Abstract: In a local positioning system, a receiver is adapted for receiving signals from a land-based transmitter. The receiver includes an analog decorrelator for decorrelating the transmitted spread spectrum signals. A down converter connected with an antenna may be spaced away from other portions of the receiver. The down converter down converts received ranging signals and provides them to the remotely spaced receiver portions. A signal line connecting the down converter to the receiver may be operable to transmit any two or more of a reference signal provided to the down converter, the down converted intermediate frequency signals provided to the receiver, and power provided to the down converter. The receiver may be positioned adjacent to or as part of a land-based transmitter. By determining positions of two or more antennas, the location of the associated transmitter is determined.

Abstract: A method estimates a distance between transceivers in a wireless communications network. A first time interval T is set in a transmitter and a receiver. A signal is transmitted from the transmitter to the receiver at a time t2 according to a first clock of the transmitter. The signal is received in the receiver at a time t3. Processing delays of the receivers are determined. A reply to the signal is sent from the receiver to the transmitter at a time t6 such that |t3?t6|=T. The reply is received in the transmitter at a time t7 of the first clock and a distance d between the transmitter and the receiver is determined according to d=c(|t2?t7|?T)/2, where c is the speed of light.

Abstract: There is provided a radio base station apparatus which is capable of increasing the probability of detection of a first path even if a radio transmission path fluctuates due to fading or the like, and of downsizing and reducing the cost of mobile radio terminal apparatus. SIR estimators 13-1 through 13-N calculate reception SIRs for respective subcarriers from output signals from pilot demodulators 12-1 through 12-N. SIR averager 14 averages the SIRs for the respective subcarriers to calculate an SIR for the overall signal. Based on the calculated SIR, threshold value setting unit 15 sets a threshold value for a path search. First path detector 19 conducts a path search based on the threshold set by threshold value setting unit 15. Arrival time calculator 21 calculates an arrival time based on a first path detected by first path detector 19.

Abstract: Location of mobile units in a wireless local area network is based on use of signal strength ratios and other criteria. In one embodiment absolute value of signal strength is used to derive a second value of location. The second value may be used as the location if the system is not calibrated and may also be used to calibrate the system. Alternatively time difference of arrival may be used in combination with signal strength ratio.

Abstract: An apparatus and method for locating a UE using a GPS and a dead-reckoning sensor are disclosed. At an initial time, the UE calculates its initial position and the initial position of a serving Node B using a received GPS satellite signal and calculates a first distance between the UE and the Node B based on a first RTT received from the Node B. A predetermined time later, the UE calculates a second distance between the UE and the Node B based on a second RTT received from the Node B, calculates the distance that it has moved using the first and second distances and its position angle measured the predetermined time later, and calculates a displacement in correspondence with the distance using the position angle. Then the position of the UE is obtained by adding the displacement to the initial position of the UE.

Abstract: A position for a beacon in a location system is determined based on distances measured from positions in a local coordinate system for the location system and from intersection points of circles. The circles each have a center point of one of the positions in the local coordinate system and a radius of one of the measured distances.

Abstract: A first transceiver (4, 30) can position itself by forming an ad hoc network (20) of transceivers which assist the first transceiver in acquiring its position. A dedicated infrastructure such as GPS satellites is not required. The first transceiver (4, 30), once it has acquired its position, can be involved in a network (20) by another transceiver (32, 34, 36, 38, 40) to assist in the positioning of that transceiver. The acquisition of the position may involve factors such as the trustworthiness of the transceivers in the network and/or the positions of transceivers with which the first transceiver cannot directly communicate.

Abstract: Mobile terminal implementing a ranging signal receiver and method. Means are provided to incorporate ranging signal reception capability into a mobile terminal (such as a UMTS terminal) notwithstanding the fact that the ranging signal has a bandwidth that is wider than the bandpass of filtering for native signals within the terminal. A ranging signal receiving subsystem receives broadband signals that comprise synchronization bursts, which are equally spaced in time, such as from digital television stations. A common filter will have a bandpass that it is smaller than the bandwidth of the ranging signals. However, the correlation subsystem of the mobile terminal enables recovery of synchronization bursts by correlating the ranging signal with a known sequence that has been predistorted to account for the bandpass of the common filter.

