| 摘要 |
The number of simultaneous equations needed to find the location solution of an asset being tracked, such as a railcar, or, in the alternative, to improve the localization accuracy of any of several positioning methods used to track assets, is reduced by using a railway track database. Known railway track locations are used to constrain the railcar (i.e., asset) location solutions. This constraint makes the Cartesian coordinate location x, y and z values interdependent and reduces the number of simultaneous equations needed to find the location solution. Since all relevant railcars must be supported on railway tracks, and railway track locations and elevations throughout North America are available in a database, the number of satellite signals required is reduced. The railway track database represents a complex set of railway tracks. Instead of forming the complete set of function factors that make up the railway track data base every time a railcar location solution is needed, a start is made from a previous solution and only those railway tracks and/or branches that are feasible (i.e., nearby) are tried. Thus, the complexity of forming all railway track function terms is reduced to forming only those needed in a short railway track "tree search".
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