Abstract: A system comprises a computer including a processor and a memory. The memory storing instructions executable by the processor to cause the processor to detect a roadside device via at least one vehicle sensor of a plurality of vehicle sensors; determine a location of a vehicle based on a fixed location of the roadside device; determine a location correction adjustment, wherein the location correction adjustment comprises a difference between an assumed location of the vehicle and the determined location of the vehicle, wherein the assumed location is obtained from a navigation system of the vehicle; and adjust the assumed location based on the location correction adjustment.

Abstract: Provided is an estimation device capable of estimating a current position with a high degree of accuracy. A driving support system includes: a vehicle mounted device 1 that is mounted on a vehicle and performs a control concerning vehicle driving support; a LIDAR 2; a gyroscope sensor 3; and a vehicle speed sensor 4. The vehicle mounted device 1 acquires, from the LIDAR 2, a measurement value ztk indicating a positional relationship between a reference landmark Lk of an index k and the own vehicle. The vehicle mounted device 1 calculates a post estimated value x{circumflex over (?)}t by correcting a prior estimated value x?t estimated, on the basis of the measurement value ztk and a position vector mk of the reference landmark Lk included in a map DB 10, from a moving speed measured by the vehicle speed sensor 4 and an angular rate measured by the gyroscope sensor 3.

Abstract: A travel control method comprises: learning points which a vehicle has traveled over based on images of the surroundings of the vehicle captured with a camera mounted on the vehicle; learning the travel trajectory of the vehicle based on vehicle signals obtained from the vehicle; determining whether the vehicle has passed the points based on the images captured with the camera; and performing travel control of the vehicle by using the travel trajectory learned based on the vehicle signals as a target trajectory between the points.

Abstract: The present invention extends to methods, systems, and computer program products for evaluating autonomous vehicle algorithms. Aspects use (e.g., supervised) machine learning techniques to analyze performance of autonomous vehicle algorithms on real world and simulated data. Machine learning techniques can be used to identify scenario features that are more likely to influence algorithm performance. Machine learning techniques can also be used to consolidate insights and automate the generation of relevant test cases over multiple iterations to identify error-prone scenarios.

Abstract: Smart car method to navigate a road includes detecting one or more objects using a camera and a sensor to delimit boundaries of a road; creating a 3D model based on outputs of the camera and sensor; and navigating the road with a vehicle.

Abstract: Methods, systems, and devices are disclosed for estimating environmental conditions. An example method can comprise determining location information associated with a vehicle and determining status information indicative of time periods when one or more vehicle accessories are engaged. An example method can also comprise providing the location information and the status information to a device configured to estimate environmental conditions based on the location information and the status information.

Abstract: Systems and methods are provided for selecting landmarks for navigation. In one embodiment, a system comprises an IMU that provides inertial measurements for a vehicle and at least one image sensor that acquires measurements of the vehicle's environment. The system also comprises a processing unit that calculates a navigation solution for the vehicle based on the inertial measurements, identifies a plurality of landmarks in the acquired measurements, and identifies a plurality of usable landmarks from the plurality of landmarks. The processing unit also selects a subset of useable landmarks from the plurality of useable landmarks such that the subset of landmarks has a smaller dilution of precision (DOP) than other possible subsets of landmarks from the plurality of useable landmarks, and calculates an updated navigation solution from the subset of landmarks. The DOP is an amplification factor of measurement errors derived from the geometry of the subset of useable landmarks.

Abstract: Operational efficiency and/or control systems and methods for vehicles are provided in order to improve fuel efficiency when traveling in a fuel powered vehicle from point A to point B. The systems and methods can determine the “best” or most efficient route to take based on one or more priorities, make driving recommendations to the operator, and/or automatically control one or more systems (e.g., engine, brakes, transmission, etc.) of the vehicle. The systems and methods can calculate the “best” route based on predefined trip requirements, including cost, schedule, route preferences, and/or risk of potential delays, etc.

Abstract: In a system and method for navigating a moving object according to signals from satellite, a moving object receives satellite navigation signals from a number of satellites. The moving object also receives moving base data from a moving base. The received moving base data includes satellite measurement data of the moving base. At the moving object a relative position vector of the moving object relative to the moving base is determined, based on the received moving base data and the received satellite navigation signals. The moving object sends a signal reporting information corresponding to the relative position vector.

