Abstract: A height output device includes a GPS processing unit that calculates a GPS height of a moving body based on GPS signals, an atmospheric pressure measurement unit that measures atmospheric pressure, a determination unit that determines reliability of the GPS height calculated by the GPS processing unit, and an output unit that outputs an absolute height of the moving body depending on the reliability determined by the determination unit. When the reliability satisfies a predetermined output reference, the output unit outputs the latest GPS height calculated by the GPS processing unit, as the absolute height of the moving body, and when the reliability does not satisfy the output reference, the output unit outputs a height, which is calculated by using a past output value of the absolute value and the atmospheric pressure measured by the atmospheric pressure measurement unit, as the absolute height of the moving body.

Abstract: This disclosure is directed to methods and systems for locally generating calculated ephemerides that may be used by a navigation device to calculate position information before a broadcast ephemeris from a given navigation satellite has been completely received or when the broadcast ephemeris from the satellite is not available. Generally, the invention includes the steps of calibrating the initial satellite velocity from the last available broadcast ephemeris, correcting the clock for a prediction time period, predicting the satellite position during the time period and formatting the predictions into a calculated ephemeris to be used by the receiver to determine position information.

Abstract: Repairing GPS data is disclosed. Repairing GPS data includes repairing an effort, comprising determining that the effort includes inaccurate GPS data; and adjusting the effort using a repaired base map. Repairing GPs data includes repairing a segment, comprising determining an inaccurate shape data in the segment; and adjusting shape data for the segment based on a repaired base.

Abstract: A device for controlling self-propelled mobile apparatus(es) (300), includes:—a stationary base station (200), provided with a receiver for a satellite location system, referred to as a stationary GNSS receiver, and a radiofrequency transmitter/receiver to enable communication with at least one mobile apparatus, and including: a positioning module, a command module, and a control module for controlling the movement of each mobile apparatus on the ground;—at least one mobile apparatus (200), including a moving element, a mobile GNSS receiver, and a radiofrequency transmitter/receiver for transmitting, to the base station (200), information received by the mobile GNSS receiver and receiving a movement command.

Abstract: In a position registering apparatus, an acquiring unit acquires traveling state information indicating a traveling state of a mobile object and a position identifying unit specifies the current position of the mobile object, based on the traveling state information and map information. After the current position of the mobile object is identified to be on a road within a predetermined range from a destination set by a destination setting unit and is then identified to be at a place other than the road, if the parking determining unit determines that the mobile object is parked, a registering unit registers, into a storage unit, a deviation point from the road as an entrance point of a parking lot of the destination.

Abstract: A method of determining an absolute position for a motor vehicle is disclosed. The method includes steps of receiving information related to the absolute positions of one or more remote sources. The method further includes steps of determining distances to the one or more remote sources. Methods for selecting a subset of remote sources from a set of all available remote sources to be used in determining an absolute position for the motor vehicle are also disclosed.

Abstract: The wearable tactile navigation system frees you from requiring to use your eyes as there is no display, all positional information is conveyed via touch. As a compass, the device nudges you towards North. As a GPS navigator, the device orients you towards a landmark (i.e., home) and lets you feel how far away home is. A bluetooth interface provides network capabilities, allowing you to download map landmarks from a cell phone. The bidirectional networking capability generalizes the device to a platform capable of collecting any sensor data as well as providing tactile messages and touch telepresence. The main application of the device is a wayfinding device for people that are blind and for people that suffer from Alzheimer's disease but there are many other applications where it is desirable to provide geographical information in tactile form as opposed to providing it in visual or auditory form.

Abstract: Systems and methods are disclosed that monitor the speed that a mobile device is traveling, such as when the user of the mobile device is driving or riding in a vehicle. A speed monitoring system described herein receives a request from a third party to monitor a speed of a mobile device. The system periodically queries a mobile network for a location of the mobile device over a time period, and receives responses from the mobile network indicating locations of the mobile device. The system then determines a speed of the mobile device based on the locations indicated during the time period, and may determine the speed limit the roadway the mobile device is traveling on. The system then sends a notification message to the third party that includes an indication of the speed of the mobile device and possibly the speed limit.

