5results about How to "High range resolution" patented technology

The invention discloses a high-noise-immunity ranging imaging method and system based on quantum correlation measurement, belongs to the technical field of quantum radar and single photon detection, and particularly relates to a high-noise-immunity ranging imaging system and method based on quantum correlation measurement. Comprising a narrowband energy-time entangled two-photon source, a free space optical transceiving unit and a physical information acquisition unit, two photons with entanglement characteristics output by the narrowband energy-time entanglement two-photon source are respectively input into the free space optical transceiver unit and the physical information acquisition unit. The physical information acquisition unit jointly receives the photons directly output by the narrowband energy-time entanglement two-photon source and the photons output by the free space optical transceiving unit, so that the physical information of the measured object is obtained; according to the invention, the problems of small signal-to-background ratio and input saturation of the single-photon detector in the quantum correlation measurement field are solved, so that the system can carry out clear imaging under the condition of larger background noise.

The present invention discloses an inverse synthetic aperture imaging method based on a frequency diversity array, which intercepts the effective time period within the scanning cycle of FDA for a certain target, repeatedly transmits the effective time period, and uses the formed repeated signal as the transmitting beam of ISAR. The method utilizes the time period pointing to other useless directions, and continuously transmits a focused beam in the direction that needs to be detected, thereby achieving a stable tracking effect. In addition, the beam generated by this method also solves the distance angle coupling problem existing in FDA. At the same time, the continuous FDA beam can obtain the distance resolution capability, and obtain the azimuth image resolution capability through the relative motion between the target and the radar, which enables the radar imaging system to have the ability of two-dimensional imaging, and finally uses the imaging algorithm to perform two-dimensional imaging on the target.

The invention belongs to the technical field of laser radars, and particularly discloses a water body temperature profile coherent measurement system based on Brillouin scattering. Comprising a laser seed source, a first coupler, a pulse modulation and amplification module, an acousto-optic modulator, a sinusoidal signal generator, a collimator, a transmitter-telescope, a water body, a receiving telescope, a second coupler, a photoelectric detector, an AD acquisition card, a computer and a connection relation thereof. The invention further discloses a water body temperature profile coherent measurement method based on Brillouin scattering. The heterodyne detection technology is utilized, the system works under the conditions of wide pulse width and low peak power, and water body profile temperature information can be obtained with high sensitivity and high range resolution through coherent detection and a fast Fourier transform algorithm.

The invention belongs to the technical field of wind measurement radars, and relates to a weak Doppler signal extraction method based on random modulation narrow pulse, which comprises the following steps: generating a random signal by adopting a random sequence generator, generating a narrow pulse signal by adopting a sine wave generator, modulating the random signal on the narrow pulse signal to obtain a modulation signal, and transmitting the modulation signal; receiving an echo signal after the modulation signal is transmitted, carrying out frequency mixing and amplification filtering, and carrying out integral accumulation after random signal autocorrelation test to obtain a sampling sequence; doppler frequency shift is extracted according to the sampling sequence, wind speed calculation is carried out after preprocessing, decimation filtering and FFT filtering are carried out in sequence, and the wind speed and the wind direction are obtained. According to the invention, weak Doppler frequency shift signals can be extracted in a short near-space range.

This invention provides a novel scanning laser wind-measuring radar, employing a high-stability, narrow-linewidth semiconductor laser as the transmitting device. A high-speed optical switch precisely modulates the continuous laser in the time domain to generate ideal laser pulses. High-power amplifiers and low-noise amplifiers are used to enhance the transmitted power and echo signal quality, significantly compensating for the decrease in atmospheric echo power and improving range resolution and wind speed accuracy. The high-stability, narrow-linewidth laser improves the signal-to-noise ratio through a triple mechanism of increased coherence efficiency, reduced background noise, and sharpened spectral resolution, enabling long-range detection. When using a transceiver telescope system, it avoids a reduction in the scanning field of view due to a decrease in signal-to-noise ratio. The semiconductor laser solution is lighter than fiber lasers, suitable for airborne platforms, and enables miniaturized laser wind-measuring radar equipment. Furthermore, the high-stability, narrow-linewidth semiconductor laser used meets temperature and vibration stability requirements, ensuring the long-term reliability of the wind-measuring radar in field environments.