Predictive drop and load algorithm for an object-based geographical information system

A method, comprising the steps of:

• receiving a signal at a mobile receiver;
• calculating an estimation of the current position of the mobile receiver based upon the received signal;
• accessing one object-based database comprising geometrical objects representing topological features and navigable routes, each geometrical object comprising a tessellation identifier attribute and a geometry attribute defining the geometry of a complete representation of the topological feature or navigable route, the topology being divided into a plurality of tessellations;
• determining a probable geometrical object representing a navigable route where the mobile receiver is probably located and determining a tessellation associated with the determined geometrical object;
• fetching geometrical objects having a tessellation identifier attribute associated with the determined tessellation from the one database and geometrical objects associated with three additional tessellations adjacent to the determined tessellation wherein the four fetched tessellations form a 2.times.2 array;
• loading the fetched geometrical objects into a virtual blackboard;
• comparing the estimated position of the mobile receiver to the probable geometrical object representing a navigable route and if the estimated position differs from a position coinciding with a portion of the probable geometrical object, adjusting the estimated position to a probable position coinciding with a portion of the probable geometrical object;
• drawing topological features using the fetched geometrical objects and drawing a representation of the mobile receiver in the probable position on the display;
• and
• continually determining the probable position of the mobile receiver and as the mobile receiver changes its probable position and crosses a boundary between the determined tessellation and an unloaded adjacent tessellation and performing the further steps of:
• unloading two of the loaded tessellations from the virtual blackboard;
• fetching geometrical objects having a tessellation identifier associated with two additional unloaded tessellations adjacent to the determined tessellation;
• loading the fetched geometrical objects of the two additional tessellations into the virtual blackboard, one of which is the tessellation in which the mobile receiver is located;
• drawing topological features using the fetched geometrical objects of the loaded adjacent tessellation in which the mobile receiver is located and drawing a representation of the mobile receiver in the probable position on the display.

A method, comprising the steps of:

• receiving a signal at a mobile receiver;
• calculating an estimation of the current position of the mobile receiver based upon the received signal;
• accessing one object-based database comprising geometrical objects representing topological features and navigable routes, each geometrical object comprising a tessellation identifier attribute and a geometry attribute defining the geometry of a complete representation of the topological feature or navigable route, the topology being divided into a plurality of tessellations;
• determining a probable geometrical object representing a navigable route where the mobile receiver is probably located and determining a tessellation associated with the determined geometrical object;
• fetching geometrical objects having a tessellation identifier attribute associated with the determined tessellation from the one database;
• comparing the estimated position of the mobile receiver to the probable geometrical object representing a navigable route and if the estimated position differs from a position coinciding with a portion of the probable geometrical object, adjusting the estimated position to a probable position coinciding with a portion of the probable geometrical object;
• and
• drawing topological features using the fetched geometrical objects and drawing a representation of the mobile receiver in the probable position on the display.

An article, comprising:

• at least one sequence of machine executable instructions;
• a medium bearing the executable instructions in machine readable form,
• wherein execution of the instructions by one or more processors causes the one or more processors to:
• access at least one object-based database comprising geometrical objects representing navigable routes, each geometrical object comprising a topological region identifier attribute and a geometry attribute defining the geometry of a complete representation of the navigable route;
• determine a probable geometrical object representing a navigable route where a mobile receiver is probably located from among geometrical objects having a region identifier attribute associated with a topological region in the at least one database;
• and
• compare an estimated position of the mobile receiver to the probable geometrical object and if the estimated position differs from a position coinciding with a portion of the probable geometrical object, adjusting the estimated position to a probable position coinciding with a portion of the probable geometrical object.