Abstract: The performance and ease of management of wireless communications environments is improved by a mechanism that enables access points (APs) to perform automatic channel selection. A wireless network can therefore include multiple APs, each of which will automatically choose a channel such that channel usage is optimized. Furthermore, APs can perform automatic power adjustment so that multiple APs can operate on the same channel while minimizing interference with each other. Wireless stations are load balanced across APs so that user bandwidth is optimized. A movement detection scheme provides seamless roaming of stations between APs.

Abstract: Methods of providing an estimate of the location of a first device are discloses comprising the steps of determining the location of a separately housed, second device located near to the first device; providing the location of the second device to the first device; and using the location of the second device as an estimate of the location of the first device. Either the second device is arranged to perform a function based on its location other than providing its location as an estimate of the location of the first device, or the location of the second device is provided to the first device using a wireless communications link.

Abstract: The performance and ease of management of wireless communications environments is improved by a mechanism that enables access points (APs) to perform automatic channel selection. A wireless network can therefore include multiple APs, each of which will automatically choose a channel such that channel usage is optimized. Furthermore, APs can perform automatic power adjustment so that multiple APs can operate on the same channel while minimizing interference with each other. Wireless stations are load balanced across APs so that user bandwidth is optimized. A movement detection scheme provides seamless roaming of stations between APs.

Abstract: A method and system for extensible positioning that uses a primary reference node at a known first position and a secondary reference node at a second position, where a range is measured between the secondary reference node and the primary reference node. The second position is determined based upon the first position and the measured range. A second range is measured between the secondary reference node and a non-fixed node. A third position corresponding to the non-fixed node is determined based upon the second position and the second range.

Abstract: Systems and Methods are described for determining proximity motion of a mobile wireless device around a fixed target node. The present invention provides a method of regressively analyzing the signal strength on a receiver node, which may be either the mobile wireless device or the fixed target node, as a function of time to determine the proximity of the sending node, which may be either the mobile wireless device or the fixed target node, to the receiving node. The method includes detecting motion of mobile wireless device with a fixed wireless device within a proximity range of less than about 15 cm, and more preferably within around 5 cm. The system provides accurate proximity motion sensing that is not susceptible to multipath effects, and which can be implemented in a wide variety of wireless applications.

Abstract: A wireless node location mechanism that dynamically adapts to changes to a surrounding physical environment that affect the propagation of radio signals. The wireless node location mechanism assesses radio signals from transmitters associated with a wireless node location infrastructure to adjust one or more parameters used to estimate location of a wireless node. In one implementation, path loss exponents are re-computed based on the signals transmitted between infrastructure radio transceivers. These path loss exponents are used, in one implementation, to compute the distance between a wireless node and a given infrastructure radio transceiver and, ultimately, to determine the location of the wireless node based on triangulation. In one implementation, path loss exponents are computed on demand based on the signals observed between infrastructure radios that detect the wireless node whose location is to be estimated.

Abstract: An apparatus and associated methods to provide precision ranging measurements in an ultrawideband (UWB) wireless communication system are generally described. In this regard, according to one example embodiment, an innovative ranging agent is introduced that effectively computes one or more of the time of signal propagation, the difference in local clocks and frequency offsets to calculate an increasingly accurate estimate of the proximal distance between two or more devices in UWB communication.x.

Abstract: A method and system for determining the location of an object. The system may implement a number of sensors at different locations that are positioned to receive a transmitted or reflected signal from the object. Also disclosed is a system and method of calculating object position based upon the time difference of arrival (TDOA) from each sensor, or the relative time difference of arrival (RTDOA). A known distribution of noise is added to the time of arrival (TOA) prior to calculating the object position.

Abstract: A method and network provide mobile information for emergency calls based on mobile position during a call in progress. As soon as an Emergency Services Call is invoked, the Mobile Station position information is gathered using a Serving Entity. The position is then sent to an Anchor Entity [typically an Anchor Mobile Switching Center (AMSC) and Anchor Mobile Position Center (AMPC)] in communication with the Emergency Services Network Entity (ESNE). After receiving the position information, the Anchor Entity makes the call setup to the ESNE, and the AMSC updates the AMPC. In one alternative embodiment, the Position Determining Entity determines the troubled and non-troubled locations and sends them to the ESNE. In a second alternative embodiment, only the troubled party location is sent to the ESNE as a result of the non-troubled party triggering a special key code during the request for the ESNE.

