Abstract: Disclosed is an approach for improving positioning quality via a feedback loop between a radio-based positioning system and a client device, such as a tracking system. In particular, the tracking system or other client device may request and then receive a position estimate from the positioning system. The tracking system could then make a determination that the position estimate is incorrect, such as by determining that it is an outlier relative to a location trace, for instance. Responsive to this determination, the tracking system may transmit, to the position system, an indication of radio node(s) associated with the incorrect position estimate. Based on this indication, the positioning system could then exclude one or more of those radio node(s) from a radio map, thereby improving quality of the radio map and in turn quality of future position estimates, among other advantages.

Abstract: The locations of electronic devices in an institutional facility are determined based on interaction with the wireless mobile devices of users who roam though the facility and interact with (or are detected by) the devices.

Abstract: A method includes obtaining or holding available a radio map that has been determined based on radio node observation data of radio signals emitted from radio nodes of a radio node network. The method obtains asset observation data of one or more radio signals that have been emitted from an asset and observed by radio nodes of the radio node network. The method also determines a position estimate of the asset based on the asset observation data and the radio map. A corresponding system is also disclosed.

Abstract: An example system connects to a location engine in a mesh network, transmits a first message indicating a bus master service hosted by a bus master, and receives a message indicating a location service hosted by a location engine and an aggregation service hosted by an aggregator connected to the location engine. The bus master stores a first entry corresponding to the location service and a second entry corresponding to the aggregation service. The bus master transmits a request to access the location service; receives a response confirming a subscription to the location service; and receives timing data indicating times at which the multiple receivers in a clinical environment received a wireless signal from a tag. The bus master aggregates the timing data into a data stream and transmits data stream to the location service in accordance with the subscription.

Abstract: Disclosed herein are techniques for obtaining location data for a sensor fusion device. The techniques include transmitting or receiving a signal from or to the sensor fusion device. The techniques also include obtaining angle-based location data, based on the signal and on an angle-based location finding technique. The techniques also include determining location data for the sensor fusion device or an auxiliary device associated with the sensor fusion device, based on the angle-based location data.

Abstract: A radio frequency sensor system comprising a housing defining a resonant cavity. Radio frequency probe(s) in the cavity transmit and/or receive radio frequency signals. A radio frequency control unit is in communication with the radio frequency probe(s) for determining one or more states of the radio frequency sensor system based on changes in the characteristics of the radio frequency signals. A machine learning system is in communication with the radio frequency control unit for identifying and developing transfer functions and calibrations based on the changes in the characteristics of the radio frequency signals and determining the one or more states of the radio frequency sensor system.

Abstract: A method and a device for zone-based localization of mobile devices are described. In an example, a zone from amongst a plurality of zones of an indoor space in which a mobile device is present is identified. The identification of the can be based on instantaneous localization information obtained from the mobile device. Further, a localization criterion to be employed for localizing the mobile device is determined based on the identified zone. The localization criterion may be indicative of a selectivity in use of sensor data for localizing the mobile device. Subsequently, the mobile device is localized in the indoor space, based on the localization criterion.

Abstract: In a geolocation system, ancillary parameter values, i.e., those produced during the geolocation process but not directly related to the calculation of the geolocation, are recorded and stored. These “ancillary” parameter values include signal characterization data and secondary measurements produced in the calculation of the geolocation. These parameter values are processed, in one approach, with respect to a weighted matrix in order to determine a confidence or fidelity value of the determined geolocation. Confidence is an indication of the likelihood that the geolocation result produced is in fact the desired target and that the identified location has a reasonable degree of quality so as to be practical or accurate.

Abstract: Techniques are provided for emitter geolocation. A methodology implementing the techniques according to an embodiment includes measuring phase differences between radar signals received at one or more pairs of antennas. The method also includes calculating hypothesized phase differences based on ray tracings from hypothesized emitter locations at a first set of grid points, to the antennas. The method further includes generating scores based on correlations between the measured phase differences and the hypothesized phase differences. The method further includes generating an error ellipse based on candidate grid points associated with scores that are above a threshold. The process may be repeated on a second set of grid points, bounded by the error ellipse, to generate a second set of scores. The grid point, from the second set of grid points, that is associated with the highest of the second set of scores is selected as the estimated emitter geolocation.

