Inter-vehicle distance measuring system

US5249027A · kind A · utility

Assignee

• Rockwell International Corporation · US

Inventors

• Bimal Mathur · Thousand Oaks, US
• H. Taichi Wang · Thousand Oaks, US

Key dates

• Filing date: Mar 16, 1992
• Grant date: Sep 28, 1993
• Expiry date: Mar 16, 2012

Classification

• Technology area (CPC G): Physics
• CPC primary: G01S11/12
• WIPO field: Measurement
• WIPO sector: Instruments

Abstract

A system of active emitters and sensors is provided for measuring distance and communicating between vehicles on an automated highway. The preferred system utilizes a pair of spaced apart sensors at the front of each vehicle for stereo depth perception, two temporally modulated emitters on the rear of each vehicle for redundancy and inter-vehicle communication, and temporally modulated emitters positioned at intervals along the highway for communication from the highway to the vehicles. The emitters may transmit radiation at a wavelength, such as 1 .mu.m IR, for example, that can be detected by low cost detectors. The emitters are modulated temporally to transmit a binary code, resulting in signal-to-noise improvement and increased clutter rejection and operational range. Each sensor may include an array of IR detectors and associated readout circuitry, an imaging lens, a lens array for improving detector fill factor, a filter and polarizer to reject clutter and reduce noise, and a cylindrical lens to provide a good vertical field of view. Detector charge integration is controlled by the binary code of the emitters and depends on the code length and local background illumination. T…