Abstract: The present invention discloses a method for positioning signal sources in a wireless network, e.g. in a WLAN or WiMAX network. The located signal source might be a end user, an interfering source or a base station. At least one monitoring station is placed in the network, which use directional antennas. By combining e.g. the direction of the used antenna beam, the received relative signal levels, propagation delay measurements and several different measurement locations for one or several monitoring stations, the location of the signal source can be determined accurately. The method can also track whether the end user is connected to the most optimal base station by transmitting test signals through base stations.

Abstract: Embodiments of the present invention include systems and methods for optimizing the transmitter and receiver weights of a MIMO system. In one embodiment, the weights are optimized to create and steer beam nulls, such that each transmitted signal is substantially decoupled from all other signals between a MIMO transmitter a MIMO receiver. In another embodiment, the weights are selected such that, the signal strength of each weighted signal transmitted through a communications channel along a respective signal path is substantially equivalent, but for which the weighting vectors are not necessarily orthogonal. In a further embodiment, each transmitted signal is coupled only between its own transmitter and receiver antennas with a gain, or eigenvalue, that is a consequence of the weights, and which is bounded to within a desired range of values while at the same time the weighing vectors are orthogonal. Embodiments employing various decomposition techniques are also provided.

Abstract: A method, including: receiving, at an apparatus, first and second radio signals from a first location; discriminating the first and second radio signals, in order to estimate a bearing from the first location; and estimating, using the bearing and constraint information which is independent of the radio signals, a position of the apparatus.

Abstract: A method for calibrating an antenna and signal processing system enabling angle of arrival (AOA) determination for a frequency hopping signal, in which a calibration coefficient is determined in response to one or more calibration signals injected into the system at one or more of the frequencies in the hopping sequence and proximate in time to reception of the communication signal. The calibration coefficients are reflective of a frequency and time dependent parameter of a path between the antenna and wireless location sensor. The AOA is determined as a function of the calibration coefficient and the radio frequency energy of the received communication signal. Several embodiment of the method are illustrated.

Abstract: Disclosed is radio monitoring apparatus which includes a radio station distinction unit, a direction measurement unit, a transmission source location estimation unit and a transmission source location classification unit. The radio station distinction unit outputs radio station distinction information for uniquely discriminating a radio station that is a transmission source of a transmitted signal from a received signal. The direction measurement unit measures an arrival direction of the transmitted signal. The transmission source location estimation unit estimates a location of the transmission source from results of the direction measurement and outputs an estimated location as transmission source location information. The transmission source location classification unit relates the radio station distinction information and the transmission source location information and outputs them.

Abstract: The invention concerns a navigation device for a mobile robot comprising means for measuring the amplitude and the phase of an electromagnetic signal emitted by a wire acting as limit for a working area of the robot. The measuring means samples the amplitude of the signal during each time interval, the result of each measurement is stored in a memory and the measurements are repeated for several time intervals, the collected results being added in said memories until the content of a memory reaches a reference threshold. The number of samples required and the content of each memory is interpreted by numerical analysis to determine the distance or distance variation relative to said limiting elements. Any phase change corresponding to a passage beyond the limiting wire is easily detected and results for example in a command returning the robot to its working area.

Abstract: An electromagnetic radiation source locating system including an electromagnetic radiation sensor including an antenna configured to detect a radiant energy transmission. A position detector is in communication with the controller and is configured to detect the position of the antenna relative to a reference coordinate system, while an orientation sensor is in communication with the controller and is configured to detect the orientation of the antenna and provide an orientation signal to the controller. A range sensor is configured to detect the distance to an aligned object in the path of a directional vector and provide a distance signal indicative thereof to the controller. An aerial vehicle may be in communication with the controller and configured to drop a marker for guiding navigators to the source of the radiant energy transmission.

Abstract: Kalman gain is used to calculate range accuracy for a passive angle-of-arrival determining systems, most notably for short-baseline interferometry, in which Kalman gain after arriving at a minimum proceeds to within a predetermined fraction or percent of zero gain, at which time the range estimate accuracy is known.

Abstract: A method and arrangement for finding the direction to an emitter source by determining the spatial frequency of a signal received from the source in a sensor panel and comparing the spatial frequency with the instantaneous frequency. The panel includes a first matrix of sensors and a second matrix of sensors interleaved with the first matrix. The spatial frequency is determined by comparing the signals received by the first and second sensor matrices.

