Coupler for eliminating a hardwire connection between a handheld global positioning system (GPS) receiver and a stationary remote antenna

• US 5,239,669 A
• Filed: 02/04/1992
• Issued: 08/24/1993
• Est. Priority Date: 02/04/1992
• Status: Expired due to Fees

• Current Assignee: Trimble Navigation Limited (Trimble Inc.)
• Original Assignee: Trimble Navigation Limited (Trimble Inc.)
• Inventors: Woo, Arthur N., Mason, Stanley L., Weber, Lynn
• Primary Examiner(s): Eisenzopf, Reinhard J.
• Assistant Examiner(s): VO, NGUYEN THANH
• Application Number:
  US07/830,737
• Time in Patent Office: 567 Days
• Field of Search: 455/14, 455/345, 455/346, 455/280, 455/12.1, 455/54.1, 455/54.2, 455/272, 455/3.2, 455/3.3, 455/13.1, 455/11.1, 343/701, 343/713, 343/702, 343/700 MS, 343/767, 333/17.2
• US Class Current: 455/12.1
• CPC Class Codes: G01S 19/36 relating to the receiver frond end
• CPC Class Codes: H01Q 1/2258 used with computer equipment
• CPC Class Codes: H01Q 1/3233 particular used as part of a sensor or in a security system, e.g. for automotive radar, navigation systems
• CPC Class Codes: H01Q 13/10 Resonant slot antennas
• CPC Class Codes: H01Q 23/00 Antennas with active circuits or circuit elements integrated within them or attached to them

Abstract

A system, according to an embodiment of the present invention, comprises a coupler, a remote antenna, and a handheld GPS receiver. The remote antenna has a microstrip RHCP receiving element and a low noise amplifier (LNA) powered by the coupler over an interconnect cable. The coupler has a slotline antenna and a driver circuit. The coupler re-radiates GPS satellite signals received by the remote antenna with a slotline antenna to the GPS receiver. In a typical installation, such as a car, a user holds the GPS receiver while in the front seat. The coupler mounts to the windshield and the cable runs to remote antenna mounted on the roof of the car. The coupler can then re-radiate GPS satellite signals effectively to the GPS receiver even when the two are separated by as much as six feet. The shielding of GPS signals by the metal of the car is thereby avoided as a problem that can prevent operation of the GPS receiver.

Claims

1. A GPS radio signal coupler, comprising:

a remote antenna unit for receiving GPS signals at non-obstructed locations from GPS satellites in orbit around the earth and including a microstrip antenna, said microstrip antenna being a right-hand circularly-polarized (RHCP) type, and a low noise amplifier (LNA) for amplifying signals received by said microstrip antenna;

a connecting cable for conducting amplified GPS signals output from said LNA and for conducting regulated DC power to operate said LNA; and

a reradiation coupling unit including a slotline antenna connected to the connecting cable for radiating GPS signals amplified by said LNA, said slotline antenna comprising a slot that is a meandered type implemented on a printed circuit board (PCB), said slot being on the same side of said PCB as an associated groundplane and opposite to a feedpoint, and a power supply means connected to the connecting cable for regulating said DC power to said LNA, said power supply means including a voltage regulator, a current limiting circuit and a filter to separate radio frequency signals from DC power, all of which are mounted to said printed circuit board.

2. The coupler of claim 1, wherein:

said power supply means further comprises a jack for receiving a power cable for supplying DC power, and a jack for connecting the connecting cable to the reradiation coupling unit.

3. The coupler of claim 1, further comprising:

a housing for the reradiation coupling unit including a cradle wherein said slotline antenna is held in close proximity to a handheld GPS receiver that is captive within said cradle.