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: A telecommunications system includes a plurality of network clients (150) including a positioning controller (504) and a communications controller (502); and a positioning server (152) including a coordinating controller (161) for maintaining a database of network clients to be tracked and provide updates of position-related information to a presence server; wherein said plurality of network clients are configured to transmit position information received via said positioning controller (504) to said positioning server via said communications controller (502), said positioning information including information related to a speed of movement.

Abstract: An apparatus having corresponding methods comprises a signal generator to generate an radio-frequency (RF) signal comprising a ranging signal comprising a component of a television signal; a wireless transmitter to wirelessly transmit the RF signal; and a self-check unit comprising a receiver to receive the RF signal, and to recover the ranging signal from the RF signal, a pseudorange circuit to determine a pseudorange based on the ranging signal, and a self-test circuit to generate a self-test output based on the pseudorange.

Abstract: A process for determining the location of entities carrying transmitters (TXs) that transmit TX ID messages to at least one receiver (RX) connected to a computer, in a network of computers. Each RX sends data messages to its associated computer which includes an identifier identifying the TX transmitting the TX ID message, the signal strength of the received TX ID message, and a RX identifier. Each RX computer generates badge hit messages from each data message, and provides them to a centralized computer of the network. The centralized computer generates a badge hit table having a separate entry for each badge hit message, which has fields including the information received in the badge hit message and a hit time indicating the time the entry was added to the table. The badge hit table data is used to determining the location of the TXs, and so the entities.

Abstract: The invention provides a system and method for activating an in-vehicle wireless communication device. A mobile identification number associated with the wireless communication device is provided. A broadcast signal containing the mobile identification number and a satellite radio subscriber identifier is received at an in-vehicle satellite radio receiver. The mobile identification number is stored in the wireless communication device based on the satellite radio subscriber identifier.

Abstract: Methods and apparatus, including computer program products, implementing and using techniques for using a location aware device to determine a current location, recording a location bookmark for the current location using the location aware device, storing the location bookmark, detecting at some later time that a location of the location aware device is within a specified proximity to the bookmark location and that a user-defined condition is satisfied by the bookmark content, and automatically notifying a user of the location aware device of the location bookmark. A location bookmark includes a bookmark location and bookmark content, the bookmark location being the current location and the bookmark content including data associated with the current location.

Abstract: A method and device for magnetic measurement of the position and orientation of a mobile object relative to a fixed structure. The device comprises, Integral with the structure, a magnetic fields emitter assembly having three orthogonal emission coils defining a reference frame and a sensor assembly, integral with the mobile object, having three channels for measuring the field received on three orthogonal detection coils, these channels each incorporating a feedback loop providing an output voltage and a measurement current. A calibration voltage, at frequencies differing from the useful frequencies of the fields, is injected into the channels of the sensor without disturbing the continuous measurement by measurement acquisition channels, while a calibration current is superimposed on the measurement resistors. It is thus possible to identify the variable components of the system and correct the measurements through the inverse of the respective transfer functions of the channels of the sensor.

Abstract: Mobile devices having wired and/or wireless network connectivity, when operating in a location, contact one or more map servers to share connectivity information with the map server to allow the map server to create a global map. For example, if a mobile device has two different wireless connectivity options, such as Bluetooth and 802.11, when the mobile device is operated in the location, the mobile device tests whether both connectivity options are available in the location. The results of the test are provided to the central map server, which may integrate the results into the global connectivity map. A mobile device may also receive a connectivity map from the server indicating connectivity options available to the client in the location and possibly other locations as well. The connectivity map may include characteristics of connectivity options, such as cost, availability, etc., to allow the mobile device to choose a preferred connectivity option if multiple options are available.

Abstract: A system and method is disclosed for locating people or objects. In particular, a system and method for locating a wireless mobile station using a plurality of mobile station location estimators is disclosed. The system is useful for 911 emergency calls, tracking, routing, people and animal location including applications for confinement to and exclusion from certain areas. Additionally, a computational system and method for calibrating the relative performance of multiple models for various application domains is disclosed (e.g., medical, vehicle, communication diagnosis, robotics, seismic signal processing, recognition of terrestrial and/or airborne objects from satellites), wherein each such model may generate hypotheses (e.g., estimates and/or predictions) of an unknown condition. Additionally, the computational system and method may be distributed across a network such as the Internet.

