Abstract: An initialization system for a personal navigation system associated with a user, including: a first reference point arrangement configured for communication with the personal navigation system of the user and to facilitate the generation of a first user data set including horizontal position and azimuth angle (x1, y1, ?1); a second reference point arrangement configured for communication with the personal navigation system of the user and to facilitate the generation of a second user data set including horizontal position and azimuth angle (x2, y2, ?2); and at least one control device configured to determine a common coordinate system based at least in part upon the first user data set and the second user data set. An initialization process and arrangement are also disclosed.

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: In an embodiment, a user equipment (UE) tracks its location using a first positioning scheme (PS) (e.g., an indoor PS or outdoor PS) while operating inside or outside of an enclosed environment, whereby the UE maintains transition region information related to the enclosed environment that characterizes one or more outdoor-to-indoor (OI) and/or indoor-to-outdoor (IO) transition regions of the enclosed environment. If the UE determines it has entered a transition region of the enclosed environment based on its location tracking using the first PS, the UE begins to track its location using a second PS. When the quality of the second PS rises above a threshold (e.g., such as the UE moves further inside or outside of the enclosed environment), the UE can switch to the second PS and turn off the first PS.

Abstract: Techniques are provided, which may be implemented in various methods, apparatuses, and/or articles of manufacture, to obtain an encoded routability graph representative of feasible paths in an indoor environment represented by an encoded map, and assign likelihoods of transition from an ingress edge in the encoded routability graph to individual egress edges through a junction connecting the ingress edge to a plurality of egress edges based, at least in part, on one or more features of the encoded map.

Abstract: Client devices periodically capture ambient audio waveforms, generate waveform fingerprints, and upload the fingerprints to a server for analysis. The server compares the waveforms to a database of stored waveform fingerprints, and upon finding a match, pushes content or other information to the client device. The fingerprints in the database may be uploaded by other users, and compared to the received client waveform fingerprint based on common location or other social factors. Thus a client's location may be enhanced if the location of users whose fingerprints match the client's is known. In particular embodiments, the server may instruct clients whose fingerprints partially match to capture waveform data at a particular time and duration for further analysis and increased match confidence.

Abstract: A method and a system for dispatching vehicle are provided. The method for dispatching vehicle includes the following steps: A. obtaining the vehicle information, which includes vehicle numbers, vehicle states and relative positions; B. placing the vehicle icons corresponding to the vehicle numbers in the corresponding positions on the virtual line schedule map according to the vehicle states and the relative positions; C. displaying the virtual line schedule map refreshed via step B. The system for dispatching vehicle includes vehicle information obtaining unit, vehicle states judging and processing unit, displaying unit and dispatching unit. The system realize the visual vehicle dispatching method by utilizing the virtual line schedule map, so as to implement vehicle monitoring and dispatching.

Abstract: A method and apparatus for using a predetermined portion of terrain elevation maps in a database for aiding in computing a three-dimensional position of a wireless station. Instead of using the entire terrain model of the earth or an entire country, the database consists of an incomplete model, which includes only the most populous areas or specific regions. This reduces the size of the information in the database, which in turn reduces the amount of time to compute the positions of the wireless device.

Abstract: A navigation system can comprise a microprocessor, a memory, a navigational signal receiver configured to receive a radio signal from at least one external system, a motion sensing device, and a navigation program executable by the microprocessor. The navigational signal receiver can be communicatively coupled to the microprocessor via a communication port. The navigation program can be configured to receive messages from the navigational signal receiver by communicating to the driver of the communication port. The communication port driver can adjust the current position based on the data returned by the motion sensing device.

Abstract: Systems and methods for monitoring the accuracy of a global positioning system (GPS) receiver in a marine vessel utilize a GPS receiver receiving a plurality of satellite signals, calculating a global position of the GPS receiver based on the plurality of signals, and determining a signal to noise ratio (SNR) of each signal in the plurality of signals; and a control circuit having a computer readable medium having executable code, and being connected to the GPS receiver by a communication link. The control circuit calculates an average SNR of the plurality of signals and compares the average SNR to a threshold SNR. In one example the threshold SNR varies depending upon a number of satellites sending the plurality of signals and a speed at which the marine vessel is traveling.

Abstract: A driver assistance system for a motor vehicle has a surroundings sensor and an evaluation unit for evaluating the surroundings sensor data. The evaluation unit receives data from a positioning device. Furthermore, a reduced or limited subset of data taken from a digital roadmap is stored in a non-volatile memory, which is provided to the evaluation unit. The reduced data are selected to include only data relevant for the function(s) of the driver assistance system. Thereby the driver assistance system does not need to be connected for data transmission with a navigation system.