Abstract: A system for locating an object in a volume of space can include a communication device of the object disposed in the volume of space, where the communication device broadcasts a first communication signal into the volume of space, where the first communication signal includes a first identification of the object. The system can also include multiple integrated sensor devices disposed in the volume of space, where each integrated sensor device includes at least one sensor, at least one receiver, and at least one transmitter, where the at least one receiver of a subset of the integrated sensor devices receives the first communication signal, where each of the subset determines a signal strength of the first communication signal. The system can further include at least one access controller that receives at least one second communication signal sent by the subset.

Abstract: A system for appending an emergency call (e.g., E911) with a location is described herein. The system appends the emergency call to a public safety answering point (PSAP) with a location from which the E911 call occurred. A user equipment (UE), which places the emergency call, connects to the beacon via short-range communication and acquires the location from a beacon. The UE transmits the location to the PSAP via a telecommunications network.

Abstract: In a general aspect, a method is presented for detecting a location of motion using wireless signals that propagate along two or more paths of a wireless communication channel. The method includes storing a set of eigenvectors derived from first motion-sensing data associated with a first time frame. The first motion-sensing data is associated with a first motion-sensing topology of a wireless mesh network. The method also includes obtaining a motion vector based on wireless signals transmitted between access point nodes in the wireless mesh network during a second, subsequent time frame. The wireless mesh network operates in a second, distinct motion-sensing topology during the second time frame. The motion vector is compared with the respective eigen vectors, and a probability vector is generated based on the comparison. A location of the motion of the object during the second time frame is determined based on the probability vector.

Abstract: A tracking system for use in head-mounted display apparatus includes at least one emitter that emits signals; a first receiver and a second receiver that sense the emitted signals and generate sensor data, the first receiver and the second receiver being arranged on a first portion and a second portion, respectively, wherein the first portion faces a user when the head-mounted display apparatus is worn by the user, and the second portion is a part of a user-interaction controller of a head-mounted display; and a processor configured to process the generated sensor data to determine relative positions and orientations of first receiver and second receiver with respect to the emitter, and to determine a relative position and orientation of the second receiver with respect to the first receiver.

Abstract: A radio wave environment analysis device includes: a processor configured to analyze a radio wave environment corresponding to a radio wave transmitted from a wireless transmitter arranged within an area including observation points using a scattering body having a volume of an initial value or higher; and a memory configured to store the radio wave environment at each of observation points of an area where based on the analysis. The processor is configured to: analyze the radio wave environment using a scattering body having a volume reduced by a first predetermined value, and terminate the analysis if a difference between first and second radio wave environments at each observation point based on analyses using the scattering bodies before and after reduction of the volume, respectively, is equal to or lower than a second predetermined value.

Abstract: A travel coordination system provides suggestions to providers for where they should go to reduce the wait time between trips. A geographic region is broken down into zones and a score is generated for each zone. A zone score can be generated by determining the estimated wait time for the zone and generating a model for the wait time. A zone score can also be generated using a model for the wait time using factors that likely contribute to the wait time. The zone score for each zone is displayed to the provider on a road map of the geographic region along with the boundaries of each of the zones and the provider's position within the region. The travel coordination system also suggests driving routes. The travel coordination system selects a target zone and generates candidate routes to the zone. A route is selected based on route scores.

Abstract: A system simulator for simulating a wireless system for testing a wireless device under test comprises an uplink signal receiver for receiving an uplink signal generated by the wireless device under test and providing data blocks embedded in the uplink signal, and an uplink signal impairment unit that based on a predetermined probability value sets the data blocks provided by the uplink signal receiver as valid or erroneously received.

Abstract: The disclosure generally relates to a method, system and apparatus for autonomous Wi-Fi location determination by using information from neighboring access points (APs) along with an optional range measurements. In one embodiment, a root AP determines its location as a function of neighboring AP's location and the distance measured between the root AP and each of the corresponding neighbors. The location information can be stored internally or reported to external resource.

Abstract: A radar system located on an antenna array mounted on a moving carrier and including plurality of antenna elements; a transmitter portion coupled to the antenna and configured to transmit a plurality of transmit beams, each including a corresponding orthogonal transmit waveform of a plurality of orthogonal transmit waveforms, each of the plurality of transmit beams having a transmit phase center spatially located at a respective point along the antenna array, the transmitter portion being configured to transmit each transmit beam during at least a portion of a pulse repetition interval, wherein the transmitter portion is configured to shift the transmit phase center of each transmit beam for each pulse repetition interval to a respective point along the antenna array in a direction opposite the movement of the carrier, such that a speed of the respective transmit phase center of each beam remains is reduced.

