203 results about "Radial velocity" patented technology

Aircraft landing gear comprised of a wheel hub motor/generator disks stack, includes alternating rotor and stator disks mounted with respect to the wheel support and wheel. The wheel hub motor/generator can provide motive force to the wheel when electrical power is applied, which may be applied prior to touch-down thus decreasing the difference in relative velocities of the tire radial velocity with that of the relative velocity of the runway thus greatly reducing the sliding friction wear of said tire. After touchdown the wheel hub motor/generator may be used as a generator thus applying a regenerative braking force and/or a motorized braking action to the wheel. The energy generated upon landing maybe dissipated through a resistor and/or stored for later use in providing a source for motive power to the aircraft wheels for the purpose of taxiing and ground maneuvers of said aircraft.

A device and method of geolocating a transmitter. First and second receivers, in motion, receive a signal from the transmitter. Digitizers in the receivers digitize the signal. Converters in the receivers for converting the digitized signals to complex-valued signals. Transmitters on the receivers transmit their digitized signals, locations, and velocities at the time the signal was received to a processor. A central processing unit on the processor determines a difference in radial velocities of the receivers relative to the transmitter. The difference in radial velocities and delay time between the signals received at the receivers are used to geolocate the transmitter.

In a method for operating a radar system, the object is to determine by simple means and at low cost the distance and/or the radial velocity of at least one target object with high resolution. For this purpose, in each measuring phase of the measurement process in the "pulse FMCW radar system", switchover between a transmission mode and a receiving mode is effected a multiple number of times and at short intervals of time. In the transmission mode, all receiving units of the radar system are switched off, while a pulse-shaped (frequency-modulated) transmission signal with time-successive transmission pulses having a specific pulse-on time and a specific carrier frequency is emitted from at least one transmitter unit of the radar system. In receiving mode, all transmitter units are switched off in the pulse-off times of the transmission pulses, while from at least one receiver unit all reflection signals originating from the last emitted transmission pulse are detected as received signal from the entire observation range before emission of the next transmission pulse. The distance and/or the radial velocity of the reflection objects is determined indirectly by the signal processing unit of the radar system by evaluation of the frequency difference and/or phase difference between the transmission signal and the received signal.

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.

An improved wafer-to-wafer bonding method includes aligning an upper and a lower wafer and initiating a bond at a single point by applying pressure to a single point of the upper wafer via the flow of pressurized gas through a port terminating at the single point. The bond-front propagates radially across the aligned oppositely oriented wafer surfaces at a set radial velocity rate bringing the two wafer surfaces into full atomic contact by controlling the gas pressure and/or controlling the velocity of the motion of the lower wafer up toward the upper wafer.

A method of detecting radar returns and measuring their parameters with or without clutter present and no clutter cancellation employed which includes transmitting at least one pulse; processing the returns surpassing a threshold detected in one range azimuth bin and by processing and separating out the returns based on their different range and azimuth. Another method includes transmission of many pulses and has minimum of one channel return surpassing detected threshold, which is detected in one range Doppler bin. The method also includes processing and thereby separating out the returns based on their different radial velocity and or azimuth and comparing the returns to a database of expected returns and adaptively processing returns that do not correspond to the expected returns. The method identifies the non-corresponding returns as indicative of at least one of clutter, land sea interface, clutter discretes and antenna sidelobe returns each without utilizing clutter cancellation.

A method and system are disclosed for tracking objects which are crossing behind a host vehicle. Target data from a vision system and two radar sensors are provided to an object detection fusion system. Salient points on the target object are identified and tracked using the vision system data. The salient vision points are associated with corresponding radar points, where the radar points provide Doppler radial velocity data. A fusion calculation is performed on the salient vision points and the radar points, yielding an accurate estimate of the velocity of the target object, including its lateral component which is difficult to obtain using radar points only or traditional vision system methods. The position and velocity of the target object are used to trigger warnings or automatic braking in a Rear Cross Traffic Avoidance (RCTA) system.

A method for operating a radar system using at least two antennas provides an increased angular resolution for determining the angular position, radial velocity, and/or distance to a reflection object. A plurality of successive measuring phases are carried out in at least one measuring process. In each measuring phase, operation is repeatedly switched between a transmitting operation in which a transmitted signal pulse is emitted, and a receiving operation in which reflection signals are detected as received signals in the pulse pause interval between successive transmitted pulses. In at least one measuring phase, two different neighboring antennas of the radar system are used respectively as the transmitting antenna for emitting the transmitted signal and as the receiving antenna for detecting the reflected signal. In this manner, the respective receiving antenna monitors only the angular range of overlap between the emitted beam of the transmitting antenna and the field of view of the receiving antenna. The information provided by the detected signals in this overlapping angular range achieves an increased angular resolution. The method is particularly suitable for operating a separation distance warning system for a motor vehicle.