Abstract: Disclosed herein is a radiodetermination technology, a radiodetermination device according to one embodiment of the disclosure comprising a positioning mode determination part and position Information generating part, thereby enhancing accuracy and speed of positioning in a resource-limited mobile terminal environment and also further improving energy efficiency and user conveniences.

Abstract: A wireless communication system is disclosed. The wireless communication system transmits a location measure signal for determining a location of a user equipment to the user equipment by allocating the location measure signal to at least one of symbols to which a synchronization signal is transmitted conventionally. In this case, a location related parameter of the user equipment can be measured with higher accuracy.

Abstract: A navigation system includes a navigation radio and a sensor onboard a vehicle. The navigation radio receives and processes low earth orbit RF signals to derive range observables for a corresponding LEO satellite. A sensor is operable to generate at least one of vehicle speed data, acceleration data, angular rate data and rotational angle data under high vehicle dynamics. The navigation radio includes a navigation code operable to obtain a position, velocity and time solution (a “navigation solution”) based on the one or more range observables, ephemerides for the corresponding LEO satellite, a heading pseudomeasurement, a navigation radio altitude pseudomeasurement; one or more vehicle velocity pseudomeasurements orthogonal to the altitude pseudomeasurements; and the generated at least one of vehicle speed data, acceleration data, angular rate data and rotational angle data. The navigation radio uses the navigation solution to acquire a GPS signal during interference with a coarse acquisition GPS signal.

Abstract: A graphics-aided geodesic device is provided. The device includes an antenna for receiving position data from a plurality of satellites and a receiver coupled to the antenna. The device further includes orientation circuitry for obtaining orientation data. The orientation data represents an orientation of the apparatus with respect to a plane parallel with a horizon. The device further includes positioning circuitry for determining the position of the point of interest based at least on the position data and the orientation data.

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 of tagging a location using a mobile device entails obtaining position data for a current location of the mobile device, detecting a proximity of another device using a short-range wireless interface, and automatically storing the position data for the current location of the mobile device in response to the detecting of the proximity of the other device. The proximity detector may comprise a near field communication (NFC) interface, a Bluetooth® transceiver or another short-range wireless technology that may be employed to detect the proximity of another device. This technology enables two devices to store a current location to facilitate a subsequent rendezvous back at that same location.

Abstract: Systems and methods for monitoring navigation state errors are provided. In this regard, a representative system, among others, includes a receiver that is configured to receive GPS signals and calculate pseudorange (PR) residuals, the receiver including a navigation state error manager that is configured to: calculate a distance traveled by the receiver having the PR residuals, determine whether a navigation state has errors based on the calculated PR residuals and calculated distance, and responsive to determining that the navigation state has errors, send an error message indicating that the navigation state has errors.

Abstract: Methods, program products, and systems for adaptive location determination are described. A server computer can receive location information from location-aware mobile devices (e.g., GPS-enabled devices) located in a cell of a cellular communications network. The server computer can calculate an average geographic location using the received locations and distance between each location and the calculated average. The server computer can exclude locations that are sufficiently far away from the average. The server computer can repeat the calculation and exclusion until a level of precision is achieved for the average geographic location. The average geographic location and an error margin can be associated with the cell. The server computer can provide the average geographic location and the error margin to a mobile device (e.g., a non-GPS-enabled device) that is in the cell. The mobile device can display the information on a map display of the mobile device.

Abstract: An asset's TCU, or a mobile device coupled thereto, receives and stores geographical boundary definitions to a memory. A processor uses the boundary definition to determine an initial-location boundary based on the definition and the current location of the TCU at the time it received the boundary request message. As the TCU's GPS unit generates location information, the processor retrieves the initial-location boundary definition from the memory and compares the current location from the GPS receiver to it according to an algorithm. If the processor determines that the current location of the vehicle has crossed the boundary, the processor generates an alert message, which may be an e-mail, SMS, telephonic, interne, IM, or other electronic message indicating that an asset crossed the boundary, and sends it wirelessly using a transceiver to a central computer for further processing, or directly to another device, according to a notification destination identifier.

Abstract: An electronic device 1 receives ephemeris information from a GPS satellite at intermittent timings TE1, TE2, and TE3 and stores the received information in its memory. In addition, the electronic device 1 receives time information at intermittent timings TC1, TC2, TC3, and TC4, and corrects a clocked time based on the received time information. Then, at positioning timing T1, the electronic device 1 captures a transmission signal from the GPS satellite while synchronizing timing with the GPS satellite based on the clocked time, and performs positioning based on the captured transmission signal and the ephemeris information stored in the memory.

