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:
Apr. 17, 1990
Filed:
Dec. 28, 1988
Fred W Phillips, Afton, VA (US);
Kelly L Mahoney, Louisa, VA (US);
Edmund S Zavada, Charlottesville, VA (US);
Sperry Marine Inc., Charlottesville, VA (US);
Abstract
A Long Loop GPS receiver converts the pseudo random noise code bi-phase modulated input signal to a first IF frequency. The first IF is correlated against a duplicate of the pseudo random noise code that modulates the input signal. The correlator output is converted to a last IF having a frequency of one-half the pseudo random noise code sequence repetition rate. Local oscillator leakage into the receiver input is spread in spectrum by the correlator into spectral lines that do not lie on the received signal. A bandpass filter in the last IF removes the leakage spectral lines. A hard limiter converts the last IF to digital format. A digital phase detector adjusts the local oscillator to lock the local oscillator signal to the receive signal. The correlator pseudo random noise code signal is clocked by the local oscillator.