Abstract: A method and system for location-determination of a mobile comprising of a receiver with a variable processor gain of up to 45.15 dB for detecting signals transmitted from transmitters that at a farther distance as well as from transmitters that are situated in sparsely populated areas. The system also includes a plurality of terrestrially deployed transmitters known as “pseudolites” that broadcast GPS-like signals, and in addition implementing the use of existing, available information from modulated signals, such as phase, amplitude and convolution with pseudorandom codes.

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: A system and method for networking a plurality of nodes is disclosed. A network of data devices having data representations of connectivity, network node position, and/or position topologies is also disclosed, wherein the network may be self-configuring and the network nodes spatially addressable. In another embodiment, a unique form of signal acquisition assistance intrinsic in the signal structure may also be used. A data positioning device capable of operating as a node in a network of the present invention is also disclosed.

Abstract: The present invention provides a method and an apparatus for detecting at least one repeater between a base station and a mobile unit. The method includes determining a first estimate of a distance traveled by a signal on a wireless communication link between the base station and the mobile unit, determining a second estimate of the distance traveled by the signal on the wireless communication link between the base station and the mobile unit, and comparing the first and second estimates. The method also includes determining whether the signal was processed by the at least one repeater based upon comparing the first and second estimates.

Abstract: An emergency evacuation guiding system for guiding people to run away in a building system as an accident occurs comprises a detector system for detecting an accidents which is occurred in the building system; an informing system for informing people that an accident occurs; a receiving system for receiving wireless signals from the informing system so as to know the message about the occurring of an accident; a guiding system for guiding people to run away from an accident area to a safety place; the guiding system including the at least one transmitter of the informing system and at least one receiver of the receiving system. The guiding system guides people to run out of the accident area by using the strength of the received signal in the receiver. The receiving system including at least one wireless receiver for detecting the strengths of the signals transmitted from the transmitter to the receiver.

Abstract: A locator system for processing commercial 911 requests is disclosed. An e911-enabled wireless network including a switching center is configured to route emergency 911 calls to a Public Safety Answering Point (PSAP); and is further configured to receive a commercial 911 request from the mobile station, and then route the commercial request to a location other than the PSAP. The routing of the commercial 911 request may be accomplished using a protocol indicating that the 911 request is of a commercial nature.

Abstract: A radio frequency identification (RFID) device, locator, wired and/or wireless communicator system comprising one or more than one antennas for receiving Radio Frequency (RF) signals from one or more RFID and or location determining and/or communication transmitters. The system has one or more receivers and demodulators for reception and demodulation of signals to baseband signals. A processor circuit processes the baseband signals and provides them to a cross-correlator circuit for cross-correlating the processed baseband signals and for generation of cross-correlated baseband signals. One or more modulators modulate the baseband signals and provide them to one or more transmitters. circuitry.

Abstract: A technique for estimating the location of a wireless terminal at an unknown location in a geographic region is disclosed. The technique is based on the recognition that there are traits of electromagnetic signals that are dependent on topography, the receiver, the location of the transmitter, and other factors. For example, if a particular radio station is known to be received strongly at a first location and weakly at a second location, and a given wireless terminal at an unknown location is receiving the radio station weakly, it is more likely that the wireless terminal is at the second location than at the first location.

Abstract: A First Responder Communications System (FRCS), also referred to as an Automated Incident Control System, is provided that supports inter-agency and intra-agency communications among first responders including fire, police, border patrol, emergency medical service, safety, and/or other agencies. The FRCS also increases situational awareness of personnel by automatically providing position information as well as other sensor information. The FRCS also provides position and time information via Global Positioning System (GPS) and/or other positioning systems, and data from deployed and/or personal sensors to provide enhanced communications, command and control capabilities to the first responders and incident command. The FRCS includes a heads up display (HUD) including one or more LEDs or LCDs and a signal receiver that attaches to a faceshield or windshield (shield) to receive/display instructions via an electromagnetic or sonic signal via a transmitter coupled to a computer or other source.