Abstract: A dipole antenna array comprising a ground plane, at least one dipole antenna including an active antenna element and a grounded antenna element, at least one reflector and integrated electronics, wherein the active antenna element is isolated from the ground plane and extends substantially perpendicular to the ground plane and the grounded antenna element extends in a direction substantially opposite to the active antenna element, the ground plane is contained within the area bounded by the reflector; the integrated electronics include at least one of a signal down converter and a signal up-converter, and at least some of the integrated electronics are contained in a space defined by at least one of a portion of the ground plane and a portion of the reflector.

Abstract: An interactive graphical user interface (GUI) for displaying frequency, amplitude and direction information provided by an intelligence system is provided comprising: a plot of RF versus amplitude, and a graph of frequency versus direction. The intelligence system has a front end to generate digital data based on received radio frequency (RF) signals, a post processing stage to process the digital data, and a direction finding stage to prevent the post-processing stage from processing portions of the digital data that correspond to RF signals arriving from a direction other than a predetermined direction. The GUI is updated continuously in near real time. Methods of operating the GUI are also provided.

Abstract: A system processes signals exchanged between a near end terminal and a far end terminal over a communication path. The system selects the processing characteristics of a near end terminal based on characteristics of the communication path. The communication path may include the near and the far end terminal and their respective codecs, and the networks. The system may select processing characteristics of the near end terminal based on characteristics of the communication path. Selecting the processing characteristics may include selecting a predetermined operation. The system may adapt a selected operation based on a real time analysis of the communication path.

Abstract: A spectrum of a set of samples from a data stream of sampled data is estimated until a targeted signal to noise ratio is achieved.

Abstract: An ES tracker for tracking an emitter target, including ships and airborne targets, includes a sensor for receiving a signal emitted by the target; a sensor processor for processing the signal and outputting a measurement; and an information processor for processing the measurement. The information processor includes an IMM bearing filter having a mixing section for receiving the measurement and producing a mixed output signal; a first order Kalman filter for receiving the mixed output signal for stationary target tracking; a second order Kalman filter for receiving the mixed output signal and tracking bearing and bearing rate; and a third order Kalman filter for receiving the mixed output signal and tracking bearing, bearing rate, and bearing acceleration.

Abstract: A signal wave arrival angle measuring device includes: an observation data vector generation section generating an observation data vector necessary for an angle measurement of a signal wave from an electrical signal having been converted at a sensor group converting the signal wave of an observation target to the electrical signal; an ESPRIT angle measurement processing section calculating an arrival angle of the signal wave from the generated observation data vector; an arriving signal wave estimation section estimating information other than the arrival angle of the arriving signal wave from an angle measurement processing process data of the ESPRIT angle measurement processing at the ESPRIT angle measurement processing section; and a reliability determination section determining whether or not an angle measurement result of the calculated arrival angle is correct based on an estimation result of the arriving signal wave estimation section, and excluding an erroneous angle measurement result.

Abstract: A system for indicating the relative direction of a target object or location as determined from the current position of a wireless communication device. The system employs Direction of Arrival determination using an antenna array for indicating the direction of a target device and includes facilities to activate a location-indicating transmission in a target device, the ability to request that a location-indicating transmission be activated in a remote target device, relevant information reception from a target device and the display of all potential target devices within effective transmission range of the wireless communication device.

Abstract: An incoming direction estimation apparatus estimates an incoming direction of a radar wave using three or more sensors or antennas simultaneously. An arithmetic expression for estimating an incoming direction of a radar wave is configured as sin?1((1/2?a)*tan?1b). The “a” is d/? determined by an antenna interval and by a wavelength ? of a carrier, or such, carrying the radar wave. A simultaneous use of three antennas makes it possible to set the a as a value depending on a value d0=a0? based on the interval between first antennas and value d1=a1? based on the interval between second antennas. Therefore, if a wide field of vision of an incoming direction is needed, it is only necessary to adjust (d1?d0)/?=(a1?a0), in place of the absolute interval of antennas a=d/?, thereby making it possible to lessen a limitation on the design of antennas and set a field of vision of the incoming direction appropriately.