Abstract: A search frequency correction method includes: obtaining correlation values by correlating between a received signal that is modulated by direct sequence spread spectrum modulation and a replica code of a spread code with respect to I and Q components at a predetermined search frequency, obtaining accumulated correlation values by accumulating the correlation values of each polarity inversion interval with respect to the I and Q components, calculating a plurality of combinations of the accumulated correlation values in both signs, selecting one of the combinations based on the calculation results of the respective combinations, and correcting the search frequency based on a time variation of an IQ phase represented by the accumulated correlation values of the one of the combinations.

Abstract: A method for defining a following path for a following vehicle to autonomously follow a leader, the method including acquiring waypoints associated with a path that the leader traverses; filtering the acquired waypoints, wherein the filtering removes waypoints located outside an area of interest; generating intermediate waypoints by interpolating between adjacent pairs of the filtered waypoints if the adjacent pairs of the filtered waypoints are separated by a distance that exceeds a threshold distance; and defining a following path through the filtered waypoints and the intermediate waypoints using a least-squares spline fit to calculate the following path.

Abstract: A marine electronic device such as a chartplotter which includes a display; a location determining component; and a processing system for receiving location data from the location determining component and for causing information to be displayed by display. The processing system causes the display to display information which assists an operator in navigating and ascertaining characteristics of bodies of water, objects on nearby shores, and other vessels.

Abstract: A method for estimating the position of a telematics-equipped vehicle during navigation includes: receiving a partial map corresponding to a route; receiving Global Positioning System (GPS) data corresponding to a current position of the vehicle; performing a closest street (CS) mapping based on the GPS data and the partial map so as to provide an estimation for a vehicle position on a street of the partial map; performing speed sum (SS) mapping based on the estimated vehicle position and speed readings corresponding to vehicle speed so as to provide an estimation of distance traveled with reference to a previous vehicle position; and presenting a map matched vehicle position to a user based on the CS mapping and the SS mapping.

Abstract: According to one embodiment of the disclosure, a method for use in telemetry processing includes receiving telemetry data originating from a satellite, such that the telemetry data comprises a plurality of data segments. The method includes processing the plurality of data segments simultaneously and transmitting a signal to the satellite, in response to the processing, for effecting a change in the direction of the satellite.

Abstract: A method and apparatus for routing using a positioning device and a map having a plurality of segments; generating a first route from a first location to a second location; generating signals to provide directions along the first route using positioning information from the positioning device; detecting that the positioning device is off-route at a third location, the third location being adjacent to the first route; generating a second route by tracking the position of the positioning device from the third location to to a fourth location, and, in some cases, storing the second route for use in route generation.

Abstract: In a hydraulic shovel positional guidance system, an optimal work position calculation unit is configured to calculate an optimal work position of a main vehicle body where a diggable range in which a target surface and an operability range overlap is largest. A display unit is configured to display a guidance picture showing the optimal work position.

Abstract: A method of generating maps, which includes generating a first map corresponding to a first code, and generating a second map including a starting point and an ending point including a plurality of second codes representing links from the starting point to the ending point. Further, when one of the links is selected, a detailed map of the selected link is displayed.

Abstract: When a vehicle is located within the area of coverage of a radio station, a navigation system outputs audio guidance on the basis of traffic information received from the radio station, provided a predetermined audio output condition related to a congested area is satisfied or stores the traffic information in a storage section if the predetermined audio output condition is not satisfied. Then, when the vehicle is located outside of the area of coverage of the radio station, the navigation system outputs the stored traffic information as audio guidance.

Abstract: A system and method for locating, tracking, and/or monitoring the status of personnel and/or assets (collectively “trackees”), both indoors and outdoors, is provided. Tracking data obtained from any number of sources utilizing any number of tracking methods may be provided as input to a mapping application. The mapping application generates position estimates for trackees using a suite of mapping tools to make corrections to the tracking data. The mapping application further uses information from building data, when available, to enhance position estimates. Indoor tracking methods including sensor fusion methods, map matching methods, and map building methods may be implemented compute a more accurate tracking estimate for trackees. Outdoor tracking methods may be implemented to enhance outdoor tracking data by combining tracking estimates such as inertial tracks with magnetic and/or compass data if and when available, and with GPS, if and when available.