An article comprising:

• at least one sequence of machine executable instructions;
• a medium bearing the executable instructions in machine readable form,
• wherein execution of the instructions by one or more processors causes the one or more processors to:
• access at least one object-based database comprising geometrical objects representing topological features and navigable routes, each geometrical object comprising a tessellation identifier attribute and a geometry attribute defining the geometry of a complete representation of the topological feature or navigable route, the topology being divided into a plurality of tessellations;
• determine a probable geometrical object representing a navigable route where a mobile receiver is probably located and determining a tessellation associated with the determined geometrical object;
• fetch geometrical objects having a tessellation identifier attribute associated with the determined tessellation from the at least one database;
• compare the estimated position of the mobile receiver to the probable geometrical object representing a navigable route and if the estimated position differs from a position coinciding with a portion of the probable geometrical object, adjusting the estimated position to a probable position coinciding with a portion of the probable geometrical object;
• and
• draw topological features using the fetched geometrical objects and draw a representation of the mobile receiver in the probable position on a display.

A computer architecture, comprising:

• accessing means for accessing at least one object-based database comprising geometrical objects representing navigable routes, each geometrical object comprising a topological region identifier attribute and a geometry attribute defining the geometry of a complete representation of the navigable route;
• determining means for determining a probable geometrical object representing a navigable route where a mobile receiver is probably located from among geometrical objects having a region identifier attribute associated with a topological region in the at least one database;
• and
• comparing means for comparing the estimated position of the mobile receiver to a probable geometrical object and if the estimated position differs from a position coinciding with a portion of the probable geometrical object, adjusting the estimated position to a probable position coinciding with a portion of the probable geometrical object.

A computer architecture comprising:

• accessing means for accessing at least one object-based database comprising geometrical objects representing topological features and navigable routes, each geometrical object comprising a tessellation identifier attribute and a geometry attribute defining the geometry of a complete representation of the topological feature or navigable route, the topology being divided into a plurality of tessellations;
• determining means for determining a probable geometrical object representing a navigable route where the mobile receiver is probably located and determining a tessellation associated with the determined geometrical object;
• fetching means for fetching geometrical objects having a tessellation identifier attribute associated with the determined tessellation from the at least one database;
• comparing the estimated position of the mobile receiver to the probable geometrical object representing a navigable route and if the estimated position differs from a position coinciding with a portion of the probable geometrical object, adjusting the estimated position to a probable position coinciding with a portion of the probable geometrical object;
• and
• drawing topological features using the fetched geometrical objects and drawing a representation of the mobile receiver in the probable position on a display.

A computer system comprising:

• a processor;
• and
• a memory coupled to said processor, the memory having stored therein sequences of instructions, which, when executed by said processor, cause said processor to perform the steps of:
• accessing at least one object-based database comprising geometrical objects representing navigable routes, each geometrical object comprising a topological region identifier attribute and a geometry attribute defining the geometry of a complete representation of the navigable route;
• determining a probable geometrical object representing a navigable route where a mobile receiver is probably located from among geometrical objects having a region identifier attribute associated with a topological region in the one database;
• and
• comparing an estimated position of the mobile receiver to the probable geometrical object representing a navigable route and if the estimated position differs from a position coinciding with a portion of the probable geometrical object, adjusting the estimated position to a probable position coinciding with a portion of the probable geometrical object.

A computer system comprising:

• a processor;
• and
• a memory coupled to said processor, the memory having stored therein sequences of instructions, which, when executed by said processor, cause said processor to perform the steps of:
• accessing at least one object-based database comprising geometrical objects representing topological features and navigable routes, each geometrical object comprising a tessellation identifier attribute and a geometry attribute defining the geometry of a complete representation of the topological feature or navigable route, the topology being divided into a plurality of tessellations;
• determining a probable geometrical object representing a navigable route where a mobile receiver is probably located and determining a tessellation associated with the determined geometrical object;
• fetching geometrical objects having a tessellation identifier attribute associated with the determined tessellation from the at least one database;
• comparing an estimated position of the mobile receiver to the probable geometrical object representing a navigable route and if the estimated position differs from a position coinciding with a portion of the probable geometrical object, adjusting the estimated position to a probable position coinciding with a portion of the probable geometrical object;
• and
• drawing topological features using the fetched geometrical objects and drawing a representation of the mobile receiver in the probable position on a display.