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

Abstract: An exemplary radio-based navigation system uses a small multimode direction-finding antenna and a direction-finding receiver capable of determining platform position, velocity, attitude, and time while simultaneously providing protection against narrowband and broadband sources of interference. Global Navigation Satellite System (GNSS) signals such as those from the Global Positioning System (GPS) provide attitude measurements with a compact multimode direction-finding antenna (e.g., a small two-arm spiral with improved angle-of-arrival performance over the entire hemisphere enhanced through the use of a conductive vertical extension of the antenna ground plane about the antenna perimeter and/or conductive posts placed evenly around the antenna perimeter) which provides simultaneous protection against jammers. The multimode spiral may be treated as an array of rotationally-symmetric antenna elements.

Abstract: The radiowave direction detector has a radiowave direction detecting unit detects an arrival direction of the desired radio wave, a converting unit including a plurality of electromagnetic-to-electric converters to convert the desired radio wave, and a computing unit for determining the arrival direction of the radio wave, which matches a preset condition, by comparing the levels of electric signals that are transferred from the converting unit.

Abstract: A system and method for discovering and tracking communication directions is disclosed herein. In one embodiment, communication directions for two devices with asymmetric antenna systems are discovered. In one embodiment, a contention access period (CAP) is partitioned into an association CAP and a regular CAP, either of which may be further partitioned into sub-CAPs corresponding to different reception directions. In one embodiment, an association request command is transmitted by a device at different association sub-CAPs to train a transmission direction of the device. In one embodiment, further training is performed to find the best communication directions, as collisions may occur when association request commands are transmitted at different association sub-CAPs.

Abstract: A locator includes a base unit and a handheld unit. The base unit, which is typically stationary, includes an FSK transceiver and printed circuit antennas. The handheld unit, which is typically mobile, also includes an FSK transceiver and printed circuit antennas. The handheld unit computes at least one bearing to the base unit over multiple frequencies and transmitting antennas, processes statistics of bearing results, determines a cyclic average of the bearing results, calculates an overall variance, assesses quality of a computed bearing result based on the overall variance, and upon assessing, either displays the computed bearing result or disqualifies the computed bearing. The handheld unit computes a height difference between the base unit and the handheld unit. The height difference is calculated using altimeters within the units. Alternatively, the height difference is calculated using GPS.

Abstract: A direction-of-arrival estimation apparatus has a signal vector generation unit operable to generate a signal vector v composed of N baseband signals v1 to vn from arriving signals received from a target by N sensors. The direction-of-arrival estimation apparatus includes a Hankel matrix generation unit operable to preferentially set an order of a column of a matrix at a natural number M where 1?M and M?(N?1)/2 and generate an (N?M)×M matrix Rf1, Rf2, Rb1, or Rb2 from elements v1 to VN?1 of the signal vector. The direction-of-arrival estimation apparatus also includes an estimation unit operable to generate a matrix R using the matrices Rf1, Rf2, Rb1, or Rb2, divide the matrix R into two submatrices R1 and R2 by R=[R1|R2]T, and estimate a direction of arrival of the arriving signal based on the submatrices R1 and R2.

Abstract: A method, device and system for determining a DOA of a signal are described. Determination of the DOA of the signal may include receiving first and second UWB waveforms of the signal at one or more antennas of a UWB transceiver. A window may be defined in the first and second UWB waveforms such that the window is defined in a leading portion of the signal. First and second amplitude values of the respective first and second UWB waveforms in the window may be calculated. An amplitude ratio may be calculated with the first and second amplitude values and compared with calibration data to determine the DOA of the signal.

Abstract: The invention relates to a method for updating antenna beam angles of one or more directional antennas of a wireless device to communicate with a plurality of other wireless devices, each one of the antenna beam angles being associated with one of the plurality of other wireless devices, said method being characterized in that it comprises the steps of: determining at least one angle correction to update the antenna beam angle associated with at least one first wireless device among the plurality of other wireless devices (601, 702, 706); and first updating of the antenna beam angle associated with at least one second wireless device using the determined at least one angle correction of the antenna beam angle associated with the first wireless device (602, 703). The invention also relates to an apparatus and computer program for updating antenna beam angles.

