Boots – shoes – and leggings
Patent
1988-12-22
1991-03-12
Lall, Parshotam S.
Boots, shoes, and leggings
364449, 364447, 364460, 73178R, G06F 1550
Patent
active
049997831
DESCRIPTION:
BRIEF SUMMARY
TECHNICAL FIELD
The present invention relates in general to a location detecting method, and in particular, to such a method which detects the location of a vehicle being travelling on an arbitrary place of road traffic network without receiving data from the outside via radio waves and the like.
BACKGROUND ART
As a conventional location detecting system which detects the location of a vehicle being travelling on an arbitrary place of road traffic network, there has been proposed a system which uses the principle of dead reckoning and comprises a distance sensor, a heading or direction sensor and a processing unit for giving necessary processes to output signals from the distance and heading sensors. In the dead reckoning, a data regarding the present location of a vehicle is obtained by integrating the amount of change in distance and heading. However, there is the drawback that the distance and heading errors that are inevitably inherent in the distance and heading sensors are accumulated with vehicle travel, and the errors in the present location data obtained by the distance and heading sensors are also accumulated.
In order to overcome the drawback described above, map matching methods have been proposed in U.S. Pat. No. 3,789,198, Japanese patent laid-open publication No. 58-99715, Japanese patent laid-open publication No. 58-113711, "LANDFALL A HIGH-RESOLUTION AUTOMATIC VEHICLE-LOCATION SYSTEM", D. KING, GEC Journal of Science & Technology, Vol. 45, No. 1, 1987, and "Experimental Study to Automotive Travel Electronic Technology", Society of Automotive Travel Electronic Technology, March, 1982. In the map matching methods, the present location data obtained in accordance with the aforementioned dead reckoning is compared with a previously stored road traffic network data, the departed amount of the present location data from the road data is computed as an accumulated error, and the present location data is corrected by the accumulated error and matched with the road data.
More specifically, (1) in the location detecting method described in the U.S. Pat. No. 3,789,198, the present location data of a vehicle is calculated upon the travel distance data obtained by a distance sensor and the travel heading data obtained by a heading sensor. The calculated present location data is compared with a previously stored road location data. If the difference between the present location data and the road location data is within a predetermined threshold value, the present location data is corrected so as to correspond with the nearest road, and on the other hand, if the difference between the both data exceeds the predetermined threshold value, no correction is made, in order that the correction can be made with high precision and the present location data can be displayed accurately.
(2) In the location detecting method described in the Japanese patent laid-open publication No. 58-99715, to display an accurate present location, the present location data of a vehicle is updated at every predetermined distance by calculating the amount of distance change with respect to the coordinate directions of road map, and when the present location data is departed from the road, the location data corresponding to the nearest road is merely determined as a present location data.
(3) In the vehicle location detecting method described in the Japanese patent laid-open publication No. 58-113711, to display an accurate present location, errors arising from a travel heading sensor for detecting a heading or direction of vehicle travel with respect to the earth's magnetic axis are corrected by comparing the radius of curvature obtained upon the travel heading with the radius of the road.
(4) In the vehicle location detecting method described in the "LANDFALL A HIGH-RESOLUTION AUTOMATIC VEHICLE-LOCATION SYSTEM", road traffic network is grouped into non-branch parts and a plurality of typical branch parts, and when the vehicle is travelling from any one of the branch parts to other branch part, the distance between the two branc
REFERENCES:
patent: 4679147 (1987-07-01), Tsujii et al.
patent: 4782447 (1988-11-01), Ueno et al.
patent: 4796191 (1989-11-01), Honey et al.
patent: 4807127 (1989-02-01), Tenmoku et al.
Mito Kunihiko
Shimizu Osamu
Shimizu Toshiyuki
Tenmoku Kenji
Lall Parshotam S.
Sumitomo Electric Industries Ltd.
Zanelli Michael
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