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:
Sep. 13, 1994
Filed:
Apr. 28, 1992
Kamran K Abadi, Menlo Park, CA (US);
Steven C Evans, Soquel, CA (US);
Ashtech, Inc., Sunnyvale, CA (US);
Abstract
A method and apparatus for pre-filtering a global positioning system receiver, which includes the steps of: receiving a plurality of L-band radio frequency signals having unique modulation and originating in a plurality of global positioning system satellites; splitting the plurality of radio frequency signals into at least a first L1 radio frequency signal and a second L2 radio frequency signal; passing the first L1 radio frequency signal to a first radio frequency receiving section through a L1 signal passage defining a path from a common junction point to the L1 radio frequency receiving section, while simultaneously passing the L2 radio frequency signal to a second radio frequency receiving section through a L2 signal passage defining a path from the common junction point to the L2 radio frequency receiving section; filtering the L1 radio frequency signal from the L2 signal passage and filtering the L2 radio frequency signal from the L1 signal passage, while substantially preserving the L1 radio frequency and the L2 radio frequency signals; and feeding the L1 and the L2 radio frequency signals to the first L1 radio frequency receiving section and the second L2 radio frequency receiving section, for determining position information.