Abstract: The invention relates to methods and systems for accurate ranging and geo-locationing using coherent multicarrier (CM) signals and based on a high-resolution estimation of a receiver timing offset in a signal receiver that receives ranging CM signals. A transmitter transmits a ranging CM signal having a known subcarrier modulation pattern. The receiver samples the ranging CM signal it receives reflected back from an object or from the remote transmitter, and processes the sampled signal that preserves relative subcarrier phases using a high-resolution model channel response function to determine the receiver timing offset with resolution much better than the receiver sampling period. The receiver timing offset is used to determine a flight time for the ranging CM signal with high accuracy.

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 for assisting in the use by an operator of the operating element of a tool at desired locations at a worksite, includes a stationary control and a position sensor secured to the tool. The stationary control is located at the worksite, and has data stored therein specifying one or more desired locations for operation of the operating element of the tool at the worksite. A position sensor is mounted on the tool. The position sensor determines the position of the operating element of the tool. The position sensor includes a communication device for communicating with said stationary control, a sensor for determining its relative position with respect to said stationary control, and a display for providing indications to the user of the tool of the desired location for the operating element of the tool and of the actual location of the operating element of the tool.

Abstract: Methods and apparatuses for location determination in wireless assisted positioning systems. In one aspect of the disclosed method and apparatus, a method to determine a position of a mobile device in a positioning system includes: computing a second estimated position of a mobile device using a first assumed geometric relationship for a location of the mobile device in relation to a navigational transmitter (e.g., a basestation, a pseudolite, or a Satellite Positioning System (SPS) satellite). The first geometric relationship is linearly independent from the altitude of the mobile device (e.g., obtained from an altitude aiding) and a second geometric relationship based on range information (e.g., a range from the mobile device to the navigational transmitter, a pseudorange, an arrival time, or a round trip time) measured with respect to the navigational transmitter.

Abstract: There are provided a method and apparatus for detecting the transmission locations of radio waves transmitted from multiple radio resources.

Abstract: An emergency rescue system and a rescue-information judgment method are disclosed. The emergency rescue system includes a plurality of fixed nodes, a dynamic node and a back-end processing platform. Each fixed node has its own fixed node identification. The dynamic node can be a portable device with an emergency illumination module. If the dynamic node is manipulated to broadcast a mayday signal, at least one of the fixed nodes senses the mayday signal. Each fixed node which senses the mayday signal sends the fixed node identification thereof and signal strength of the sensed mayday signal to the back-end processing platform. Thereby, the back-end processing platform calculates and determines a rescue location relative to the dynamic node.

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: A device and method for determining a distance and/or orientation of a movable object includes a transmitter that is located on the object and a receiver. One of the transmitter and the receiver has an antenna having a known polarization plane. The other of the transmitter and the receiver has a counterclockwise circular polarized antenna and a clockwise circular polarized antenna.

Abstract: Disparate positional data derived from one or more positional determinative resources are fused with peer-to-peer relational data to provide an object with a collaborative positional awareness. An object collects positional determinative information from one or more positional resources so to independently determine its spatial location. That determination is thereafter augmented by peer-to-peer relational information that can be used to enhance positional determination and modify behavioral outcomes.

Abstract: A positioning system includes a signal transmitter and a signal receiver. The signal transmitter is to be attached to a movable object and includes a transmitting module configured to transmit an electromagnetic wave. The signal receiver includes at least three receiving ports arranged on an imaginary plane defined by a first axis and a second axis perpendicular to the first axis, spaced apart from one another in a direction along each of the first and second axes, and configured to receive the electromagnetic wave respectively as received signals. The signal receiver further includes a calculating module for calculating a position of the signal transmitter relative to the signal receiver on the imaginary plane based on the received signals.

Abstract: Systems and methods for locating one or more radio frequency identification (RFID) tags are provided. A phase difference of received information signals of illuminated RFID tags is utilized to locate the RFID tags. One or more exciters transmit interrogation signals to illuminate the RFID tags in which the exciters may have a plurality of antenna selectively configured to transmit through two or more antennas and to receive on one antenna. Multiple reads of the same RFID tag can also be performed to generate a probability model of the location of the RFID tag. An enhanced particle filter is applied to probability model to determine the exact location of the RFID.