Abstract: A method and system for creating a sky visibility map, using data from a vehicle and its neighbors. A host vehicle with satellite-based navigation capability measures the quality of signals it receives from available satellites, where azimuth and elevation angles of the satellites are known from an ephemeris or almanac. The host vehicle also receives satellite signal data from surrounding vehicles via vehicle-to-vehicle communication. Using data from all of the vehicles, a sky visibility map is constructed, indicating where obstructions to satellite visibility exist for different locations. The sky visibility map is used to anticipate satellite signal quality. A driving environment classification can be used to configure other vehicle systems. The sky visibility map can also be constructed without using data from surrounding vehicles; the host vehicle can store its satellite signal data long-term and use it to estimate satellite visibility when returning to a location previously visited.

Abstract: A method for transmitting additional information in a satellite navigation system includes providing a navigation message having a plurality of parameters, selecting at least one parameter from the plurality of parameters for the transmitting of the additional information, replacing the at least one parameter, at least partially, by the additional information so as to form a changed navigation message, and sending the changed navigation message.

Abstract: A positioning device for obtaining position data of a plurality of points on a movement route, including a positioning unit that can measure a present position; a movement measuring unit for measuring a relative positional change; a position calculating unit for calculating position data of the plurality of points on the movement route on the basis of position data of a first reference point and positional change data obtained through measurement of the movement measuring unit; and a correcting unit for correcting the position data of at least one of the plurality of points calculated by the position calculating unit on the basis of difference information representing difference between a position represented by the position data calculated by the position calculating unit and a position represented by a positioning result of the positioning unit with respect to any second reference point on the movement route.

Abstract: Security systems may include sensing, networked communications, stealth, alarms, and countermeasures, any or all of which may adapt to threats. These systems may also include armor and barriers of concrete and/or steel. They can adapt to severity of threats, weather, and/or other situational aspects. They can anticipate at least some threats in order to obtain early warning and react more quickly to those threats. They can adapt by altering their configurations, including alterations in communication networking structures and methods, and changes in data-storage and processing duties at processing nodes. Defensive and/or offensive countermeasures can be employed to deter, confuse, trap, and/or disable terrorists. The systems are capable of self-maintenance, self-healing, and self-restoration as threats subside. The systems can include subsystems capable of autonomous operation.

Abstract: A map-centric service for creating, finding, and organizing social events is described. Social events may include gatherings, goods or services for sale or other types of events about which a group of people may wish to share information. The service provides a graphical indication of the location of a plurality of social events superimposed on a map, providing a geographic context to social events. The geographic context may be augmented with text graphical indications or information in other forms, further identifying characteristics of the social event. Information about social events may be made accessible to multiple users through a web service. A user may search for social events by specifying desired characteristics of the social event. The service can also generate an optimal route for user selected events.

Abstract: Accuracy of a positioning device may be determined without requiring the device to be at any specific location, such as a test location. Instead of comparing the reported location and directional data to a known location and directional data, the present technology may use multiple discrete location and directional reports for comparison with the reported data at multiple locations. The multiple comparisons are used to assess the relative accuracy of the positional telematics system. The reported location may be a GPS location or from another positioning system.

Abstract: This disclosure provides a navigation aid device that includes a calculation time setting module for setting two or more calculation points of time for calculating trial information, a ship-concerned information acquisition module for acquiring ship-concerned information including a position of a ship concerned at every predetermined ship-concerned information acquisition time, a ship-concerned trial information calculating module for calculating ship-concerned trial information including the position of the ship concerned at each calculation point of time based on the ship-concerned information acquired at the newest information acquisition time with respect to the calculation point of time.

Abstract: An inter-moving body interferometric positioning system for carrying out positioning in coordination with three or more moving bodies that can mutually communicate, including: a reference vehicle decision unit for deciding on a single moving body to function as a reference vehicle from among three or more moving bodies, and a positioning unit for interferometrically determining respective relative positions of other moving bodies relative to the reference moving body that is to function as a reference vehicle decided on by the reference moving body decision unit using satellite wave monitoring data monitored in each of the three or more moving bodies. This inter-moving body interferometric positioning system specifies relative positions among the other moving bodies using positioning results of the positioning unit.

Abstract: A computing navigation device is disclosed that includes a processor configured to control a communication module configured to receive a global positioning satellite (GPS) system signal corresponding to a vehicle position of a vehicle. The processor may be further configured to recognize a dropped signal condition in which no operational signal is detected from the GPS system, and to identify a last position of the vehicle corresponding to a time of the dropped signal condition. The processor may be further configured to retrieve on-board diagnostics data from an on-board diagnostics system of the vehicle corresponding with a movement of the vehicle. The computing navigation device may further include a kinematic module configured to calculate a calculated position of the vehicle based on the last position and the movement of the vehicle, and a display configured to display a representation of the calculated position.

