05056106 is referenced by 180 patents and cites 9 patents.

The invention disclosed herein is directed to a method and apparatus which employs a spread-spectrum based radiolocation system, using hand-held receiver units and fixed-position reference transmitters, to determine distance and direction between a golfer and key locations on a golf course, such as the distance and direction to a particular pin. The plurality of timing reference transmitters which are located throughout the vicinity of the golf course broadcast a spread-spectrum ranging signal consisting of a radio-frequency carrier directly modulated by a periodic pseudo-noise (PN) coded or similar sequence. Each transmitter broadcasts at the same RF signal but a unique PN-coded sequence is assigned to each transmitter. Golfers are provided with the hand-held receiving unit which receives the transmitter spread-spectrum signals and which synchronizes to the spread-spectrum signals in order to obtain range estimates to a selected set of reference transmitters. The hand-held receivers also include memory to store the coordinates of the reference transmitters and the pin positions and other reference points for each hole on the golf course, which are either pre-loaded into memory or transmitted (as modulating data) with the ranging signal. Each hand-held unit also includes a digital processor which incorporates a hyperbolic location algorithm to compute the hand-held unit position based on the estimated ranges to the selected transmitters and the reference transmitter coordinates. The distance and direction from the current position to the pin or other selected reference points is then displayed via an appropriate medium on the hand-held unit.

Title
Golf course ranging and direction-finding system using spread-spectrum radiolocation techniques
Application Number
7/561579
Publication Number
5056106
Application Date
August 2, 1990
Publication Date
October 8, 1991
Inventor
Robert M Grayson
3082 Inverness Dr., Los Alamitos, 90720
CA, US
James J Wang
2625 Monterey Rd., San Marino, 91108
CA, US
Agent
Hoffman Wasson & Gitler
IPC
A63B 57/00
G01S 5/12
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