Abstract: A plurality of access points located within a building structure may provide various location-based services, such as navigation, to mobile devices within the building structure. To more accurately determine the location of the plurality of access points, a floorplan of the interior of the building structure may be obtained. A plurality of images of the interior of the building structure is then obtained. At least one of the images includes an image of at least one of the plurality of access points. A plurality of reference points may also be located within the building structure and obtained. Based on the plurality of images, reference points, and the floorplan, a composite image of the interior of the structure is generated. Based on the composite image, the location of each of the plurality of access points is determined.

Abstract: Example implementations relate to device policy enforcement. In some examples, a computing device may comprise a processing resource and a memory resource storing machine readable instructions to determine when a location of a mobile device is within a geofence using global positioning system (GPS) coordinates received from the mobile device defining a location of the mobile device, determine when a distance of the computing device from the mobile device is within a threshold distance of the mobile device using proximity data received via a network relationship, and enforce a policy definition included in a computing device policy definition received from an external computing device based on the location of the mobile device and the distance of the computing device from the mobile device.

Abstract: A set of samples are returned by radio frequency identifier (RFID) reader corresponding to the readings of signals emitted from a particular RFID tag, each sample including a respective set of features identifying values of the attributes of the signals as detected. At least some of the features are provided as inputs to a random forest of decision trees, each providing a prediction that the particular RFID tag is located in one of a plurality of defined zones in a particular environment. From outputs of the plurality of decision trees based on the set of samples, it can be determined that the particular RFID tag is located in a particular one of the plurality of zones at a first instance in time.

Abstract: In one implementation, a method includes receiving versions of a message from a first satellite-based receiver and a second satellite-based receiver that both received a radio frequency (“RF”) transmission of the message, the message comprising a self-reported position of a transmitter of the message. The method also includes determining a time difference between a first arrival time of the RF transmission of the message at the first satellite-based receiver and a second arrival time of the RF transmission of the message at the second satellite-based receiver. The method further includes determining a measure of the likelihood that the self-reported position of the transmitter is valid based on the time difference between the first and second arrival times. The method still further includes transmitting an indication of the measure of the likelihood that the self-reported position is valid.

Abstract: A computer-implemented method and a server for device positioning. The computer-implemented method includes receiving a control message from a positioning server. The control message indicates a set of channels associated with an area and time periods for monitoring the set of channels. At least one measurement of a signal from at least one of a reference device for the area and a target device is obtained, according to the control message, with the reference device being located at a predefined position with respect to the area. The at least one measurement is reported to the positioning server for determining a position of the target device with respect to the area.

Abstract: A terrestrial based positioning system includes a plurality of location anchors configured to transmit and receive ultra-wide band (“UWB”) signals. In another aspect, a location tag configured to transmit and receive UWB signals uses signals transmitted by location anchors to determine its current position. In some implementations, a location tag may use Global Positioning System (“GPS”) signals or a combination of UWB and GPS signals to determine a current location. The location anchors are organized into zones used by the locations tags to determine a current position based in UWB signals. In some implementations, the locations anchors automatically create the necessary zones. Location anchors may also automatically determine the position of other location anchors. In yet other implementations, the location anchors relay data transmitted by a location tag. In addition, a location anchor may transmit GPS signals that can be used by standard GPS receivers.

Abstract: A portable electronic timepiece includes a display unit which displays an image, and a processor which is operative to display, on the display unit, route information on a traveling route of a user, switch a scale of the route information displayed on the display unit, and in a case where a given point set in association with the route information of a predetermined scale cannot be displayed within a display range of the display unit, change a display mode of the display unit to a display mode that is different from the display mode of displaying the route information.

Abstract: Poor BSE estimation accuracy resulting from conventional Extended Kalman Filtering (EKF) approaches using RF OI sensors mounted on the ground as a remote bullet tracking sensor motivated the design and development of the present disclosure. The observer based BSE removes EKF process noise (state noise) and measurement noise (OI sensor noise) covariance matrices selection and tuning which have been long recognized by the estimation community as a time consuming process during the design stage; requires no consideration of interactions when having the control input signal as part of the state propagation equation; and provides a significant improvement in velocity estimation accuracy, in some cases to less than 1 m/s errors in all axes, thereby meeting the miss distance requirement with amble margin.

