338 results about "Continuous wave signal" patented technology

A short-range inter-vehicle communication and warning apparatus comprises a forward radar and a backward radar. The apparatus uses the radars to generate Frequency Modulation/Continuous Wave (FMCW) signals, uses amplitude shift keying for data modulation and arranges a special packet format, to realize such a low cost and fast response device of collision avoidance for vehicles. The invention has the dual capabilities of detecting and communicating simultaneously. It can also measure the relative speed of a preceding/rear vehicles and the relative inter-vehicle distance. The invention also exchanges the real-time traffic information with the preceding/rear vehicles at the same time. It is applicable to a one-to-one or one-to-many inter-vehicle channel model.

A radar based sensor detection system comprises a microwave source operative to provide a continuous wave signal at an output. A pulse-former is coupled to the output of the source and is operative to provide at an output a variable length pulse that increases the transmitted energy of the radar system according to the range of object detection. A modulator is coupled to the output of the pulse-former for providing a modulated pulse signal when required. A transmit/receive switch coupled to the output of the modulator is selectively operative between a first transmit position and a second receive position. A transmit channel coupled to the transmit/receive switch transmits the pulse signal when the switch is operated in the transmit position. A receiving channel coupled to the transmit/receive switch receives the modulator signal when the switch is operated in the receive position. First and second voltage multipliers each have a local oscillator input for receiving the modulator signal in the receive position, and each have an input signal port, and an output port. A receiver channel receives a reflected transmitted signal from an object and applies the received signal to the receive signal input ports of the voltage multipliers. An autocorrelator coupled to the output ports of the voltage multipliers correlates the received signal to produce an output signal indicating the detection and position of the object.

A method for sensing occupancy status within an automotive vehicle uses a radar sensor system, the radar sensor system comprising an antenna system, at least one sensor (10) and processing circuitry (18). The method comprises illuminating, using the antenna system, at least one occupiable position within the vehicle with continuous wave (CW signals), the CW signals being frequency modulated in time. At least one sensor signal (a) reflected as a result of the CW signals, is received using at least one sensor (10) the at least one sensor (10) defining a plurality of receive channels (1 . . . i), each channel having a different frequency (f₁ . . . f_i). Processing circuitry (18) is operable for applying, for each receive channel (1 . . . i), DC offset removal to the corresponding sensor signal (a) to generate a modified signal (b); and generating, based on the modified signals (b) one or more occupancy status signals (34, 38), the occupancy status signal indicating a property related to said at least one occupiable position. A system for carrying out the method is also disclosed. The techniques provide for in-vehicle occupant detection and classification (airbag suppression), for passenger presence detection and passenger's vital sign monitoring and for seat-belt reminder functionality (SBR). The radar system may consist of one or two (or four) outputs (I/Q) per channel. The received signal may be mixed down with a single channel demodulator or an I/Q demodulator into the baseband. An advanced signal processing including an auto calibration routine and clutter removal may be used to detect occupants and their vital sign (breathing and heart beat) and to determine their distance to the radar system.

A space-borne multichannel microwave switch testing device comprises a programmable power supply, a switch state driving module, a switch telemetering acquisition module, a radio frequency switch matrix set, a detector, a signal source, an oscilloscope, a vector network analyzer and an industrial personal computer. The industrial personal computer controls the value of voltage outputted by the programmable power supply through a network, controls switching of the radio frequency switch matrix set, controls the switch state driving module to produce commands of independent driving switches in N*4 channels, controls the switch telemetering acquisition module to collect state telemetering signals of independent detected switches in N*4 channels, controls the signal source to produce continuous wave signals, controls the oscilloscope to obtain driving current values of the detected switches and switching time of the detected switches, and controls the vector network analyzer to obtain radio frequency S parameters of the detected switches; state conversion threshold voltage of the detected switches is obtained by changing driving ranges of driving commands; the service life of the detected switches is obtained by recording accurate state conversion frequency of the detected switches.

