35results about How to "Improve distance resolution" patented technology

The embodiment of the invention discloses a laser radar system. The laser radar system comprises a light source module, a modulation light module, a transmitting-receiving module, a detection module and a signal processing module, wherein double-wavelength laser beams are subjected to linear modulation through a modulation light module and are converted into double-frequency linear frequency modulation continuous wave laser beams; one laser beam is used as a local oscillation light beam and the other laser beam is used as signal light which has mutual effect with a detection target; the signal light scatters an echo signal through the detection target; the local oscillation light beam and the echo signal are subjected to coherent beat frequency, so as to obtain double-wavelength Doppler frequency shift difference value information. The laser radar system disclosed by the invention adopts double-wavelength linear frequency modulation laser so that influences, caused by non-linear linear frequency modulation and an atmospheric turbulence effect, on a speed measuring resolution ratio are extremely reduced; distance measurement and speed measurement are carried out on the detection target at the same time; the laser radar system has the advantages of high detection precision, electromagnetic interference resistance, no distance dead zones and the like.

A micro manipulator for electrode movement, a driving method thereof, and a brain signal measuring device using the same are provided. The micro manipulator has a guide member having a rectangular hollow hole therein, first and second piezo-electric clamp bodies installed perpendicular to the movement direction of the electrode between the inner opposite sides in the hollow hole of the guide member such that respective both ends thereof are selectively fixed to or separated from the inner sides of the hollow hole depending upon whether of the application of electric power thereto, a drive piezo-electric body whose both ends are connected to the opposite faces, respectively, of the first and second clamp piezo-electric bodies to selectively expand or contract in parallel with the movement direction of the electrode depending upon whether of the application of electric power thereto, and an electrode holder holding therein the electrode and installed on the first or second clamp piezo-electric body in parallel with the expansion or contraction direction of the drive piezo-electric body.

The invention discloses a phased array radar target identification system based on a positioning filtering algorithm and a method. The system comprises a phased array radar used for reporting parameters of motion targets of a detected area to a monitoring terminal, the monitoring terminal used for determining whether a set defence area scope has the motion targets according to the reported information and further transmitting the determination information to a radar monitoring host which communicates with a monitoring platform, the monitoring platform used for setting the defence area scope of the monitoring terminal in the whole monitoring area, wherein the positioning filtering algorithm is employed by the monitoring terminal according to the reported information to carry out identification positioning of the motion targets and sequentially transmit the positioning information to the radar monitoring host and the monitoring platform. According to the system, dynamic monitoring on the targets in the set effective monitoring area can be carried out, the effective targets can be identified through the monitoring target determination and filtering algorithm, interference and ineffective targets are removed, and error alarm can be effectively reduced.

An onboard ultra-wideband radar front-view imaging system comprises a radar radiofrequency front end including an antenna, a frequency synthesizer, and a switching circuit, wherein the antenna is usedfor transmitting and receiving an ultra-wideband continuous wave signal, the frequency synthesizer includes a transmitter and a receiver, and the switching circuit is used for achieving the multi-transmitting multi-receiving time-sharing operation; an information processing unit including a signal processor and a data processor, wherein the signal processor is used for generating system timing control and a large-bandwidth step-frequency signal, sampling a radar step-frequency echo signal, and finally performing a near-field front-view imaging process and transmitting a result to the data processor, and the data processor processes the signal and detects the signal by a detection algorithm in the image domain, and finally detects and identifies positive and negative obstacles and obstacles behind hidden objects such as leaf leafages. The onboard ultra-wideband radar front-view imaging system is easy to achieve, good in environmental sensing effect and high in resolution.