Abstract: An end-user can input a correction to a map error, directly on the device. The device is then able to use the correction without external processing of the correction. Hence, it is no longer necessary for an end-user to simply report errors to the map vendor over a web link, then wait for that map vendor to verify the error, update its maps and finally supply the end-user with updates—a cycle that can take months and sometimes years to complete. Instead, the navigation device can use the correction immediately. End-users can also share corrections with other end-users and also with a shared remote server that aggregates, validates and distributes correction.

Abstract: A system comprises a plurality of reference navigation systems, each reference navigation system configured to generate a respective reference navigation solution. The system also comprises a test navigation system, the test navigation system configured to generate a test navigation solution; and a processing unit configured to compare the test navigation solution to each of the respective reference navigation solutions to estimate one or more errors in the differences between the test navigation solution and the respective reference navigation solutions. The processing unit is further configured to update the respective reference navigation solutions to account for the corresponding one or more estimated errors. The processing unit is also configured to compare the test navigation solution to the updated reference navigation solutions to generate a performance score representative of the performance of the test navigation system.

Abstract: Systems and methods are for orienting a marine vessel having a marine propulsion device. A control circuit controls operation of the marine propulsion device. A user input device inputs to the control circuit a user-desired global position and a user-desired heading of the marine vessel. The control circuit calculates a position difference between the user-desired global position and an actual global position of the marine vessel and controls the marine propulsion device to minimize the position difference. The control circuit controls the marine propulsion device to orient an actual heading of the marine vessel towards the user-desired global position when the position difference is greater than a threshold. When the position difference is less than the threshold, the control circuit controls the marine propulsion device to minimize a difference between the actual heading and the user-desired heading while minimizing the position difference.

Abstract: A method of operation of a navigation system includes: generating a route for navigating to a destination; determining a travel deviation based on a current location and the route; determining an error prone scenario based on the current location, the travel deviation, and the route; and updating an error-prone-scenario switch based on the error prone scenario for displaying on a device.

Abstract: Methods and systems for location correction are provided. In one exemplary method, a first routing identifier of a first location associated with a location correction may be identified. The first location and the first routing identifier may be stored. A second routing identifier associated with a location request may be identified. A second location based at least in part on a comparison of the first routing number and the second routing number may be predicted. Finally, the location request may be responded to with the second location.

Abstract: A mode controller determines whether to use an automated control mode of the spout or operator-directed manual control mode of the spout, based on a first operational status of a first location determining receiver associated with the propelling vehicle, a second operational status of a second location determining receiver associated with the harvesting vehicle, a third operational status of the imaging device or devices. In the automated control mode, an image processing module is adapted to facilitate the determination of the relative position of the spout and the storage portion and to generate command data place the storage portion and spout in relative cooperative alignment for transferring of material into the storage portion.

Abstract: Systems and method for improving the presentation of sensed data (e.g., radar) by including a priori data. The a priori data is recast as if it were the output of a sensor. This allows the inclusion of the a priori data into an evidence grid that is combined with data from multiple types of sensors. Before the sensor data is combined into the evidence grid, the sensor data is aligned with the a priori data using an optimization algorithm. The optimization algorithm provides an optimum probability of a match between the sensor data and the a priori data by adjusting position or attitude associated with the sensor device. This removes any navigational errors associated with the sensor device data.

Abstract: A travel route evaluation system is provided which is capable of enhancing the driver's consciousness of traveling on the a recommended route, in order to improve a degree of attainment of purposes, such as suppression of a fuel consumption and shortening of a required time, that would be obtained by presenting the recommended route. The system includes: a route setting unit for setting a recommended route from a departure point to a destination, based on traveling environment information associated with a traveling environment of a vehicle and map data, a ratio calculation unit for calculating a recommended route travel ratio which is a proportion of the recommended route in a traveled route on which the vehicle traveled; and an evaluation information acquisition unit for acquiring evaluation information based on the recommended route travel ratio.

