1953results about "Radio wave direction/deviation determination systems" patented technology

Systems and methods are described for circular superdirective receive antenna arrays. A method includes calculating an minimum array efficiency of the superdirective circular receive array, calculating a maximum superdirective gain of the superdirective circular receive array, determining an amplitude weight or a phase weight for an array element in the superdirective circular receive array based on the minimum array efficiency and the maximum superdirective gain, and determining number of array elements in the superdirective circular receive array and a radius of the superdirective circular receive array.

Some embodiments use scanning devices to characterize radio signals received at a number of locations within a geographical area of interest. The signal characteristics along with the location information associated with the characteristics are stored in a centralized reference database. A mobile device characterizes signals it receives at a certain location and compares the characteristics with the signal characteristics stored in the reference database to obtain accurate location information of the certain location.

A method of determining the location of a mobile device is provided. The method receives a signal with a known radio transmission pattern at the mobile device from each of several transmitting devices. The method correlates each received signal with a corresponding signal that has a same known radio transmission pattern to determine the time the signal traveled between the corresponding transmitting device and the mobile device. The method determines the location of the mobile device based on the time the signal travelled between the corresponding transmitting device and the mobile device. In some embodiments, determining the location of the mobile device does not require calculating a distance between the mobile device and any of the transmitting devices. In some embodiments determining the location of the mobile device includes solving a function that is dependent on the time the signals traveled between each corresponding transmitting device and the mobile device.

A signal detector employs a coherent accumulation system that coherently combines the correlation results derived from segments of samples of a received signal. The segments may have non-uniform lengths and may have been obtained over different and non-overlapping time periods. The segments are obtained during sampling windows of arbitrary length and at arbitrary times, and the results of processing the segments are successively combined in a coherent manner (separate magnitude and phase accumulation) until a threshold signal-to-noise ratio (SNR) has been achieved. Coherent integration is enabled by introducing a carrier phase offset as well as a code phase offset, so that different segments are aligned in carrier phase as well as code phase. Although not limited to this application, in one implementation example, the signal detector is used in connection with and as part of a global positioning system (GPS) receiver.

Based on a received signal y(t) received by a radiating element of an array antenna including the single radiating element and a plurality of parasitic elements, an adaptive controller calculates and sets a reactance value of a variable reactance element for directing a main beam of the array antenna in a direction of a desired wave and directing nulls in directions of interference waves so that a value of an objective function expressed by only the received signal y(t) becomes either one of the maximum and the minimum by using an iterative numerical solution of a nonlinear programming method.

A satellite communication subscriber device includes a smart antenna for generating antenna beams for receiving signals from at least one satellite, and a receiver. The receiver includes a quality metric module for calculating a quality metric on the signals received by each antenna beam. A beam selector is coupled to the smart antenna for selecting the antenna beams. An antenna steering algorithm module runs an antenna steering algorithm for operating the beam selector for scanning the antenna beams, receiving the calculated quality metrics from the receiver for each scanned antenna beam, and comparing the calculated quality metrics. The algorithm selects one of the scanned antenna beams based upon the comparing for continuing to receive signals from the at least one satellite.

A method for processing received radio signals that are subject to unwanted change during propagation through the atmosphere, from a transmitter to a receiver array. The multiple signals are received as cochannel signals at the antenna array, and are processed to eliminate the effects of modification of the signals during propagation, wherein the processing step includes cumulant-based signal recovery without regard for the geometrical properties of the antenna array. In the invention as disclosed, two different information signals having two different polarization states are transmitted, and at least one of the transmitted signals is subjected to an unwanted change of its polarization state. The received signals are processed to separate and recover the two information signals without regard to their polarization states.

Angle of arrival and / or range estimation within a wireless communication device. Appropriate processing of communications received by a wireless communication device is performed to determine the angle of arrival of the communication (e.g., with respect to some coordinate basis of the wireless communication device). Also, appropriate processing of the communications may be performed in accordance with range estimation as performed by the wireless communication device to determine the distance between the transmitting and receiving wireless communication devices. There are two separate modes of packet processing operations that may be performed: (1) when contents of the received packet are known, and (2) when contents of the received packet are unknown. The wireless communication device includes a number of antenna, and a switching mechanism switches from among the various antennae capitalizing on the spatial diversity of the antennae to generate a multi-antenna signal.

A method and apparatus for spatial multiplexing and demultiplexing of radio signals. A multichannel transmitter and receiver is integrated in a base station and coupled to an antenna array. Using digital radio signals containing previously known or non-Gaussian sequences and arranged in frames, the spatial information about each mobile unit is estimated on the basis of the signal received by the receiver for the reception and transmission frequencies. This is done by known sequences or by blind source separation methods. The respective paths of each mobile unit with the power above a predetermined threshold is isolated by spatial filtering in the presence of multiple channel paths in order to provide spatial demultiplexing. Simultaneously, the intended signal is transmitted in the direction of the main path of each mobile unit while protecting each mobile unit from signals transmitted in the direction of other mobile units by spatial filtering with cancelling constraints in order to provide spatial multiplexing.