Abstract: Methods are provided for determining the length of a path traveled by a vehicle using an onboard unit that generates a sequence of position readings and a related position quality index for each position reading. A set of consecutive position readings is extracted from the sequence. Position readings are discarded having position quality indices falling below a threshold. A set quality index is determined based on the number of position readings of the set or on the position quality indices. If the set quality index exceeds a threshold, the path length is determined based on mutual distances of consecutive position readings of the set. Otherwise, the path length is determined using a digital road map composed of road segments by associating the position readings of the set with at least one road segment, and determining the path length based on the segment length of the at least one road segment.

Abstract: A system for determining a location of a vehicle in an environment provided with at least two landmarks whose location is known. The system includes at least one scanning distance sensor installed in the vehicle and configured to measure distance and direction from the vehicle to the at least two landmarks, as well as a data processing device configured to store in its memory the location of the at least two landmarks; and determine the location of the vehicle on the basis of at least the location of the at least two landmarks as well as the distance and direction from the vehicle to the at least two landmarks.

Abstract: Systems, methods, and devices are described for implementing map matching techniques relating to measured location data. Probabilistic models, including temporal Bayesian network models and Hidden Markov Models, may be used for combining multiple classes of evidence relating to potential locations of points traversed on routes over time. Multiple route segments and overall routes may be maintained under relative uncertainty as candidates. The candidate route segments and overall routes may then be reduced into a smaller number of candidates or a single most likely route as a trip progresses. As the trip progresses, route segments in proximity to each location point are identified and candidate matches are determined. A probability of an entity traversing a candidate match at a given time and a probability of an entity traversing between a first candidate match at a first time and a second candidate match at a second time are determined based on a plurality of factors.

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: There is disclosed a method of estimating the location of a plurality of electromagnetic signal sources, comprising: scanning at a first plurality of locations to generate signal source position data, the signal source position data representing estimates of the position of at least one of said signal sources; scanning at a second plurality of locations using a signal detection system to generate signal detection data, the signal detection data relating to signals received at the second plurality of locations from the signal sources; processing the signal source position data in dependence on the signal detection data to correct estimation errors in the signal source position data; and outputting the processed signal source position data.

Abstract: According to one embodiment of the present invention, a method for automatically entering favorite locations into a navigation system is provided. The method according to one embodiment includes receiving information regarding a location from an object within a vehicle using a navigation system. An identifier to the information and the information and identifier are stored in the navigation system. The user may retrieve the information from the navigation system using the identifier. The information from the objects may be received in various wireless formats, including RFID, Bluetooth and Wi-Fi.

Abstract: Methods, program products, and systems for location determination using cached location area codes are described. A mobile device can store a set of location area codes (LACs) of a cellular communications network on the mobile device. Each LAC can represent a location area of the cellular communications network that encompasses at least a predetermined number of cells. Each LAC can be further associated with an estimated geographic area. The estimated geographic area can be defined as a circle centered at a location and having a radius representing an uncertainty of the location. The mobile device can determine a current LAC of the mobile device based on a wirelessly received signal. The mobile device can determine a current location of the mobile device by performing a lookup in the stored set of LACs using the current LAC.

Abstract: A method, system, and computer program product to provide accurate positioning of a vehicle while conserving power is provided. The system includes a receiver configured to receive a positioning signal that determines a position of the vehicle and an auxiliary sensor configured to provide data to supplement the positioning signal so as to provide the position of the vehicle more accurately than with using solely the positioning signal. The system also includes an auxiliary controller coupled to the auxiliary sensor. The auxiliary controller is configured to generate a first signal to power-up the auxiliary sensor if the vehicle is proximate to entering an area that reduces accuracy of the positioning signal, and calibrate the auxiliary sensor prior to the vehicle entering the area; and generate a second signal to power-down the auxiliary sensor if the vehicle is proximate to exiting the area.

Abstract: An enhanced vehicle guidance system comprising a global navigation satellite system (GNSS) receiver and a data processor with a memory component and a computing device. The method of enhancing a vehicle's guidance system may comprise calculating the altitude, latitude, and longitude of a GNSS receiver for each of a plurality of positions; calculating the incline angle between adjacent points; and using the calculated incline angles to infer the attitude of the vehicle at any of the plurality of positions. The attitude may be used to calculated an inertial correction factor to compensate for GNSS position inaccuracies induced as a result of the vehicle rolling and pitching on uneven terrain. The altitude, latitude, longitude, and attitude of the plurality of positions may be stored in the memory such that the system may look-up the attitude for a given position without recalculating the attitude and without using an inertial sensor.

