Evaluating ASR-9 azimuth error models through analysis of targets of opportunity

Radar error models are an integral tool in the safety analysis of air traffic control systems. Radar models are utilized to establish surveillance requirements for aircraft separation standards, and to assess the surveillance performance of current and future surveillance systems. Interest in the accuracy of the current collection of radar error models has increased recently with the introduction of new surveillance and automation systems, such as Automatic Dependent Surveillance-Broadcast (ADS-B). Focusing on the ASR-9 Mode S radar specifically, the most common terminal surveillance radar in the United States, this paper compares the accuracy of a variety of azimuth error model distributions and evaluates their suitability for surveillance system safety analysis. The study leverages a method that utilizes raw time-stamped radar reports to estimate radar errors in quantities not possible using traditional flight test data analysis.