The invention discloses an SAR radar moving target detecting and imaging method based on an FM continuous wave. The method comprises the steps of establishing a geometric model of an SAR radar based on the FM continuous wave for detecting N moving targets, wherein the SAR radar based on the FM continuous wave comprises B channels, a first channel is a reference channel and N moving targets transmit the FM continuous wave signal, respectively receiving echo signals of the N moving targets by the B channels; after obtaining the echo signals of the N moving targets which are respectively received by the B channels, respectively performing imaging processing, and respectively obtaining images which correspond with the B channels; further successively performing clutter cancellation processing, moving target detecting and orientation dimension reversal conversion, and obtaining distance time domain-orientation time domain echo signals of the N moving targets; performing distance dimension FFT, obtaining original echo signals of the N moving targets after distance dimension fast Fourier transform; further calculating corresponding images of N real moving targets, and respectively calculating respective real moving speeds of the N real moving targets according to an along-track interferometry method.

The invention provides a simulation method for a linear frequency modulation continuous wave synthetic aperture radar video signal, which comprises the following steps: simulated synthetic aperture radar system parameter information is set and read; the information parameter of a target is set; a simulated time is treated with discretization; the instantaneous positions of a radar platform and the target are respectively calculated, and a distance vector between a phase center and the target is obtained according to geometric position relation; a one-dimension echo signal is obtained by combining the echo signal mathematic model of the synthetic aperture radar and radar system parameters; the one-dimension signal is divided according to pulse repetition period and formatted into a two-dimension signal, the two-dimension signal with Na multiplied by Nr is obtained after the total data is stored, thus finishing the fine simulation of the linear frequency modulation continuous wave synthetic aperture radar video signal. The more accurate echo simulation signal can be obtained by utilizing the simulation method, and the simulation method is especially suitable for a frequency modulation continuous wave signal with high-speed movement, long distance and severe oblique observation condition of the radar and has more excellent realization efficiency, and stronger adaptability and compatibility.

The invention relates to a meteorological radar system based on continuous wave system and a control method, wherein the system comprises an emission extension which is used to receive a linear frequency modulation continuous wave signal from an extension and obtain a continuous wave emission signal after amplification processing, and output the signal to an emission antenna module; a reception extension which is used to output the linear frequency modulation continuous wave signal to the emission, receive a meteorological echo signal from an antenna module, and output the signal to a digital processing extension after frequency conversion amplification processing; an emission antenna module, which is used to emit the continuous wave emission signal; a reception antenna module, which is used to receive the meteorological echo signal; and a digital processing extension, which is used to receive the signal from the extension and process it to obtain the meteorological data information and perform instruction control to the radar system state at the same time. According to the continuous wave system, the emission signal employs continuous wave signal, which has a higher distance resolution compared to a pulse system radar, therefore the meteorological radar system is especially suitable for refined meteorological detection.

The invention discloses a target detection method of an auxiliary vehicle driving radar. The method comprises steps that an emission waveform mode of the radar is determined to be a multi-order frequency stepping continuous wave MS-FSCW, one integral MS-FSCW waveform comprises two parts of an upper frequency sweeping segment and a lower frequency sweeping segment, and signals of each frequency sweeping segment are composed of multiple frequency stepping dot frequency continuous wave signals arranged in an alternative mode; MS-FSCW emission waveform parameters of the radar are determined, waveform parameters are determined according to a largest distance measurement scope, a largest speed measurement scope, distance measurement precision and a system detectable smallest signal to noise ratio, and the waveform parameters comprises frequency sweeping band width, a frequency sweeping period, a sampling rate, the quantity of frequency stepping continuous wave signals and initial frequency difference among the frequency stepping continuous wave signals; an MS-FSCW emission signal echo of the radar is processed to acquire a target distance and the speed information. Through the method, distance and speed detection blind zones caused by transceiving leakage can be reduced, and target distance measurement and speed measurement precision is improved.