Abstract: A method for determining location such as vehicle location receives data at a predetermined frequency, validates the received data, stores the received data based on the validation and computes a location based on the stored data. The validation includes verifying a presence of particular data substrings within the received data, verifying a presence of a plurality of data fields within each data substring, computing a parameter based on information contained in two of the plurality of data fields and comparing the computer parameter with a pre-defined threshold.

Abstract: In a method for refining a position estimate of a low earth orbiting (LEO) satellite a first position estimate of a LEO satellite is generated with a GNSS receiver on-board the LEO satellite. Corrections are received at the LEO satellite. The corrections are processed on-board the LEO satellite such that a corrected LEO satellite position estimate of the LEO satellite is generated for the first position estimate.

Abstract: A vehicle tracking system includes a wheel containing sensor circuitry capable of sensing various types of conditions, such as wheel rotation, wheel vibration caused by skidding, and specific electromagnetic and/or magnetic signals indicative of particular wheel locations. The sensor circuitry is coupled to an RF transceiver, which may but need not be included within the wheel. The wheel may also include a brake mechanism. In one embodiment, the wheels are placed on shopping carts and are used to collect and monitor shopping cart status and location data via a wireless network. The collected data may be used for various purposes, such as locking the wheel of an exiting cart if the customer has not paid, estimating numbers of queued carts, stopping wheel skid events that occur during mechanized cart retrieval, store planning, and providing location-based messaging to customers.

Abstract: A driving assistance apparatus is configured such that, in a case in which determination has been made there is a road marking within a predetermined range from a vehicle, the road marking is detected based upon an image acquired by a rear-side camera. In a case in which there is a single control target solely associated with the road marking thus detected, or in a case in which there are multiple control targets associated with the road marking, and the difference in the marking-target distance is equal to or greater than a driving control threshold distance, the target-vehicle distance, which is the distance between the vehicle and the control target that is a target for guidance and vehicle control, is calculated. The driving assistance apparatus performs guidance and vehicle control according to the control target based upon the target-vehicle distance thus calculated.

Abstract: A navigation system determines its usage mode. In some embodiments, a method comprises determining a usage mode of a navigation system based on at least one of an acceleration indicator, a speed indicator, and a magnet sensor. The usage mode is at least one of a pedestrian mode, a vehicular mode, an aerial mode, a train mode, and a marine mode. The method further comprises configuring a navigation subsystem based on the usage mode.

Abstract: A method and apparatus for receiving a signal from transmitters such as GPS satellites, for fixing the location of the receiver. Each of the transmitted signals includes a unique periodically-repeating sequence. A received signal is stored by the receiver for at least two repetitions of the periodically-repeating sequence. FFT operations are performed, and the resulting data frequency samples are pruned responsive to a hypothesized residual frequency, a procedure which significantly reduces the total number of subsequent calculations and therefore significantly reduces processing time. A correlation series is determined from the pruned samples and reference frequency samples corresponding to a hypothesized transmitter. If a match is found in the examination of this series, a code phase offset is determined; if not the process is repeated with another hypothesized residual frequency. Multiple correlation series similarly obtained may also be incoherently combined prior to this examination.

Abstract: A method and apparatus for detecting location information using a navigation algorithm are provided. The method includes searching for neighboring Global Positioning System (GPS) satellites, receiving, if at least one GPS satellite is detected, pseudo-range information from at least one of the detected GPS satellites and storing the received pseudo-range information, calculating a displacement of a pedestrian terminal based on step detection of a pedestrian, correcting the calculated displacement of the pedestrian terminal using the received pseudo-range information, and measuring the location of the pedestrian terminal is measured using the corrected displacement.

Abstract: A method for determining the position of a mobile body at a given instant and for monitoring the integrity of the position of said mobile body includes a step of determining a sustained position at the given instant by adding the integral of the hybrid speed between the preceding instant and the given instant to the position of the mobile body at the preceding instant; a step of determining the sustained protection radius associated with the sustained position by adding the integral of the hybrid speed protection radius between the preceding instant and the given instant to the position protection radius of the preceding instant; a step of determining a better position at the given instant, the better position being: when information from the first positioning device is available, the position associated with a better protection radius, the better protection radius being selected by comparing the intermediate protection radius with the sustained protection radius according to a predetermined selection criteri

Abstract: Methods and apparatuses for estimating a user's altitude with respect to the mean sea level are provided. According to some aspects, the present invention is able to estimate altitude in both open sky as well as in degraded GPS signal environments such as dense urban canyon environments where GPS performance is affected by fewer available satellites and/or multipath error. According to other aspects, the present invention uses data from a pressure sensor to estimate altitude, either with or without the use of GPS aiding data. According to further aspects, estimated altitude is integrated with other types of dead reckoning data to provide user context detection pertaining to changes of altitude.

