225results about "Radio wave finder monitoring/testing" patented technology

An apparatus and method for combining the functionality of multiple airborne traffic surveillance systems that operate in the L-band frequency range. The apparatus and method combine the functionality of both a Traffic Alert Collision Avoidance System (TCAS) and a Mode-Select (Mode-S) transponder in an integrated L-band traffic surveillance apparatus having a single processor that is embodied in a single Line Replaceable Unit.

The invention is directed to a system for detecting and defeating a drone. The system has a detection antenna array structured and configured to detect the drone and the drone control signal over a 360 degree field relative to the detection antenna array including detecting the directionality of the drone. The system also includes a neutralization system structured and configured in a communicating relation with the detection antenna array. The neutralization system has a transmission antenna structured to transmit an override signal aimed at the direction of the drone, an amplifier configured to boost the gain of the override signal to exceed the signal strength of the drone control signal, and a processing device configured to create and effect the transmission of the override signal. The invention is also directed to a method for detecting and defeating a drone.

A technique is disclosed for calculating the phase and amplitude weighting factors for use with a specific compact antenna range that synthesize an in phase, constant amplitude planar wave front that appears to have been transmitted from the far field. The weighting factors are used to weight RF signals after they are received by a full size or scaled radio direction finding array mounted on a platform during testing of the antenna array on the compact antenna range. The weighted received signals accurately replicate the antenna array response in the far field, including electromagnetic glint caused by the platform on which the antennas are mounted, and are stored in complex voltage form as a calibration table for the array.

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.

Methods and apparatus are provided for determining a direction of arrival (DOA) (46) of a Radio Frequency (RF) signal (32) transmitted by a remote unit (22) in a wireless communication system (20). The methods comprise receiving the RF signal (32) with multiple antennas (34,36,38,40,42,44) of the antenna array (26) and determining a preliminary direction of arrival (DOA) (78) for the RF signal (32) received with the multiple of antennas (34,36,38,40,42,44) of the antenna array (26). The methods also comprise selecting a coefficient (80) for the antenna array (26) based at least in part upon the preliminary DOA 978), modifying the RF signal (32) with the coefficient (80) to generate a modified RF signal (82), and determining the DOA (46) of the RF signal (32) with the modified RF signal (82).

A tentative location of a transmitter in an indoor environment is determined by triangulation, using at least two direction finders. The tentative location is made more accurate by performing at least one added action selected from the following: checking the likelihood that the tentative location is an accurate location by comparing measured transmitter signal strengths with calculated signal strengths, using a known indoor environment structure, using a record of the transmitter movement through the indoor environment for determining whether the transmitter is located in an obscured area of the indoor environment or performing an alignment procedure on the antennas to improve the triangulation.

Methods and systems for carrying different signals required for MIMO communication using a single coaxial cable between two endpoints of a distributed antenna system (DAS) network. Original MIMO signals having the same frequency are frequency-separated at a first endpoint of the network. The frequency-separated signals are propagated together over the single coaxial cable and then reconstructed to their original frequency at a second endpoint of the network.

The invention discloses an amplitude-phase combined measuring method measuring coning wave direction information; the method can effectively reduce the dependence relation of the phase difference measuring precision with the antenna array dimensions, and can effectively reduce the antenna array dimension; the method comprises the following steps: in a radio direction finding scene, a radio direction finding system employs direction finding antennas of a plurality of array elements to form a multi-channel direction finding antenna array so as to capture coming wave radiation signals; a radio direction finding device uses a radio frequency switch to control a radio frequency channel to select an input antenna signal or a calibration signal, and the radio frequency channel simulates, convertsfrequency, filters and amplifies and outputs the signal to a processing module; the processing module associates obtained space coming wave amplitudes with the phase difference information so as to obtain the coming wave characteristic vectors, selects samples from a sample database according to the signal frequency received in real time, and carries out Euclidean distance operation according tothe real time calculated association vectors and the sample data from the sample database, thus determining the distance extreme value, and obtaining the direction of the coming wave signals.

