Patent Number: 7,085,537

Title: System and method for the detection and compensation of radio signal time of arrival errors

Abstract: A system and method are disclosed by which the effects of time of arrival errors may be reduced. In a mobile unit, such as a CDMA device, a correlation pulse is generated when a transmitted code matches a stored reference code. In the absence of multipath effects, correlation pulses are generated in response to the detection of multiple transmissions of the reference code from multiple transmitters. However, multipath effects distort the generated correlation pulses leading to errors in the time of arrival measurements. The present invention calculates the width of the correlation pulses and determines a delay correction factor based on the pulse width. The delay correction factor is added to the measured delay time to provide a more accurate delay time, thus permitting more accurate location measurements based on time of arrival. In alternative embodiments, other signal factors may also be used to apply delay correction factors. The actual location determination may be performed by the mobile unit, or any other positioning determining entity (PDE). The system is also capable of applying correction factors to time of arrival signals received from global positioning system (GPS) satellites.

Inventors: Fernandez-Corbaton; Ivan J. (San Diego, CA), Rick; Roland (San Diego, CA), Amerga; Messay (San Diego, CA)

Assignee: Qualcomm Incorporated

International Classification: H04B 1/00 (20060101)

Expiration Date: 8/01/02018