Abstract: The present disclosure relates to a method and a mobile system for evaluating signal propagation over a radio channel. Predicted values for the radio channel are acquired at the mobile system, the predicted values being distributed over a geographical area. The mobile system follows a test route defined within the geographical area, the test route including a plurality of measurement points distributed over the geographical area. For each measurement point, the mobile system acquires one or more metrics on the radio channel and compares each of the one or more metrics with a corresponding predicted value. The mobile system evaluates a radiation pattern of an antenna transmitting on the radio channel based on the comparisons. The mobile system may produce a graph of the antenna radiation pattern and maps showing the acquired metrics on the geographical area.

Abstract: The disclosure relates to distance determining apparatus for determining a distance between an anchor and a tag. The apparatus is configured to select a first frame type or a second frame type for a message that is to be transmitted, to optimize an energy of the first frame type for a secure preamble detection, and to optimize an energy of the second frame type for a data transmission.

Abstract: The disclosure provides examples of systems and methods for determining locations of a number of radio frequency-enabled devices such as mobile devices and radio frequency-equipped beacons/luminaires within an indoor location. The radio frequency-enabled devices may be part of an indoor positioning system and/or content delivery system. The examples describe obtaining an angle of arrival (AoA) of the signals received by the respective radio frequency-enabled devices. The AOA data is used to identify the relative positions of the radio frequency-enabled devices as the mobile device moves about the indoor location. Upon comparing AOA measurements of the collected data related to a map of the location, the system may generate a data structure that may be presented graphically as a map of positions of the devices at the location. The described examples may enable a rapid commissioning process with respect to the radio frequency-enabled devices in a network.

Abstract: Disclosed is a positioning system and a node network. A terminal included in the present invention is characterized by an invisible light sensing unit that detects invisible light signals, that were emitted from one or more signaling nodes with the same intensity, carrying the location data of each signaling node; and a controller that calculates the user's position based on the location data included in one or more invisible light signals and their received signal strength.

Abstract: A system and method for verifying ADS-B messages received at an aircraft from other aircraft within its ADS-B range. This disclosure enhances the current Automatic Dependent Surveillance-Broadcast (ADS-B) IN surveillance systems, and the disclosed system is an onboard system designed to enable ADS-B IN capable aircraft to verify the information received via ADS-B from the rest of the aircraft within its ADS-B range. The system's performance is based on the principles of multilateration (MLAT). The system performs MLAT calculations to determine whether the ADS-B messages received are truthful or not truthful. The disclosed system relies on a communication protocol based on a series of requests and responses to interchange the information needed by the aircraft involved in the process to carry out the MLAT calculations.

Abstract: Systems and methods for determining locations and configuring controllable devices are provided. Example systems and methods include determining a first location estimate for a computing device using a first interior location estimating technique. The example systems and method may also include determining a second location estimate for the computing device by refining the first location estimate using a second interior location estimating technique, the first interior location estimating technique being different than the second interior location estimating technique. The first interior location estimating technique may be based on round-trip time to multiple wireless communication devices. The second interior location estimating technique may be based on image data.

Abstract: Positioning mobile devices in a three-dimensional space includes receiving multiple traces, each trace corresponding to a sequence of atmospheric pressure readings from a respective mobile device, receiving indications of signals received by the mobile devices from signal sources concurrently with the atmospheric pressure readings, generate similarity metrics for the multiple traces using the indications of other signals received by the mobile devices, the similarity metrics being indicative of associations between the signal sources and the atmospheric pressure readings, and determine estimated changes in elevation over time for the multiple traces using the generated similarity metrics.

