Abstract: Mobile devices are able to determine their location based radio transmitters that are visible at the device to provide geographic location services. A knowledge of the location of the transmitters is required for the mobile device to determine a location estimate, however this can be difficult in network environments where the transmitters are temporary and their locations are not identified in location databases. Locations of temporary transmitters can be provided to mobile devices in order to augment the available location data used in determining the mobile device location. 3rd parties can provide temporal location data on transmitters that are set up for short period of time, as well as better control the distribution of the location data.

Abstract: A wireless device provides location data concerning an object by use of geolocation in order to provide distance tracking and local location techniques in order to provide local tracking. The geolocation and local location techniques may be implemented at the same time or individually, reconfigurable on demand, in both the tracking and tracked devices. The tracked wireless device includes a wireless communication circuit capable of communication with a multiuser wireless subscriber network. A geolocation reading circuit provides GPS or similar location data and is capable of obtaining geolocation data concerning the object. A local locating device parses local location data, and an indication is provided of geolocation based on the geolocation data, and is further responsive to the local location data which is used to modify the geolocation data with the local location data.

Abstract: Apparatus for determining an estimated value for a location of a receiving element within a reference system which may receive signals of a signal source movable to different measuring positions, it being possible to measure—on the basis of the signals received—localization data which indicate a relative location of the receiving element with respect to the movable signal source, the apparatus being configured to determine the estimated value on the basis of at least two different measuring positions and localization data corresponding thereto by means of an evolutionary algorithm. On the basis of the localization data measured, a fitness function of the evolutionary algorithm is formed, the localization data having an angle of arrival of the received signals on the receiving element, and/or a signal arrival time from which a distance from the signal source may be determined.

Abstract: A method of modifying calibration data used to geo-locate a mobile station located in an indoor environment is disclosed. When a mobile station is located indoors, the signal strength of signals received and/or transmitted by the mobile station have the tendency to be lower than the strength of the signals received by a mobile station located outdoors. As a result of these lower signal strengths, geo-location efforts which rely on signal strengths may result in unsatisfactory location accuracy. Modifying pre-existing calibration data obtained outdoors may provide a way to simulate indoor calibration data characteristics.

Abstract: A semiconductor device is provided with a power supply circuit having a function to generate a power supply voltage from a wireless signal and an A/D converter circuit having a function to detect the strength of the wireless signal by an A/D conversion of a voltage generated from the wireless signal. This enables to provide a semiconductor device which does not require replacement of batteries, has few limitations on its physical shape and mass, and has a function to detect a physical position. By formation of the semiconductor device with use of a thin film transistor formed over a plastic substrate, a lightweight semiconductor device, which has flexibility in physical shape and a function to detect a physical location, can be provided at low cost.

Abstract: A method of determining an indication of the position of an electronic device. The method includes: obtaining (100) information relating to a radio signal received by the device. The received radio signal are transmissions from one or more satellites of a satellite-positioning system from which information an inference can be made about the true position of the device at the time the signal was received. The method also involves obtaining (110) a plurality of hypotheses about the true position of the device; and evaluating (120, 130, 140) the plurality of hypotheses by assessing a degree of consistency between the information relating to the radio signal and the hypotheses. Using the outcome of the evaluations, the method also includes selecting (150) one or more of the hypotheses; and outputting (160) an indication of the selected one or more hypotheses.

Abstract: The subject matter disclosed herein relates to systems, methods, apparatuses, devices, articles, and means for updating radio models. For certain example implementations, a method for one or more server devices may comprise receiving at one or more communication interfaces at least one measurement that corresponds to a position of a first mobile device within an indoor environment. At least one radio model that is stored in one or more memories may be updated based, at least in part, on the at least one measurement to produce at least one updated radio model. The at least one radio model and the at least one updated radio model may correspond to the indoor environment. The at least one updated radio model may be transmitted to enable a second mobile device to use the at least one updated radio model for positioning within the indoor environment. Other example implementations are described herein.

Abstract: In at least one embodiment, an apparatus for determining a locating a wireless device with respect to a vehicle is provided. The apparatus comprises a controller for being operably coupled to a plurality of antennas in a vehicle and each antenna transmitting a first wireless signal to a wireless device to locate a primary antenna. The primary antenna being one of the plurality of antennas that transmitted the first wireless signal at a strongest signal strength. The controller being configured to store a first signal strength for a first control point that is positioned about the vehicle and away from the primary antenna. The controller being configured to determine the location of the wireless device based on a comparison of the first signal strength to the strongest signal strength.