A method for locating a point in a first region based on receipt of a rf signal from the point. An antenna array is in the first region at a first position rotatable about an axis. A series of phase-array patterns is provided for implementation with the antenna array to provide measures of rf signal strength. Each pattern provides a plurality of reference values as a function of angle. A plurality of the phase-array patterns are used to acquire, in the first region, a plurality of rf signal strength values based on reception of the rf signal. A set of correlation values is determined where each value is a correlation between signal strength reference values and rf signal strength values acquired based on reception of the rf signal from the point. The correlation values identify a direction relative to the first position along which the point is located.

Disclosed is a hybrid antenna array (100) comprising a plurality of digital branches (145), each digital branch including an analogue beamforming sub-array (e.g. 110-1), each sub- array having a plurality of antenna elements (120), a phase shifter (130) adapted to apply a phase shift to the signal from each antenna element, and a combiner (e.g. 135-1) adapted to combine the phase-shifted signals. Each digital branch also includes a signal chain (e.g.140-1) adapted to convert the output of the sub-array to baseband. The hybrid antenna array also comprises a digital processing module (150), including: an angle of arrival estimation sub-module (155) adapted to estimate an angle of arrival of a signal at the antenna elements; a phase control sub-module (170) adapted to control the phase shift applied by each phase shifter depending on the estimated angle of arrival; and a digital beamformer (165) adapted to combine the baseband signals from the digital branches using a weight vector to form an output signal (180).

Antenna enclosure apparatus are provided that may be used to verify the signal path integrity, amplitude and / or phase of a single antenna or multiple antennas of direction finding (DF) antenna array and associated electronics without interference of external signals such as ground interference signals present when an aircraft-based antenna is tested on the ground. An individual antenna test enclosure may in one embodiment be provided as an antenna hood having a cavity dimensioned for internally receiving an antenna, such as an aircraft external blade antenna. The cavity of the antenna enclosure may be lined with a RF absorbing material inside the enclosure to allow for RF path testing with substantially no “ringing”, so that accurate phase and gain testing of a received antenna and its RF signal path may be accomplished.

A system for calculating the bearing of a signal source, with a directional antenna, provides corrections for distortion, such as due to a small fuselage of the monitoring aircraft and the elevation angle of an intruder aircraft with respect to the monitoring aircraft. A correction is applied to the bearing estimate that is based on relevant factors, such as the fuselage size and the elevation angle of the intruder aircraft. The correction can be calculated or applied through the use of a look-up table, which may be either pre-selected or selected after calculation of the elevation angle of the intruder aircraft.

Method and system of determining a location of a wireless transmitting device, such as a cellular phone, a wireless PDA or a radio tag, and guiding the searching personnel to physically reach the wireless transmitting device are disclosed that employ a “Movable Detection Station” and a “Guiding and Reference Device”, and optionally a “searching robot”. The movable detection station is carried on board of a moving platform, such as a police car, an ambulance or a fire truck, or carried by searching personnel. The guiding and reference device is a handheld device including a display device that displays position and guiding information to a user, and a reference wireless transmitter that works with a movable detection station. A searching robot is a robot with a reference transmitter installed on it.

A system for enhancing the performance of a wireless communication device (WCD) while executing a direction of arrival (DoA) estimation. The performance may be improved through device management, and may include the collection of information from one or more sensors installed within the WCD. The sensor information may initially be used to determine an appropriate configuration for the device. Further, the sensor information may also be used to affect the behavior of the device while performing the DoA estimation.

Systems and methods for providing antenna calibration can be used in a variety of applications. A method of calibrating an antenna array for use in a traffic advisory system or traffic alert and collision avoidance system provide a mechanism that renders complex combining circuitry unnecessary in the array. A method can include receiving an unsolicited reply that contains absolute position information of an intruder aircraft. The method can also include determining a bearing of a signal encoding the reply based on a phase relationship of the signals from an antenna array not configured to operate with an internal self-test phase calibration mechanism. The method can further include comparing the bearing based on the phase relationship with a bearing calculated by a comparison of the absolute positions of a host aircraft and the intruder aircraft. The method can additionally include calibrating the antenna array based on the result of the comparison.

System, method and computer program product for determining bearing using ADS-B and TCAS standard reply bearing estimates are disclosed. In one embodiment, a method for determining bearing based upon ADS-B signals includes receiving ADS-B signals and standard transponder reply signals. A first bearing estimate is based on the ADS-B signal. A second bearing estimate is based on the standard transponder reply signals. A database is developed according to the first and second bearing estimates via the ADS-B and standard transponder reply signals. In one embodiment, where ADS-B signals are unavailable, associated ADS-B signals associated with the standard transponder reply previously stored in the database are used to determine bearing.