The invention discloses a pulse compression method for the field of linear frequency modulation signals. The method comprises the following steps: the orthogonal demodulation is implemented for the linear frequency modulation signals in the time domain; the low-pass filtering is implemented for the orthogonally demodulated linear frequency modulation signals in the time domain; the Fourier transform and the frequency band transfer are sequentially implemented for the low-pass filtered linear frequency modulation signals in the time domain to obtain linear frequency modulation signals in the frequency domain; the Fourier transform and the frequency band transfer are sequentially implemented for matched filtering signals in the time domain to obtain matched filtering signals in the frequency domain; the matched filtering signals in the time domain are converted to the matched filtering signals in the frequency domain; the complex conjugate multiplication is implemented for the linear frequency modulation signals in the frequency domain and the matched filtering signals in the frequency domain to obtain pulse compression signals in the frequency domain; and the Fourier inversion is implemented for the pulse compression signals in the frequency domain to obtain pulse compression signals in the time domain. The pulse compression method of the invention can improve the range resolution, reduce the loss of signal-to-noise ratio, and modify the image quality.

The invention provides an optical generation method and system for a radio frequency arbitrary waveform based on a digital logic operation, belonging to the field of arbitrary waveform generation. Thesystem comprises n optical power modulation units, a wavelength division multiplexer or an optical coupler, a photodetector and a filter, wherein each optical power modulation unit comprises a laser,a modulator, two microwave phase shifters and a digital signal generator. The method comprises the following steps: generating n pairs of digital signals according to an expression of a target radiofrequency analog signal waveform and a logic operation relationship realized by the modulator, correspondingly generating non-return-to-zero code microwave digital signals by using the digital signalgenerator, inputting each pair of non-return-to-zero code microwave digital signals to the modulator to perform intensity modulation on a path of laser, obtaining n paths of optical signals, and thencoupling the n paths of optical signals into one path of optical signal, converting the optical signal into an electric signal, and finally obtaining the target radio frequency analog signal waveformthrough the filter. According to the scheme of the invention, the range resolution of radars, satellite detection systems and other systems can be effectively improved, and high-precision imaging canbe realized.

An ultrasonic device includes an ultrasonic transducer that has a vibration film and transmits an ultrasonic wave from a first surface side of the vibration film, an acoustic matching layer that is provided on the first surface side of the vibration film, and an acoustic lens that is provided on the acoustic matching layer on an opposite side to the vibration film, in which the acoustic matching layer is formed of even-numbered layers including a first layer and a second layer having acoustic impedance lower than acoustic impedance of each of the first layer and the acoustic lens, and the first layer and the second layer are disposed in this order toward the acoustic lens from the vibration film, and in which each of the first layer and the second layer has a thickness corresponding to an odd-numbered multiple of λ/4 with a wavelength of the ultrasonic wave as λ.

The invention discloses a two-phase coding radar signal distance super-resolution method based on target sparsity. The method comprises the following steps: 1) carrying out matched filtering processing on a two-phase coding echo signal of a radar target; 2) establishing a distance dimension sparsity model of the target echo signal; and 3) resolving the maximum posterior probability estimation of the sparse amplitude vector to obtain a target signal amplitude, and obtaining a target distance and realizing distance super-resolution. Under the condition that the bandwidths of the two-phase coded signals are the same, the Rayleigh limit of conventional pulse pressure is broken through, and distance super-resolution is achieved; and radar target detection, imaging and classification identification performance is improved by distance super-resolution.

The invention provides a low-cost linear frequency modulation ground penetrating radar system and a use method, the low-cost linear frequency modulation ground penetrating radar system comprises a radio frequency part, a digital signal processing part and an upper computer part, the radio frequency part is in data intercommunication with the digital signal processing part, and the digital signal processing part is in data intercommunication with the upper computer part; the radio frequency part is used for receiving a linear frequency modulation control signal of the digital signal processing part, transmitting a linear frequency modulation electromagnetic wave, receiving an echo signal and transmitting the echo signal back to the digital signal processing part, and the digital signal processing part is used for controlling the frequency of the transmitted signal and generating the linear frequency modulation control signal; the digital signal processing part is used for receiving echo signals, performing digital signal processing and transmitting the echo signals back to the upper computer part after processing is finished, and the upper computer part is used for controlling working parameters of the digital signal processing part and processing and displaying the returned echo signals. And the range resolution can be improved while the detection depth is not reduced.