Abstract: Systems, methods, and computer program products are provided for identifying a serviceable address associated with a street network connection point and an actual location point. For example, in one embodiment, the serviceable address may be associated with a street network connection point that is part of a digital map. The serviceable address may also be associated with a parcel drop-off point that includes parcel drop-off point information, such as a parcel drop-off point geo coordinate associated with the parcel drop-off point.

Abstract: The present invention relates to a device for assisting in the navigation of a person, both inside and outside a building. The device, being fitted to the person, comprises at least: a computer (41) comprising in memory a digitized map of the place (1) in which the path of the person is planned between a departure point and an arrival point, and a location software; a human-machine interface linked to the computer; a set of sensors (42) worn by the person and linked to the computer, the sensors delivering information about the movements of the person; the location software performing a processing of the signals originating from the sensors (42) and from the interface, and performing the fusion of the data provided by the digitized map and the information arising from the sensors and from the interface, and then calculating on the basis of these data the absolute location of the person on the map and correcting the position estimation errors.

Abstract: A method for adaptive driver guidance for navigation and location-based services. A navigation system onboard a vehicle records errors, including both system errors and user errors, where the errors can be detected by missed turns, re-routing, and similar events. The error data is transmitted to a central server, where the data is analyzed to determine patterns of errors, both for an individual driver and across many drivers. Roadway locations which frequently experience driver navigational errors have the error type integrated as a route feature, and future navigational guidance is adapted to improve driver performance. Adaptations can include increased or decreased frequency, detail, timing and location of navigational instructions. Individual driver guidance can also be adapted based on the driver's tendency to make errors in response to specific guidance instructions. Adaptation of guidance for location-based services is also provided.

Abstract: A section defining method separates a road between a departure point and a destination point into a plurality of links under a predetermined condition and defines a section based on a link cost, which is an index indicating ease of travel and set for each link. The section is used to generate guide information provided to a driver of a vehicle. The section is defined by combining, among the plurality of links between the departure point and the destination point, at least two continuous links that yield a decrease in standard deviation, which is based on sums of the link costs.

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 determining system for localization methods combination which determines a combination of a plurality of localization methods used in a vehicle includes: a unit that stores therein a localization accuracy influence parameter which is determined for each position in a travel environment; a unit that stores therein a relation between the localization accuracy influence parameter and a localization accuracy of each of a plurality of the localization methods; a unit that stores therein correspondence information between the localization accuracy influence parameter and each of the localization methods; a unit that acquires the localization accuracy influence parameter in the travel environment; and a unit that acquires the correspondence information on the localization accuracy influence parameter, references the relation based on the correspondence information, and thereby predicts a localization accuracy of each of the localization methods at each position in the travel environment.

Abstract: Aspects of the disclosure relate generally to localizing mobile devices. In one example, a first location method associated with a first accuracy value may be used to estimate a location of the mobile device. A confidence circle indicative of a level of confidence in the estimation of the location is calculated. The confidence circle may be displayed on a mobile device. When other location methods become available, the size of the displayed confidence circle may be expanded based on information from an accelerometer of the client device or the accuracy of the other available location methods. This may be especially useful when the mobile device is transitioning between areas which are associated with different location methods that may be more or less accurate.

Abstract: A motor drive device includes an inverter circuit, a driver circuit for outputting a PWM signal to the inverter circuit, a booster circuit for boosting a power supply voltage supplied from a power supply circuit, a fail safe circuit arranged between the inverter circuit and the motor, and a fail safe drive unit for outputting a signal for turning ON/OFF a semiconductor switching element of the fail safe circuit. A boost voltage output from the booster circuit is supplied to the driver circuit and also supplied to the fail safe drive unit. The fail safe drive unit drives the semiconductor switching element of the fail safe circuit by such boost voltage.

Abstract: An improved approach to satellite-based navigation (e.g., GPS) is provided. In one embodiment, a method includes receiving a first set of tracking information. A nominal orbital path for the navigation satellite is determined using the first set of tracking information. Ephemeris data corresponding to the nominal orbital path is computed and uploaded to the navigation satellite. Long-term navigation information corresponding to the nominal orbital path is transmitted to a communication system for broadcast to a plurality of navigation devices. A second set of tracking information is received, an orbital path of the navigation satellite using the second set of tracking information is predicted, and a difference between the predicted orbital path and the nominal orbital path is determined. Commands configured to instruct the navigation satellite to adjust an actual orbital path of the navigation satellite to substantially conform to the nominal orbital path are uploaded to the navigation satellite.