A system and method for determining angular offset of an impulse radio transmitter using an impulse radio receiver coupled to two antennae. The antennae are separated by some known distance, and, in one embodiment, one antennae is coupled to the radio with cable delay. Impulse signals from the antennae are measured to determine the time difference of arrival of one such signal received by one antenna compared to that of the other antenna. Time differential is measured by autocorrelation of the entire impulse radio scan period, by detecting the leading edges of both incoming signals or various combinations of these methods. Using a tracking receiver, the pulses may be continuously tracked thus providing real time position information.

A Multi Input Multi Output (MIMO) Wireless Communication System method and apparatus are proposed whereby in a 2-way wireless communication system with scattering, random and imperfectly estimated propagation channels the ubiquitous and inherent MIMO cross-talk interference problem is solved so that robust and predictable Extended Communication Range and Extended Data Rate are achieved.

An approach is provided for supporting transmission in a multi-input-multi-output (MIMO) communication system including a plurality of terminals. A preamble portion of a frame is transmitted by a multiple transmit antennas of a hub using Orthogonal Frequency Division Multiplexing (OFDM) to the terminals over a channel, wherein each of the terminals determines a characteristic of the channel with respect to the transmit antennas as feedback information. The hub receives the feedback information from the terminals. The hub selects, according to the feedback information, a subset of the antennas for transmission of a remaining portion of the frame to the terminal.

An antenna apparatus that can increase capacity in a wireless communication system is disclosed. The antenna operates in conjunction with a station and comprises a plurality of antenna elements, each coupled to a respective weight control component to provide a weight to the signal transmitted from (or received by) each element. The weight for each antenna element is adjusted to achieve optimum reception during, for example, an idle mode when a pilot signal is received. The antenna array creates a beam former for signals to be transmitted from the mobile station, and a directional receiving array to more optimally detect and receive signals transmitted from the base station. By directionally receiving and transmitting signals, multipath fading and intercell interference are greatly reduced. The weights are adjusted in a coarse and a fine mode. In the coarse mode all the weight control components are jointly adjusted or changed so that the antenna beam scans through a predetermined sector of a circle until a signal quality metric of the received signal is optimized. The coarse adjustment mode is followed by a fine adjustment mode during which the weights of are independently adjusted to further optimize the signal quality metric.

A signal detector is provided in which correlation analyses of multiple segments of a received signal from separate and distinct periods of time are combined to improve the detection capability of the signal detector. In one embodiment, the signal detector is part of a GPS receiver.

In a cellular mobile telecommunications system the position of a mobile station can be estimated in terms of its bearing and range from a cell site. A multi-element direction finding antenna at the cell site receives signals from the mobile station and a receiver circuit estimates the bearing using the relative phase of signals received at different antenna elements and estimates the range by measuring round trip delay of signals to and from the mobile station. Motion of the mobile station can introduce errors into the bearing estimate due to frequency offset and frequency spread when element sampling is non-simultaneous. Compensation for these errors is introduced by using signal samples successively received at the same antenna element to estimate Doppler frequency offset and spread. It is necessary to ensure accurate calibration of the direction finding antenna and the receiver circuit. This is done by injecting calibration signals into the circuit near the antenna or into the antenna itself from a near field probe. Other aspects of calibration, such as antenna position, are calibrated using a remote beacon. A beacon emulating a mobile station but at a fixed, known location, or a beacon at an adjacent cell site may be used.

Disclosed is a wireless positioning system and method that can perform a high-precision position tracking. The wireless positioning system includes a target device that is an object of wireless positioning, beacon devices and a processing unit. The beacon devices transmits wireless signals and sense reception time points of the wireless signals transmitted from the other beacon devices and the target device and received at time points after the transmission of the wireless signal. The target device receives the wireless signal transmitted from at least one of the beacon devices, and then transmits the wireless signal to the beacon devices. The processing unit obtains the position of the target device by calculating distances between the beacon devices and the target device using information about the reception time points of the wireless signals sensed by the respective beacon devices.

A system and method for an arrayed sensor to resolve ambiguity in received signals, improve direction of arrival accuracy and estimate a location of one or more targets in an environment including signal interference.

In a mobile communication system, each base station is provided with an array antenna, a section for estimating the respective directions of one or more mobile stations with which the base station is in communication, based on estimated incoming directions of radio waves received from these mobile stations, and sections for operating on respective signals of the antenna elements constituting the array antenna such as to shape the radiation pattern of the antenna to form peaks of directivity which are oriented in the estimated directions of these mobile stations, and can include a capability for shaping these peaks in accordance with estimated positions of these mobile stations, thereby minimizing interference between transmissions from that base station and communication being executed between other adjacent stations of the system, and minimizing the number of different transmission frequencies required in the overall system.

Some embodiments use scanning devices to characterize radio signals received at a number of locations within a geographical area of interest. The signal characteristics along with the location information associated with the characteristics are stored in a centralized reference database. A mobile device characterizes signals it receives at a certain location and compares the characteristics with the signal characteristics stored in the reference database to obtain accurate location information of the certain location.