Abstract: A method and system are provided for locating an impulse radio. Impulse radio signals are communicated between a first impulse radio and a plurality of second impulse radios. A received signal strength measurement is determined for each of the impulse radio signals. One of a plurality of radio propagation path models is selected and used to estimate a plurality of separation distances between the first impulse radio and the plurality of second impulse radios. The plurality of separation distances is used to determine a location relating to the first impulse radio.

Abstract: The present invention relates to a system and method for locating the direction and distance to a RF signal source from an avalanche beacon to find an avalanche victim. The system and method includes a RF signal locator and a graphical display residing on the signal locator. The receiver graphical display provides the searcher with an initial way point reading that includes directional and distance data associated with the beacon RF signal source from the avalanche beacon. The directional and distance data is based upon the received RF signals. A processor within the locator receiver receives and measures RF signals emitted by the RF signal source. The locator advantageously provides continuous subsequent way point readings for the user, where the subsequent way point readings include directional and distance data associated with the RF signal source. The distance data provided by the subsequent way point readings is based upon a path loss slope of the received RF signals from the avalanche beacon.

Abstract: A system and method use a wireless tether comprising a transmitter and a receiver to alert a caregiver that an object has been left unattended. A detector senses the presence of the object, usually a child, located in a position such as a safety seat. The detector is operatively coupled to the transmitter, which is located near the object. The transmitter transmits at least one wireless signal when the object is in the position. The receiver, which is remotely located from the transmitter, senses the at least one signal as long as the receiver is within a prescribed range of transmission. By performing a timing function, the receiver monitors the proximity of the caregiver, who maintains possession of the receiver, to the transmitter. The system communicates an alarm to the caregiver when the caregiver ventures outside the range of transmission without having removed the object from the position.

Abstract: A method and system for determining location and/or motion for one or more wireless devices communicating at short range (i.e. less than about 30 feet) with other wireless devices on a wireless network. Signal strength measurements are passed within communication frames between wireless devices which can be used to represent an inverse of the distance, wherefrom a distance vector is determined between wireless devices. Using multiple distance vectors from multiple wireless network devices, a 2-D or 3-D coordinate representation for position of each wireless network in 2-D or 3-D space can be calculated. These coordinates can be utilized for determining the precise traveled position of a specific wireless network device in motion and for establishing a motion sensing system. The motion sensing system can be configured as input to a user interface to control devices and systems which integrated within or connected to devices communicating on the wireless network.

Abstract: A system for locating mobile units in a data communications system based on signal strength measurements of mobile unit transmissions is calibrated for variations in mobile unit transmitter power by determining range of a mobile unit from an access point using two way time ranging. The time ranging is compared to the value for range based on signal strength and a correction value for the mobile unit is updated based on the difference between range based on time ranging and the range based on signal strength.

Abstract: Information received by a calculating unit via a signal from a transmitting station to a receiving station is provided with a code, a number of integral multiples of the code coming into the receiving station during the signal transfer time that the signal requires to travel between the transmitting station and the receiving station. During a first iteration, the number of integral multiples of the code is calculated and the calculated number is used at least in a second iteration without a fresh calculation being carried out.

Abstract: An arrangement comprising a master unit and one or more slave units, where the master sends out bursts, at specified intervals, in a frequency hopping manner, with each burst being at a different frequency. The slave responds with acknowledgements, and the signal strengths of the acknowledgments are used to select one or more of the acknowledgments as the signals used for distance, or range, estimation. Advantageously, the durations of the intervals are fairly long during normal operation, and short at times when certain conditions occur, such as loss of communication or when accurate range estimation is required. Also, the slave is adapted to sleep while it is not expecting a burst transmission from the master, thereby saving power. The frequency hopping sequencing is preferably pseudo random, with a different sequencing of the same set of frequencies at different modes of operation.

