Bidirectional data-transmission method for defining distances between first/second transmitter/receiver units (TRUs) remote from each other, evaluates signal runtime between TRUs to define remoteness

摘要

A first transmitter/receiver unit (TRU) (1) transmits at a relatively low first frequency (f1). A second TRU (2) transmits at a higher second frequency (f2). During transmission, both first and second TRUs are synchronized in time as they operate. Evaluating signal runtime between first and second TRUs determines remoteness in the first TRU at the same time as data is transmitted. An Independent claim is also included for a system for bidirectional data transmission and determining distances between first and second transmitter/receiver units remote from each other.