VEHICLE USER IDENTIFICATION METHOD Russian patent published in 2003 - IPC

FIELD: transport engineering; security systems. SUBSTANCE: transport with individual code is given to each user. Coded enquiry and answer in form of interrupted radio pulses with fixed carrier frequency representing unities and zeroes are generated in stationary part of security complex and in transponder on supergenerative stages with external superization. For said stages, starting signals are formed with smoothly building up leading edges and frequencies constant in process of transmission of each digit, F_C"1",F_T"1" or F_C"0",F_T"0". Answers are generated simultaneously with enquiry. Enquiry code digit received by transport and answer code digit received by stationary part are determined with account of transmitted code digit and frequency difference providing pulselength modulation of radio pulses. Answer frequencies (F_T"1",F_T"0") are set depending on enquiry frequencies (F_C"1",F_C"0") and chosen ratio M of frequencies of pulse-length modulation . Coincidence and noncoincidence of transmitted and received digits are determined by presence of pulse-length modulation of radio signal envelope with frequencies (F_C"1"-F_C"0")/(M+1) and M(F_C"1"-F_C"0")/(M+1, respectively. EFFECT: improved reliability of protection against hi-jacking. 3 cl, 6 dwg