The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Mar. 10, 2015
Filed:
Aug. 12, 2011
Applicant:
Terry M. Schaffner, Warrenville, IL (US);
Inventor:
Terry M. Schaffner, Warrenville, IL (US);
Assignee:
Digi International Inc., Minnetonka, MN (US);
Attorney:
Primary Examiner:
Int. Cl.
CPC ...
G01S 13/08 (2006.01); G01S 13/32 (2006.01); H04B 1/69 (2011.01); G01S 11/04 (2006.01); G01S 13/00 (2006.01); H04B 1/00 (2006.01);
U.S. Cl.
CPC ...
H04B 1/69 (2013.01); G01S 11/04 (2013.01); H04B 2001/6912 (2013.01);
Abstract
Distance between two radio frequency devices is estimated by receiving a plurality of spread spectrum chirp signals frequency offset from one another, and evaluating the received plurality of spread spectrum chirp signals for relative phase shifts between the plurality of spread spectrum chirp signals. A fine propagation time is derived using the phase shifts between the spread spectrum chirp signals. A frequency domain despreading window is shifted to reduce the influence of time-delayed near multipath signals in receiving the plurality of spread spectrum chirp signals.