System for identifying and displaying data transmitted by way of unique identifying frequencies from multiple vehicles

A system for detecting and indicating relative location and speed of a number of vehicles on a closed racetrack where each vehicle generates a unique radio frequency identification signal, said vehicle making a plurality of laps around said racetrack in a given race and also temporarily leaving and then re-entering said racetrack, said system comprising:

• a plurality of antennas on said track at spaced locations for sensing said signals as said vehicles pass;
• a first pair of antennas spaced relatively close together compared to the overall racetrack length to provide a speed trap;
• a second pair of antennas spaced significantly greater apart than said first pair and located relatively far from said first pair;
• common cable means for interconnecting all of said antennas for receiving said signals of various frequencies on a common transmission path;
• timing means connected to said cable means for recording elapsed times of vehicles between antenna locations having minimum valid times between said various antenna locations and having preset and different maximum times for the passage of a vehicle between said two antennas of said first pair and said antennas of said second pair, said maximum times being based on said antenna pair spacing and a minimum vehicle speed, said timing means including update means responsive to a vehicle not passing through one of said antenna pairs in said preset maximum time for said one antenna pair for updating the location of said vehicle to said other antenna pair, whereby the true location of said vehicle on said racetrack is established despite pitstops and/or mechanical difficulties.