Patent ID: 8157219

Claim:
A railroad train detection system comprising: a first multidimensional anisotropic magnetoresistive (AMR) sensor fixed in proximity to a railroad track; a second multidimensional AMR sensor fixed in proximity to the railroad track and spaced apart from the first AMR sensor; wherein each AMR sensor is configured to generate multidimensional analog waveform data representative of changes in a generally constant magnetic field environment due to the presence of a railroad train passing on the railroad track; a signal processor configured to generate multidimensional digital waveform data based on multidimensional analog waveform data generated by the first and second AMR sensors; and a waveform data transmitter configured to transmit multidimensional digital waveform data from the signal processor to a system processing apparatus, wherein the system processing apparatus is configured to control an active warning device at a railroad track crossing using the transmitted digital waveform data; wherein the signal processor comprises: a filter and amplifier configured to convert multidimensional analog waveform data to processed multidimensional analog waveform data; an analog-to-digital converter configured to convert processed multidimensional analog waveform data to multidimensional digital waveform data; and an encoder configured to encode multidimensional digital waveform data to generate encoded multidimensional digital waveform data; further wherein waveform data transmitter transmission of multidimensional digital waveform data comprises transmission of encoded multidimensional digital waveform data; and further wherein the waveform data transmitter is further configured to transmit using spread spectrum radio transmission.