Abstract: A method for determining a road profile of a lane located in front of a vehicle via sensed image data (1) and/or sensed inherent vehicle movement data (2). An estimating device (3) is provided, to which the sensed image data (1) and/or the sensed inherent vehicle movement data (2) are supplied. A road elevation profile (P) of the lane located in front of the vehicle is determined via the sensed image data (1) and/or the sensed inherent vehicle movement data (2).

Abstract: Aspects of the disclosure relate generally to localizing mobile devices. In one example, a first location method associated with a first accuracy value may be used to estimate a location of the mobile device. A confidence circle indicative of a level of confidence in the estimation of the location is calculated. The confidence circle may be displayed on a mobile device. When other location methods become available, the size of the displayed confidence circle may be expanded based on information from an accelerometer of the client device or the accuracy of the other available location methods. This may be especially useful when the mobile device is transitioning between areas which are associated with different location methods that may be more or less accurate.

Abstract: A system comprises a plurality of reference navigation systems, each reference navigation system configured to generate a respective reference navigation solution. The system also comprises a test navigation system, the test navigation system configured to generate a test navigation solution; and a processing unit configured to compare the test navigation solution to each of the respective reference navigation solutions to estimate one or more errors in the differences between the test navigation solution and the respective reference navigation solutions. The processing unit is further configured to update the respective reference navigation solutions to account for the corresponding one or more estimated errors. The processing unit is also configured to compare the test navigation solution to the updated reference navigation solutions to generate a performance score representative of the performance of the test navigation system.

Abstract: Systems and methods are provided for selecting landmarks for navigation. In one embodiment, a system comprises an IMU that provides inertial measurements for a vehicle and at least one image sensor that acquires measurements of the vehicle's environment. The system also comprises a processing unit that calculates a navigation solution for the vehicle based on the inertial measurements, identifies a plurality of landmarks in the acquired measurements, and identifies a plurality of usable landmarks from the plurality of landmarks. The processing unit also selects a subset of useable landmarks from the plurality of useable landmarks such that the subset of landmarks has a smaller dilution of precision (DOP) than other possible subsets of landmarks from the plurality of useable landmarks, and calculates an updated navigation solution from the subset of landmarks. The DOP is an amplification factor of measurement errors derived from the geometry of the subset of useable landmarks.

Abstract: Embodiments include systems and methods of navigation. In on embodiment, a plurality of position and motion states of a vehicle are estimated. The states may be estimated based on information received from a satellite receiver and an inertial measurement sensor. Estimating the states comprises performing one or more of a plurality of update steps at the rate that information is received from the satellite receiver. The states are estimated at a rate greater than the rate at which the update steps are performed. In one embodiment, the states are estimated using a stepped extended Kalman filter.

Abstract: A method of determining a GPS position fix is disclosed together with a corresponding GPS receiver and server for the same. The method comprising the steps of: (i) providing standard GPS ephemeris corresponding to that transmitted by a GPS satellite; (ii) providing supplemental GPS ephemeris including at least one parameter describing the fluctuation over time of at least one satellite orbit parameter of standard GPS ephemeris; (iii) measuring psuedoranges to GPS satellites; and (iv) determining a GPS position fix from both the standard and supplemental GPS ephemeris provided in steps (i) and (ii) respectively and the psuedoranges measured in step (iii).

Abstract: The invention consists in merging together the predicted and measured meteorological data to supply them to the flight prediction calculation system so as to smooth the discontinuities brought about in the prior art by the simple update which is carried out. This merging is advantageously done by linear weighting of the data, the weighting coefficient depending upon the positioning in vertical and horizontal distances between the predicted point and the aeroplane in relation to chosen thresholds.

Abstract: A system for processing information relating to a vehicle includes one or more electronic control units which can be connected to one another through a vehicle network. The system includes an electronic control device adapted to interface to and exchange data with the network and a nomadic device adapted to exchange data with the electronic device, wherein the electronic control device includes an automatic configuration module adapted to automatically detect parameters of the network so as to retrieve a network database of the vehicle. The network database includes the information required for properly interpreting the data circulating in the network.

