Secondary Surveillance Radar Mode Research Articles

Development of a Flight Time Uncertainty Model for Four-Dimensional Trajectory Management

The paper presents a model of the flight time uncertainty based on flight conditions and weather forecasts for aircraft flying at arbitrary distances for use in four-dimensional (4-D) trajectory management. Fluctuations in meteorological conditions inevitably result in an increased flight time uncertainty despite constant monitoring and control of the aircraft’s Mach number, flight altitude, and direction. A series of actual flight data acquired from secondary surveillance radar mode S and numerical weather forecast data was analyzed to provide a large number of samples for flight time errors. A mathematical model of the flight time uncertainty as a function of ground speed, Mach number, flight distance, and wind and temperature forecasts was modeled based on the law of propagation of uncertainty considering the correlation between temperature and wind fluctuations. Cluster and linear regression analyses were used to determine the function coefficients. The evaluation results show that the proposed model can accurately estimate the flight time uncertainty for an aircraft flying at arbitrary distances, even under calm or severe weather conditions. The proposed model has the potential to simultaneously improve the safety and efficiency of 4-D trajectory management.

Adaptive prediction of flight time uncertainty for ground-based 4D trajectory management

An adaptive prediction model of level flight time uncertainty is derived as a function of flight and meteorological conditions, and its effectiveness for ground-based 4D trajectory management is discussed. Flight time uncertainty inevitably increases because of fluctuations in meteorological conditions, even though the Mach number, flight altitude and direction are controlled constant. Actual flight data collected using the secondary surveillance radar Mode S and numerical weather forecasts are processed to obtain a large collection of flight time error and flight and meteorological conditions. Through the law of uncertainty propagation, an adaptive prediction model of flight time uncertainty is derived as a function of the Mach number, flight distance, wind, and temperature. The coefficients of the adaptive prediction model is determined through cluster analysis and linear regression analysis. It is clearly demonstrated that the proposed adaptive prediction model can estimate the flight time uncertainty without underestimation or overestimation, even under moderate or severe weather conditions. The proposed adaptive prediction is able to improve both safety and efficiency of 4D trajectory management simultaneously.

Real-time motion detection for high-assurance aircraft tracking system using Downlink Aircraft Parameters

With the rapid increase in air traffic demands, the more accurate and reliable tracking system for aircraft surveillance is required to improve the capacity, safety and efficiency of Air Traffic Control services. As a considered part of the surveillance infrastructure, the Secondary Surveillance Radar Mode S has been widely used in the aircraft tracking systems. Moreover, in the Mode S Enhanced Surveillance, the Downlink Aircraft Parameters are available for obtaining updated and detailed information from aircrafts. However, this information of aircraft parameters has not been used systematically to improve the performance of current tracking systems. In this paper, a high-assurance aircraft tracking system is proposed by applying these aircraft parameters. The system with a high-accuracy estimator and a high-reliability checker enables not only tracking aircraft with changing flight modes in real time but also identifying potential faults of these parameters by pre-to-post data verification. The results of computer simulation and practical experiment show the effectiveness of proposed system by comparing with the Interacting Multiple Model estimator.

Global navigation satellite system in an integrated air traffic management constellation

Enhanced surveillance, communications and navigation are the primary functions needed for an advanced air traffic management (ATM). To provide ATM globally, including areas not covered by terrestrial systems, the advantages of satellite technology must be exploited. In a previous work, a novel architecture based on low-elevation elevation orbit satellites was described and evaluated. The satellite constellation is designed to supply the surveillance and data link capabilities equivalent to an advanced secondary surveillance radar mode S, as well as to provide satellite communication and navigation functions. Such a co-operative independent surveillance integrating navigation and communication (CISINC) is fully compliant with the communication, navigation and surveillance/air traffic management concept endorsed by the ICAO in 1991. The space-based implementation of CISINC is called ATM-Star. The paper treats the navigation component of ATM-Star called GNSS-LEO, which is compatible with today's GPS receivers and aims to be a solution for the global navigation satellite system phase 2.

Space-based SSR constellation for global air traffic control

Advanced surveillance and communications are the main functions needed for an efficient Air Traffic Control/Management (ATC/ATM). In order to perform them over the entire Earth, a novel architecture is described and evaluated. It supplies the surveillance and data link capabilities of advanced Secondary Surveillance Radar (SSR) Mode S world-wide by means of a constellation of medium orbit satellites carrying SSR Mode S interrogators with phased-array antennas; no new equipment is required on-board aircraft, because the standard transponders are used. The rationale for the study, the system geometry, the link budget computation, the accuracy requirements as well as the subsequent design of the payload and of the optimized constellations needed for global coverage with high location accuracy are described. Moreover, details are given about the design of the spacecraft and of the main units of the space segment. The encouraging results of this overall system study pave the way to a demonstration based on simulators and ground prototypes of the critical parts.

Wind vector derivation using the SSR Mode S data link

The need for good meteorological data is a problem of great importance for the aviation community. This need is related to areas of major interest such as aircraft operating costs and the Air Traffic Control systems automation. The wind vector derivation problem is investigated and a simple algorithm is proposed, capable of running together with all potential trackers. The new algorithm requires the transmission of the on board heading and true air speed measurements to the ground station via the Secondary Surveillance Radar Mode S data link. The algorithm performance is evaluated, and the results obtained are shown to be very satisfactory.

Using Roll-Angle Measurements to Track Aicraft Maneuvers

Present day radar trackers used for air traffic control purposes perform satisfactorily during straight-line flight, but their performance during maneuvers is sometimes degraded. The introduction of the secondary surveillance radar mode S system makes transmission of several airborne measurements to the ground station possible. This paper investigates the use of one such parameter, roll angle, to assist present trackers during maneuvers to achieve accuracies comparable to those achieved during straightline ine flight.