The invention provides a near / far field broadband mixed source far field source direction finding method based on an amplitude-phase error array, relates to a near / far field broadband mixed source far field source direction finding method, and is to solve the problem of inaccurate estimation of direction of arrival of a far field information source in a near / far field broadband mixed information source when array amplitude-phase errors exist at present. The near / far field broadband mixed source far field source direction finding method based on the amplitude-phase error array comprises the following specific steps: 1) constructing an information source model under an ideal condition; 2) constructing an information source model under the array amplitude-phase errors according to the information source model constructed under the ideal condition; and 3) calculating a far field information source direction-of-arrival estimation value according to the information source model constructed under the array amplitude-phase errors. The method is used in the signal processing field.

The invention provides an interferometer array integrated correction method. The method includes the steps of firstly, parameterizing a target signal initial incidence direction, a processing and installing comprehensive error and a feeder line passageway comprehensive error; secondly, obtaining a measuring equation set according to a known track rotation antenna array, and obtaining error parameters and incidence signal directions through parameter estimation; thirdly, modifying the error parameters into an interference angle measurement formula to obtain a precisely-corrected angle through the iteration technology. By means of the method, the incidence signal directions do not need to be accurately calibrated, the basic known quantities of the method are the rotation angle and the phase difference measurement value, the interferometer array processing and installing comprehensive error and the feeder line passageway comprehensive error can be obtained at the same time through parameter estimation, the problem that the direction error and the pitching error are coupled can be solved through the iteration technology when the angle measurement error correction is executed, and finally the precisely-corrected angle is obtained. The interferometer array integrated correction method is accurate in error model, simple in execution process, high in correction precision and capable of improving the correction efficiency and the angle measurement accuracy of an interferometer.

The invention discloses a co-prime array DOA (direction of arrival) estimation method of an arrival freedom degree increase type based on compressed sensing, and mainly solves problems in the prior art that the freedom degree is limited and the calculation complexity is high. The method comprises the implementation steps: configuring a receiving end antenna according to a co-prime array structure; receiving an incident signal through a co-prime array; constructing a compressed sensing kernel; achieving the compression of the received signal through the compressed sensing, and obtaining a contour signal of the received signal of the co-prime array; calculating the covariance matrix of the contour signal after compressing; calculating an equivalent virtual signal corresponding to the contour signal; constructing a virtual domain sparse signal reconstruction optimization problem according to the equivalent virtual signal deduced from the contour signal, and solving the virtual domain sparse signal reconstruction optimization problem; and obtaining a DOA estimation result through spectrum peak searching. The method makes the most of the advantage that the co-prime array can improve the freedom degree, and the compressed sensing technology. The method achieves the increase of the freedom degree of a DOA estimation method while reducing the calculation complexity, and can be used for passive positioning and target detection.

A system for calculating the bearing of a signal source, with a directional antenna, provides corrections for distortion, such as due to a small fuselage of the monitoring aircraft and the elevation angle of an intruder aircraft with respect to the monitoring aircraft. A correction is applied to the bearing estimate that is based on relevant factors, such as the fuselage size and the elevation angle of the intruder aircraft. The correction can be calculated or applied through the use of a look-up table, which may be either pre-selected or selected after calculation of the elevation angle of the intruder aircraft.

In an ultra-wideband (“UWB”) receiver, a received UWB signal is periodically digitized as a series of ternary samples. During a carrier acquisition mode of operation, the samples are continuously correlated with a predetermined preamble sequence to develop a correlation value. When the value exceeds a predetermined threshold, indicating that the preamble sequence is being received, estimates of the channel impulse response (“CIR”) are developed. When a start-of-frame delimiter (“SFD”) is detected, the best CIR estimate is provided to a channel matched filter (“CMF”). During a data recovery mode of operation, the CMF filters channel-injected noise from the sample stream. Both carrier phase errors and data timing errors are continuously detected and corrected during both the carrier acquisition and data recovery modes of operation. The phase of the carrier can be determined by accumulating the correlator output before it is rotated by the carrier correction. By comparing the carrier phases of two receivers separated by a known distance, d, the angle of incidence, θ, of the signal can be determined.

