57results about "Direction-finding diversity systems using radio waves" patented technology

A method and apparatus for determining the range, radial velocity, and bearing angles of scattering objects reflecting RF signals or for determining the range, radial velocity, and bearing angles of sources RF signals. An array of antenna elements is utilized, the array of antenna elements each having an associated two state modulator wherein transmitted and / or received energy is phase encoded according to a sequence of multibit codes, the bits of the multibit codes each preferably having two states with approximately a 50% probability for each of the two states occurring within each given multibit code in said sequence of multibit codes, thereby allowing the determination of range, radial velocity, and bearing angles through digital computation after the scattered signals have been received.

A positioning system includes a device, having an antenna and a reflector with a known position proximate to the antenna, that transmits at least an electromagnetic pulse having a carrier signal frequency. The device receives a return signal over a period of time, wherein the return signal includes a return pulse from an object within a radar detection area of the device and at least one multi-path pulse. The device processes the return signal so as to isolate the return pulse and the at least one multi-path pulse from the return signal. The device determines a range from the device to the object and the position of the device relative to the object. The range is determined in accordance with a time of arrival of the return pulse and the position is determined in accordance with a time of arrival of the at least one multi-path pulse.

In a direction finding system, pluralities of signals provided by different sets of less than all of a plurality of arrayed antennas are code division multiplexed, downconverted by a single receiver, A / D converted and separated to derive signals that are processed to estimate the directions of arrival of the signals received by the different sets of antennas at different frequencies. The signals from different antennas are coded with different codes that have a common M-sequence and different phases for the different antennas. The derived signals are processed to detect the presence of signals and simultaneously demodulate and estimate the directions of arrival of signals by the antennas at the different frequencies. The different sets of antennas from which the received signals are provided for coding and multiplexing are selectively varied in accordance with the estimated directions of arrival and estimated magnitudes.

An apparatus and method are provided for simply estimating joint channel and Direction-of-Arrival (DOA) to efficiently estimate a channel impulse response associated with a spatially selective transmission channel occurring in a mobile radio channel, and performing efficient beam forming using the simplified joint channel and DOA estimation are provided. A receiver estimates the total interference power using power for each interference signal, estimates a spectral noise density, calculates steering vectors considering predetermined DOAs, and jointly calculates optimal weight vectors for each DOA of each user by applying the interference power and the spectral noise density to the steering vectors. The beam forming reduces implementation complexity of a TDD system such as a TD-SCDMA and increases beam forming efficiency in a mobile environment by efficiently using spatial diversity.

A method and apparatus for generating accurate estimates of a radar target's azimuth and elevation angles for a phased-phased array rotating radar. Scan modulated coherently integrated (SMCI) monopulse curves are generated from a measured one-way transmit antenna pattern and three receive antenna patterns. The SMCI monopulse curves are calculated in advance for the expected beam steers. To utilize the SMCI monopulse curves, two-way Sum, Delta-Azimuth and Delta-Elevation target returns are coherently integrated, the target's monopulse ratios calculated, and the SMCI monopulse curves or polynomials used to calculate the target's U-offset and V-offset sine-space angles, which are added to the radar's beam steer to get an improved estimate of the target's sine-space angular position denoted as Utgt and Vtgt. A coordinate system transformation transforms Utgt and Vtgt to azimuth and elevation angles in a non-rotating coordinate system.

The present invention relates to methods and apparatus for tracking moving objects, such as ballistic missiles and aircraft, on the basis of discrete sensor measurements, such as radar reports and reports from optical sensors. In particular, but not exclusively, the invention is useful for the simultaneous tracking of multiple, fast moving, closely spaced objects, such as deploying ballistic missiles and raids of fast agile aircraft, in which the track dynamics of each object are modelled using a collection of autonomous, i.e. non-interacting, multiple dynamics models. Embodiments of the invention were particularly developed to be effective in tracking ballistic missiles using early warning radar, and similarly demanding and complex battle scenarios.

The reconfigurable radio direction finder system and method uses a reconfigurable antenna to electronically cycle through a plurality of different antenna configurations to determine a signal direction. Specifically, the reconfigurable antenna is cycled through N different antenna configurations, where N is an integer greater than one, where each antenna configuration has a pointing direction associated therewith defined by an elevation angle θn of an n-th antenna configuration, where n is an integer between 1 and N, and an azimuthal angle φn of the n-th antenna configuration. A received signal strength of the radio signal is measured for each of the antenna configurations as a power output of the n-th antenna configuration, Pn. A spherical weighted directional mean vector (XDF, YDF, ZDF) is then estimated for the radio signal asXDF=1NΣn=1NPncos(φn)sin(θn),YDF=1NΣn=1NPnsin(φn)sin(θn)andZDF=1NΣn=1NPnsin(θn).

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.