A sense-and-avoid system, for an unmanned air vehicle (UAV), configured to detect and estimate the relative position and velocity of a nearby object and to enable determination whether the nearby object poses a collision threat to the UAV. In one embodiment, the sense-and-avoid system is provided with a frequency modulated continuous wave (FMCW) synthesizer adapted to generate at least one swept-frequency waveform. The sense-and-avoid system may also be included with an RF subassembly. In some embodiments, the RF subassembly may include at least one transmit antenna adapted to transmit the at least one swept-frequency waveform. The at last one swept-frequency waveform may illuminate the nearby object. The sense-and-avoid system may be further provided with a plurality of receive antennas adapted to receive an echo signal from the nearby object. In some embodiments, the echo signal results from the illumination of the nearby object by the swept-frequency waveform. Additionally, the sense-and-avoid system may be provided with a signal processor configured to analyze the received echo signal and to derive object data for the nearby object. The object data may include at least range, radial velocity, and two-dimensional angle of arrival.

A centrifugal pump having a turbine impeller having a plurality of curved vanes. The vanes curve from the inlet end to the outlet end in the direction of pumping rotation of the impeller, such that the leading wall of each vane re-directs a portion of the radial velocity of the fluid flowing through the passage to increase the total tangential velocity provided by the impeller. Each curved passage has cooperating inlet and outlet areas and a smooth curved shape to ensure that the radial velocity of the liquid does not decrease dramatically while flowing through the passage, while ensuring that any solid particulates and contaminants entering the impeller will pass therethrough.

An apparatus separates liquid, gas and solid components of a mixture in a fluid system. An inlet for receiving the mixture opens into a separation chamber tangentially with a cylindrical side wall and a gas outlet has an opening in a first end wall adjacent the inlet to allow gas to exit the separator. A fluid outlet is located in an opposing second end wall. A debris passage extends through the cylindrical side wall and oriented so that the radial velocity of the particles within the separation chamber directs the particles through the debris passage. The debris passage leads to a particle collection chamber in which the particles accumulate. Unlike prior separators that relied on the tangential velocity of the particles, the present apparatus utilizes the greater radial velocity to drive the particles from the separation chamber into the particle collection chamber.

The invention discloses a method for non-meteorological noise in radar echoes, which comprises the steps of: identifying noise areas existing on an 1.5 DEG elevation plane and an 0.5 DEG elevation plane by simply classifying the radar echoes, then analyzing reflectivity factor values of the echoes and then orderly referring radial velocity values and spectrum width values; performing a best noise rejection strategy on different noises after the noise areas are correctly identified; directly adopting a rejection strategy for noises under the conditions of clear sky and no precipitation echoes at peripheries; and adopting an approximate value filling mechanism for noises which are mixed in the precipitation echoes or are adjacent to the precipitation echoes so as to achieve better rejection effect.

The invention discloses a method of moving-target relocation and velocity ambiguity resolution based on a velocity synthetic aperture radar (VSAR) system, which mainly solves the problems that the velocity estimation accuracy of a moving target is low and the velocity of a fast moving target is ambiguous in the radar detection system. According to the method of moving-target relocation and velocity ambiguity resolution based on the VSAR system, the process includes perform range-doppler algorithm imaging to received data of each of array elements of the VSAR system; detecting the moving target and recording the corresponding position of the moving target after image registration, clutter suppression and cell average constant false alarm detection processing; using subspace fitting algorithm to estimate normalized velocity frequency after phase compensation so that the velocity estimation accuracy is effectively improved; extracting speed channel of the target, using multi-look differential frequency method to estimate doppler ambiguity number; calculating radial velocity of non-ambiguity according to the ambiguity numbers and estimate value of the velocity frequency and achieving an accurate location of the target. According to the method of moving-target relocation and velocity ambiguity resolution based on the velocity synthetic aperture radar (VSAR) system, the estimation accuracy and the detection performance are improved. Due to the fact that the ambiguity resolution processing is merely required for 2-3 iterations, the calculation is reduced, the accurate probability of understanding doppler ambiguity is improved and the effectiveness of the method is proved in a simulation experiment.