Abstract: A method of providing an estimate of the location of first and second devices MS1, MS2 comprising the steps of obtaining at least one range measurement from the first device MS1 to a known reference point BS1, GPS SVs; obtaining at least one range measurement from the second device MS2 to a known reference point BS1, GPS SVs, the second device MS2 being located near to the first device MS1; and calculating an estimate of the location of the devices MS1, MS2 using range measurements obtained with respect to both the first and second devices MS1, MS2.

Abstract: A location discovery method using location data items that originate at known locations (X,Y) and are passed to, and diffused between, entities (A,B) by short-range communication. Each location data item received by an entity (A,B) indicates a maximum distance of the entity from one of the known locations (X,Y). Each entity (A,B) prior to using a location data item for location determination or transferring it to another entity, is operative to increase the maximum distance indicated by the location data item to take account of movement of the mobile entity since receiving that item. A mobile entity (A) effects location determination by finding locations (40) simultaneously consistent with the maximum distances (31,36) it knows of and any applicable route constraints for how the location data items passed to the mobile entity.

Abstract: A method, apparatus, and computer-readable media comprise receiving a broadcast digital television signal comprising data relevant to one or more particular locations; generating a pseudorange based on the broadcast digital television signal; and determining location of an apparatus based on the pseudorange and a location of a transmitter of the broadcast digital television signal, and selecting a portion of the data relevant to the one or more particular locations based on the determined location of the apparatus.

Abstract: A wireless network having wireless network access devices may determine the location of newly added wireless network access devices.

Abstract: The present invention relates to a system and method for locating the direction and distance to a RF signal source, primarily for search and rescue. The system and method includes a RF signal locator and a graphical display residing on the signal locator. The receiver graphical display provides the user with an initial way point reading that includes directional and distance data associated with the beacon RF signal source. The directional and distance data is based upon the received RF signals. A processor within the locator receiver receives and measures RF signals emitted by the RF signal source. The locator advantageously provides continuous subsequent way point readings for the user, where the subsequent way point readings include directional and distance data associated with the RF signal source. The distance data provided by the subsequent way point readings is based upon a path loss slope of the received RF signals.

Abstract: A passive object detection system (1) comprises first and second antennas (4, 6) and a processor (8). The first antenna (4) is adapted to receive a signal transmitted by a mobile telephone base station; the second antenna (6) is adapted to receive the signal transmitted by a mobile telephone base station (2) after it has been reflected off an object (3) and the processor compares the signal received from the mobile telephone base station with the signal reflected from the object to derive speed or position information relating to the object therefrom.

Abstract: Embodiments of the present invention are directed at gathering position information of mobile and stationary entities and using the position information in a wide variety of applications. Various embodiments use a plurality of signal transmitting devices and/or a plurality of signal gathering devices to gather position information. In one embodiment, the signal transmitting device is an existing mobile electronic device. In another embodiment, the signal transmitting device is a radio frequency identification (RFID) tag attached to an entity. In another embodiment, the signal gathering device is a collection of wall mounted antennas. The entity location is calculated by gathering the phase difference or other timing information of signal generated by the signal transmitting device on the entity. This location information is then given to end user applications. One embodiment is a network security application using gathered location information of wireless ethernet cards.

Abstract: A user terminal comprises a receiver adapted to receive, at the user terminal, a broadcast digital television signal transmitted by a television transmitter and comprising a pseudo-noise code; and a controller adapted to generate a pseudorange based on the pseudo-noise code; wherein the location of the user terminal is determined based on the pseudorange and a location of the television transmitter.

Abstract: An autonomous zone forming method of autonomously forming a zone which is a service area of a base station in a wireless communication system having the base station is provided. In the method, it is detected that a zone is newly formed around the base station, and a zone which is the service area of the base station is autonomously changed according to a newly formed zone. When determining the zone, receive quality of a signal received from a surrounding base station is used. In addition, a congestion state of a surrounding base station of the base station is detected, and a zone which is the service area of the base station is enlarged to the direction of the surrounding base station according to the congestion state.

Abstract: A method, apparatus, and computer-readable media for determining the position of a user terminal comprises receiving, at the user terminal, a broadcast analog television signal comprising a chirp-type signal; and generating a pseudorange based on the chirp-type signal; and wherein the location of the user terminal is determined based on the pseudorange and a location of a transmitter of the broadcast analog television signal.