Abstract: The subject matter disclosed herein relates to systems, methods, apparatuses, devices, articles, and means for updating radio models. For certain example implementations, a method for one or more server devices may comprise receiving at one or more communication interfaces at least one measurement that corresponds to a position of a first mobile device within an indoor environment. At least one radio model that is stored in one or more memories may be updated based, at least in part, on the at least one measurement to produce at least one updated radio model. The at least one radio model and the at least one updated radio model may correspond to the indoor environment. The at least one updated radio model may be transmitted to enable a second mobile device to use the at least one updated radio model for positioning within the indoor environment. Other example implementations are described herein.

Abstract: The subject matter disclosed herein relates to systems, methods, apparatuses, devices, articles, and means for updating radio models. For certain example implementations, a method for one or more server devices may comprise receiving at one or more communication interfaces at least one measurement that corresponds to a position of a first mobile device within an indoor environment. At least one radio model that is stored in one or more memories may be updated based, at least in part, on the at least one measurement to produce at least one updated radio model. The at least one radio model and the at least one updated radio model may correspond to the indoor environment. The at least one updated radio model may be transmitted to enable a second mobile device to use the at least one updated radio model for positioning within the indoor environment. Other example implementations are described herein.

Abstract: A method for locating an interferer is provided. The method includes determining, from a time delay of arrival (TDOA) signature between signals received from the interferer at two satellites, a first curve on which the interferer lies, determining, from direction of arrival information generated using signals received from the interferer at a plurality of elements of a linear array, a second curve on which the interferer lies, and determining, based on an intersection between the first and second curves, the location of the interferer.

Abstract: Methods, systems, and products determine electromagnetic reflective characteristics of ambient environments. A wireless communications device sends a cellular impulse and receives reflections of the cellular impulse. The cellular impulse and the reflections of the cellular impulse may be compared to determine the electromagnetic reflective characteristics of an ambient environment.

Abstract: System and method for hybrid positioning using blended Wi-Fi and GNSS solution is presented, which provides an overall good positioning accuracy as compared to feed forward blending solution. Feeding back Wi-Fi and GNSS blended solutions to replace position states in GNSS enables blended solution to improve using past Wi-Fi information and also enables early correction of GPS drifts in urban canyons. Smart blending prevents early degradation of blended solution due to bad Wi-Fi information. Additionally, it gives good performance in open sky and mild urban canyons where GPS performance is generally quite good. Constrained blending enables good blending even with dependent or clustered Wi-Fi positions. It also keeps feedback loop stable by limiting changes to a blended solution.

Abstract: A method of tracking an entity by monitoring a signal, the signal tending to vary spatially and be generally time-invariant, the entity moving from a first location within an area to a second location within the area, the method being suitable for use when the location of the source of the signal is unknown, the method comprising providing a plurality of particles for use with a particle filter, each particle being associated with a first particle location, a first particle location being an estimate of the first location of the entity, providing an estimate of the motion of the entity between the first location and the second location, using the estimate of the motion and using the particle filter, for each particle, updating the first particle location for that particle thereby producing an updated particle location, the updated particle location being an estimate of the second location of the entity, for each updated particle, estimating at least one expected signal parameter at the updated particle locati

Abstract: Object tracking anti-jitter filtering systems and methods. A plurality of raw location points for a tracking tag attached to a tracked object is received. The raw location points are stored within a raw location points buffer. Raw location points within an averaging window are averaged to generate an averaged location point. The averaged location point is stored within an averaged location points buffer for use within the object tracking system.

Abstract: The present invention provides systems and methods for self-labeling access points with their geographic location from received beacon frames. In particular, the present invention transmits beacon frames including temporary location information from mobile devices. The beacon frames are received by an access point, filtered by the access point and then used to determine a location. Once the location has been determined, the access point uses the determined location to self-label itself by converting the location information to a geographic code and inserting it as part of the SSID of the access point's beacon signal. The present invention also includes a number of methods using geographic codes including a method for generating and transmitting geographic codes for mobile devices, a method for determining a location of an access point, a method for self-labeling an access point, and a method for filtering beacon frames.

Abstract: A system has short-range transmission devices, each of which corresponds to a range of zones in a three dimensional space. The short-range devices are positioned at various locations within the three dimensional space and periodically broadcast signals. The zones are determined according to a plurality of signal characteristics sensed by client devices proximate to the short-range beacon transmission devices. In addition, the zones are assigned definitions.