The invention provides a ground moving target detection and parameter estimation method. The technical scheme realizes the moving target detection and two-dimensional velocity estimation by combining with an interference image sequence with multiple sub-bands and sub-apertures on the basis of a three-way ultra-wide bandwidth (UWB) synthetic aperture radar (SAR) image. The specific steps of the method are as follows: 1, generating a sub-band sub-aperture image sequence; 2, generating a sub-band sub-aperture interference image sequence; 3, detecting the moving target; and 4, estimating the two-dimensional velocity of the moving target. By using the ground moving target indication and parameter estimation method provided by the invention, the moving target and a static target can be distinguished on an imaging position and a phase position; the radial velocity of the moving target can be estimated clearly; and the azimuth speed and distance speed can also be estimated.

The invention discloses an ocean current field inversion satellite-borne SAR system based on angle diversity, and a method thereof. The satellite-borne SAR system comprises two radar antennas which are arranged in the flying direction of a satellite, wherein the two radar antennas respectively generate two radar wave beams; and the two wave beams have different squint angles and can irradiate the same area on the ocean surface in different time. The method comprises: utilizing the satellite-borne SAR system and taking a doppler center frequency as the observation variable to perform inversion on an ocean current field; and obtaining a complete velocity vector of an ocean current, that is, the ocean current information obtained through inversion not only includes the radial velocity information of the ocean current but also includes the azimuth velocity information. Compared with a traditional ocean surface current field inversion means, such as field observation and shore-base radar observation, the ocean current field satellite-borne SAR system based on angle diversity can realize inversion of a worldwide ocean current field, can comprehensively know about temporal and spatial variation of the ocean current, and can work all day long and all weather without limitation of meteorological conditions.

The invention provides a high-speed mobile platform TDMA satellite communication synchronization control method based on ephemeris. A radial velocity and location of a satellite relative to an earth station are obtained by using high-precision satellite ephemeris information, a platform location and a radial velocity are obtained through the navigation information of the platform, the speeds of the two components are superposed, the platform roughly estimate a distance measurement distance between the two components according to the positions of the two components according to a result compensation frequency deviation, and the platform compensates a timing deviation according to real distance measurement information and finally meets the synchronization requirements. By adoption of the high-speed mobile platform TDMA satellite communication synchronization control method provided by the invention, the Doppler frequency and delay variation caused by the high-speed movement of low orbitsatellites and the platform can be compensated.

The present invention belongs to the radar identification technological field and provides a Radon transform-based moving object imaging method, a Radon transform-based moving object imaging device, an electronic device, and a computer-readable storage medium. The imaging method includes the following steps that: the echo signals of a moving object are obtained; distance compression is performed on the acquired echo signals; distance bending correction is performed; the radial velocity of the moving target is calculated through Radon transform; a phase term introduced into a calculation process is compensated and corrected; and the azimuth velocity of the moving target is calculated through using a BIDI technique; and matched filtering is performed on the moving target in the azimuth Doppler domain, so that the focused imaging of the moving target can be obtained. With the imaging method of the invention adopted, the accuracy of the positioning and imaging result of the moving target can be improved.

The invention relates to a deep convolutional adversarial neural network-based human body action radar image classification method. The method comprises the steps of constructing a data set; realizingradar image data enhancement through a DCGAN: establishing the DCGAN, using the network to individually learn each radar spectrogram, generating new radar spectrograms according to characteristics learned by the network, expanding training set samples under the condition of a certain data amount, adjusting parameters by the network to ensure that fewest failure images are generated, and expandingthe data set to the maximum extent, thereby realizing the data enhancement; and extracting upper, middle and lower envelopes in each radar image to serve as eigenvectors, taking the three eigenvectors as inputs of a support vector machine classifier, and classifying radar image data by utilizing a support vector machine, wherein the upper and lower envelopes represent echo radial velocities of human limbs, the middle envelope represents an echo radial velocity of a human trunk.

A method for classifying vehicles in which an angle-resolving radar device yields measurement signals which have frequencies corresponding to a Doppler shift and which originate from measured vehicles and from which radial distances, object angles and radial velocities can be derived. The frequencies of the acquired measurement signals are stored as functions over the measurement time period, and a spectrogram is formed for every vehicle therefrom. Subsequently, the spectrograms are checked for assessment regions with maximum bandwidth of the frequency. These assessment regions are compared with assessment regions of stored spectrograms for different vehicle classes and associated with the most similar such that the measured vehicles are classified.