Abstract: A controlling method for making and keeping appointments includes: inputting information concerning an appointment; finding out urban lines according to the starting point and the destination of the appointment, and obtaining detailed information of each urban line found, wherein the detailed information of each urban line is used to create the steps of the total journey whereby the user should arrive at the destination from the starting point at a particular time; selecting an urban line from the urban lines found; calculating when the user should leave according to the selected urban line and the detailed information of the selected urban line; and informing the user accordingly.

Abstract: A method for mapping a railroad track is provided. The method includes defining a plurality of track segments that form the railroad track and determining coordinates of each track segment. The method also includes storing the coordinates of each track segment in a database as map segments and linking the map segments stored in the database to create a multi-dimensional railroad track map.

Abstract: A vehicle control device for a vehicle system automatically stops an internal combustion engine of a vehicle when a predetermined stop condition is satisfied and automatically starts the automatically stopped internal combustion engine when a predetermined start condition is satisfied. A stop point detection unit detects a stop point, at which the vehicle possibly stops, while the vehicle travels based on map information stored in a map information storage unit. A traveling information control unit stores traveling information, which includes a state of the vehicle stopping at a stop point and a state of the vehicle passing by the stop point, in the traveling information storage unit. A stop determination unit determines whether to stop the internal combustion engine when the vehicle stops at a stop point based on the traveling information of the stop point stored in the traveling information storage unit.

Abstract: An acquisition and tracking apparatus is provided for tracking digitized spread spectrum navigation signals modulated with a spreading code according to any of a set of modulation types including Binary Phase Shift Keying (BPSK) with and without Frequency Domain Multiplexing Access (FDMA), time multiplexed BPSK, Quadrature Phase Shift Keying (QPSK), sine and cosine Binary Offset Carrier (BOC), modified, complex, and time multiplexed BOC (TMBOC), the apparatus comprising a plurality of universal tracking channels, each coupled to an interrupt module. The universal tracking channel includes a carrier demodulation module, a code generation module, a correlator module, a code frequencies generation module, and a subcarrier combining module for efficiently using the correlator resources in the correlation of the data and the pilot components of the signal within a single universal tracking channel. A corresponding method of operation is also provided.

Abstract: The accuracy of a reverse geocode for a GPS fix in a mobile phone navigation device is improved significantly by considering together the user's last known location on an original route, the elapsed time between the last known location on the original route and the latest GPS fix, and the likelihood that the user could have traveled from the last known location on the original route to one of numerous candidate locations (generated from the reverse geocode) in the elapsed time. The navigation server relies only on a GPS fix, timestamps, and a back-end routing database to provide improved or superior accuracy of reverse geocoding a GPS fix (selection of a point on a road) when a relevant user has deviated from the intended route. The reverse geocoding allows for accurate and functional re-routing capabilities.

Abstract: In embodiments of the present invention, a computer program may use GPS coordinates associated with cell phones located within multiple cars to measure real time traffic conditions. These traffic conditions may be measured based at least in part on using parameters including, but not limited to, a time of day, a day of the week, a weather condition, a road condition, or some other parameter relating to traffic conditions. The traffic conditions may be used to calculate a vehicle speed between two locations and predict related travel time. The real-time traffic condition information may be manually accessed by a user from their cell phone or automatically presented to a user's cell phone when the cell phone enters a specific geographic location or region.

Abstract: A method and apparatus for estimating a location of a device. For each of a plurality of locations of a device, a set of positional data is determined from signals received from a plurality of satellites. The positional data is filtered and compared with data from a road network database. This comparison may be a function of a distance from at least one point defined by a set of the filtered positional data to a road in the road network database and an angle between a line representing a best fit for plural points defined by corresponding plural sets of the filtered positional data to a line defined by a road in the road network database.