Abstract: Example methods, apparatuses, or articles of manufacture are disclosed herein that may be utilized to facilitate or otherwise support one or more processes or operations in connection with defining and determining a plurality of venue types and binning a plurality of venues into categories based, at least in part, on signal propagation characteristics associated with such venues.

Abstract: A method and system arc disclosed for determining the geographic location of a user communicating on a communications network such as the Internet. In one embodiment, a provider of a product or service: (a) receives the user's phone number (or other identification for contacting the user's station), and (b) supplies the user's station with a distinctive identifier. The provider then supplies a location determining service with the user's phone number (or other identification). A phone call is made to the phone number by the location determining service for retrieving the distinctive identifier from the network station having the phone number. If the distinctive identifier is retrieved and the location determining service determines that the user's station is within an appropriate geographical area (or not within an inappropriate area), then the provider can provide the requested product or service to the user.

Abstract: Methods, systems and computer program products for resolving multiple magnitudes assigned to a target vector are disclosed. A target vector that includes one or more target vector dimensions is received. One of the target vector dimensions is processed to determine a total number of magnitudes assigned to the processed target vector dimension. Also, a source vector that includes one or more source vector dimensions is received. The received source vector is processed to determine a total number of features associated with the source vector. When it is detected that the total number of magnitudes assigned to the processed target vector dimension exceeds one, one of the assigned magnitudes is selected based on one of the determined features associated with the source vector.

Abstract: A radio-frequency identification (“RFID”)-based asset tracking system uses a mobile RFID reader to move among stationary assets and communicate with RFID tags attached to the assets. The mobile RFID reader has means for estimating its own location, so the location of a tagged asset can also be estimated by reference to the RFID reader's location when the RFID tag was seen. Location and tag information can be reported back to a central database in real time, or collected and uploaded to the database when the mobile RFID reader returns to a base station. The systems can be used to keep track of vehicles on a dealer's lot or in a warehouse or parking structure.

Abstract: A signal receiver receives a time-domain signal that includes a plurality of pilot tones at a plurality of corresponding frequencies. The time-domain signal is transmitted from a transmit location. The signal receiver extracts from the received time-domain signal pilot phase values corresponding to the pilot tones. The signal receiver computes a signal propagation time of the received time-domain signal by fitting an interpolation function to residual pilot phase values, corresponding to the extracted pilot phase values, and determines a slope of the interpolation function. The signal receiver computes a range between the transmit location and the signal receiver by multiplying the computed signal propagation time with the speed of light.

Abstract: A method of near-field electromagnetic ranging and location exploits the long-wavelength, near-field characteristics of low-frequency RF signals like those in the vicinity of the AM broadcast band. These signals are robust against scattering from small objects and only mildly perturbed by the urban landscape including building structures. They are thus amenable to an RF fingerprinting approach exploiting a coarse calibration to capture the behavior of the gradually varying signal characteristics. In embodiments, a method of near-field electromagnetic ranging and location may exploit transmit tags transmitting to an infrastructure of locator-receivers, or locator-receiver tags detecting signals from an infrastructure of fixed transmitter beacons. In still further embodiments, fixed transmitter beacons may be supplemented by uncooperative signals sources including signals-of-opportunity like AM broadcast band signals.

Abstract: Embodiments order observed beacons based on relative signal strength to create a correspondence between beacon sets and positions. A computing device such as a mobile device provides a positioned observation including a plurality of observed beacons and a position of the mobile device during observation. The observed beacons are ordered based on quality indicators such as signal strength relative to each other. A set of the beacons are selected based on the ordering (e.g., the beacons with the strongest signal strength are selected in order). The position of the observing mobile device is associated with the beacon set to enable location inference for other devices providing observations including the same beacon set.

Abstract: A wireless positioning apparatus receives a plurality of channel responses for a plurality of locations, generates a plurality of channel response patterns from the plurality of channel responses, and stores the plurality of channel response patterns. The wireless positioning apparatus receives an estimated channel response from a mobile station and compares the estimated channel response with the plurality of channel response patterns to estimate a location of the mobile station. The wireless positioning apparatus provides the estimated location information to the mobile station.