An embodiment of the invention includes a step of transmitting an OFDM waveform including several frequency carrier signals transmitted simultaneously, the frequency carrier signals being coded in order to improve the Doppler response. An embodiment of the invention includes a step of receiving the echoed waveform from the target. The initial phase of each frequency carrier signal is recovered from the echoed waveform. The recovered initial phase of each frequency carrier signal is cyclically shifted in order to compensate for the Doppler effect and subsequently decoded. A compressed pulse is synthesized from the decoded initial phases.

In certain embodiments, a wireless communication link includes a wireless receiver that receives a circular polarized signal from a remotely configured transmitter. The circular polarized signal has a polarization vector that rotates at a radial velocity. The wireless receiver determines a phase deviation in the radial velocity of the polarization vector and demodulates information from the circular polarized signal according to the determined phase deviation. The phase deviation is caused by a frequency deviation of the circular polarized signal generated by the transmitter.

Method for determining navigation parameters of an aircraft, characterized in that it consists at least in determining the geographic speed {right arrow over (V)}, expressed in a given local fixed coordinate system {{right arrow over (i)}, {right arrow over (j)}, {right arrow over (k)}}, based on the measurements m, of carrier phase increments Δφ_i of the radio navigation signals originating from a plurality of radio navigation satellites in sight of said aircraft, each of said measurements m_i constituting an estimate of the relative speed of said aircraft relative to said satellite projected onto the sight axis linking the aircraft to the satellite, each of said measurements m, being compensated by the apparent radial speed of the satellite.

The invention proposes a target motion parameter estimation method for a random frequency hopping radar, and solves the problem that the existing speed measurement scheme has a long accumulation time,a large calculation amount and a poor anti-noise performance. The method comprises the main steps of: designing a waveform parameter for transmitting a random frequency hopping signal and receiving atarget echo; preprocessing digital signals; preprocessing the slow time sampling vector; constructing a difference frequency vector group; constructing a Doppler domain generalized Fourier transformmatrix group; carrying out the generalized Doppler transform and non-coherent processing; carrying out motion compensation processing; and carrying out the coherent integration of distance dimensionsand de-redundance processing to obtain a one-dimensional range profile with the correct target in the plurality of range gates. According to the target motion parameter estimation method for the random frequency hopping radar, a set of dimension decreasing difference frequency vectors are constructed from the target echoes, generalized Doppler processing is performed on each difference frequency vector, and an estimated value of the target radial velocity can be read in the generalized Doppler spectrum after non-coherent integration. The method is short in accumulation time, small in calculation amount and good in anti-noise performance, and is used for target detection and pulse accumulation of the random frequency hopping radar.

The present invention provides an innovative apparatus, system and method for onboard spacecraft location determination and navigation by employing the observation of extrasolar planetary star system motion. In one apparatus embodiment a gas absorption cell is placed between a sensor and the light from a reference star system with at least one exoplanet, such that the sensor can detect the spectrum through the gas absorption cell. Radial velocities can be calculated via Doppler Spectroscopy techniques and incorporated into a spacecraft navigation solution. The present invention can enable and enhance significant mission capabilities for future manned and unmanned space vehicles and missions.

An improved axial gas bearing for a gas-driven NMR MAS sample rotor is disclosed that utilizes inward flow with a low rotational component over a rotor conical end. A conical flow region is formed between the rotor conical end and a conical stator bearing surface such that the included angle defining the stator surface is not less than the included angle defining the rotor conical end. Gas is injected radially inward with a significant axial rearward component from a number of small holes at high velocity from the periphery into the conical flow region. Compared to the radial velocity components, the tangential flow components of the injected gas are small and preferably opposed to the direction of the rotor rotation. The high and accelerating negative radial velocities may result in significant Bernoulli effect, such that the mean axial pressure over the conical rotor end may be less than atmospheric pressure for a given axial clearance, but as the clearance decreases, the hydrostatic effects exceed the Bernoulli effects and the mean axial pressure over the conical rotor end may then exceed atmospheric pressure by a substantial amount. Thus, a self-stabilizing axial bearing is formed with improved stability and stiffness for rotor surface speeds up to at least 80% of the speed of sound. Motive power required to spin the rotor may be provided by a radial-inflow microturbine at the opposite end of the rotor in a way that is readily compatible with automatic sample change.