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:
Jun. 06, 1995
Filed:
Feb. 22, 1994
David S Sprague, Portola Valley, CA (US);
Arthur Woo, Cupertino, CA (US);
Trimble Navigation Limited, Sunnyvale, CA (US);
Abstract
A data/voice modem embodiment of the present invention comprises an asynchronous-to-synchronous data converter for interface with a GPS receiver, a minimum space keyed modem, and a continuous tone controlled sub-audible squelch controller that modulates a radio transceiver interface with a discrete tone such that both voice and data may share a common radio channel. The data/voice modem periodically keys-up the radio transmitter through its interface and transmits a packet of information that contains user position and velocity obtained through the GPS transceiver interface and adds a user identification code and time tag. Incoming message packets from the radio transceiver that are sent from other similarly equipped mobile units are used to supply individual network member absolute positions and velocities, and this information is stored by user identification number as goal or waypoint equivalents. As such, distance-to-goal, estimated-time-of-arrival and velocity-made-good estimates are made available on a target track screen included in the respective GPS receiver.