Abstract: Computerized systems and methods are provided for locating at least one object within a predefined cell or location. In accordance with one implementation, a location system is provided which comprises at least first and second receivers and first and second transmitters, respectively, including first and second internal clocks, the receivers and the transmitters, respectively, having known locations. The location system further includes a transmitter and a receiver, respectively, worn or carried by the object and designed to communicate by signal exchanges with the receivers and the transmitters, respectively. The location system further includes electronic circuits designed to compute position related information of the object based on the signal exchanges.

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: Systems, methods, and machine-readable media are disclosed to assign one or more tasks to a plurality of warehouse employees. In one embodiment, a method is provided which comprises receiving an order for an item stored in a warehouse. A location of the item in the warehouse can be determined. A current location of each of the warehouse employees can be determined based on a strength of a signal from a wireless device assigned to each of the warehouse employees. The signal can be detected by at least two wireless access points at different location in the warehouse. At least one of the warehouse employees can be selected to fill the order based on the current location of each of the warehouse employees and the locations of the item.

Abstract: A method and system for positioning mobile units using angle measurements taken by neighboring mobile units is disclosed. A selected mobile unit and mobile units in the vicinity of the selected mobile unit are selectively instructed to measure and report information related to the position of the selected mobile unit. The reported information is used to compute a position of the selected mobile unit.

Abstract: A system for determining the movement of a swaying structure, on which a receiver is fixedly mounted, is proposed, wherein at least three reference transmitters having known and fixed positions are provided and transmit the transmission signals received by the receiver at defined carrier frequencies. In addition, an evaluation unit is provided, which determines measured phase values from the received signals, taking into account the defined carrier frequency, wherein the distance from the reference transmitters and the changes in position of the receiver and therefore of the swaying structure can be calculated from said phase values.

Abstract: Systems and methods for the selection of antennas in aircraft navigation systems are provided. In one embodiment, a navigation receiver system for an aircraft comprises: a first aircraft antenna that receives transmitter signals from fixed-location ground transmitters and a second aircraft antenna that receives transmitter signals from the fixed-location ground transmitters, wherein the first aircraft antenna has a first gain pattern that is different from a second gain pattern of the second aircraft antenna; a switch coupled to a first receiver and the first and second aircraft antenna; and a switch controller coupled to the switch. The switch controller operates the switch to electrically couple the first receiver to either the first or second aircraft antenna based on a determination of whether the first gain pattern or the second gain pattern provides higher gain in a direction of a first fixed-location ground transmitter of the fixed-location ground transmitters.

Abstract: Aspects of the present disclosure provide systems and methods for generating models of a wireless network environment in an indoor space which may be used to predict an indoor location. The disclosure relates to collecting wireless network access point identifier information and power level observed at various locations are collected to generate various signal maps. The signal maps may be used to generate models of the indoor space. In one example, a voting model may use a probability distribution of a plurality of signal maps in order to identify a location with a highest probability of overlap with current signals received at a client device. Once a location has been identified, it may be used to assist with any number of navigational functions, such as providing turn by turn directions to another indoor location, for example, a conference room or exit, or simply providing information about the current location.

Abstract: A sensing system includes integrated sensor locating capability. Sensors can transmit spread spectrum encoded data pulses which are received at mobile nodes. Based on time of arrival information and known locations of the mobile nodes, locations of the sensors can be determined.

Abstract: The disclosed subject matter generally relates to hybrid positioning systems and methods and, more specifically, systems and methods of detecting moved WLAN assess points using a wireless local area network based positioning system (WLAN-PS) and a satellite-based positioning system (SPS) with at least two satellites measurement.

Abstract: Plurality of broadcasting transmitters each receives distribution of digital broadcast signals via a network (NET) to transmit them toward an area under control by using wireless waves of which the frequencies are the same. Here, when signals transmitted from the plurality of broadcasting transmitters into the area, an occurrence of a deviation of a fixed value or more poses an interference fault and results in a reception disabled state. Therefore, monitors are provided in the area to receive wireless waves from the plurality of broadcasting transmitters, monitors reception states, and controls output power, output timing, etc., of broadcasting transmitters that are transmission origins of the received wireless waves to make the reception states appropriate.