Abstract: A Real-time Emitter Locating (EL) System and Method is disclosed. The system provides a technique for taking in data sets (lines of bearing) from DF receivers and characterizing those signals with their respective probabilities of error. Then using a unique method, the preferred system applies a recursive processing technique to this continuous stream of data, displaying transmitter positions with significantly less uncertainty. Furthermore, the preferred system is able to perform these functions in real-time. The system is further capable of being fully automated to reduce the processing time and reduce the necessity of human intervention. Still further, in an alternative embodiment of the present invention the system can be remotely controlled over a communications network whereby collected locating data from a single DF set, or alternatively from more than one DF sets can be combined to arrive at estimated positions for a transmitter.

Abstract: An information processing apparatus includes a motion information receiving portion that receives multiple pieces of motion information, which is time-series information, a motion information alteration portion that alters a positional relationship in a time axis direction between the multiple pieces of the motion information, a correlation information acquisition portion that acquires, for multiple pieces of the motion information, correlation information, which is information relating to a correlation between pieces of the motion information, and a motion information acquisition portion that acquires, based on the correlation information acquired by the correlation information acquisition portion, multiple pieces of the motion information having a positional relationship in the time axis direction at which the correlation between the pieces of the motion information is optimal.

Abstract: A location system in a cellular communication network has a first set of base stations which transmits and receives signals in a first communication format. The second set of base stations transmits and receives signals in a second communication format. All the base stations transmit known signals at predetermined times for use in deriving location data. A transmitting and receiving unit of the known location determines the times of arrivals of these signals from each base station in each set of base stations. Similarly, a mobile unit at an unknown location determines the times of arrival of the signals from each base station. By comparing timing differences between signals received at the unknown location and signals received at the known location, it is possible to determine the unknown location therefrom. This can then be transmitted back to either of the sets of base stations. In a situation where two communication networks are used, the mobile units will be dual mode transmitting and receiving units.

Abstract: A precision timing generator and an associate method provide a precise clock signal based on a reference clock signal. Using the reference clock signal in a phase locked loop or delay locked loop, a number of clock signals of equal frequency are generated separated consecutively by a known phase. Two of these clock signals of consecutive phases are selected for interpolation for higher precision according to predetermined weights. The resulting interpolated clock signal has a phase offset that is intermediate between the selected clock signals in proportion to the predetermined weights. In one implementation, a second interpolated clock signal is created by selecting and weighting a second group of clock signals using independent selection and weights. The two interpolated clock signals are then combined by logic operations to provide a precise clock signal of predetermined duty cycle and phase.

Abstract: A personal digital assistant (PDA) detects its position by a two-axis acceleration sensor provided therein. While the PDA is within a communicable range where the PDA can communicate with the printer, a position of the PDA, which is located at time when the position of the PDA is detected, is recorded as an origin point and the origin point is periodically updated to the detected position. When the PDA moves to a position (current position) through a position which is out of the communicable range of the printer, guidance information for guiding the PDA into the communicable range of the printer is created based on a relative positional relationship between the current position and the origin point, which is recorded immediately before the PDA moves to a position out of the communicable range, and then the guidance information is displayed on the PDA.

Abstract: A system for locating an object within a monitored environment includes receivers arranged in loosely coupled networks. A tag transmitter acts as a network node and bridge between the loosely coupled networks. A processor is operative with each receiver within each network for defining a clock timing for each network, a system time for all networks, and tracking its relationship to the clock timing for each network for time synchronizing all receivers. The processor is also operative for conducting differentiation of time of arrival signals received from a tag transmitter to locate an object associated with the tag transmitter.

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 multistatic radar has a radar transmitter for illuminating a target with a radar signal. The target reflects the radar signal to three separate radar receivers, each performing a bistatic range measurement to the target. The three bistatic range measurements are combined in a quadratic equation having two solutions (roots). One solution (root) corresponds to a correct three dimensional target position with respect to the radar transmitter while the other is an incorrect three dimensional target position with respect to the radar transmitter. The incorrect three dimensional target position is identified and eliminated by comparing the three dimensional target position to the transmitter location, and the receiver locations. The incorrect three dimensional target position is also identified by the target altitude exceeding a threshold, typically set above 80,000 feet AGL.