Abstract: A device for aligning a vehicle with a next pass through a field comprises a camera which takes a corresponding natural picture. A receiver is provided for receiving a navigational signal from a navigational satellite system. A central processing unit is connected to the camera for receiving the natural picture and the receiver for receiving the natural satellite signal. The CPU generates a master signal comprising a video signal of the navigational picture, an actual indicator signal representing the actual position of the vehicle, and a desired indicator signal representing the desired position of the vehicle. A display is connected to the CPU for receiving the master signal and generating a master image comprising a natural picture image, an actual indicator image, and a desired indicator image. The vehicle is driven to cause an alignment of the actual indicator image with the desired indicator image.

Abstract: A method for providing and utilizing navigation data can include identifying a grid that includes a plurality of geographical regions. Each geographical region can have an associated navigation data set which includes street level mapping data. Linking references for each geographical region can be defined. Geographical navigation bundles can be identified that conform to an OSGi compliant framework. Each bundle can correspond to one of the geographical regions and can include a navigation data set and a manifest file. The manifest file can include a version, date, and the linking references. A GPS equipped device can dynamically install and activate the geographical navigation bundles. The GPS equipped device can perform at least one navigation process based upon the navigation data set. The GPS device can predict when new navigation data is needed and can automatically acquire suitable geographical navigation bundles in response to these predictions.

Abstract: A route search device includes: a parameter calculator for calculating a parameter of each section in a route; a driving repetition information obtaining element for obtaining driving repetition information in each section from an external server; a parameter changing element for increasing a parameter of first one of the sections when a driving repetition of the first one of the sections is smaller than a first parameter threshold; and a route search element for searching the route to minimize a total of parameters of the sections in the route.

Abstract: The navigation system described here utilizes GPS and Galileo satellite signals combined with Inertial Navigation Systems (INS), where a Coupled Antenna (CAN) provides both GNSS and Inertial Measurement Unit (IMU) data to a Highly Integrated GNSS-Inertial (Hi-Gi) receiver. Such receiver makes use of a high fidelity relation between GNSS unprocessed Correlator Output (COUT) I and Q data and the user trajectory, and inertial sensor data, which in turn are combined within a Kalman Filter (KF). The KF determines the navigation solution that is also used to provide feedback to the receiver demodulation signal processing stage, thus eliminating the need of dedicated structures such as Delayed Locked Loops (DLL) and Phase Locked Loops (PLL), allowing a significant improvement in navigation performance.

Abstract: The field sampling method provides a mobile device, a central memory and a data transfer interface. The mobile device has a main storage, which contains GPS receiver, a mapping program, an external TSP algorithm program and at least one database. The mapping program displays a plurality of sampling point on the user interface of the mobile device. The user has the ability to select a set of sampling points on the user interface. The sampling points are written to a first database. The selected sampling points are processed by the external TSP algorithm program to determine an optimal route. The external TSP algorithm program sends the optimal route to the mapping program. The mapping program displays the optimal route on the screen of the mobile device such that the user can visit points and collect sampling data.

Abstract: A golf GPS device is disclosed herein. The device includes a GPS unit, a memory for storing data for a plurality of golf courses, a display for displaying animations of portions of golf courses, a user input for inputting a plurality of location points on the display, and a processor comprising means for rendering the animations of portions of golf courses from a plurality of latitude and longitude coordinate points.

Abstract: Provided are systems and methods for tracking resources at a site and initiating audio and video communication with tracked resources using multiple input and output modalities. The systems include a location tracking system, including a positioning engine and a presentation engine, an environmental tracking system, location and environmental sensors, either permanently installed or temporarily deployed, and portable devices such as mobile phones or personal digital assistants carried by the tracked resources and users. The methods include tracking such resources at a site, displaying their locations on a portable device using a visual map display, and providing the ability to initiate bidirectional audio and video communications with one of more of the tracked resources.

Abstract: An integrated positioning apparatus includes a processing module, a satellite positioning module, an inertial positioning module, a transmission interface and a switching module. The processing module is utilized for executing a navigation program. The satellite positioning module functions to provide satellite positioning information. The inertial positioning module is used for generating inertial positioning information. The switching module is connected between the processing module and the transmission interface for receiving a control signal furnished by the processing module and is selectively switched to a first status or a second status based on the control signal. While in the first status, the switching module drives the transmission interface to connect to the satellite positioning module so as to transmit the satellite positioning information to the processing module for navigating.

