast and wide area multilateration) demands the extension of those procedures. In this paper bias estimation architecture is designed, based on error models for all those sensors. The error models described rely on the physics of the measurement process. The results of these bias estimation methods will be exemplified with simulated data

Correction of propagation errors in wide area multilateration systems

Methods to estimate and correct slow time-variant position errors due to bad synchronization and propagation in Wide Area Multilateration Systems (WAM) are presented. The procedure does not use emitters at known locations. Instead it uses opportunity traffic emissions (from the aircraft present in coverage). The need for these methods came from the difficulty to install reference beacons that can be seen simultaneously by all WAM base stations

Air-to-Air Surveillance for Future ATM Systems

This paper describes a prototype implementation of ADS-B in an air-to-air surveillance system. This air surveillance system was defined for an experimental project on future civilian air traffic management, which imposes new requirements over both air and ground surveillance systems. In this paper the relation between the different airborne and ground systems related to air surveillance is detailed, and the air surveillance and its algorithms are described. It is related with current ADS-B and TIS-B proposals, and defined as an extension of those systems. Finally, performance of the air surveillance is detailed, based on simulated scenarios, and some conclusions for future enhancements of ADS-B function are derived

TRES: Multiradar-Multisensor Data Processing assessment using Opportunity Traffic

In this paper we describe a new tool being currently developed by Eurocontrol for Air Traffic Control multiradarmultisensor data processing systems assessment. This tool, called TRES (Trajectory Reconstruction and Evaluation Suite), will become in a near future a replacement for some parts of current versions of SASS-C (Surveillance Analysis Support System for Centres) suite. The paper describes the overall architecture of the assessment system, and details the methods used in TRES for the calculation of reference trajectories, taking into account sensor detection characteristics, available information, sensor accuracies, biases, ... The whole system has been tested with real traffic and simulated data, some illustrative examples are presented at the end