Abstract: A system and method for determining if a first and second device are co-located includes first and second sensors for receiving a sample signal. Each sensor is coupled to the first and second devices. The first and second devices each responsively generate a first and second signal representing the sampled signal. Also included is a transmission device located at the first device for transmitting the first signal to the second device and a receiving device located at the second device for receiving the first signal from the first device. Finally, a signal analysis device determines if the first and second devices are co-located.

Abstract: A system and method supports multiple wireless carrier mobile station location requirements with a common network overlay location system. The common network overlay location system shares geolocation assets such as location measurement units (LMU), geo-location control system (GCS), and, optionally, mobile positioning centers (MPC). The shared location assets are configured to operate with each of the sharing carrier systems. The number of sharing carriers in the same market is not limited. LMUs are configurable and switchable to measure attributes of the transmitted signal from mobile stations belonging to any of the wireless carriers which are used by the common location system to estimate the location of the mobile station using time of arrival, time difference of arrival, angle of arrival, signal power, and combinations of the same. The location of the LMUs are configured to provide an acceptable level of accuracy while minimizing a function such as the need for additional LMUs and cost.

Abstract: The present invention provides for a method of, and related system for, determining the position of a mobile radio terminal (10,M) arranged for communication with a plurality of base stations (BS1, BS2) and including the steps of employing a Time Of Arrival calculation in combination with a Time Difference Of Arrival calculation, characterized by performing the combined Time of Arrival and Time Difference Of Arrival calculations on signals transmitted in the downlink channel from the base stations (BS1, BS2) to the mobile radio terminal (10,M).

Abstract: A method is provided for at least one of detecting and tracking an object within a wide-area. The method including: deploying three or more sensors within the wide-area, each of the sensors having one or more polarized radio frequency waveguides; transmitting polarized radio frequency radiation from at least one source; detecting a reflection of the transmitted polarized radio frequency radiation; and calculating one of a detection or position of an object within the wide-area based on the detected reflection. At least one of the three or more sensors and at least one source can be a mobile platform, which can be manned or unmanned. The three or more sensors can be deployed manually or remotely, such as from a projectile.

Abstract: A method of determining the position of a target comprising the steps of: providing a transmitter or a plurality of transmitters to transmit a signal to the target, providing a receiver or a plurality of receivers to receive signals reflected from said target. Determining the time of arrival information of said reflected signal at the or each receiver; using information pertaining to the position of the or each receiver and/or the or each transmitter and with the information obtained determining the target position. Preferably the signal includes a modulated or coded portion unique to the transmitter; and said signal portion is associated with the or each particular transmitter by virtue of said signal portion. The signal maybe a mobile phone transmission, DAB, digital TV, digital Radio or digital satellite transmissions.

Abstract: The invention provides a method and apparatus for increasing the accuracy for locating a cellular mobile station in an urban area.

Abstract: A method and a system of triangulating an object by means of at least two sensors. Each sensor is placed in a respective local reference system. Each of the at least two sensors at least provide a bearing to the object in their respective local reference system. According to the invention a triangulation reference system is created. The triangulation reference system is different to any one of the local reference systems and suitably such that at least two local reference systems are rotated more in relation to each other than each one is in relation to the triangulation reference system. Sensor positions and bearings are transformed into the triangulation reference system where the triangulation is performed. Suitably the triangulated position is then transformed into a desired reference system.

Abstract: A radio-parameter control method allowing fine radio-parameter setting to improve communication quality is disclosed. Fixed stations are distributed at predetermined locations in a service area. A fixed station monitors reception condition of a pilot channel signal and transmits the monitored condition data back to a corresponding base station. A radio network control station statistically analyzes the monitored condition for each fixed station and estimates a future location of a mobile station. Radio parameters for use in radio communication between the mobile station and a base station corresponding to the future location of the mobile station are controlled based on statistical condition data at the future location of the mobile station.