Abstract: Methods, systems, and apparatus, including computer programs encoded on computer storage media, are disclosed for track simplification and correction. In one aspect, a track data set having track points defining a course can be accessed and inaccurate track points and incorrect track points can be identified, wherein identifying inaccurate track points includes comparing, for one or more of the track points, a dilution of precision (DOP) value associated with the track point to a DOP threshold, and identifying incorrect track points includes performing an error correction process. Also, a corrected track can be generated by removing identified inaccurate track points and incorrect track points from the track data set. Further, identifying an inaccurate track point can include determining that the DOP value associated with the track point exceeds the DOP threshold. Additionally, the DOP threshold can be specified by user input.

Abstract: An apparatus for placing marks on a resurfaced roadway. The apparatus includes a GPS-based locator for sampling discrete geographical location data of a pre-existing roadway mark evident on the roadway before resurfacing. A computer determines a continuous smooth geographical location function fitted to the sampled geographical location data. And a marker is responsive to the GPS-based locator and geographical location function for replicating automatically the pre-existing roadway mark onto the resurfaced roadway. The apparatus is typically part of a moving vehicle. A related method is disclosed for placing marks on a resurfaced roadway. A similar apparatus can be used to guide a vehicle having a snow plow along a snow covered roadway, or a paving machine along an unpaved roadway surface.

Abstract: A smart phone senses audio, imagery, and/or other stimulus from a user's environment, and acts autonomously to fulfill inferred or anticipated user desires. In one aspect, the detailed technology concerns phone-based cognition of a scene viewed by the phone's camera. The image processing tasks applied to the scene can be selected from among various alternatives by reference to resource costs, resource constraints, other stimulus information (e.g., audio), task substitutability, etc. The phone can apply more or less resources to an image processing task depending on how successfully the task is proceeding, or based on the user's apparent interest in the task. In some arrangements, data may be referred to the cloud for analysis, or for gleaning. Cognition, and identification of appropriate device response(s), can be aided by collateral information, such as context. A great number of other features and arrangements are also detailed.

Abstract: A current position detector for a vehicle includes: an angular speed sensor; a speed sensor; a GPS receiver; a traveling trajectory estimating element for estimating a relative trajectory based on an orientation change amount and a traveling distance, and for estimating a traveling trajectory based on the relative trajectory and a GPS signal; and an error estimating element for estimating and correcting each error of an angular speed signal, a speed signal and the GPS signal. The error estimating element estimates a gain error of the angular speed signal such that an attachment angle gain error attributed to an attachment angle of the angular speed sensor and an angular speed gain error attributed to a non-linear gain property of the angular speed sensor are independently estimated.

Abstract: Traffic management reports are created by providing vehicle sensor devices at different location in a region. Each device captures data of vehicles that pass the device. The vehicle data is communicated to a central computer database. At the central computer database, a user interface selects one or more criteria from a plurality of criteria for filtering the vehicle data. Traffic management reports are then automatically created from the filtered vehicle data using the selected criteria.

Abstract: Systems and method for improving the presentation of sensed data (e.g., radar) by including a priori data. The a priori data is recast as if it were the output of a sensor. This allows the inclusion of the a priori data into an evidence grid that is combined with data from multiple types of sensors. Before the sensor data is combined into the evidence grid, the sensor data is aligned with the a priori data using an optimization algorithm. The optimization algorithm provides an optimum probability of a match between the sensor data and the a priori data by adjusting position or attitude associated with the sensor device. This removes any navigational errors associated with the sensor device data.

Abstract: A system and a method for commanding a spacecraft to perform a three-axis maneuver purely based on “position” (i.e., attitude) measurements. Using an “inertial gimbal concept”, a set of formulae are derived that can map a set of “inertial” motion to the spacecraft body frame based on position information so that the spacecraft can perform/follow according to the desired inertial position maneuvers commands. Also, the system and method disclosed herein employ an intrusion steering law to protect the spacecraft from acquisition failure when a long sensor intrusion occurs.