The invention discloses an unmanned airborne system for SAR imaging and moving-target detection by utilizing millimeter-wave Ka-frequency-band frequency modulated continuous waves. Ka-frequency-band wavelength is shorter, and an antenna is smaller than a lower-frequency-band antenna in size under the condition of the same beam width. A millimeter-wave device is smaller than a lower-frequency-band device in size, weight and power consumption. The system can be miniaturized, images finer than other lower-frequency-band images can be obtained by utilizing millimeter-wave Ka-frequency-band signals to perform SAR imaging, target edge and corner characteristics are obvious, and target recognition is facilitated. Ka-frequency-band signals of higher relative band width can be obtained, so that higher image resolution can be obtained compared with lower-frequency-band signals. The system for SAR imaging by utilizing the frequency modulated continuous waves is simple in device, low in complexity, small in data volume by adopting a de-chirp mode and capable of performing real-time imaging processing.

A radar system includes radars and a controller. The controller controls waveform patterns of the radars. As a signal processing unit of each of the radars receives an instruction from the controller, the signal processing unit selects a frequency modulation pattern of a VCO between an FM-CW mode and a CW mode stored in a waveform memory to perform mode switching, and then outputs a radio wave from a transmission antenna. Then, the controller instructs each signal processing unit for a frequency modulation pattern of each radar or an output timing of each pattern so that a time, at which continuous wave signals output from the radars have the same frequency, is not continuous.

The invention discloses a forward and reverse passive inter-modulation (PIM) testing device and method for an isolator. The testing device comprises a first continuous wave signal source, a second continuous wave signal source, first automatic switching equipment, second automatic switching equipment, a cavity combiner, a duplex combiner, a receiver and a central control unit. The testing method comprises the following steps: setting the testing mode to be forward or reverse testing; setting carrier frequency and carrier power required in a test; testing the forward or reverse PIM level of the isolator; and calculating the difference value between a PIM level value and a carrier power value, wherein, the difference value is the relative inter-modulation level. In the invention, different test platforms are not required in the case of the forward and reverse PIM testing, thus improving the maneuverability and the testing efficiency, lowering the residual inter-modulation of a system, improving the testing accuracy, eliminating power consumption of a 3dB electrical bridge, and enhancing the transmission efficiency and performance of a radio frequency signal; and a central processingunit is adopted instead of a frequency spectrograph, so the testing result can be directly obtained.

The invention discloses a landslide MIMO radar monitoring system and monitoring method. Emitting and receiving antennas of the system are an MIMO radar antenna array. Emitting and receiving time-sharing selectors are connected with emitting and receiving antenna array elements respectively. A system synchronization control unit is connected to the emitting and receiving time-sharing selectors through an antenna time-sharing control unit. The monitoring method is characterized by carrying out MIMO antenna array time-sharing emission and step frequency continuous wave signal reception; carrying out inverse Fourier transform and distance compression on echo data, carrying out phase discontinuous correction on radar echo data, calculating time delay compensation factor and carrying out beam forming method azimuth focusing to obtain a high-resolution complex image; carrying out continuous monitoring to obtain a plurality of complex images and forming complex image pairs; and calculating differential interference phase after complex image pair registering and extracting deformation value and carrying out early warning. According to the landslide MIMO radar monitoring system and monitoring method, non-contact remote monitoring is achieved, monitoring range is wide, azimuth resolution ratio is high, real-time performance is high, data acquisition is quick, system device is light and portable, and layout is adjustable.

A system and method for a rangefinding instrument incorporating pulse and continuous wave signal generating and processing techniques for increased distance measurement accuracy. The use of the former technique effectively solves the ambiguity issues inherent in the latter while allowing for relatively simple circuit implementations. Thus, a potentially more accurate phase-based distance measurement technique can be utilized which is also completely independent of the maximum range to the target.

A method and apparatus provide simultaneous bi-directional communications through a barrier using a pair of piezoelectric transducers. Outside-to-inside transmission of differentially encoded binary data is only sampled at the inside when a known repeated bit in a Barker sequence is transmitted in the other direction. Differentially encoded data is translated based on the absolute value of differences between each signal envelope sample and the previous signal envelope sample. Inside-to-outside data is transmitted by varying an electrical load on the inside transducer to vary the proportion of a continuous wave signal it reflects. The reflected portion of the continuous wave changes the electrical impedance of the outside transducer and this change is measured and interpreted as binary data. Two frequency selection algorithms select minimally sufficient and then optimal frequencies for power and data transmission by a frequency stepping process.