The invention relates to an electronic device having arrival angle detection capabilities. An electronic device may be provided with wireless circuitry that includes first, second, and third antennasused to determine the position and orientation of the electronic device relative to external equipment. The antennas may include patch elements on respective substrates mounted to a flexible printed circuit. Each substrate may include fences of conductive vias that are coupled to ground and that laterally surround the corresponding patch element. Control circuitry may identify phase differences between the first and second antennas and between the second and third antennas and may identify an angle of arrival of received ultra-wide band signals using the phase differences. The control circuitry may compare the phase differences to a set of predetermined surfaces of phase differences to identify environmental loading conditions for the antenna. The control circuitry may correct the angle ofarrival using offsets identified based on the environmental loading conditions.

A radio communication apparatus includes a variable directivity antenna and a control unit and performs radio communication with another radio communication apparatus. The control unit calculates a position of the another radio communication apparatus by measuring a distance to the another radio communication apparatus and measuring directivity of the another radio communication apparatus by switching directivity of the wave of radio communication using the variable directivity antenna with a MEMS switch. Moreover, the control unit controls the output of the variable directivity antenna according to the calculated position of the another radio communication apparatus.

An Advanced Focal Plane Array (“AFPA”) for parabolic dish antennas that exploits spatial diversity to achieve better channel equalization performance in the presence of multipath (better than temporal equalization alone), and which is capable of receiving from two or more sources within a field-of-view in the presence of multipath. The AFPA uses a focal plane array of receiving elements plus a spatio-temporal filter that keeps information on the adaptive FIR filter weights, relative amplitudes and phases of the incoming signals, and which employs an Interference Cancelling Constant Modulus Algorithm (IC-CMA) that resolves multiple telemetry streams simultaneously from the respective aero-nautical platforms. This data is sent to an angle estimator to calculate the target's angular position, and then on to Kalman filters FOR smoothing and time series prediction. The resulting velocity and acceleration estimates from the time series data are sent to an antenna control unit (ACU) to be used for pointing control.

Provided are a method and an apparatus for generating and transmitting feedback signals for a plurality of reference signals having different directionality, in a wireless communication system. A terminal may receive the plurality of reference signals having different directionality, and transmit, to a transmission end, a feedback signal including a beam index which indicates one of the plurality of reference signals.

Systems and methods for the selection of antennas in aircraft navigation systems are provided. In one embodiment, a navigation receiver system for an aircraft comprises: a first aircraft antenna that receives transmitter signals from fixed-location ground transmitters and a second aircraft antenna that receives transmitter signals from the fixed-location ground transmitters, wherein the first aircraft antenna has a first gain pattern that is different from a second gain pattern of the second aircraft antenna; a switch coupled to a first receiver and the first and second aircraft antenna; and a switch controller coupled to the switch. The switch controller operates the switch to electrically couple the first receiver to either the first or second aircraft antenna based on a determination of whether the first gain pattern or the second gain pattern provides higher gain in a direction of a first fixed-location ground transmitter of the fixed-location ground transmitters.

The disclosure provides a channel-based positioning device, a channel-based positioning system and a channel-based positioning method. The channel-based positioning method includes: calculating a plurality of angles of arrival (AoA), a plurality of angles of departure (AoD) and a plurality of time of flight (ToF) of signals according to a plurality of channel state information transmitted from a terminal apparatus to a base station; determining a path type of the signals according to the plurality of AoA, AoD and ToF of the signals; and calculating a position information of the terminal apparatus relative to the base station through a specific algorithm.

An arrival angle estimation system includes a transmitting device and a receiving device and estimates an arrival angle at which frames transmitted by radio from the transmitting device arrive at the receiving device. The transmitting device includes two directional antennas each arranged so that its directivity is tilted at ±θ degrees with respect to the front of the transmitting device. The receiving device includes a directional antenna having directivity toward the front of the receiving device. Frames are transmitted alternately from the respective directional antennas of the transmitting device, and received signal strengths of the frames on the receiving device side for the respective transmitting directional antennas are compared with each other to estimate the arrival angle.

This patent concerns a compact and portable system for real-time detection and location of electromagnetic emissions in the spectrum used by mobile devices (cell phones and Wi-Fi / Bluetooth devices). The principle of detection and location is based on phased array technology, which enables the synthesis of a directional radiation beam that can be electrically controlled in terms of both its shape and direction. This technology is used primarily in military and astronomical applications. The device also includes localization and control algorithms. This device will allow for detecting and locating electromagnetic emissions by means of an antenna beam scan within a field of view of 80×80 degrees. Once the detection and location have been established, the results are overlaid to a visual image captured by a video camera.

Iterative methods for direction of arrival estimation of a signal at a receiver with a plurality of spatially separated sensor elements are described. A quantized estimate of the angle of arrival is obtained from a compressive sensing solution of a set of equations. The estimate is refined in a subsequent iteration by a computed error based a quantized estimate of the direction of arrival in relation to quantization points offset from the quantization points for the first quantized estimate of the angle of arrival. The iterations converge on an estimated direction of arrival.

