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Self-powered vehicle speed sensor

  • US 7,558,695 B2
  • Filed: 08/10/2004
  • Issued: 07/07/2009
  • Est. Priority Date: 08/10/2004
  • Status: Active Grant
First Claim
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1. A method of sensing vehicle speed comprising:

  • self-powering a speed sensor, wherein the speed sensor comprises a Doppler speed sensor that includes a microwave source and a microwave receiver, which are designed to measure a speed corresponding to one or more objects using a Doppler shift in a microwave that a) originated from the microwave source, b) was received at the microwave receiver, and c) was back-reflected from one of the one or more objects;

    taking a sample of Doppler speed sensor data from the Doppler speed sensor;

    processing the sample of Doppler speed sensor data to calculate one or more speeds corresponding to the one or more objects;

    determining a traffic speed based at least in part on the one or more speeds calculated using the sample of Doppler speed sensor data; and

    wirelessly transmitting the traffic speed to a server.

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