The invention discloses a signal generating device and calibration method of TD-SCDMA system net rule, net optimization and facility test, which comprises the following parts: logical module, up converter, DA converter, IF magnification filtering modular, frequency mixer, RF magnification filtering modular, power detector, handler, thermostatic crystal oscillator, temperature sensing modular, voltage controller, phase-locked loop, local oscillator, communication serial port, wherein the device can launch continuous wave signal of base station work frequency band, TD-SCDMA signal of launching base station or terminal, which can realize TD-SCDMA network planning, network optimization and device test work.

An intrusion detection system that differentiates between a vehicle intrusion event and a non-intrusion event includes transmitter (16) for transmitting a continuous wave signal that is reflected of surfaces within the vehicle's interior and/or a moving object (i.e., an intruder). The associated reflected signals subsequently return to a receiver (18). An ECU (26) demodulates the return signal into frequency and amplitude components. The ECU (26) further determines a waveform envelope of the demodulated return signals and monitors the envelope waveform during time windows to determine whether their corresponding envelope waveform is indicative of an intrusion event or an non-intrusion event. When an intrusion event is detected, the ECU (26) outputs a control signal to actuate an alarm (34).

The invention firstly simplifies a human body target motion into a compound motion of a typical motion form, and puts forward a human body walking and running empirical model according to measured biomechanical experiment data. On the basis of an XYZ convention, an Euler rotation matrix is used for establishing and perfecting human body motion animation models under a state of marching on the spotand a walking and running state; then, on the basis of a continuous wave signal, an integral radar echo model of a human body walking and running target and a radar echo model of each position of thetarget are constructed; and a Matlab simulation tool is used for analyzing radar echo characteristics under different human body motion states and generating a corresponding time domain graph throughthe short-time Fourier transform so as to lay a theoretical foundation for the moving human body target characteristic extraction and the walking and running state of the human body. The time domaingraph of the human body motion is divided into a training set, a verification set and a testing set, the improved convolutional neural network is input for training, the network parameter is regulatedto realize model convergence, and the network can correctly classify the human body motion state.

The present invention relates to a frequency modulated continuous wave speed measurement and distance measurement method. The method comprises the steps of S1 transmitting a frequency modulated continuous wave signal of which the frequency changes along a combined waveform modulating signal to N targets, and obtaining a corresponding beat signal; S2 carrying out the one-dimensional FFT processing of a fast time domain on the beat signals within a cycle TTa and a cycle TTb to extract the spectral peak frequencies corresponding to the N targets in the cycle TTa and the cycle TTb; S3 calculating to obtain the corresponding distance speed matrixes in the cycle TTa and the cycle TTb; S4 finishing the correlation matching of multiple targets to obtain the distance r and the unambiguous inaccurate speed v corresponding to each target; S5 calculating to obtain the ambiguous accurate speed vapre corresponding to each target; S6 calculating to obtain the unambiguous accurate speed vpre corresponding to each target. According to the present invention, by utilizing an improved modulating signal and combining a two dimension FFT method, the purpose of high-precision speed measurement and distance measurement can be achieved under a smaller FFT point number.

The invention relates to an accurate positioning method based on the linear frequency modulation continuous wave technology, and accurate positioning devices based on the linear frequency modulation continuous wave technology. The accurate positioning method based on the linear frequency modulation continuous wave technology includes the following steps that in the one-time distance measurement process, the device B transmits linear frequency modulation continuous wave signals, the device A receives the signals, both the device A and the device B generate linear frequency modulation continuous wave signals periodically, and supposing that local oscillators at the two ends of the device A and the two ends of the device B have fixed difference t0, the oscillators of the device A are in front of the oscillators of the device B, the flying time of the linear frequency modulation continuous wave signals in air is tau, and the signals received by the device A are the signals transmitted by the device B and having been delayed in the air for the time of tau. The invention further provides the accurate positioning devices based on the linear frequency modulation continuous wave technology. The method and the devices have the advantage that on the basis of the accurate positioning technology of the FMCW technology, accurate measurement between two points is achieved by measuring the flying time of radio waves in the air.

