Method and apparatus for processing multipath reflection effects in timing systems

• US 6,252,546 B1
• Filed: 10/19/2000
• Issued: 06/26/2001
• Est. Priority Date: 03/24/1999
• Status: Expired due to Term

• Current Assignee: Trimble Navigation Limited (Trimble Inc.)
• Original Assignee: Trimble Navigation Limited (Trimble Inc.)
• Inventors: Smith, Scott R., Lennen, Gary R.
• Primary Examiner(s): Blum, Theodore M.
• Application Number:
  US09/692,006
• Time in Patent Office: 250 Days
• Field of Search: 342/361, 342/362, 342/363, 342/364, 342/365, 342/366
• US Class Current: 342/363
• CPC Class Codes: G01S 19/22 Multipath-related issues
• CPC Class Codes: G01S 19/428 using multipath or indirect path propagation signals in position determination
• CPC Class Codes: H01Q 21/24 Combinations of antenna units polarised in different directions for transmitting or receiving circularly and elliptically polarised waves or waves linearly polarised in any direction circularly polarised patch antennas H01Q9/0428; circularly polarised horns H01Q13/0241; cross-polarised horns H01Q13/0258; polarisation converters H01Q15/242; cross-polarised rear feeds H01Q19/136; crossed polarisation dual antenna H01Q25/001
• CPC Class Codes: H01Q 9/0435 using two feed points
• CPC Class Codes: H04B 7/02 Diversity systems; Multi-antenna system, i.e. transmission or reception using multiple antennas RAKE receivers H04B1/7115
• CPC Class Codes: H04B 7/10 Polarisation diversity; Directional diversity
• CPC Class Codes: H04B 7/2125 Synchronisation

Abstract

A method and apparatus for processing multipath reflection effects in timing systems is disclosed in which a determination is made of whether a received signal is a reflected signal. A detector provides from an input signal a pair of signals representative of whether the input signal contained right-hand circularly polarized and left-hand circularly polarized components. The representative signals are separately processed in synchronized logic circuits to determine relative power levels. The power levels are compared to determine the nature of the dominant polarization of the input signal.

Claims

1. A method comprising the steps of:

receiving a satellite navigation signal that can be RHC polarized or LHC polarized;

determining if it is RHC polarized and if so deriving timing information from it; and

determining if it is LHC polarized and if so selectively deriving timing information from it or rejecting it.