Systems and methods of correlating potential transmitters with received radio signals is provided. Image data is provided including paths traveled by potential transmitter. Potential transmitters are identified within the image data along with path segments traveled by potential transmitters. A first and second transmitter calculate certain parameters of received signals assuming that signals originated along the path segments. The calculated signal parameters are then compared to measured signal parameter to determine whether a transmitter is associated with a particular path.

A lightning detection system for detecting and locating an initial discharge of an initial leader stroke of a lightning flash. An initial lightning discharge produces a pulse that can be used to accurately detect lightning, and more particularly, the location of the initial lightning discharge. In one embodiment, at least three sensors detect and determine the location of the first pulses from initial lightning discharges using time difference of arrival information of the pulses at each of the three sensors. In another embodiment, a single sensor is used to determine the range of an initial lightning discharge from the amplitude of a corresponding initial detected pulse, and to determine the direction from a crossed loop antenna An alternative embodiment of a single sensor system determines a distance of a lightning event from a peak amplitude value derived from a pulse amplitude distribution. In a further embodiment, a lightning detection system provides enhanced lightning location by incorporating weather data from a weather radar with detected lightning information.

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

A beamforming device includes a Direction Of Arrival (DOA) estimation unit for estimating DOAs of the received signals based on a data subcarrier matrix; a pre-spatial filtering unit for using the estimated DOA, performing a filtering operation for the data subcarrier matrix, and generating filtering matrixes; a signal identification unit for using a data sequence, identifying original and interference signals, and generating the DOAs of the original and interference signals; a spatial filtering unit for generating an interference-plus-noise covariance matrix by using the DOA of the interference signal, eliminating the interference signal by using the covariance matrix and the DOA of the original signal, and forming final beams for the original signal; and a channel estimating and signal combining unit for performing a maximal ratio combining operation so that the final beams are combined as one combined final beam.

Systems and methods that may be implemented to determine the location of an emitter of electromagnetic radiation having an unknown location, using a cooperative TDOA-based location methodology. The cooperative TDOA-based location methodology (e.g., such as TDOA / TDOA, TDOA / FDOA, etc.) may be implemented using at least one cooperative transmitter that transmits a cooperative electromagnetic (EM) signal from a known location that is received at multiple different EM sensing platforms that are also each of known location. The known geolocation of the cooperative transmitter may be used to resolve the signal arrival timing relationships between the different sensing platforms that is utilized to determine the location of another EM transmitter of unknown location.

A system and method for finding the direction of a wave source using an array of sensors. The system includes a sensor array for measuring waves from the wave source, an approximate-direction finder for finding the approximate direction of the wave source in terms of a sensor pair from the sensors, a precise-direction finder for finding the precise direction of the wave source based on the approximate direction found, and a measurement qualification unit for evaluating the validity of the precise direction under a measurement criterion and discarding the measurements if the criterion is not met.

A feed network for an antenna subarray includes a first feed arrangement having an sum output, a second feed arrangement having an delta output, a fixed attenuator having a first port and a second port, the first port connected to the delta output of the second feed arrangement, a first power divider / combiner having a first and second port and a third port; the first port connected to the second port of the fixed attenuator, a variable phase shifter having a first port and a second port, the first port connected to the second port of the power divider / combiner, a variable attenuator having a first port and a second port, the first port connected to the second port of the variable phase shifter, a second power divider / combiner having a first and second port and a third port; the first port connected to the second port of the fixed attenuator, a first circulator having a first port, a second port and a third port, the first port connected to the sum output of the first feed arrangement, and a third power divider / combiner having a first and second port and a third port; the third port connected to the second port of the circulator and the second port connected to the second port of the variable attenuator.

There is provided a transmit antenna array device with at least two antennas and a method thereof in which a transmission beam is appropriately formed based on a weight vector to be transmitted to a specific mobile station in a mobile communication system. For this purpose, a base station device has a reverse processor for processing a reverse signal received through the antenna array, a forward fading information extraction unit for extracting forward fading information from the received reverse signal, a beam formation controller for generating a weight vector for formation of a transmission beam using the forward fading information and the received reverse signal, and a forward processor having a transmission beam generator for generating a transmission beam for a transmission message based on the weight vector. A mobile station device has a forward processor for processing a received forward signal, a forward fading estimator for estimating forward fading information of the forward signal for each path, a forwarding fading encoder for combining the estimated forward fading information and encoding the combined forward fading information, and a reverse processor for multiplexing the encoded forward fading information with a transmission message and feeding back the forward fading information in the multiplexed signal to a base station.

The present invention is in general related to target type estimation in target tracking systems. The invention enables a low complexity estimation of target type, using, e.g. ESM sensor data, by the introduction of an ambiguity restoring procedure in certain likelihood calculations. The invention further enables the systematic use of target type probability information in the calculation of strobe track crosses and their associated quality which is particularly useful for deghosting purposes. Methods for utilisation of target type probability information in the processes of strobe tracking, association, track quality evaluation and multiple hypothesis tracking are also disclosed.