Abstract: A method for measuring certain parameters of the impulse response of a propagation channel involving emitters and reflectors that are fixed or mobile, and for detecting and determining the parameters regarding the position and kinematics of the emitters and reflectors, or for auto-locating the reception system implementing the invention, in a system comprising N sensors receiving signals from the emitters or from the reflection on the reflectors. The method determines an ambiguity function which couples the spatial analysis and the delay-distance/Doppler-kinematic analysis, and determines at least one sufficient statistic ?(l,m,K) corresponding to the correlation between the known signal s(kTe) corresponding to the complex envelope of the signal emitted and the output of a filter w(l,m) where l corresponds to a temporal assumption and m corresponds to a frequency assumption.

Abstract: A location service for wireless devices is described. In embodiments, a connection identifier is received that indicates a wireless device is linked to a communication node for wireless communication. Additional wireless devices are also linked to the communication node for wireless communication, and the additional wireless devices can each identify its geographic location. Location data is received from the additional wireless devices, where the location data indicates the respective geographic locations of the additional wireless devices. A location of the communication node can be determined from the location data that is received from the additional wireless devices, and a current location can then be assigned to the wireless device based on the determined location of the communication node.

Abstract: A system for indoor commercial facilities includes a multiplicity of access points to provide connectivity to mobile communications devices in the facility, a tracking module to determine locations for the devices based on connection data provided by the access points as the devices move through the facility, and an I/O module to receive the connectivity data and to transmit a map of a current location to the devices, where the map is relative to a location as determined by the tracking module. A mobile communications device includes a Wi-Fi transceiver to communicate with a multiplicity of Wi-Fi access points arrayed in a facility, where connection data between the transceiver and the access points is suitable for determining a current location of the device in the facility, and a map display to display a map of at least a part of the facility relative to the current location.

Abstract: A system and method for estimating a location of a subscriber station receiving a first signal from a first base station and receiving a second signal from a second base station where the first and second base stations are nodes in a WiMAX or LTE network. A message may be received from the subscriber station containing first and second information, and a range ring determined from the first base station using the first information. A location hyperbola may be determined using the second information wherein the location hyperbola has the first and second base stations as foci. A location of the subscriber station may be estimated using the range ring and the location hyperbola.

Abstract: A destination analysis module is described which estimates at least one destination of a user given a partial path taken by the user within a geographic area. The destination analysis module operates by detecting a mode of transportation that a user uses to traverse the path (e.g., automobile, public transportation, walking, etc.). The destination analysis module then loads a model associated with the mode of transportation into a destination prediction module and estimates at least one destination based on the path and the model. The model has various components that depend on the mode of transportation, such as routing network information and prior probability information.

Abstract: A wireless communication method and apparatus are provided for selecting quality-reporting sub-carrier bands based on sub-carrier band quantity information received from a base station. The method includes generally four steps. First, from a base station, information indicating quantity of sub-carrier bands is acquired. Second, channel quality of each of a plurality of sub-carrier bands within a communication band is measured from a received signal. Third, sub-carrier bands are selected from the plurality of sub-carrier bands, wherein quantity of the selected sub-carrier bands corresponds to the quantity of sub-carrier bands indicated by the acquired information. Fourth, information indicating channel quality of the selected sub-carrier bands is reported to the base station.

Abstract: The present disclosure describes a method and system for detecting and determining the position of a target or intruder using a plurality of sensors positioned throughout a secured perimeter and a single antenna. The system of the present disclosure detects and determines the position of a target by first analyzing the return signal strength values of each of the sensors. Next, Zvalues for each of the sensors are calculated. Based on the Zvalues, certain sensors are selected to compute a signal strength center-of-mass location, which is then used to determine the position of the target.

