US Patent 7379016 Carrier phase detection system for radar sensors

A pulse detection system for expanded time radar, laser and TDR sensors detects specific cycles within bursts of cycles. A sensor transmits and receives short bursts of RF cycles. A transmit pulse detector triggers on a selected cycle of the detected transmit burst and starts a range counter. A receive detector triggers on a selected cycle within a received echo burst to stop the range counter, thereby indicating range. Cycle selection is enabled by an analysis window of time. The detection system can provide accuracies on the order of one picosecond and is well-suited to accurate ranging along an electromagnetic guide wire.