Abstract: Embodiments of the present invention provide a method of providing hazard information by an electronic device, comprising determining: determining a location of an electronic device in relation to hazards in a geographic region of interest, the location of the electronic device being determined by a location determining unit of the electronic device and the location of the hazards being determined from map data accessible to the electronic device; displaying, in a first display mode on a display of the electronic device, an indication of the hazards in the geographic region of interest in relation to a scale indicative of a distance from the location of the electronic device; and displaying, in response to a predetermined user input, in a second display mode on the display, an indication of one or more of the hazards in a portion of the geographic region of interest, each indication being associated with at least one item of distance information indicative of a distance of the hazard from the location of the

Abstract: Methods, apparatus, and processor-readable storage media for local determination of geo-location data by user devices are provided herein. An example computer-implemented method includes obtaining geo-location data attributed to one or more access points within a given proximity of a previously-determined geo-location of a user processing device; detecting one or more access points within the given proximity of the user processing device; comparing the one or more detected access points to the obtained geo-location data; and determining geo-location data attributed to the user processing device based at least in part on the comparing of the one or more detected access points to the obtained geo-location data.

Abstract: The network ID of a mobile device can be securely employed as a possession factor. When an access to a restricted access application server or a restricted access account on the application server is attempted via a computing device, and possession of a mobile device programmed with a network ID is employed as a verification factor, the application server or a network ID monitoring server can determine whether certain information associated with the network ID has been changed within a predetermined time interval, indicating potentially fraudulent activity. Based on the presence or absence of recent changes in the information associated with the network ID, the user activity is either authorized or denied.

Abstract: In accordance with an example implementation of this disclosure, a multifunction radar transceiver comprises a transmitter and a receiver. The transmitter is operable to modulate data onto a first radar burst, beamform the first radar burst, and transmit the first radar burst via a plurality of antenna elements. The receiver is operable to receive a reflection of the first radar burst, perform beamforming of the reflection of the first radar burst, demodulate the first radar burst to recover the data modulated on the first radar burst, and determine characteristics of an object off of which the first radar burst reflected based on characteristics of the reflection of the first radar burst.

Abstract: Systems, apparatuses and methods may provide for visually or audibly indicating to users what areas are being covered or monitored by cameras, microphones, motion sensors, capacitive surfaces, or other sensors. Indicators such as projectors, audio output devices, ambient lighting, haptic feedback devices, and augmented reality may indicate the coverage areas based on a query from a user.

Abstract: The network ID of a mobile device can be securely employed as a possession factor or as an identifier of a mobile device that is authorized to receive a funds transfer. When an access to a restricted access application server or a restricted access account on the application server is attempted via a computing device, and possession of a mobile device programmed with a network ID is employed as a verification factor, the application server or a risk indicator server can determine whether certain changes in information associated with the network ID and one or more attributes of a cellular account associated with the network ID are risk indicators. Based on the presence or absence of such risk indicators associated with the network ID, the user activity is either authorized or denied.

Abstract: A system for localizing a transmitting wireless device within a known volume, the system comprising: antennae deployed in respective locations at least some within the known volume, each of the antennae operative to receive and output a signal from the transmitting device; analog-to-digital converter/s; and a processor receiving digital sampled received signals and computing real time output parameter/s as function of: sampled received signals S, received from the transmitting wireless device at antenna i; and of sampled signals, received from the transmitting wireless device at antenna j and sampled, simultaneously with reception at antenna I and sampling of sampled received signals S, function being independent of power level at which transmitting device is transmitting, and to estimate transmitting wireless device's location within volume by comparing the parameter/s to reference output parameters respectively having known correspondence to known possible locations/s within volume, for at least 2 of the an

Abstract: A method includes a mobile device receiving data from a first beacon in a plurality of beacons, wherein the data indicates a plurality signals strengths of signals received by the first beacon from the other beacons in the plurality of beacons. The mobile device uses multivariable regression based on the data received from the first beacon and signal strengths of signals received by the mobile device from the other beacons in the plurality of beacons to determine distances from the mobile device to the beacons. The mobile device determines a location of the mobile device based on the determined distances.

Abstract: A network system uses Wi-Fi signals or other types of short-range transmissions to determine navigation to pickup locations for users receiving services provided via the network system. In an embodiment, the network system builds a database of reference signatures of short-range transmissions previously detected by client devices of users at a geographical region, where the reference signatures are mapped to corresponding locations of the geographical region. By comparing a signature detected by a particular user's client device to the reference signatures, the network system may check for similarities between the short-range transmissions. Responsive to finding a match, the network system determines a current location of the particular user at the geographical region. Accordingly, by leveraging the database, the network system may determine a route for travel by the particular user from the current location to a pickup location without having to use GPS signals.