Abstract: The present invention is to enable reduction of constraint brought by generation of ID codes of reference signals to be used for cooperative reception and the allocation of the reference signals when radio communication is carried out between a plurality of base station apparatuses and a terminal unit. Terminal units UE201 to UE205 are terminal units existing in the cellular zone of a base station apparatus BS200 and are performing communication with base station apparatus UE200. When terminal unit UE201 is located at the edge of cell and its reception characteristic degrades, another base station apparatus, specifically, base station apparatus BS100 also performs cooperative transmission while terminal unit UE201 performs cooperative reception.

Abstract: An inventive precision pinpoint tracking method and system is provided for devices that provide spot location measurements of objects. Embodiments of the location measuring device have a RF antenna, a tracking module in electrical communication with the RF antenna, and a tilt-compensated (TC) compass. In embodiments of the location measuring device, a measuring tip is offset at a distal end from the tracking module and the RF antenna is located at the proximal end of the tracking module. In embodiments, the TC compass provides data to calculate a translation of the position of the measuring tip with respect to the RF antenna to enable spot measurements of locations of a target object.

Abstract: A method for localizing an object, including the acts of: transmission of a first signal by a first transmitter assigned to the object and of a second signal by at least one second transmitter; reception of the first and of the second signal by at least three receivers; in each receiver and for the first and the second signal: a) generation of a first and of a second reference signal; b) correlation between the first signal and the first reference signal and between the second signal and the second reference signal; c) interpolation of samples resulting from the correlation; d) deduction of the propagation time of the first and of the second signal; e) calculation of the difference between the propagation times of the first and of the second signal; and, by triangulation, deduction of the position of the object.

Abstract: A method and system for positioning mobile units using angle measurements taken by neighboring mobile units is disclosed. A selected mobile unit and mobile units in the vicinity of the selected mobile unit are selectively instructed to measure and report information related to the position of the selected mobile unit. The reported information is used to compute a position of the selected mobile unit.

Abstract: An indoor location system uses an electrical power line, power line signal injection devices, and portable position receivers (tags) to generate location data relating to positions of the tags in a structure such as a residence or business. The indoor location system fingerprinting of multiple signals transmitted along the power line to achieve sub-room-level localization of the positioning receivers. In one embodiment, the fingerprinting techniques utilizes wideband power line positioning (WPLP) that injects up to 44 different frequencies into the power line infrastructure of a structure. The WPLP technique improves upon overall positioning accuracy, improved temporal stability and may be implemented in commercial indoor spaces.

Abstract: A system and method is provided for processing communication signals in a wireless personal area network (WPAN) using a transceiver comprising a first transmitter and a first receiver operable to transmit and receive signals using a first transmission protocol and a second transmitter operable to transmit signals using a second transmission protocol. In various embodiments, the first receiver is used to receive a first signal that was transmitted using the first communication protocol and the second transmitter is used to transmit a second signal using the second transmission protocol in response to receipt of the first signal. The second signal is then processed to determine the location of the object. In some embodiments, the first transmission protocol is compliant with an Institute of Electrical and Electronics Engineers 802.15.4 transmission protocol and the second transmission protocol is compliant with an Ultra-Wide Band (UWB) protocol.

Abstract: A system for tracking entities at a site comprises a mesh of radio frequency identification (RFID) tags. Each of the tracked entities, which may move about the site, is associated with and attached to a portable RFID tag. Each RFID tag is at least periodically caused to transmit a signal that includes an identification of the RFID tag. The signal is received by other RFID tags that are within range, which determine a location indicative parameter. Some of the RFID tags receiving the signal are fixed at predefined locations. Specific fixed RFID tags are designated as controller nodes. Data comprising an identification of the RFID tag receiving a signal, the location indicative parameter, and the identification of the portable RFID tag transmitting the signal are communicated to a location engine server, which processes the data to determine at least a relative position of the portable RFID tags on the site.

Abstract: Methods of communicating the location of an unmanned aerial system (UAS). Implementations of the method may include receiving position data for a UAS with an air traffic control reporting system (ATC-RS) from a ground control station (GCS) in communication with the UAS, where the ATC-RS and the GCS are coupled together and located on the ground. The method may include transmitting the position data using one or more telecommunication modems included in the ATC-RS to an air traffic control center (ATC) and transmitting the position data using an automatic dependent surveillance broadcast (ADS-B) and traffic information services broadcast (TIS-B) receiver to one or more aircraft.

