Vehicle navigation assistance device having fast file access capability
First Claim
1. An apparatus for assisting a user in navigating a vehicle, the apparatus comprising:
- a processor;
a database including a data file, the data file including a plurality of data subsets having a logical sequence within the data file;
a sensor subsystem coupled to the processor;
an output subsystem coupled to the processor for outputting navigation information to the user;
wherein the processor is configured to;
compute a present location of the vehicle based on data from the sensor subsystem and the database; and
cause the output subsystem to output an indication of the present location to the user; and
wherein the processor is further configured to;
determine the logical order of the data subsets within the data file from a first table, the first table including a plurality of references to the data subsets, wherein the plurality of references are arranged within the first table in a sequence different from the logical sequence of the data subsets within the data file; and
store in consecutive locations of a second table the same plurality of references to the data subsets stored in the first table, according to the logical sequence of the data subsets within the data file.
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Accused Products
Abstract
A method of using a DOS file system to access a file in a database is provided. In one embodiment implemented in an on-board vehicle navigation system, the file includes map data for a given geographic area. A file access table (FAT) is associated with the file system and references the file. The FAT has a plurality of locations, each location including a reference to one of the data clusters of the file and to another location in the FAT, forming a linked list of the references. The logical order in which the data clusters occur within the file is determined by following the linked list in the FAT for that file. A cluster table is then constructed for the file. The references to the data clusters are stored in consecutive locations of the cluster table according to the logical order of the data clusters within the file. The file is then accessed by sequentially accessing the consecutive locations in the cluster table to retrieve the data clusters.
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Citations
18 Claims
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1. An apparatus for assisting a user in navigating a vehicle, the apparatus comprising:
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a processor; a database including a data file, the data file including a plurality of data subsets having a logical sequence within the data file; a sensor subsystem coupled to the processor; an output subsystem coupled to the processor for outputting navigation information to the user; wherein the processor is configured to; compute a present location of the vehicle based on data from the sensor subsystem and the database; and cause the output subsystem to output an indication of the present location to the user; and wherein the processor is further configured to; determine the logical order of the data subsets within the data file from a first table, the first table including a plurality of references to the data subsets, wherein the plurality of references are arranged within the first table in a sequence different from the logical sequence of the data subsets within the data file; and store in consecutive locations of a second table the same plurality of references to the data subsets stored in the first table, according to the logical sequence of the data subsets within the data file. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9)
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10. An apparatus for use in an automobile to assist a user in navigating, the apparatus comprising:
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means for storing a data file, the data file including a plurality of data subsets having a logical sequence within the data file; means for detecting movement of the automobile; means for computing route guidance information based on the detected movement of the automobile and the data file; means for determining the logical order of the data subsets within the data file from a first table, the first table including a plurality of references to the data subsets, wherein the plurality of references are arranged within the first table in a sequence different from the logical sequence of the data subsets within the data file; means for storing, in consecutive locations of a second table, the same plurality of references to the data subsets stored in the first table, according to the logical sequence of the data subsets within the data file; and means for outputting the route guidance information to the user. - View Dependent Claims (11, 12, 13, 14)
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15. An apparatus for assisting a user in navigating a vehicle, the apparatus comprising:
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a processor; a first storage region coupled to the processor and storing a database including a data file, the data file including a plurality of clusters of data; a second storage region coupled to the processor and storing a file access table (FAT) having a plurality of locations, each location including a reference to one of the clusters of the data file and a reference to another location in the FAT indicating a next cluster of the data file, wherein the references to the clusters of the data file may be located in non-consecutive locations in the FAT; a sensor subsystem coupled to the processor; an output subsystem coupled to the processor; wherein the processor is configured to; identify, from the FAT, the logical order of the clusters within the data file; construct a cluster table by storing the references to the clusters in consecutive locations of the cluster table based on the logical order; access the data file by sequentially accessing the consecutive locations in the cluster table to retrieve the clusters of the data file; compute route guidance information based on outputs of the sensor subsystem and the data file; and cause the output subsystem to output the route guidance information. - View Dependent Claims (16, 17, 18)
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Specification