Abstract: In aspects of location correlation in a region based on signal strength indications, a mobile device implements a location module that determines a current location of the mobile device in a region within communication range of a first radio system based on location data received in radio signals from the first radio system. The location module determines received signal strength indication (RSSI) values from signals received from a second radio system at the current location of the mobile device. The location module can then associate the current location of the mobile device in the region with the RSSI values, and generate a location mapping of the region based on the current location and subsequent locations of the mobile device in the region. The location mapping correlates the locations of the mobile device in the region with the determined RSSI values at the respective locations.

Abstract: Two or more objects, or an object and an environment are each fitted with two or more range measurement devices. Each of the range measurement devices is provided with a transceiver capable of outputting a unique code and information that can be used in range measurement, and receiving from other range measurement devices unique codes and information that can be used in range measurement. Range measurements from range measurement devices on the object or located in the environment are used to derive the relative position of the range measurement devices, from which a relative position of the objects, or of the object and an environment can be derived.

Abstract: A beacon anchor may include a signal generator configured to generate an ultra-wide band signal inclusive of a unique identifier associated with the beacon anchor, where the UWB signal is a pulse sequence. A transceiver may be in communications with the signal generator. Responsive to receiving the UWB signal from the signal generator, the UWB signal may be broadcast. A processing unit may be in communication with the transceiver, and, responsive to receiving a unicast communications session request from a portable device, be configured to establish a unicast communications session with the portable device to enable a distance between the portable device and beacon anchor to be determined. Through use of UWB signals, relative position (e.g., in front of or behind the beacon anchor) may be determined, thereby enabling different actions to be taken in response to determining the relative position.

Abstract: A method is described of using the mobile device so as to control the drain of power from the power source of the mobile device, the mobile device having at least two location determination techniques having respective power drain characteristics, the method includes selecting the location determination technique having a lower power drain characteristic the greater the determined distance of the mobile device from a predetermined location or area, and selecting the location determination technique having the greater power drain characteristic the smaller the determined distance of the mobile device from a predetermined location or area. The method thus uses the least accurate technique when furthest away and the most accurate technique when closer to a predetermined location or area.

Abstract: Systems and methods for determining an angle of arrival (AoA) of a signal received from an emitters at a pair of antennas spaced apart by more than one half wavelength of the received signal. Features of the signal are determined, including a phase difference between signal components detected at the antennas, and a time difference of arrival (TDOA) having a known measurement error. A set of TDOA possibilities bounded by the known TDOA measurement error and a set of AoA estimates using phase interferometry (PI) within the range are calculated. The TDOA set is iteratively reduced to determine a precise AoA estimate for the emitter.

Abstract: A method for improving target location accuracy in direction finding systems is disclosed. A target search region is identified based on a set of received signals, and the target search region is projected onto the earth's surface. An initial search grid, which is smaller than the target search region, is placed within the target search region. Next, the initial search grid is expanded to a full search grid by using an optimum number of virtual grid points in order to cover the entire target search region. The correlation coefficients at the virtual grid points between the estimated phases of emitted signals and the estimated phases of the received signals are then calculated. A target is designated as being at a location associated with the highest correlation coefficient. At this point, a new travel path can be initiated to engage or avoid the target.

Abstract: An indoor positioning system and method that correlates map locations to respective wireless access point (AP) fingerprints, and wherein each wireless AP fingerprint is a plurality of wireless AP signal measurements associated with the correlated map location. The method includes receiving position-inference data associated with a user; determining a probable location inside the building based on the position-inference data; receiving wireless AP signal measurements detected by a wireless device associated with the user; associating the probable location with the wireless device based on the association between the position-inference data and the user of the wireless device; and updating the wireless AP fingerprint correlated to the probable location using the received wireless AP signal measurements. The method and system use crowd-sourcing to build and refine the wireless AP fingerprints.

Abstract: Systems (100) and methods for determining a location of a tag (310). The methods involve: receiving, at each detector of a plurality of detectors (202-216, 306, 308), a device transmission periodically transmitted from the tag; determining, by the detectors, Received Signal Strength Indictors (“RSSIs”) for the device transmission received thereat; determining, by a computing device (218), a probable location of the tag within the passage, first demarcated area or second demarcated area using the RSSIs and relationships between the RSSIs; determining a first likelihood value indicating the likelihood that the probable location is correct; and determining an estimated location of the tag within the passage, first demarcated area or second demarcated area based on the probable location when the first likelihood value meets a first criteria.