Abstract: Active RFID technologies are used to tag assets and people within buildings or open areas, such as parking lots or military bases; and to identify, preferably within a few meters, the real-time location (RTL) of the tag, i.e. to create a real-time location system, known as an RTLS. A novel and complex algorithm is provided that combines signal strength computations with factors that incorporate physical realities, such as walls and floors, to determine a tag's real-time location more accurately.

Abstract: Embodiments of the present invention include a method of determining a location of a mobile device. The method comprises transmitting a signal between a plurality of known locations and receiving signal at device of unknown location such as a mobile device. The signal may include multiple tones having different frequencies and resulting in sets of residual phase differences. The location of the mobile device may be determined using the known locations and the frequency and phase differences between the transmitted tones. In one embodiment, OFDM signals may be used between an access point and mobile device, for example, to determine the location of the mobile device.

Abstract: A system for determining location and timing information in a cellular network includes a space-time calibration unit (SCU) and a plurality of nodes in communication with the SCU. Each node includes a node ping driver that receives frame synchronization information from a respective subset of cell sites, and associates the frame synchronization information with respective receive count stamps generated using a local node clock. The system also includes a user handset that includes a handset ping driver that receives the frame synchronization information from a serving cell site and one or more neighbor cell sites, and associates the frame synchronization information with respective receive count stamps generated using a local handset clock. The SCU uses the information from the node and handset ping drivers to determine a handset location.

Abstract: The invention relates to a localization system for determining a state of a device that can move on a floor, comprising a floor transceiver system having a plurality of floor transceivers which each have floor antennas for marking position points within the plane of the floor, and a transceiver tablet which is connected to the movable device and has a transmitting/receiving surface which is located opposite the floor and is suitable for continuously determining the position of at least two floor antennas within the transmitting/receiving surface simultaneously.

Abstract: A receiver receives information from a physical broadcast channel signal, wherein the receiver includes a blind processing and decoding unit that utilizes a hypothesis about how many transmit antennas were used to transmit the signal. Received signal characteristics are detected that indicate how many transmit antennas were used. Each transmit antenna hypothesis in a stored list represents how many transmit antennas were used. For each of the stored hypotheses, a probability value is determined based, at least in part, on the detected signal characteristics. The list of hypotheses is modified to associate the probability values with respective ones of the transmit antenna hypotheses. The modified list is used to provide antenna hypothesis probabilities, and the blind processing and decoding unit is operated such it begins with a most probable antenna hypothesis and continues with increasingly less probable antenna hypotheses until successful decoding occurs or all antenna hypotheses have been made.

Abstract: Disclosed herein is a method of sensor network localization through reconstruction of a radiation pattern with a characteristic value of an antenna depending on orientation thereof. The method can minimize errors using an antenna characteristic value and a signal strength depending on the orientation. In addition, the method can minimize errors using an artificial neural network to characterize a distorted radiation pattern of an antenna and using it for the localization of a triangulation method. Furthermore, the method can increases the localization rate even in a passive localization method by characterizing an asymmetric antenna radiation pattern and constructing the antenna characteristic through an artificial neural network.

Abstract: Methods of forming a downlink beam in an adaptive antenna system of a communications system that may reduce inter-system and/or intra-system interference include receiving vectors of signals including signals transmitted by user terminals of the communications system and signals transmitted by transceivers of an independent communications system, obtaining spatial information for the user terminals of the communications system and the transceivers of the independent communications system, generating complex transmitting weights that form spatial nulls directed at the transceivers of the independent communications system, and transmitting a downlink communications signal using the complex transmitting weights. Related systems are also disclosed.