Abstract: An intrusion detection system and method are provided that can utilize impulse radio technology to detect when an intruder has entered a protection zone. In addition, the intrusion detection system and method can utilize impulse radio technology to determine a location of the intruder within the protection zone and also track the movement of the intruder within the protection zone. Moreover, the intrusion detection system and method can utilize impulse radio technology to create a specially shaped protection zone before trying to detect when and where the intruder has penetrated and moved within the protection zone.

Abstract: A network, network device and method is disclosed. In one embodiment, a method includes transmitting communication signals from a first network node to a second network node, where the first and second network nodes comprise a network and each include a receiver portion and a transponder portion. The method further comprises receiving, by the first and second network nodes, position signals from a plurality of navigation beacons, and generating transmitter codes for the transponder portions using local code generators of the receiver portions.

Abstract: An object tracking system includes a plurality of tags. Each tag includes a mechanism for transmitting a triangulation signal and a position signal that is indicative of a change of position of the respective tag in a time period since a respective reset event. A plurality of triangulation stations receive the triangulation signals from the tags. At least one antenna receives the position signals from the tags. A computer is coupled to the triangulation stations and to the antenna. The computer is programmed to switch between (a) a first tag location algorithm to determine a current location of one of the tags using a differential time of arrival procedure based on the triangulation signal, and (b) a second tag location algorithm to determine a current location of the tag based on the position signal transmitted by the tag and a previous known location of the tag.

Abstract: Methods, apparatuses, and systems directed to a wireless node location mechanism that uses a signal strength weighting metric to improve the accuracy of estimating the location of a wireless node based on signals detected among a plurality of radio transceivers. In certain implementations, the wireless node location mechanism further incorporates a differential signal strength metric to reduce the errors caused by variations in wireless node transmit power, errors in signal strength detection, and/or direction-dependent path loss. As opposed to using the absolute signal strength or power of an RF signal transmitted by a wireless node, implementations of the present invention compare the differences between signal strength values detected at various pairs of radio receivers to corresponding differences characterized in a model of the RF environment.

Abstract: Systems and methods for determining location by implication are described. A responsive environment includes a location determination method that operates in an area that is only partially instrumented with location-sensing devices. Some of the with location-sensing devices sense location ambiguously. For example, a location-sensing device may be deployed at a boundary between two target objects or areas of interest. The location of the target object, as reported by such devices, is considered ambiguous. While the object or person is known to be in a space, it is not clear which specific space. The location of ambiguously located objects can be disambiguated based on changes in the location of other objects. For example, if a document is placed on a shelf in an office, such action strongly implies that someone is in the office. Therefore, if a person is known to potentially be in the office or the outside hallway, the person's location is changed to be in the office.

Abstract: Certain aspects of the disclosure relate to combining uplink and downlink location technologies into a single location-service system, to obtain the benefits offered by both of technologies while eliminating many of their individual shortcomings. Mobile devices that support downlink can then be located using the downlink mode, and mobile devices that do not support downlink can be located using the uplink mode. A mobile device may even be located based on a combination of uplink measurements and downlink measurements. Other aspects of the disclosure relate to providing a single location-service system to locate mobile devices that communicate using a plurality of different communication protocols.

Abstract: In calculation of a position of a terminal, there arises, when creating a delay profile, a problem to select a transmission code for a sector of a base station to create the delay profile. According to a position of a base station and a bearing of each antenna forming a sector of the base station, a wireless position calculation method selects a transmission code for a sector of a base station to create a delay profile. Under a condition that the number of delay profiles to be created is limited, each delay profile is created in consideration of the antenna bearing. Therefore, the number of base stations at mutually different positions is increased to calculate the position and precision of the position calculation is improved.

Abstract: A first transceiver can position itself by forming an ad hoc network of transceivers which assist the first transceiver in acquiring its position. A dedicated infrastructure such as GPS satellites is not required. The first transceiver, once it has acquired its position, can be involved in a network by another transceiver 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: The invention relates to a method and apparatus for locating and tracking persons by use of an implantable device. The described invention is an implant able device composed of biocompatible materials in all areas where contact with organic tissue occurs. The gross anatomic siting of the device includes any limb, the torso, including back and perineum, the neck, and the head. The surgical anatomic siting of the device includes: (1) Supramuscular: for example, deep to the epidermis, dermis, and subcutaneous fat, on or attached to muscle and/or muscle fascia. Such a location is currently used for implantation of commercially available buried intravenous access ports, which are positioned on, and attached to, the pectoralis major muscle fascia; (2) Intramuscular: for example, within or between the muscles of a limb; (3) Submuscular: for example, deep to a large muscle.

