Algorithms for Calculating the Coverage Area of the Radio Frequency Reader Antenna in Determining the Location of a High-Speed Object

Abstract

The analysis of modern systems of automatic identification of a moving objects condition with use of means of radiofrequency identification is carried out. The requirements to the system for automatic identification of high-speed objects are formulated. An approach to solving the problem of locating a high-speed object based on the use of a complex of radio frequency identification means is proposed, in which a number of passive radio frequency tags are placed along the path of the object, and a radio frequency reader is installed on the object itself. The probabilistic model of the response formation is considered. Based on the analysis of the relative location of the time interval during which the RF tag is in the coverage zone of the antenna and the radiation intervals of the antenna bundles of the probing pulses, the distribution law of the random variables corresponding to the overlapping time of the first and second bursts of pulses is constructed. The sensitivity of the RF tag (the probability of forming a response of RF tag from one bundle of probing pulses depending on the width of the packet) is given in the form of a logistic function with parameters determined experimentally. It is shown that at high speeds of the object with a small width of the coverage zone of the antenna, the appearance of the response of the RF tag is unlikely. The problem of justifying the required width of the antenna coverage zone is formulated, which ensures the formation of a response of the RF tag with a probability not less than a given value. The solution of the problem is illustrated for a complex of radio frequency identification means with known sensitivity parameters of the RF tag and with a required duration of probing and a radiation cycle. For a given values of maximum speed of motion and the required probability of occurrence of at least one response, laws of distribution of mixed random variables - the time of overlapping of the first and second bursts of impulses for different speeds of the object's motion are constructed, which allows us, through statistical modeling, to find the empirical distribution function of the frequency of occurrence of at least one RF tag response. For a given level of reliability, it is possible to construct a quantiles dependence of the required level of the random frequency of obtaining at least one response for different values of speed and the length of the coverage zone, which in turn makes it possible to justify the required width of the coverage zone of the transmitting antenna of the automatic identification system.