Abstract: A high accuracy search and tracking system that uses a round-trip messaging scheme in which the time of arrive (TOA) of ranging signals is accurately determined to yield the range estimates between a target communications device and one or more search communications devices. Successive ranging estimates are used by a search device to home in upon the target device. The physical location pinpoint communications system can be used alone, or in combination with other location estimation systems that can be used initially, or throughout the search and tracking process to pinpoint the physical location of the target device. The search radio(s) transmits ranging signals to the target radio which responds by transmitting reply ranging signals. Upon reception of the reply ranging signal, the search radio determines the range to the reference radio from the signal propagation time. Errors in TOA estimates can be minimized using advanced processing techniques, if required.

Abstract: Described is a way for computing proximity (location-based proximity or preference-based proximity) between mobile wireless subscribers (who use different services) without either divulging their location/preference to the other (preservation of privacy). Privacy is kept by providing location/preference information in steps, along with an evaluation function. The services receive partial results and then locally compute the final result, or proximity. The term proximity includes not just physical proximity but also multi-dimensional data such as preference profiles and vectors (e.g., an affinity for baseball, apple pie, and ballroom dancing).

Abstract: Information received by a calculating unit via a signal from a transmitting station to a receiving station is provided with a code, a number of integral multiples of the code coming into the receiving station during the signal transfer time that the signal requires to travel between the transmitting station and the receiving station. During a first iteration, the number of integral multiples of the code is calculated and the calculated number is used at least in a second iteration without a fresh calculation being carried out.

Abstract: A hazardous area warning system with a non-directional magnetic field based proximity receiver for warning personnel of an attendant hazard. The receiver includes a x-axis receiver with an antenna directed in a x direction, a y-axis receiver with an antenna directed in a y direction and a z-axis receiver with an antenna directed in a z direction. The antennas may be a wire loop wrapped around a ferrite core. The output from each of the three receivers are combined in an adder. The combined result from the adder is representative of the distance between the receiver and a warning transmitter antenna. A comparator determines whether the received signal indicates an attendant hazard, i.e., the receiver is too close to the warning transmitter. The receiver wearer is warned of the attendant hazard, visually and/or tactilly, e.g., with warning lights and/or vibrations. An encoder encodes the signal indication and a transmitter transmits the encoded signal.

Abstract: A method determines range from a moving platform to an emitter. The method receives a RF signal from the emitter; counts a number of phase reversals of the received RF signal during a period of time; measures a Doppler frequency during the period of time; and determines the range to the emitter based on both the number of counted phase reversals and the measured Doppler frequency.

Abstract: An electromagnetic signal emitted from a first known point is received at a second known point and is retransmitted to a third unknown point. The same signal from the first known point is also received at the third unknown point. Comparison of the two signals received at the third unknown point yields the distance between the second known point and the third unknown point.

Abstract: A system and a method for position determination by impulse radio using a first transceiver having a first clock providing a first reference signal and a second transceiver placed spaced from the first transceiver. The system determines the position of the second transceiver. The second transceiver has a second clock that provides a second reference signal. A first sequence of pulses are transmitted from the first transceiver. The first sequence of pulses are then received at the second transceiver and the second transceiver is then synchronized with the first sequence of pulses. A second sequence of pulses are transmitted from the second transceiver. The first transceiver receives the second sequence of pulses and the first transceiver is synchronized with the second sequence of pulses. A delayed first reference signal is generated in response to the synchronization with the second sequence of pulses.

Abstract: A user terminal comprises a receiver adapted to receive, at the user terminal, a broadcast digital television signal transmitted by a television transmitter and comprising a pseudo-noise code; and a controller adapted to generate a pseudorange based on the pseudo-noise code; wherein the location of the user terminal is determined based on the pseudorange and a location of the television transmitter.

