US 7,253,722 B2Granted

Sensor alignment detection method for an infrared blind-zone sensing system

AssigneeDelphi Technologies, Inc.

InventorsKevin M. Deasy, Adil Ansari

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Abstract

A diagnostic method for a blind-zone sensing system including leading and trailing passive IR sensors periodically determines a separation distance between coverage areas of the leading and trailing sensors to diagnose sensor alignment. Signals produced by the leading and trailing sensors are sampled and stored over a defined interval of time for processing. A condition in which the sensor coverage areas abruptly encounter a stationary region of cooler temperature is detected when corresponding signal deflections are identified. The elapsed time between the identified signal deflections is measured and used along with an accurate measure of the vehicle speed to compute the separation distance between coverage areas of the leading and trailing sensors.

Claims5

Dependent claims

An alignment detection method for a sensing system of a motor vehicle, the sensing system having first and second passive sensors mounted on the vehicle and aligned to detect radiant energy in first and second coverage areas laterally spaced from the vehicle and longitudinally separated by a predetermined distance for purposes of sensing an object of interest, the alignment detection method comprising the steps of:

sampling and storing first and second signals produced by said first and second sensors;
monitoring the sampled signals to identify deflections of said first and second signals that are indicative of a change in detected radiant energy caused by a stationary object or region;
determining a time difference between occurrences of the identified deflections of said first signal and second signals;
calculating a distance using said determined time difference and a measured speed of said vehicle;
and
comparing said calculated distance to said predetermined distance to determine if said first and second passive sensors are properly aligned.

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Dependencies are inferred from the claim text.