Modeling of the"thin" structure probability discrepancy distribution in the indications of ADS-B and SSR. Uncompensated latency

• Published in: Nauchnyĭ vestnik MGTU GA (Online) Vol. 22; no. 4; pp. 8 - 20
• Main Authors: Alipov, I. V., Kuznetsov, V. L.
• Format: Journal Article
• Language: English; Russian
• Published: Moscow State Technical University of Civil Aviation 22-08-2019
• Subjects: date discrepancy of ads-b and ssr; distribution asymmetry; uncompensated latency
• ISSN: 2079-0619; 2542-0119
• DOI: 10.26467/2079-0619-2019-22-4-8-20

The upcoming transition to a new generation of the elements in the ATC system - AZN-B - has set a number of tasks related to confirming the integrity of the data received, and determining their accuracy characteristics. Radar surveillance systems which are used up to now have established a good reputation and the matter of succession is naturally associated with the comparison of these two recording systems data. Discrepancies (differences) in the AZN-B registrations and radar data are an additional source of information related to reliability and accuracy of their measurements. The problem lies in the method of information extraction. The article analyzes the stable features of discrepancy distribution (histograms) probability obtained in the "Air Navigation Research and Development Institute" branch of GosNII GA by analyzing the observations of aircraft operations in Moscow region. The presence of asymmetry in these histograms is supposed to be interpreted as the presence of uncompensated latency in the transmission of data from AZN-B, which is typical for a certain portion of aircraft in the airspace of Russia. The emphasis on the "territorial affiliation" of the effect is due to the fact that we don’t have any information about the works abroad devoted to the phenomenon under discussion. In accordance with the hypothesis stated, a mathematical model of the measurement procedure with the following parameters to be estimated was constructed: the average value of the uncompensated delay and the expected share of aircraft, characterized by this defect. The values of the sought-for parameters were discovered according to the condition of minimum "distance" between the experimental histogram and the corresponding model analytical dependence. The estimates made revealed that about 30% of the aircraft, out of the total observed number, report their coordinates with an additional error of 75 m. at an average.