Abstract: A base station (e.g., a central device including a transducer assembly of one or more orthogonal transducers) transmits a magnetic field at a known power level and direction. The magnetic field signal includes data information transmitted from the base station to a movable remote station. The remote station includes a transducer assembly of one or multiple transducer coils to receive the magnetic field generated by the base station. Location and orientation of the remote station (with respect to the base station) are determined based on the magnitude, amplitude, and/or phase of magnetic field signals received on each of the remote station's transducers. The remote station may transmit the location and orientation information (e.g., raw measured data or converted data) to the base station using the same coils as used by the remote station to receive the magnetic field generated by the base station.

Abstract: In one embodiment, techniques are employed to estimate a position of a wireless local area network (WLAN) enabled mobile device. The mobile device sniffs one or more WLAN packets destined for one or more WLAN devices other than the mobile device. Information identifying one or more WLAN APs is extracted from the one or more WLAN packets destined for the one or more WLAN devices other than the mobile device. A record of the one or more WLAN APs is generated that includes at least some of the extracted information. A WLAN positioning system (WPS) is cooperated with, to use the generated record of the one or more WLAN APs to obtain an estimate of a position of the mobile device.

Abstract: Embodiments of the present invention include radio frequency identification location systems and methods. In one embodiment, RF signals are transmitted from one or more RFID readers, and in accordance therewith, backscattered signals are received from a tag to be located. A plurality of measured position parameters are used to determine a location of the tag. In one embodiment, one reader may transmit and three readers may receive signals to determine the position of a tag. In other embodiments, multiple readers may transmit and receive. In another embodiment, one reader may transmit from different positions to locate a tag. Embodiments of the invention may be used to track a moving tag. A reader's position may be determined using GPS, reference tags, or the reader may be positioned in a known location. A map may be provided to a user to display the location or movement of a tag or a corresponding item.

Abstract: Present novel and non-trivial apparatus and method for generating low latency position information from position signals transmitted in a narrow bandwidth channel of a radio frequency are disclosed. An aircraft (i.e., ownship) and each target (e.g., aircraft) of a time-division multiple access (“TDMA”) network receives its respective position derived from its individual source such as a satellite navigation system. A processing module of a communication device installed in ownship and each target generate position signals, and during the allocated time slots of an interface protocol, exchange position information with the others in the network over a narrow bandwidth channel (e.g., bandwidths of 25 KHz or less) of a radio frequency in the VHF range or lower UHF range. The interface protocol may also be comprised of a voice contention time slot for the transmission of messages and an order wire for the administration of the network.

Abstract: A system for use with an excavator of the type having a chassis, bucket support elements including a boom extending from the chassis and a dipper stick pivotally mounted on the end of the boom, and an excavator bucket pivotally mounted on the end of the dipper stick, determines the position of the excavator bucket during operation of the excavator at a worksite. The system includes a plurality of fixed ranging radios that are positioned at known locations at the worksite. A pair of ranging radios is mounted on the chassis of the excavator. A third ranging radio is mounted on one of the bucket support elements. A measurement circuit is responsive to the pair of ranging radios and to the third ranging radio, and determines the position and orientation of the excavator chassis, the bucket support elements, and the bucket with respect to the plurality of fixed ranging radios.

Abstract: Techniques are generally described for determining locations of a plurality of communication devices in a network. In some examples, methods for creating a location discovery infrastructure (LDI) for estimating locations of one or more of a plurality of communication nodes may comprise one or more of determining a plurality of locations in the terrain to place a corresponding plurality of beacon nodes, determining a plurality of beacon node groups for the placed beacon nodes, and determining a schedule for the placed beacon nodes to be active. Additional variants and embodiments are also disclosed.

Abstract: A method and a system for indoor positioning are provided. In the present method, a default positioning weight is defined at first. Then, a plurality of neighboring ranging devices near a target device is obtained from all wireless ranging devices deployed in an indoor space, and a current positioning weight of each of the neighboring ranging devices is calculated. Next, the current positioning weight of each of the neighboring ranging devices is respectively compared with the default positioning weight, so as to obtain a plurality of reference ranging devices from the neighboring ranging devices. After calculating at least one candidate coordinate according to a deploy coordinate of each of the reference ranging devices, a positioned coordinate represents the current location of the target device is estimated according to the at least one candidate coordinate.