Abstract: Information (e.g. traffic information) is retrieved from a server. The content of the information is reviewed in order to determine which of a plurality of prestored speech files should be used to report the information. The selected speech files are concatenated to form an audio presentation. The speech files may include phrases identifying incident types, locations, severity and/or timing information, as well as other filler words that improve the audio presentation. In some embodiments, the audio presentation is accompanied by video and/or graphics that can be referenced by the audio presentation.

Abstract: A typical pathfinding system provides a user with a set of directions for following a path from an origin to a destination in a network. If the user deviates from the path, the system for recalculating a path determines a new path which directs the user from the user's new location, which is off the original path, to the destination. To decrease the amount of time needed to determine the new path to the destination, the system adds links to the network. Each of the added links connect nodes from the original path directly to the destination. A new path is determined from the new location to the destination using the augmented network.

Abstract: A cost zone about an origin on an digital map includes the area on the map that can be traveled to, from the origin, which has a cost of travel less than a predetermined cost. The cost can be measured in distance, time of travel, ease of turning, tolls, etc. The steps of creating a cost zone include identifying a set of decision points on the map that are within a predetermined factor of the desired cost, triangulating the decision points to create a set of triangles and interpolating along a subset of the sides of the triangles to estimate the locations along the sides that can be traveled to at the desired cost.

Abstract: A method for storing map data in a database and a method of searching the database to find objects in a given area and to find objects nearest to a location. To generate the map data, a map plane is divided into a number of squares and the squares are numbered with spatial key numbers according to a space filling curve. Objects identifying places such as restaurants or hotels are placed in a main table of the database along with one of the spatial keys (object keys) intersecting an area of the map occupied by the object. A secondary table of the database is then created with one column including object keys corresponding to the main table, and other columns identifying ranges of spatial keys for objects identified by the object keys. To search the database to find objects in a given area, ranges of spatial keys are calculated for the given area and compared with ranges in the secondary table to identify object keys. The object keys identified are then used to obtain the desired objects from the main table.

Abstract: A system is disclosed for determining a path in a network that decreases the number of disk accesses needed during the pathfinding computation. The network is divided in to a set of tiles. Certain sub-paths are pre-computed. The pre-computed sub-paths are grouped into webs. When finding a path, the system will perform a pathfinding exploration within the tile for the origin and a pathfinding exploration within the tile for the destination. A number of the webs will be used with the two explorations to determine a path from the origin to the destination.

Abstract: A system for computing a path in an electronic map (or other network) starts a pathfinding exploration in the background while the system is waiting for a request to find a path. The system automatically chooses an origin. The system's memory can be divided such that a portion of memory acts as a cache. The data for the nodes in the electronic map are loaded into the cache when needed. The system terminates the pathfinding process when a predetermined condition occurs; for example, a predetermined percentage of the cache is filled. When the system terminates the pathfinding process, the system can start a new pathfinding process from a new origin. Thus, when a user requests a path to be found, the pathfinding process begins with data already loaded in the cache.

Abstract: A system for tracking an object (for example tracking an automobile as it moves over streets) using an electronic map and a GPS receiver. The GPS receiver accepts data from a number of satellites and determines a GPS derived position and velocity. Based on the previous position of the object, the GPS derived position, the velocity, the DOP and the continuity of satellites for which data is received, the system determines whether the GPS data is reliable. If the GPS data is reliable, the previous position of the object is updated to the GPS derived position. The updated position is then matched to a map of roads.

Abstract: A system is employed for finding a path in a network between an origin in a first region and a destination in a second region. In finding this path, the system finds three paths: a path between the origin and an exit node for the first region, a path between an entrance node for the second region and the destination, and a path between the exit node and the entrance node. These three paths are combined to construct the path between the origin and the destination. A set of nodes for use as exit nodes or entrance nodes for a region may be identified by identifying a set of boundary nodes for the region and identifying a set of target nodes. The target nodes are each separated from the region by a sufficient cost. The set of target nodes may serve as a set of exit nodes or entrance nodes. The set of target nodes may also be modified to improve its operation as a set of exit nodes or entrance nodes.

Abstract: A system for computing a path in a processor readable representation of a network which can minimize an identified cost. The cost can include time, distance, tolls paid, ease of turning, quality of scenery, processing time, waiting time, etc. A user of the pathfinding system can choose one or more categories of elements to avoid. For example, the user may want to avoid toll roads in a map of roads. The costs associated with the elements to avoid includes at least two levels of representation. The two levels of representation include a first level and a second level such that the second level is superior to the first level. The pathfinding system will determine a path which minimizes costs.

Abstract: A cost zone about an origin on an digital map includes the area on the map that can be traveled to, from the origin, which has a cost of travel less than a predetermined cost. The cost can be measured in distance, time of travel, ease of turning, tolls; etc. The steps of creating a cost zone include identifying a set of decision points on the map that are within a predetermined factor of the desired cost, triangulating the decision points to create a set of triangles and interpolating along a subset of the sides of the triangles to estimate the locations along the sides that can be traveled to at the desired cost.