The present invention relates to an apparatus for estimating an arrival-angle of a reception signal and a beam-forming apparatus in a radio wave receiver, such as radar. More specifically, the present invention relates to an apparatus for accurately estimating an arrival-angle of a reception signal, or an apparatus for performing the beam-forming of a reception signal by using a multi-reception array antenna, by using a reference value that is obtained by calculating the degree of distortion of the magnitude and phase of a signal for each reception angle.

Systems and related methods are delineated for employing a TCAS to provide a radar function for a UAS. One such system comprises a TCAS having at least a transceiver and an antenna, and a processor coupled to the transceiver for receiving signals generated from receipt of reflected energy received over the antenna, the reflected energy resulting from the one or more of a Mode S interrogation waveform and an ATCRBS interrogation waveform transmitted from the antenna.

The invention discloses a system and method for carrying out phase calibration. The system is composed of a direction-finding antenna array, a calibration device, a rotary table, and a direction-finding receiver. The calibration device consists of an input terminal and an output terminal; and the input terminal is connected with the direction-finding antenna array. The rotary table includes a first end and a second end; and the first end is connected with the output terminal. The direction-finding receiver includes a direction-finding receiver internal channel and a direction-finding receiver processor; and the direction-finding receiver processor is connected with the second end. The calibration device is controlled by the direction-finding receiver to transmit a radio-frequency calibration signal; the signal passes through the rotary table and the direction-finding receiver internal channel and then is sent to the direction-finding receiver processor; the direction-finding receiver processor carries out phase measurement on the radio-frequency calibration signal; phase adaption errors between receiving channels except the direction-finding antenna array among the receiving channels in the system are obtained, so that phase calibration of the receiving channels except the direction-finding antenna array can be completed based on the phase adaption errors.

Techniques are disclosed that allow for the detection, identification, direction finding, and geolocation of emergency personnel in a given multipath environment. For example, the techniques can be used to detect and identify multiple lines of bearing (LOBs) to an IEEE 802.11 emitter of an emergency responder that is inside a building or otherwise hidden from view. LOBs from multiple vantage points can be used to geolocate and / or track the emergency responder. The resulting geolocation can be plotted on a map display or model of the scene (e.g., building, etc) so the precise position of the emergency responder having the targeted wireless emitter can be known.

The invention discloses a multichannel direction-finding receiver calibration system and method based on error modification. The system includes a signal processing module, a storage module, a standard calibration module, a standard calibration antenna and multiple signal receiving assemblies; each signal receiving assembly consists of a wave filter, an amplitude limiter, an SP2T switch, a frequency conversion channel and an ADC module, wherein the frequency conversion channel of one signal receiving assembly is a reference channel, and the frequency conversion channels of other signal receiving assemblies are phase detection channels; the signal processing module is used for controlling generation of signals of a standard calibration source and switchover of the SP2T switches, processingthe received signals, obtaining phase calibration tables at different temperatures and conducting error modification on the phase calibration tables before use every time. The phase calibration tablesof the signal receiving assemblies in which the phase detection channels are located can be generated at different temperatures, error modification is conducted on the phase calibration tables beforeuse, improvement of the phase calibration precision is facilitated, and the direction-finding performance of a receiver is ensured.

The invention relates to an arrival direction self-correction method for a sensor array. According to the method, a noise subspace estimated value is determined; an array phase error of the sensor array is initialized, and an initial value of the signal arrival direction is estimated through utilizing an MUSIC algorithm; based on the calculation value of the signal arrival direction, a Hermitian positive definite matrix is calculated, and the Hermitian positive definite matrix satisfies a first equation; an array element phase error is made to satisfy the first limit condition, and the array phase error is converted to satisfy a second equation; the first equation and the second equation are solved through utilizing a Lagrangian multiplier method to acquire a vector estimated value of the array phase error; a correction value of the signal arrival direction is acquired through utilizing the MUSIC algorithm or a high resolution subspace algorithm; and iteration of the previous steps is repeatedly carried out till iteration stop conditions are satisfied. The method is advantaged in that dependence on special structure characteristics of an array output covariance matrix is avoided, excellent performance is realized under the condition of limited sampling data, and influence of the sensor array error on the arrival direction can be effectively reduced.