Abstract: The system comprises a first beatable signal source, a second beatable signal source, a phase reference signal source and a receiver. The first beatable signal source and the second beatable signal source are located at the source location; the receiver is located at the receiver location. The phase reference signal source is operable to generate a phase reference signal. The first beatable signal source is operable to transmit a first beatable signal. The second beatable signal source is spatially offset from the first beatable signal source in a reference direction, and is operable to transmit a second beatable signal differing in frequency from the first beatable signal by a frequency difference. The first beatable signal and the second beatable signal collectively have a phase relationship with the phase reference signal.

Abstract: A method is disclosed for processing all types of received, interfering radio frequency signals corrupted by noise to extract the individual signals without having any a priori knowledge about them. Received signals are converted for eigenspace processing and are subjected to repeated non-linear time domain and fast Fourier transform frequency domain processing that calculates eigenstream beam forming weights U. By performing calculations in eigenspace, the number of independent weights U that must be calculated is generally reduced, minimizing calculating time. Once the weights U have been calculated in eigenspace they are transformed into antenna beam forming weights W that are used to extract the individual signals and to determine the angle of arrival of each of the individual signals. Further time is saved because the weights W do not have to be updated for every time slice of the received signals.

Abstract: The frequency modulation radar device includes a transmitting unit (5), M receiving units for receiving a reflected signal as M channels, a mixing unit (7) for mixing the transmitting signal with the M received signals to obtain beat signals for the M channels, a frequency analyzing unit (9) for analyzing the beat signals for the M channels in frequency, and a calculating unit (1) for calculating a distance to a target object and an orientation angle based on frequency analysis results. The calculating unit (1) calculates a noise level from the frequency analysis result, extracts a peak signal of a subject target object in each of the channels based on the calculated noise level to generate a covariance matrix, discriminates between a signal eigenvalue and a noise eigenvalue among M eigenvalues of the covariance matrix, and estimates the number of incident signals based on the number of signal eigenvalues.

Abstract: An azimuth measurement apparatus including: a positioning signal receiver receiving a first impulse positioning signal and a second impulse positioning signal from a first fixed position and a second fixed position, respectively; a phase difference detector detecting a phase difference between the first impulse positioning signal and the second impulse positioning signal; and an azimuth calculator measuring an azimuth of an object of positioning, based on the detected phase difference of the two positioning signals.

Abstract: A location estimation method using label propagation. The achieved location estimation method is robust to variations in radio signal strengths and is highly accurate by using the q-norm (0<q<1), especially, for calculating the similarities among radio signal strength vectors. The accuracy in location estimation is further improved by putting more importance on the time-series similarities. Specifically, the time-series similarity is calculated by using time-series values indicating the temporal order of radio signal strengths during the measurement. If the time-series similarity is larger than the similarity between the radio signal strength vectors, the time-series similarity is preferentially used. The exponential attenuation function can also be used for calculating the similarities, instead of the q norm (0<q<1).

Abstract: A Method and Apparatus for Enhancing the Detection of Weak Emitters provide an enhanced method to eliminate the fake hits of a moving weak signal detection system. The method and apparatus have the abilities stated in the previous U.S. patent application Ser. No. 11/332,801 filed by this author, to do moving detection of weak signals, even in dense urban environments. Secondly, the method and apparatus includes additional antennas and hardware boards, in order to verify authenticity of detected targets. Thirdly, the method and apparatus include appropriate DSP algorithms loaded to program the mission. Fourthly, the method and apparatus are enabled to accurately determine the tangential distance of the target from me vehicles centerline. Finally, the method and apparatus provide the ability to continually discard false targets based upon the information provided by these approaches.

Abstract: In a detection and ranging apparatus that performs direction-of-arrival estimation using a sensor array and that enlarges an effective aperture using a plurality of transmitting sensors, adverse effects associated with time division switching are eliminated, achieving high-accuracy measurement. A transmitter wave is spread in modulators by using mutually orthogonal codes, and the resulting transmitter waves are radiated from two transmitting sensors. Signals received by receiving sensors are each split by a splitter into two parts, which are then respectively despread in a demodulator by using the same codes as those used in the transmitter.