Abstract: A GPS sensor senses a current position of a vehicle. A map database stores map data. A controller obtains road information of a road ahead of the vehicle from the map data based on the sensed current position of the vehicle. Then, the controller measures a distance from the vehicle to a predetermined object, which serves as a sensing subject, on the road when the obtained road information is predetermined road information. Then, the controller outputs the measured distance as control information of the vehicle.

Abstract: Various embodiments may include a method and system for testing data defining one or more navigation routes. A starting location may be input at a computer remote from the starting location. A destination location may also be input. Map data including GPS information based on the starting location input and the destination location input may be received. Route data may also be received. Based on the map data and the route data, data defining one or more navigation instructions may be generated for one or more routes. The one or more navigation instructions may be executed at the computer and compared to the map data. Based on the comparison, an accuracy of the navigation instructions may be determined. The data defining the navigation instructions may be corrected if the data is determined to be inaccurate.

Abstract: An efficient route-defining method includes determining a route to a destination. The exemplary method also includes determining a wireless device to server connection type and assigning a tolerance in accordance with a connection type. The tolerance is usable to determine if a vehicle is off-route, and the tolerance is increased or decreased inversely corresponding to the speed of the connection type. According to the illustrative method, the assigned tolerance is used to determine points defining the route, such that the roads comprising the route are within a bounded area. The bounded area may be defined by the tolerance in conjunction with a plurality of lines connecting successive points along the route. Finally, the method includes delivering the determined points to a vehicle computing system in communication with the server.

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: A novel Parametric Systematic Error Correction (ParSEC) system is disclosed which provides improved system accuracy for image navigation and registration (INR). This system may be employed in any suitable imaging system and, more specifically, to all imaging systems that exhibit systematic distortion. The ParSEC system may be employed to any such system regardless of sensing type (remote or in situ) or imaging media (photon or charged particle) and is further applicable to corrected imaging of any celestial body currently detectable to remove distortion and systematic error from the imaging system employed. The ParSEC system of the instant invention comprises a software algorithm that generates at least about 12 correction coefficients for each of the INR system measurements such as stars, visible landmarks, infrared (IR) landmarks and earth edges.

Abstract: Methods and apparatuses for active heave compensation, the method, in certain aspects, including the steps of: (a) measuring with a measurement device (44) the heave of a vessel (10) and outputting a heave signal representative thereof; (b) using said heave signal to compensate for said heave by moving a connection device (20) relative to said vessel (10) as a function of said heave signal, whereby movement due to said heave of a load attached to said vessel via the connection device is reduced; said heave signal comprising errors induced by said measurement device (44) whereby accuracy of said compensation is reduced; (c) processing said heave signal so as to reduce said errors and outputting an adjusted heave signal; and (d) using said adjusted heave signal to move said connection device (20) to compensate for said heave.

Abstract: A moving device (70) determines an obstacle virtual existence region (72) of a simple graphic approximating a detected obstacle (71) to detect the obstacle (71) in a real time and determine a smooth avoidance path by calculation, thereby performing collision prediction.

Abstract: A vehicle awareness system for monitoring remote vehicles relative to a host vehicle. The vehicle awareness system includes at least one object sensing device and a vehicle-to-vehicle communication device. A data collection module is provided for obtaining a sensor object data map and vehicle-to-vehicle object data map. A fusion module merges the sensor object data map and vehicle-to-vehicle object data map for generating a cumulative object data map. A tracking module estimates the relative position of the remote vehicles to the host vehicle.

Abstract: Methods, systems, and apparatus, including computer programs encoded on computer storage media, are disclosed for track simplification and correction. In one aspect, a track data set having track points defining a course can be accessed and inaccurate track points and incorrect track points can be identified, wherein identifying inaccurate track points includes comparing, for one or more of the track points, a dilution of precision (DOP) value associated with the track point to a DOP threshold, and identifying incorrect track points includes performing an error correction process. Also, a corrected track can be generated by removing identified inaccurate track points and incorrect track points from the track data set. Further, identifying an inaccurate track point can include determining that the DOP value associated with the track point exceeds the DOP threshold. Additionally, the DOP threshold can be specified by user input.