Abstract: Location of a wireless communication device is determined by a combination of geolocation and a detection of augmenting data such as acceleration and/or speed over time measurements. A last known terrestrial navigation fix is established based on reliable terrestrial navigation or GPS data. A zone of valid location fixes based on the last known terrestrial navigation fix and an output of a rate detection circuit can be established. A weighted average is taken of using independent location measurement and detected location using last known reliable position plus change in position by integrating position changes over time.

Abstract: Methods and apparatus are provided for determining and representing a location or position of a node in a network. When the node receives position measurement information from a reference node, the node generates, based on the position measurement information, a position probability space (PPS) which defines a space that encompasses possible positions where the node is possibly positioned in the network. The PPS includes a centroid (i.e., a set of coordinates), and a set of vectors which originate from the centroid and define the space around the centroid. The magnitude of each vector reflects the accuracy of the position in the direction of the vector.

Abstract: Decision trees may be built and executed to estimate an indoor location of a mobile device. In particular, a first attribute (e.g., received signal strength indication (RSSI) of one or more access points) is selected, and variations of that attribute throughout an indoor area are identified. These identified variations are mapped to the locations to generate a model. One or more decision trees are built based on the model, and an output of the decision trees estimates a location of a mobile device within the building. According to one aspect, a plurality of such decision trees may be built, and the outputs provided by the plurality of trees may be averaged to provide a more reliable result. Each of the plurality of trees may vary the attribute being analyzed, data values, or an order in which data is analyzed.

Abstract: A system and method for activating a GPS receiver or a WiFi receiver on a mobile device may be provided, which comprises determining an approximate location of the mobile device. The approximate location of the mobile device may be determined using cell tower location information. If the approximate location of the mobile device is within a predetermined distance from a desired location, or is “close enough”, then the GPS receiver or the WiFi receiver is activated. The GPS receiver or the WiFi receiver is activated to determine a more accurate location of the mobile device. The approximate and the more accurate location information may be exchanged with another mobile device to allow the user to find one another.

Abstract: A method of and system for estimating at least one of a human development level and a human activity level. A method of estimating at least one of a human development level and a human activity level includes estimating positions of radio broadcast beacons. The positions of the radio broadcast beacons are stored in an electronically readable catalog. Each of the positions is grouped into sets of positions. Each set of positions includes positions of one or more geographically-related radio broadcast beacons. For each of the sets, at least one of a human development level and a human activity level is estimated for an area encompassing the positions of the set.

Abstract: Information from one or more transmitters installed in a detection object area is received. The reception feature value of when a detection object is present in a predetermined position of the detection object area is measured. A reception pattern of when the detection object is present in the predetermined position is formed. The reception pattern is compared with reference reception patterns, and the presence position corresponding to the reference reception pattern most approximate to the reception pattern is acquired from a reference reception pattern database where the presence positions of the detection object and the reference reception patterns of when the detection object is present in the presence positions are associated with one another. The presence position of the detection object is estimated according to the acquired presence position. The estimated presence position of the detection object is associated with received detection object identification information.

Abstract: An apparatus for location determination includes a location determination receiver configured to receive location determination signals, a location determination signal quality assessment component configured to assess a quality of received location determination signals, and a location determination processor responsive to an output of the location determination signal quality component. The apparatus determining a location of the location determination receiver based on the location determination signals that are received during time periods when the location determination signal meets or exceeds a location determination signal quality threshold. A method for location determination is also disclosed.

Abstract: An apparatus and method is provided for indoor/outdoor transition detection of devices to improve selection of the navigation algorithms. To determine whether an outdoor-to-indoor transition has occurred, a mobile device can determine whether a difference between an indoor position determined using indoor position information and outdoor position determined using outdoor position information is less than a threshold and can conclude that the mobile device transitioned from outdoor to indoor of the structure, if the difference is less than the threshold. Also, to determine whether an indoor-to-outdoor transition has occurred, the mobile device can determine whether an indoor position survey area exists, determine whether an outdoor position determined based on outdoor position information is outside of the survey area, and determine whether a signal strength associated with the outdoor position location information is greater than a threshold.

Abstract: Location inference using selected beacons. Data is received representing a set of beacons observed by a computing device. The beacons are located within a first geographic area. A subset (e.g., a clique) of the beacons is selected based on a coverage area of each of the beacons, where each of the beacons in the selected subset has a coverage area that overlaps with the coverage area of each of the other beacons in the selected subset. Using known or estimated positions of the beacons, a second geographic area is defined based on the selected subset of beacons and the beacon reference data and the coverage areas associated therewith. The second geographic area, smaller than the first geographic area, represents an approximate location of the computing device. In some embodiments, the computing device is calculated to be within the second geographic area with 95% probability.