Abstract: A data storage medium storing a representation of a topological structure having topological features, on which is stored a digital data base including a plurality of carrier blocks of data representing the topological features t a given level of detail, each one of the carrier blocks being a representation of a carrier which is a closed set containing in its interior a given topological object. Also disclosed are methods for building the carrier blocks, for building a hierarchy of carrier blocks, and for searching the digital data base at all hierarchical levels.

Abstract: The method of the present invention which employs conflation is based on pairing chains of arcs in order to determine the matching intersections between them. The chains are formed a priori in each map by using both attributes and geometric properties of the arcs. The intersections of chains are treated as relations, stored in a simple external custom relational database. The matching procedure is a set of the standard operations on RDBMS, as well as the sieving out of all possible ambiguous identifications. As a result, both maps become partitioned by the chains into much smaller pairwise matched areas called wards. The positional and semantic information from the matched chains is mapped onto the merged map. The mapping is performed by a general nonlinear transformation function. The transformation is then extended to the mapping of the unmatched content of wards onto the ultimate map.

Abstract: A navigation system comprising a relative positioning system (RPS) with dead reckoning and map matching and an absolute positioning system (APS) is provided and operated in such a manner that APS position information is used for updating RPS position and contour of equal probability (CEP) information as required. The APS may comprise a Loran-C or a global positioning system (GPS). Different criteria are used for resetting the RPS depending on whether or not the navigation system comprises a Loran-C or a GPS due to the different levels of precision of the Loran-C and the GPS. When the RPS is reset or updated, it is updated to the current APS position with its offset, if any. Its contour of equal probability (CEP) may also be adjusted.

Abstract: A computer hardware and software system and method for displaying a map of streets corresponding to an area over which a vehicle may move to assist a driver to navigate, the system displaying the map on a display based on a scale-dependent street prioritization scheme, providing on the display a vehicle position symbol indicating the current position and heading of the vehicle and a moving map which moves in translation and rotation as the vehicle moves, selectively and dynamically labelling streets on the display as the vehicle moves, and providing a destination symbol on the display indicating a desired destination or the direction to a desired destination.

Abstract: A two-axis inclinometer having a central electrically conductive member inserted within and spaced from the interior walls of a non-electrically conductive vessel. A plurality of four plates are mounted symmetrically on the exterior surface of the vessel. A dielectric fluid is provided in the gap between the center member and the interior wall of the vessel so as to provide a differential change in the capacitance between opposite plate members as the inclinometer is tilted about an axis perpendicular to its longitudinal axis.

Abstract: A two-axis angular rate gyroscopic apparatus is provided having a rotatable dish. The dish has a central hub portion and a plurality of flexible members, each of which extends from the hub portion. The entire disk is electrically conductive and connected to a reference potential. A plurality of electrically conductive members which are mounted end-to-end are located on an insulated plate mounted adjacent to the disk. A motor is provided for rotating the disk at approximately 2000 rpm. In addition, each of the flexible members in the disk has a pie-shaped section removed therefrom in order to increase its flexibility. By increasing the flexibility of the movable members, performance at low motor speeds is facilitated. An electronic circuit provides an output corresponding to the differential capacitance between the rotating disk and the members on the plate mounted adjacent thereto.

Abstract: A vehicle navigational system and method for tracking a vehicle, including a programmed computer, sensors for sensing the distance traveled and heading of the vehicle, and a stored map data base identifying a map of an area over which the vehicle is moving, in which the computer calculates and advances dead reckoned positions of the vehicle in response to distance and heading data, provides data identifying a contour of equal probability containing the dead reckoned positions and having a probability of containing the actual location of the vehicle, derives multiparameters from the map data base, and updates a given dead reckoned position and the contour using a highly developed vehicle navigational algorithm if a more probable dead reckoned position exists based upon the given dead reckoned position, the contour and the derived multi-parameters.

Abstract: Disclosed is an apparatus generating accurate data regarding the heading of a land vehicle as it travels over terrain having changing conditions. The apparatus includes a first sensor means, such as a differential odometer, generating data regarding the relative direction of the vehicle. Also included is a second sensor means, such as a flux gate compass, for generating data regarding the absolute direction of the vehicle relative to the earth. The relative directional data and the absolute directional data are combined in a means for generating accurate data regarding the heading of the vehicle. A means for reducing errors reflected in signals generated by the sensors is provided to insure the accuracy of the output.

Abstract: A method and apparatus for generating a stroke on a display comprising a pair of pulse train generators coupled to a pair of charge pump and integrator assemblies by means of a switch assembly. In operation, a first pulse train corresponding to the larger of the X and Y components of the stroke and a second pulse train corresponding to the ratio of the X and Y components of the stroke control the magnitude of the output of the charge pump and integrator assemblies.

Abstract: A flux gate sensor having sense windings for providing an output proportional to the strength of an external magnetic field in which the sensor is placed. A gating circuit which is responsive to a pulse which is generated when the core of the sensor is driven into and out of saturation gates the output of the sense windings to a pair of filters which in turn provide an output proportional to the intensity of the external magnetic field. With two sense windings the outputs of the filters may be used to determine the direction of the magnetic field relative to the sensor and thereby be used as a compass.