US 5,406,491 AGranted

Navigational system for trip routing

AssigneeTrimble Navigation Limited

InventorDavid J. Lima

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Abstract

Method and apparatus for indicating and allowing a traveler to follow a chosen route from an origin point to a destination point on the Earth's surface, using a portable Satellite Positioning System and audible or visual information presentation means. Initially, the traveler positions a map or chart with the intended route thereon on a light-sensitive table and traces each segment of the route with a pressure-sensitive light pen. Information on each segment and the locations of its endpoints is entered in a microprocessor. Coded information shown on the map itself is entered into the microprocessor, using a bar code reader or similar device. Along the route, the traveler carries the microprocessor and a portable Satellite Positioning System (SPS) antenna and receiver/processor, connected to the microprocessor. As the traveler approaches each turn point or decision point in the route, determined by a common endpoint of two consecutive segments, the apparatus advises the traveler audibly or visually that the decision point is near and of the initial direction of the next consecutive segment. The traveler is also advised if the actual route deviates significantly from the chosen route and of the appropriate corrective action to be taken to reduce the deviation. Optionally, the apparatus can include information on one or more alternative routes that can be used if a portion of the chosen route is impassible or otherwise unavailable. This approach is of special usefulness to a visually impaired or visually preoccupied traveler. The SPS may incorporate differential positioning to improve the accuracy of the SPS-determined location.

Claims29

Dependent claims

A method for indicating, and allowing a traveler to follow, a chosen route from an origin point to a destination point on or near the Earth's surface, where the route does not coincide with part of an established system of roads, the method comprising the steps of:

providing a map of a region R, having approximately uniform scaling, the map having two spaced apart location indicator points whose location coordinates are known;
selecting a chosen route from a selected origin to a selected destination on the map;
entering and storing location information on the indicator points in the memory of a microprocessor that contains information on the region R;
entering and storing information on the chosen route in the memory as a sequence of location coordinates of two or more connected route segments, each having at least two endpoints, in the microprocessor, where at least one of the route segments is not part of a segment of a surveyed road;
providing for the traveler an SATPS antenna and receiver/processor, connected to the microprocessor, to receive and analyze SATPS signals from two or more SATPS satellites and to determine the present location of the SATPS antenna;
providing information on the present location of the SATPS antenna to the microprocessor;
comparing the present location of the SATPS antenna with the location coordinates of an adjacent one of said connected route segments;
and
when the present location of the SATPS antenna is not on said adjacent one of said route segments, advising the traveler if the present location of the SATPS antenna is beyond a selected distance d1 from a nearest point on said adjacent one route segment, and identifying the direction and the distance of the present antenna location relative to said nearest point on said one adjacent route segment, using error presentation means that is audibly perceptible or visually perceptible for advising the traveler.

6 more elements

Apparatus to be carried by a traveler, for indicating, and allowing the traveler to follow, a chosen route, shown on a map of a selected region R, from a selected origin point to a selected destination point on or near the Earth's surface, where the chosen route does not coincide with part of an established system of roads, the apparatus comprising:

a microprocessor having a memory;
information entry means for entering into the memory information on said chosen route from said map, the chosen route being defined by a sequence of two or more connected route segments, each segment having at least two consecutive endpoints, where at least one of the route segments is not part of an established road, and for entering into the memory information on the scale of the map and the location coordinates of at least two spaced apart indicator points on the map;
an SATPS signal antenna and received processor, connected to the microprocessor, oriented to receive SATPS signals from at least two SATPS satellites and to determine therefrom the present location of the antenna;
information presentation means for advising the traveler, by an audibly perceptible or visually perceptible message, of the present location of the SATPS antenna:
and
location comparison means for receiving and comparing the present location of the SATPS antenna with an adjacent one of said route segments for said chosen route containing a point nearest to the SATPS antenna present location and, when the SATPS antenna present location is not on said one adjacent route segment containing said nearest point and is beyond a selected distance d1 from said nearest point, for advising the traveler of the distance and direction of the present location of the SATPS antenna relative to said nearest point, using the information presentation means.

3 more elements

Dependencies are inferred from the claim text.