Abstract: Embodiments adjust device error radiuses associated with inferred device positions produced by positioning systems. Inferred beacon positions and associated beacon radiuses are accessed for beacons in a beacon fingerprint from an observing computing device. The beacon radiuses are associated with a pre-defined confidence level (e.g., an in-circle percentage). A Kalman filter is applied to at least one of the beacons using the inferred beacon positions and the beacon radiuses associated therewith to infer a device position for the computing device and to compute a device error radius for the inferred device position. The computed device error radius is adjusted as a function of the quantity of beacons input to the Kalman filter to achieve the pre-defined confidence level.

Abstract: This document presents a method for processing radio measurement reports in a location tracking apparatus, the method comprising: acquiring a plurality of radio measurement reports related to transmission of reference signals between a mobile tag being location-tracked and at least one location tracking node having a fixed location within a location tracking area, wherein each radio measurement report comprises a cycle index indicating a transmission cycle index of a reference signal associated with the radio measurement report and a radio measurement metric computed from said reference signal associated with the radio measurement report; combining radio measurement reports having the same transmission cycle index; and using the combined radio measurement reports in tracking the location of the mobile tag.

Abstract: At a current position, a measurement packet is determined by a mobile terminal device at a measurement time. The measurement packet includes transmitter identifications of radio transmitters receivable at the current position of the mobile terminal device at the measurement time. By means of reference measurement packets provided to the mobile terminal device, the mobile terminal device itself can determine its current position. Additionally, a deviation of the determined transmitter identifications of the measurement packet from reference transmitter identifications of the reference measurement packets is determined.

Abstract: Apparatus comprises one or more processors in communication with one or more memories. The one or memories have stored therein one or more computer programs that include computer code configured such as when executed to cause the processor to: receive data derived from a multi-element antenna direction finding arrangement; process the received data to provide elevation and azimuth vector data; determining whether the elevation data meets a reliability criterion. On a positive determination the elevation and azimuth data is used to calculate a location. On a negative determination, the data is processed to provide one-dimensional azimuth vector data; and the one-dimensional azimuth vector data is used in conjunction with other vector data to calculate a location.

Abstract: Systems and methods are provided for locating threats to an aircraft that are located on the ground. Associated bearings from a sensor in an aircraft are determined for each of a plurality of detected shots from a threat at ground level. A sensor ground projection is plotted along each associated bearing. Each sensor ground projection is mapped to an elliptical uncertainty area reflecting the inherent error in bearing determining instrumentation. An estimation of the position for the threat based on the intersection points between mapped uncertainty areas of the sensor ground projections is calculated.

Abstract: An autonomous navigation system for a tracked or skid-steer vehicle is described. The system includes a path planner (54) that computes a series of waypoint locations specifying a path to follow and vehicle location sensors (82). A tramming controller (60) includes a waypoint controller (62) that computes vehicle speed and yaw rate setpoints based on vehicle location information from the vehicle location sensor and the locations of a plurality of neighboring waypoints, and a rate controller (64) that generates left and right track speed setpoints from the speed and yaw rate setpoints. A vehicle control interface actuates the vehicle controls in accordance with the left and right track speed setpoints.

Abstract: A method and a system for accurately positioning an electronic device located in an indoor area, generates a request signal for determining the indoor location of the device, and sends the signal to a server coupled to the device through a network. The request signal contains certain parameters pertaining thereto, including the signal strength, and the information of the cell towers through which the device sent the signal. The server uses the signal parameters to determine information pertaining to an approximate spatial position of the device, and sends and information to the device. Multiple positioning algorithms are embedded in the computing hardware of the device, and the device executes these algorithms to determine the exact indoor location thereof.

Abstract: A method in a mobile device includes: receiving location signals at the mobile device; measuring sensor data at the mobile device; determining an oscillation rate of the mobile device from the sensor data; in response to the oscillation rate of the mobile device being undesirable, at least one of: (1) determining a desired sampling rate based on the oscillation rate, the desired sampling rate being different from the oscillation rate; and sampling the location signals at the mobile device at the desired sampling rate; (2) sampling the location signals at the mobile device at a randomized sampling rate; (3) disabling a power improvement technique; (4) increasing filtering of determined course information; (5) reducing a nominal filter bandwidth; or (6) increasing a present sampling rate of the location signals to satisfy Nyquist criteria for the oscillation rate; and determining the position associated with the mobile device using the location signals.