Abstract: A signal incoming direction estimation apparatus is constructed so as to comprise a sensor array having plural sensors and the impedance of each of the sensors being set to a predetermined value, respectively, and a variable impedance adjustment means having a variable impedance, being selectively connected to any one of the sensors of the sensor array, and controlling the current distribution of each of the above-mentioned sensors. Due to this, it becomes possible for the signal incoming direction estimation apparatus to carry out a beam scan only by manipulating at least one impedance without simultaneously manipulating all of the sensor impedances and thereby a high-speed beam scan (directional control) becomes possible.

Abstract: A method and an apparatus is disclosed for efficient cross correlation of a plurality of signal vectors. Incoming data is partitioned into several segments and processed according to an algorithm where data rotation is a function of post-correlation memory size.

Abstract: Embodiments of the present invention provide a method and apparatus for all-polarization direction finding. The method and apparatus generally include acquiring measurements at least partially corresponding to an emitted signal and generated utilizing a blind signal extraction algorithm, forming an all-polarization cost function utilizing the acquired measurements, and determining an angle of arrival for the emitted signal utilizing the formed all-polarization cost function. Such a configuration enables angles of arrivals to be easily determined for signals having any polarization without using a multiple signal classification (MUSIC) algorithm.

Abstract: The present invention relates to a method and a system for determining the direction of arrival of one or multiple radio or acoustic waves and, more particularly, to such a method and system especially advantageous in situations where the number of available observations is small and/or the available observations are received with low power. The method significantly improves the performance of traditional subspace signal processing algorithms in the low sample size regime. The algorithm is specifically designed to provide consistent estimates even when the observation dimension has the same order of magnitude as the number of observations. This guarantees a good behaviour in finite sample size situations, where the number of sensors or antennae and the number of samples have the same order of magnitude or in scenarios where the received signal power is not sufficiently high to guarantee detection via conventional one-dimensional search methods.

Abstract: An exemplary radio-based navigation system uses a single-aperture multimode direction-finding antenna capable of determining platform position, velocity, attitude, and time while simultaneously providing protection against narrowband and broadband sources of interference. Global Navigation Satellite System (GNSS)-signals such as those from the Global Positioning System (GPS) provide protection against jammers while simultaneously providing attitude measurements with a compact single-aperture multimode antenna (e.g., a small two-arm spiral with improved angle-of-arrival performance over the entire hemisphere enhanced through the use of a conductive vertical extension of the antenna ground plane about the antenna perimeter and/or conductive posts placed evenly around the antenna perimeter). The multimode spiral may be treated as an array of cylindrically symmetric antenna elements.

Abstract: A wireless communication method and antenna system for determining the direction of arrival (DOA) of received signals in azimuth and elevation, (i.e., in three dimensions), to form a beam for transmitting and receiving signals. The system includes two antenna arrays, each having a plurality of antenna elements, two first stage multi-mode-port matrices, at least one second stage multi-mode-port matrix, an azimuth phase detector, an elevation amplitude detector, a plurality of phase shifters and a transceiver. The antenna arrays and the first stage multi-mode-port matrices form a plurality of orthogonal omni-directional modes. Each of the modes has a characteristic phase set. Two of the modes' phases are used to determine DOA in azimuth. The second stage multi-mode-port matrix forms a sum-mode and a difference-mode used to determine the DOA of the received signals in elevation. A beam is formed in the direction of the received signals by adjusting the phase shifters.

Abstract: An antenna processing method for centered or potentially non-centered cyclostationary signals, comprises at least one step in which one or more nth order estimators are obtained from r-order statistics, with r=1 to n?1, and for one or more values of r, it comprises a step for the correction of the estimator by means of r-order detected cyclic frequencies. The method can be applied to the separation of the emitter sources of the signals received by using the estimator or estimators.

Abstract: Method of high-resolution direction finding to an arbitrary even order, 2q (q>2), for an array comprising N narrowband antennas each receiving the contribution from P sources characterized in that the algebraic properties of a matrix of cumulants of order 2q, C2q,x(l), whose coefficients are the circular cumulants of order 2q, Cum[xi1(t), . . . , xiq(t), xiq+1(t)*, . . . , xi2q(t)*], of the observations received on each antenna, for cumulant rankings indexed by l, are utilized to define a signal subspace and a noise subspace.