The invention discloses a velocity ambiguity resolution angle measurement method for vehicle-mounted LFMCW radar, belongs to the signal processing technology, and particularly relates to the velocityambiguity resolution and radar virtual aperture direction of arrival measurement technology. According to the invention, velocity ambiguity resolution and MIMO radar virtual aperture angle measurementprocessing are carried out in one frame of signal, a two-transmitting four-receiving radar system is taken as an example, a radar transmitting end transmits linear frequency modulation continuous wave signals with different slope durations and the same bandwidth by using a time division multiplexing technology, and a radar receiving end simultaneously receives signals reflected by two transmitting antennas through an object by using four receiving antennas. Echo signals are subjected to frequency mixing, low-pass filtering and analog-to-digital conversion and finally enter a digital signal processor DSP. 2D-FFT and two-dimensional constant false alarm detection are performed in the DSP, then resolution of velocity ambiguity and phase compensation are conducted, and finally MIMO radar virtual aperture angle measurement processing is carried out, thus realizing the purpose of the invention. The method has the effects of reducing the signal processing time and improving the radar data rate.

The invention belongs to the technical field of radar signal analysis, and discloses an LFMCW signal rapid detection and estimation method. Quasi-coherent accumulation is performed on the LFM part of each period of the same modulation frequency in LFMCW signals according to PFRFT energy so that the signals are enabled to have great energy concentration characteristic in the PFRFT domain, i.e. the PFRFT of the signals has an obvious peak value in two sections. Firstly rapid period fractional order Fourier transform is performed on the linear frequency modulation continuous wave signals, the maximum modulus square of period fractional order Fourier transform act as a target function to establish an optimization model, and the optimization model is solved by using a genetic algorithm so that the optimal parameter estimation of the signals can be obtained. Four-dimensional parameter searching is performed on the PFRFT energy of the linear frequency modulation continuous wave signals by using the genetic algorithm so that detection and estimation of radar weak signals can be realized, the method is especially applied to the design of a signal analysis system of low interception probability radar and thus the theoretical and project application of the PFRFT algorithm can be realized.

A sensor front end for an electronic radar sensor is disclosed that provides for a lower parts count while providing technical functionality by using multifunction parts, i.e., parts that are used both in transmitting and receiving. The sensor front end includes a continuous wave signal source that functions as a signal source when the front end is transmitting a signal and as a local oscillator when the front end is receiving a signal. The sensor front end also includes a tri-mode mixer that functions as a phase-modulator and transmit switch when the front end is transmitting a signal and as a mixer/down-converter when the front end is receiving a signal. The sensor front end further includes a common aperture antenna that acts as both a transmitting antenna for transmitting a sensor signal and for receiving a reflected signal from a object. A phase shifter can be added to provide a predetermined phase shift in the transmitted sensor signal, the received reflected signal, or both, such that in-phase and quadrature signal components are provided. In addition, phase coding may be added to the signal to reduce the degenerative impact of interfering signals. A receiver module is coupled to the tri-mode mixer such that, when receiving a reflected signal, the receiver provides a baseband sensor output signal that can be used to determined the position and velocity of the object. A sampling module can be added such that the sensor output signal is sampled and provided as an analog signal, or the sampled sensor output signal can be provided to an analog-to-digital converter to convert the sensor output signal into a digital format, or both.

An optical signal regeneration device having an interferometric structure with two arms. Each of the arms has a medium, the optical power output of which is variable with the optical power input. The first arm receives, through an input coupler, a continuous wave and the signal to be regenerated. The second arm receives through the input coupler, a continuous wave signal and a clock signal. A filter, centered on the continuous wave wavelength, receives the output signal of the interferometric structure through the coupler. The filter output signal constitutes the regenerated 3R signal.