The invention discloses a radar distance super-resolution method based on target sparsity and time domain dechirping. The radar distance super-resolution method comprises the following steps: 1) carrying out dechirping processing on a linear frequency modulation echo signal of a radar target in a time domain; 2) establishing a sparsity mathematical model of multi-target echo signals; and 3) constructing an optimization function about the target distance and solving the optimization function to obtain the target distance, and meanwhile, realizing radar distance super-resolution. Under the sameradar signal bandwidth, compared with conventional pulse compression processing, the method has a higher distance resolution capability, and distance super-resolution is realized; and the super-resolution in distance improves the performance of target resolution, imaging, classification and recognition, and target detection in a clutter.

The invention provides a wide band orthogonal linear frequency modulation wave light generating system and method and belongs to the orthogonal waveform generation field. The system comprises an optical-borne linear frequency modulation wave generator, an optical coupler, a code sequence generator and a DC power supply and further comprises several phase encoding units, or several equivalent phasemodulation units or several upconverted phase encoding units, wherein an output end of the optical-borne linear frequency modulation wave generator is connected with an input end of the optical coupler, and output ends of the optical coupler, the code sequence generator and the DC power supply are respectively connected with an input end of the corresponding unit. The system is advantaged in thatorthogonal phase coding linear frequency modulation waves with the wide band and high orthogonality can be generated, the system is applied to the field of an MIMO radar, the range resolution and work performance of the MIMO radar can be effectively improved, and target detection and identification capability is enhanced.

The invention discloses a high repetition frequency velocity measurement method based on frequency stepping LFMCW, which obtains a larger non-fuzzy velocity measurement range by using high repetitionfrequency, and simultaneously splices signals by using the characteristics of frequency stepping LFMCW signals to obtain higher distance resolution; and compared with the traditional high-distance resolution, low-ambiguity speed measurement range or low-distance resolution and high-ambiguity speed measurement range, the high repetition frequency velocity measurement method has more application advantages.

The invention relates to a close-range detector antenna design method, and belongs to the technical field of millimeter wave antennas. Comprising the following steps: 1, establishing a half-wave dipole antenna model and optimizing antenna parameters to obtain an optimized oscillator antenna model; 2, selecting the size and the material of the horn antenna, wherein the horn antenna comprises a horn and an antenna feed source, and the antenna feed source is the 120 GHz half-wave dipole antenna optimized in the step 1, and the loudspeaker adopts a circular waveguide; and 3, establishing and selecting the structural type, the size, the inner wall thickness and the material of an antenna hood, and determining a high-wave-transparent material medium, the thicknesses of the hood wall and the hood front end and the distance from the hood to the antenna so as to design the hood, specifically, 3.A) selecting the high-wave-transparent material medium, the thicknesses of the hood wall and the hood front end and the distance from the hood to the antenna; and 3.B) constructing modeling on the hood. The antenna designed by the method is simple in structure, wide in frequency band, large in power capacity, convenient to adjust and use and very high in resolution and tracking capability, and the anti-interference capability of a detector is greatly improved.

The invention provides a pulse compression distance measurement method of a star network conforming to an IEEE802.15.4 standard. The star network conforming to the IEEE802.15.4 standard is configured, the star network comprises a network coordinator PAN and a reduced function device RFD, the network coordinator PAN uses a carrier with collision avoidance and based on time slot to monitor multiple paths of access mechanisms accessing CSMA/CA to carry out channel competition access with the reduced function device RFD, and the distance measurement between the network coordinator PAN and the reduced function device RFD is finished by use of a pulse compression method when finishing data transmission. By adopting the pulse compression distance measurement method provided by the invention, on the basis of retaining the low complexity, low power consumption, low cost and one-to-many communication of the IEEE802.15.4 standard protocol, a pulse compression signal modulation and calculation method is merged at a carrier modulation state, compared with the existing ZigBee communication using the IEEE802.15.4 standard, a remote multi-target distance measurement function is added, higher distance measurement precision is provided, and since the existing related communication chip industry is quite mature, the cost of the technology is much less than that of traditional radars.