A receiver includes a first terminal for receiving an RF signal having a frequency of less than approximately 60 MHz, a second terminal, and a receive path having an input coupled to the first terminal and an output for providing a demodulated RF signal. The receiver further includes a detector coupled to the receive path for detecting a signal parameter in the RF signal and a controller coupled to the detector and to the second terminal. The controller provides the multiplex signal in a tuning state to the second terminal to selectively provide one of a first RF signal and a second RF signal to the first terminal and to determine at least one of a first parameter of the first RF signal and a second parameter of the second RF signal. The controller provides the multiplex signal in an operating state based on the first parameter and the second parameter.

Directional characterization of a location of a target device makes use of multiple radio transmissions that are received from the target device. In some examples, each radio transmission is received at a first antenna at a fixed location, and is also received at a second moving antenna. The received transmissions are combined to determine the directional characterization, for example, as a distribution of power as a function of direction. In some examples, the received radio transmissions are processed to determine, for each of a plurality of directions of arrival of the radio transmissions, a most direct direction of arrival, for example, to distinguish a direct path from a reflected path from the target.

The invention provides a high-precision positioning algorithm and device for a bistatic EMVS-MIMO radar, and the algorithm comprises the steps: constructing a sample matrix after the matched filteringof a receiving array, and calculating a covariance matrix estimation value of a received signal; constructing a high-order received signal covariance tensor model by using the Tucker tensor model; performing high-order singular value decomposition on the high-order covariance tensor model to obtain a new signal subspace and a new noise subspace; obtaining estimation of an azimuth angle and a pitch angle of the target and estimation of a two-dimensional polarization angle by using a rotation invariant technology and a vector cross product technology; and pairing of DODs and DOAs is realized byusing a subspace orthogonal principle. According to the method, a tensor structure for receiving array signals is considered, and high-precision target multi-parameter estimation can be obtained based on a tensor subspace algorithm.

An orientation and localization system is provided with spatial filtering capabilities that combines time polarization and space diversity to detect the direct lines of sight (LOS) and to deliver location and orientation estimates of mobile nodes.

The present invention relates to a small type antenna array aperture expanding and space signal processing method. Said method includes the following steps: making antenna array into any array form: dividing scanning area of whole antenna into several subregions, finely-dividing any one subregion of said several subregions; in the finely-divided subregion constructing actual array flow form of antenna array and array flow form of expanded array so as to further obtain the array expansion conversion matrix; utilizing the obtained array expansion conversion matrix to reconstitute the signal of expanded antenna array; then making said signal undergo the process of digital beam formation or adaptive beam formation or utilizing space high resolution algorithm to obtain space arrival angle of signal.

The invention discloses an underdetermined DOA estimation method based on target space diversity, and aims at LFMCW system radar. The method comprises the following steps: carrying out two-dimensionalFFT on each path of array antenna receiving signal by utilizing the characteristics of an LFMCW system radar; selecting one path of signal to carry out two-dimensional constant false alarm rate CFARdetection so as to acquire distance and speed information of the target; wherein each path of signal is divided into target subspaces according to the distribution of a target in a distance-speed space; and finally, performing DOA estimation on each target subspace. By means of the characteristics of the LFMCW radar, diversity is conducted on incident target signals in the distance-speed space, more target DOAs can be estimated when the number of array elements is fixed, the overall performance of the array is improved, and distance-speed-angle joint positioning of targets can be achieved. Themethod is high in angle measurement precision, good in anti-noise performance, suitable for various array structures, simple, easy to operate and convenient for engineering practical application.

Aspects of the present disclosure may compensate for cyclic shift delays (CSD) in transmitted signals when estimating angle of arrival information of a wireless signal transmitted by a transmitting device. In some aspects, a receiving device may determine a presence of CSD in the wireless signal, and estimate an angle of arrival of the wireless signal based at least in part on the presence of CSD.For example, the receiving device may determine a first tap of the wireless channel based at least in part on the CSD. The receiving device may then determine a phase difference of the wireless signal between a plurality of antennas of the receiving device based on the first tap of the wireless channel. The receiving device may estimate the angle of arrival of the wireless signal based on the phase difference.

The present invention discloses an MIMO radar target direction rapid estimation method based on a partial correlation waveform, belongings to the technical field of radar. The method comprises the steps: determining an MIMO radar, wherein the MIMO radar comprises an emission array and a receiving array which are arranged in a transmit-receive mode; emitting the partial correlation waveform by theemission array to obtain a target echo signal matrix; determining a target airspace range requiring detection to obtain a rough assessment value of the target direction and a Doppler frequency of thetarget so as to obtain MIMO radar Doppler filtering data; determining a target direction search range, and calculating a cost function value of the maximum likelihood algorithm of the receiving arrayand a cost function value of the maximum likelihood function algorithm of the emission array in the target direction search range; and determining a final estimation value in the target direction, wherein the final estimation value in the target direction is a rapid estimation result of the MIMO radar target direction based on the partial correlation waveform.