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 location system for use in a mobile communication network includes base stations which transmit known signals at predetermined times for use in deriving location data; a first transmitting and receiving units; a unit for determining times of arrival of the known signals from each base station at each of the first transmitting and receiving units; a unit for determining times of arrival of the known signals from each base station at a second transmitting and receiving unit at an unknown location; a comparing unit for comparing timing differences between the known signals received at the first transmitting and receiving units and the second transmitting and receiving unit; and location determining unit for determining the location of the second unit. Each of the first transmitting and receiving units includes a unit for deriving its location from a further set of received signals such as GPS signals.

Abstract: The receiver (1) for radio-frequency signals (SV1, SV2, SV3, SV4), modulated by specific codes of transmitting sources, such as satellites (S1, S2, S3, 54), includes receiving and shaping means with frequency conversion for the radio-frequency signals for generating intermediate signals, a correlation stage formed of several correlation channels for receiving the intermediate signals and microprocessor means connected to the correlation stage in order to process the extracted data after correlation. Each channel includes a correlator in which the intermediate signals are correlated with at least two early and late replicas of the specific code of a visible transmitting source to be searched and tracked. The correlator further includes integrator counters for the correlated signals to provide a first amplitude value of the auto-correlation function of the early signals and a second amplitude value for the late signals.

Abstract: A portable reconfigurable geolocation system is provided. The system includes a portable user node and one or more portable pseudolite nodes in communication one another and with the user node. Each of the user nodes and pseudolite nodes includes a transmitter that generates a signal on one or more carrier frequencies. Each signal is modulated with digital signals necessary to establish distances between the nodes and to convey data between the nodes. Each node also includes a receiver for receiving and demodulating the signals transmitted between the nodes, and a processor for receiving the demodulated signals, extracting data values and derived values from the demodulated signals and determining a three-dimensional position of each node in the system.

Abstract: A method of determining the relative position of a secondary station (SS) in a radio system including at least one master station (MS) and a plurality of secondary stations (SS), comprises the master station establishing a master log of the time stamp of signals transmitted by active stations and their identities and active secondary stations (SS) establishing a log of the time stamp of signals transmitted by other stations and their respective measured received quality. One of the active secondary stations forwards its log to the master station and the master station correlates the time stamps in the received log with the time stamps in the master log in order to determine the identities of the transmitters and utilizes the measured signal quality indications in the received log to determine the relative position of the secondary station with respect to the locations of the transmitters identified.

Abstract: The location of unmodified wireless assets in a wireless communication network may be identified using time differences of arrivals of a communication sequence at different network receivers. Time-stamping devices may include correlator circuits in parallel with signal decoders to time-stamp communication sequences. Cellular wireless networks may be frequency-multiplexed to increase spatial time-stamping density. Tags may be attached to passive assets to provide location identification information to network devices. Locations of assets broadcasting standard 802.11 radio frequency structures may be identified. Noise inherent in correlating a communication sequence may be reduced by using a selected correlation function.

Abstract: A system for correlating secondary surveillance radar (SSR) data and ACARS data which results in a real time correlation of data which are unique to the separate existing systems. More specifically, a method is provided to attach flight identification data from ACARS signals to real time SSR data from Mode S transponders. Aircraft Mode S addresses are decoded and then converted to aircraft registration numbers using an algorithm or lookup table. Registration numbers are then correlated with registration numbers from decoded ACARS signals. The result is a real-time system which may provide an aircraft's registration information, including registration number, owner, make, and model, as well as its current flight identification number, and ACARS messages. As part of an aircraft multilateration system, the system provides an independent air traffic control picture complete with aircraft position and identification by flight number without the use of active radar equipment.