Abstract: A navigation device is provided that includes a processor configured to track a path of the navigation device based on a first signal received by the navigation device, and calculate a calculated position of the navigation device based on a second signal different from the first signal. The navigation device may further include a graphical user interface configured to display a calculated position graphical element representing the calculated position determined based on the second signal and display a tracked position graphical element representing the path of the navigation device determined based on the first signal, the tracked position graphical element and the calculated position graphical element being distinguishable in appearance.

Abstract: The present invention includes a system and method for selecting a unique geographic feature, including a mobile device that uses position and orientation sensors to determine a user position and a user orientation. The mobile device is adapted for wireless communication with a database that houses or has access to data concerning geographic features, as well as processing and computing means for calculating specific geographic relations discussed in further detail below. The system of the present invention further includes means for selecting among those features that are topologically related to the polygon. These include means for defining the geometry of the polygon, means for filtering those features that should not be within the geometry of the polygon, and means for ranking those features within the polygon. The method of the present invention is operable in conjunction with the system through the system hardware and software.

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: A method for calculating a navigation phase for a carrier, in a navigation system involving terrain correlation, includes determining a navigability map in which each point of interest of an onboard map is associated with a navigability score. The method is applicable to all terrain aided navigation techniques, and allows the consideration of the quality of the onboard maps and terrain sensors used.

Abstract: Apparatus and methods provide a guidance kit that can be attached to a projectile, such as screwed into a fuze well of an artillery round or a mortar round. A portion of the guidance kit is configured to spin constantly during flight. In the context of an artillery round that is shot from a rifled barrel, the direction of the spin torque is counter to the direction of the spin induced by the rifled barrel. Control surfaces are present in the portion of the guidance kit that spins constantly during flight. While the portion spins, the control surfaces are actuated to steer the projectile towards an intended target via, for example, GPS.

Abstract: Systems, methods, and computer program products are provided for providing suggested transaction categories based on location. The system includes a computer apparatus including a processor and a memory; and a software module stored in the memory. The software module includes executable instructions that when executed by the processor cause the processor to determine a location of a user; access a database including a plurality of locations and associated transaction categories; determine at least one category associated with the location of the user using the database; and provide the at least one category to the user so that the user may categorize a transaction. In some embodiments, the system determines the category based on a combination of the location and a characteristic of the transaction or a previous input by the user. The system assists users in categorizing transactions so that the user is better able to track spending.

Abstract: A monitoring system is provided, by which location data and possibly other information from a wireless personal tracking device carried by an individual is transmitted to an administrative hub for processing and action according to defined rules. Simultaneous monitoring of a plurality of individuals with diverse tracking units and effective event recording and reporting can be implemented.

Abstract: An apparatus includes a display displaying a first map representing a position of the apparatus obtained as a result of a first positioning, and further displaying a second map representing the position of the apparatus and being obtained as a result of a second positioning which is started before displaying the first map, the second map being displayed without responding to a request for displaying the position of the apparatus obtained as a result of the second positioning.

Abstract: A portable electronic device comprises a controller and a display. The controller receives vector data on a position of a user of the portable device from a satellite positioning sensor associated with the user, and scalar data on movement of the user from at least one motion sensor associated with the user. The controller stores data based on the vector data and feeds a scalar parameter proportional to the scalar data to the display. The display displays the scalar parameter.

Abstract: A method for monitoring shipments of a plurality of components and enabling assembly of the plurality of components. The method can include the steps of encoding a unique identifier and specification information on each component into a data storage of a GPS device; encoding assembly instructions for each component; attaching the GPS device to the component; actuating each GPS device to provide a longitude and latitude signal to a network; tracking the location of each component; shipping the components while tracking the location of the components until the components reach a designated location; and retrieving from each component assembly instructions, specification information, and inspection information. The method can include assembling the components using the assembly instructions at the designated location, and forming a record of each route used by each component.

Abstract: A proximity search engine for carrying out a proximity search with respect to a reference location uses as a reference frame the earth divided into tiles, which are predefined geographic regions of substantially equal areas. Records that are searched based on proximity to a reference location include location pointers, each of which identifies a particular tile that encompasses the physical location indicated by the corresponding record. When the proximity search is carried out, the tiles that are within a specified distance from the reference location are obtained and records having location pointers corresponding to such tiles are selected for inclusion in the search results.