Abstract: A signal arrival direction deducing device capable of deducing the signal arrival direction even when a correlation matrix between input signals and noise correlation matrix are singular. A state is observed in which only noise is present and a state is observed in which a sound whose arrival direction is to be deduced. A short time Fourier transform is performed. Correlation matrix and an input signal correlation matrix are used to compute proper eigenvalues/proper eigenvectors and improper eigenvectors of the noise correlation matrix with respect to the input signal correlation matrix. A matrix for determining the complementary space component of the signal partial space is computed from the proper eigenvectors and the improper eigenvectors. An arrival direction search is made for the sound arrival direction using the matrix for determining the complementary space component of the signal partial space.

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

Abstract: According to a method for localizing a transmitter inside a building, a transmitter emits rays which undergo multiple reflections with the walls, ceilings and floors of the building. Each of K receivers receives rays from the transmitter, and the receivers estimates the AOA (Angle of arrival), TOA (Time of Arrival) and power of each ray. At least one of the receivers uses a known blueprint of the building and material characteristics of the walls to localize the transmitter to a higher degree of accuracy by applying a backward ray tracing algorithm.

Abstract: The invention relates to a method of localization of one or more sources, said source or sources being in motion relative to a network of sensors, the method comprising a step of separation of the sources in order to identify the direction vectors associated with the response of the sensors to a source having a given, incidence, characterized in that it comprises at least the following steps: associating the direction vectors a1m . . . aKm obtained for the mth transmitter and respectively at the instants t1 . . . tK, localizing the mth transmitter from the associated vectors a1m . . . aKm.

Abstract: A method and corresponding device for joint signal detection and direction of arrival estimation, based on the ability to identify both the existence and direction of arrival of a required signal featuring known characteristics, before it is forwarded to a modem. Optionally, after identifying the existence and direction of arrival of a required signal, the direction of arrival is entered into a beamformer featuring high resolution, for obtaining the signal coming from the required direction of arrival. The calculated signal is then entered into a modem.

Abstract: The invention relates to a radio apparatus for estimating a direction from which a received wave arrives and forming a radio transmission channel between a transmitting end of the received wave and itself. The invention aims to maintain stable transmission quality. The radio apparatus of the invention includes: two receiving sections which alternately detect two received waves that have arrived from a same transmitting end to two elements, in every period as an integer multiple of a period of each symbol of the received waves; and an arriving angle calculating section which calculates, in every period, an arriving angle as an inverse function of a difference in two phases which are proportional to a distance between the two elements, given as a function of positions of the elements and the arriving angle of the received waves, and contain a difference in phase shift amounts of the two receiving sections.

Abstract: A rotating antenna is used in a wireless system to impart a phase onto a received signal by electronically moving the effective receiving antenna location along a circular path such that the modulation phase angle indicates the bearing of the radio transmission and the gain of a signal transmitted by the antenna is increased in the direction of the received signal to enhance the link between transmitter and receiver. In order to simulate a rotating antenna, the antenna preferably comprises an antenna array having a plurality of antennae for use by one receiver. During reception of a signal from a remote transmitter, a scanner is adapted to scan through the plurality of antennae and in turn provide a signal received from each of the plurality of antennae to the receiver in the wireless system. The signal is modulated by virtue of the antenna rotation to include a Doppler frequency component.

Abstract: A method for calibrating an antenna and signal processing system enabling angle of arrival (AOA) determination for a frequency hopping signal, in which a calibration coefficient is determined in response to one or more calibration signals injected into the system at one or more of the frequencies in the hopping sequence and proximate in time to reception of the communication signal. The calibration coefficients are reflective of a frequency and time dependent parameter of a path between the antenna and wireless location sensor. The AOA is determined as a function of the calibration coefficient and the radio frequency energy of the received communication signal. Several embodiment of the method are illustrated.

Abstract: The present invention discloses a communication system and method for determining and recording the geographical location of an object attached with a short range wireless device, over a wide area, in a vicinity of a radio beacon that can be located by a remote control station, upon establishing or interrupting a wireless connection between said wireless device and said radio beacon. One embodiment of the invention relates to a system for search and rescue of a man overboard (person overboard), a quite frequent and fatal accident at sea.

Abstract: A communication system with an antenna array having a respective antenna for each of a multitude of communication modules and a control system which seiectiyely reassigns communication over a first of said multitude of communication modules to a second communication module of said multitude of communication modules in response to identification of a predicted interference within a predetermined interference matrix.