Abstract: A method and system for managing the turning of a vehicle comprises establishing a boundary of a work area. A location-determining receiver determines an observed position and velocity of the vehicle in the work area. An estimator estimates a first duration from an observed time when the vehicle will intercept the boundary based on determined position and velocity of the vehicle. An alert generator generates an alert during a second duration from the observed time. The second duration is less than or approximately equal to the first duration. An operator interface allows an operator to enter a command to control a path of the vehicle prior to or at the boundary.

Abstract: A method and apparatus for determining protection levels in a satellite navigation system includes the following steps: (1) determining an integrity risk at the alert limit for a plurality of application situations—for example, starting from approaches in category I (Category I precision approach) up to the operation “oceanic enroute;” (2) determining an interval of the alert limits between the largest set of alert limits which produces too high an integrity risk, and the smallest set of alert limits which produces an acceptable integrity risk; and (3) carrying out an interval nesting for the interval of the alert limits that was determined in the previous step, the integrity risk between the horizontal and the vertical being divided in the same way as it is obtained from the relationship between these integrity risks in the largest set of alert limits.

Abstract: Remote sensor units for a vehicle are described. A remote sensor unit may comprise an electronic assembly. The electronic assembly may comprise an electronic component. The electronic assembly may comprise one or more signal terminals coupled to the electronic component. The electronic assembly may comprise a protective enclosure arranged to encapsulate the electronic component. The protective enclosure is arranged to isolate the electronic component from thermal energy, pressure or residual material stress associated with one or more satellite housings. Other embodiments are described and claimed.

Abstract: This invention relates to a GPS navigation system comprised of a submerged vessel having a navigation processor associated via buoyant cable with a buoy having a GPS device; wherein the cable contains: a data link between the vessel and the GPS device; and a location device for the determination of the location of the cable to the vessel; and wherein the processor computes a GPS position relative to the vessel. The invention also relates to a navigation process comprising the steps of: attaching a cable between a buoy and a submerged vessel; providing a GPS data relative to the buoy and cable location data over the cable to the submerged vessel; and using the GPS position of the buoy and location data to compute the GPS position of the submerged vessel.

Abstract: A computer-implemented navigation method for identifying one or more points of interest (POI) in a geographic location includes calculating a navigation route and receiving a reference point input. The reference point input may be unrelated to the navigation route and usable for identifying one or more POIs. The method further includes receiving one or more search parameters for searching for one or more POIs with respect to the reference point and identifying the one or more POIs based on the search parameters and reference point. The method also includes presenting the one or more POIs on a vehicle computer display.

Abstract: The described method and system provide for treatment of certain areas as neutral zones during GPS navigation to avoid unnecessary off-route notifications and route recalculation. A GPS unit determines whether the user has entered a geographic region designated as a neutral zone, and does not provide the user with off-route notifications while the user is within the neutral zone. Not providing off-route notifications may be implemented by the GPS device by considering the user to be within the calculated route while the user is within a neutral zone, or by disabling off-route notifications (and route recalculation) while the user is within the neutral zone. The neutral zone may be defined by a set of GPS coordinates. The neutral zone may further be polygonal, and the size of the neutral zone may be based on the accuracy of the GPS device.

Abstract: The described method and system provide for utilizing portals during GPS navigation to avoid unnecessary off-route notifications and route recalculation in problem areas. The method and system are described in the context of a GPS unit that is part of a telematics unit in a vehicle. If the route calculated by the GPS unit includes certain problem areas such as tunnels and stacked bridges, the GPS unit may utilize portals to process GPS navigation through those areas. When a user enters a portal, normal GPS navigation is suspended and certain features are disabled. For example, the user will not longer receive Turn-by-Turn (TBT) directions, off-route notifications, error notifications, and route recalculation notifications, until the GPS unit determines that the user has arrived at a second portal or until the user manually re-enables those features. The portals should be preferably located at the inlets and outlets to the problem areas.

Abstract: A method and apparatus to optimize energy consumption in a mobile phone having a navigation system is disclosed. The navigation-based method and apparatus efficiently use a smartphone battery to provide the highest possible location accuracy to the driver. When the driver is travelling from a complex route segment to a less complex route segment, current location sensor is switched to another location sensor with lower location accuracy which consumes less battery power. When the driver is travelling from a less complex route segment to a complex route segment, the navigation system continues to use a location sensor with lower accuracy until the navigation system determines that switching to higher accuracy location sensor is necessary to conserve more battery power. The navigation system can determine a best timing to switch according to the driver's familiarity with the route segment or geographical area.