Publications

The UNISYS Corporation has developed a microburst prediction radar (MBPR) to provide detection and short-term predictions of the most hazardous form of low altitude wind shear in the vicinity of an airport. The MBPR is intended for deployment on- or near-airport so as to minimize range coverage (and associated radar power-aperture) requirements. Like the airport surveillance radar wind shear processor (ASR-WSP), the cost of the MBPR is significantly less than that of the terminal Doppler weather radar (TDWR) so that its deployment at smaller airports might be economically justified if the performance is operationally acceptable. Field tests of engineering prototypes of the MBPR have been conducted in conjunction with FAA-sponsored TDWR and WSP demonstration programs. We assess the capabilities and limitations of each of these systems using a consistent methodology that emphasizes the comparative analysis of the significant parameters of each radar in relation to wind shear phenomenology. An extensive database on wind shear event radar cross section, spatial structure and intensity distribution-derived through our FAA-sponsored testing of TDWR and ASR-WSP prototypes is an important asset in developing this comparison.

The Terminal Doppler Weather Radar (TDWR) system which has been developed by Raytheon Co. for the Federal Aviation Administration (FAA), provides automatic detection of microbursts and low-altitude wind shear. Microburst- and gust front-induced wind shear can result in a sudden, large change in airspeed which can have disastrous effect on aircraft performance. during take off or landing. The second major function of TDWR is to improve air traffic management through forecasts of wind shifts, precipitation and other weather hazards. The TDWR system generates Doppler velocity, reflectivity, and spectrum width data. The base data are automatically dealiased and clutter is removed through filtering and mapping. Precipitation and windshear products, such as microbursts and gust fronts, are displayed as graphic products on the Geographic Situation Display which is intended for use by Air Traffic Control supervisors. Alphanumeric messages indicating the various windshear alerts and derived airspeed losses and gains are sent to a flat panel ribbon display which is used by the controllers in the control tower. The TDWR proof-of-concept and operational feasibility have been demonstrated in a number of FAA-sponsored tests and evaluations conducted by Massachusetts Institute of Technology's Lincoln Laboratory (MIT/LL) in Memphis, TN (1985); Huntsville, AL (1986); Denver, CO (1987, 1988); Kansas City, MO (1989, and Orlando, FL (1990-1992). In order to verify that the TDWR meets FAA operational suitability and effectiveness requirements, an Operational Test & Evaluations (OT&E) was conducted at the Oklahoma City site during the period from 24 August to 30 October 1992. The testing addressed National Airspace System (NAS)-SS-1000 requirements, weather detection performance, safety, operational system performance, maintenance, instruction books, Remote Maintenance Monitoring System (RMMS), system adaptable parameters, bullgear wear, and limited Air Traffic (AT) suitability. The TDWR OT&E Integration and Operational testing was conducted using a variety of methods dependent on the area being tested. This paper discusses primarily the weather detection performance testing. A rough analysis was performed on the algorithm output and the base data to determine the performance of the TDWR in detecting wind shear phenomena. Final results will be available after additional testing, which is scheduled for Spring of 1993, and post analysis in conducted.