Abstract: Asset tracking system that utilizes a time-based ping in which the ping rate and the ping period are based on a predetermined event. Over the period of use of the system and device, the ping rate and ping period are adjusted based on the expected occurrence of an event. The system has lower operational cost, particularly battery maintenance cost, than conventional active ping systems that have a set ping rate or a random ping rate.

Abstract: An apparatus and method for building a base station almanac at a non-carrier location server is shown. A mobile device cooperates by informing the non-carrier location server of observed time difference of arrival (OTDOA) assistance data it receives. The non-carrier location server collects enough OTDOA assistance data through crowd souring or spoofing to generate an OTDOA library. The non-carrier location server using the OTDOA library to generate a base station almanac. Once created, non-carrier location server uses the base station almanac to provide assistance data to mobile devices without assistance from the carrier. Also, a mobile device may use the base station almanac to determine transmission timing between itself and neighboring and distant base stations.

Abstract: Methods, systems, computer-readable media, and apparatuses for determining locations of access points (AP) are presented. Techniques are described for determining relative and absolute locations of APs. In one embodiment, a device may send and receive messages to one or more APs for from various locations for determining the distance between the device and the AP. The device may additionally keep track of its own displacement for the purposes of determining the location of the one or more APs. In one embodiment, the device also determines the turnaround calibration factor (TCF) for the AP that compensates for the processing time at the AP may also be used for increasing the accuracy of the determination of the location of the AP.

Abstract: A method of operation of a mobile communication system includes: receiving a base carrier frequency signal from a cell tower location; generating a power spectral density from the base carrier frequency signal; measuring a Rician K factor from the power spectral density; estimating a line-of-sight Doppler frequency based on the base carrier frequency signal; determining the cell tower location based on the Rician K factor; and activating a handover decision handler based on the cell tower location.

Abstract: An object of the present invention is to achieve a position information detection system with high precision when an obstruction and a reflective object exist. A position information detection system includes a reader/writer whose position is known, a first RF chip whose position is known, and a second RF chip attached to an object to be detected; and calculates a distance between the reader/writer and the second RF chip from a first calculated distance between the reader/writer and the first RF chip, which is calculated from a signal intensity of a communication signal transmitted from the reader/writer, detected by the first RF chip, a second calculated distance between the second RF chip and the reader/writer, which is calculated from a signal intensity of a communication signal transmitted from the reader/writer, detected by the second RF chip, and a distance between the reader/writer and the first RF chip.

Abstract: Apparatus and method for dynamically updating a channel model used for wireless local area network based positioning. In one embodiment, a wireless device includes a positioning system. The positioning system is configured to determine a position of the device based on signals received from wireless local area network access points. The positioning system is also configured to determine a likelihood that the wireless device is positioned at each of a plurality of points of a positioning grid based on a received signal strength value for each of a plurality of access points. The positioning system is further configured to update a reference power estimate for each access point based on the likelihoods. The positioning system is also configured to update the path loss exponent of the channel model.

Abstract: A system, method and product for determining a vehicle key fob location. The system may include a control unit for mounting in a vehicle and configured to receive multiple signals, each representing a strength of a wireless signal transmitted between the fob and one of multiple antennas located on a vehicle, and multiple neural networks having a cascade topology. The neural networks may include a first neural network for determining one of a vehicle internal position and a vehicle external position of the fob based on the wireless signal strengths, a second neural network in communication with the first neural network for determining one of multiple vehicle interior positions of the fob based on the wireless signal strengths, and a third neural network in communication with the first neural network for determining one of multiple vehicle exterior positions of the fob based on the wireless signal strengths.

Abstract: Communication between a remote locator and a transponder is used to determine the relative position of the transponder. The transponder and locator each include a transmitter and a receiver. The locator transmits an inquiry in the form of a relatively powerful cyclically encoded signal with repetitive elements, uniquely associated with a target transponder. Periodically, each transponder correlates its coded ID against a possible inquiry signal, determining frequency, phase and framing in the process. Upon a match, the transponder transmits a synthesized response coherent with the received signal. The locator integrates multiple cyclical response elements, allowing low-power transmissions from the transponder. The locator correlates the integrated response, determines round-trip Doppler shift, time-of-flight, and then computes the distance and angle to the transponder. The transponder can be wearable, bionically implanted, or attached to, or embedded in, some object.