Abstract: A system and a method for distance measurement utilizes a radio system. The distance is measured by determining the time it takes a pulse train to travel from a first radio transceiver to a second radio transceiver and then from the second radio transceiver back to the first radio transceiver. The actual measurement is a two step process. In the first step, the distance is measured in coarse resolution, and in the second step, the distance is measured in fine resolution. A first pulse train is transmitted using a transmit time base from the first radio transceiver. The first pulse train is received at a second radio transceiver. The second radio transceiver synchronizes its time base with the first pulse train before transmitting a second pulse train back to the first radio transceiver, which then synchronizes a receive time base with the second pulse train. The time delay between the transmit time base and the receive time base can then be determined.

Abstract: A multi function personal alert safety cell system having condition responsive sensors and an alarm for emergency type personal. The personal alert safety cell system having a transceiver. The transceiver for transmitting and receiving at several different radiated power levels, defined as P1, P2, P3, P4, P5, through Pn that vary in signal strength from 1 microwatt through 1 watt. Each power level P1, P2, P3, P4, P5, through Pn being transmitted and received with encoded data and a personal ID uniquely assigned to the transceiver of the cell system. Also, the transceivers transmitting and receiving data being contained within a time frame and having digital instructions and coded format sectors. The power level ID varying in field strength for defining a distance at which the transceiver detects the transmitted and received signal from another of PASS transceiver and the signal being indicative of the distance the transceiver is from the other PASS transceivers.

Abstract: A local positioning system (LPS) uses the radio propagation parameters in a CDMA forward link or TDMA reverse link to establish a mobile station's position. The mobile station receives pilot channel signals from at least three distinct base stations and records the PN chip offset of the pilot channel signals. The LPS time difference of arrival triangulation approach requires no additional signal detection capabilities. Base stations send out pilot channel signals that arrive at a mobile station with a particular phase and at least a predetermined minimum strength. The mobile station reports back the “visible” pilot channel signals, their phases and signal strength to the LPS which uses a location non-linear system, expressed as a set of cost functions, to estimate the mobile location. The LPS can also solve the 9-1-1 mobile location problem for wireless CDMA systems by determining the position of a person in distress that has a digital cellular phone.

Abstract: The invention provides a positional system intended to supplement positional information derived by means of a Global Positioning System (GPS), so as to provide positional data coverage in situations where the GPS data may be unreliable, for example due to local attenuation of satellite signals, in order to permit members of a group traversing difficult terrain to retain reasonably accurate information as to the whereabouts of the other group members should the GPS system fail. The positional system of the invention provides each group member with a readily transportable and relatively inexpensive inertial navigation system to generate approximate positional data and utilises radio location techniques to improve the accuracy of the approximate positional data.

Abstract: A method of tracking changes in position of a plurality of remote stations, each having, the method comprising: (a) assigning a plurality of transmission slots to each of the remote stations; (b) determining, by the respective stations, of their positions; (c) initially transmitting, by the respective stations of their positions; (d) determining, by the respective stations, of their positions, relative to the previously determined and transmitted positions; and (e) subsequently transmitting, by the respective stations, of the determined relative positions, wherein the slots themselves indicate the relative determined position and wherein the determined relative position is indicated by the presence or absence of a signal in one or more of said plurality of slots.

Abstract: Under a multi-path environment, receive timing for the incoming wave of the minimum propagation delay time cannot be accurately measured using the prior art.

Abstract: An impulse radio system estimates a separation distance between an impulse radio transmitter and an impulse radio receiver. The system includes an impulse transmitter that transmits an impulse signal having an ultra-wideband frequency characteristic. An impulse receiver spaced from the transmitter receives the transmitted impulse signal and measures a signal strength of the received impulse signal. The receiver estimates the separation distance based on the measured signal strength. The receiver classifies a signal propagational/multipath environment using the received impulse signal, and then selects a radio propagation path loss model corresponding to a classified multipath environment. The receiver translates the measured signal strength to a separation distance based on the selected radio propagation path loss model.

Abstract: A method of providing an estimate of the location of first and second devices MS1, MS2 comprising the steps of obtaining at least one range measurement from the first device MS1 to a known reference point BS1, GPS SVs; obtaining at least one range measurement from the second device MS2 to a known reference point BS1, GPS SVs, the second device MS2 being located near to the first device MS1; and calculating an estimate of the location of the devices MS1, MS2 using range measurements obtained with respect to both the first and second devices MS1, MS2.