Abstract: A terahertz graphene Josephson junction detection system based on readout of a microwave resonant circuit includes a graphene Josephson junction detector, a microwave resonant readout circuit, and a microwave network analyzer. The graphene Josephson junction detector and the microwave resonant readout circuit form a microwave resonant circuit. A terahertz signal causes a change of an equivalent microwave inductance of the graphene Josephson junction detector, such that a resonant frequency and a quality factor of the microwave resonant circuit are changed. The present disclosure monitors the resonant frequency and the quality factor of the microwave resonant circuit with the microwave network analyzer, thereby realizing high-sensitivity detection on the terahertz signal. Compared with conventional direct-current (DC)-biased readout, readout of the microwave resonant circuit is not interfered by an external magnetic field, and has a strong interference resistance.

Abstract: A terahertz graphene Josephson junction detection system based on readout of a microwave resonant circuit includes a graphene Josephson junction detector, a microwave resonant readout circuit, and a microwave network analyzer. The graphene Josephson junction detector and the microwave resonant readout circuit form a microwave resonant circuit. A terahertz signal causes a change of an equivalent microwave inductance of the graphene Josephson junction detector, such that a resonant frequency and a quality factor of the microwave resonant circuit are changed. The present disclosure monitors the resonant frequency and the quality factor of the microwave resonant circuit with the microwave network analyzer, thereby realizing high-sensitivity detection on the terahertz signal. Compared with conventional direct-current (DC)-biased readout, readout of the microwave resonant circuit is not interfered by an external magnetic field, and has a strong interference resistance.

Abstract: In a search and tracking method for full time-domain laser detection of space debris, a set of latest precision orbital parameters of a debris object and start and end moments of a current transit of the object are first obtained. Search-specific guidance data is generated based on the above information and in combination with estimation of a maximum along-track error of the orbital parameters of the object during the current transit. A DLR system performs multi-elevation search on the object based on the search-specific guidance data, obtains a plurality of pieces of detection data of the object after detecting the object during the search, determines an along-track error of the orbital parameters of the object based on the detection data, and corrects the orbital parameters of the object in real time based on the along-track error, so as to guide the DLR system to subsequently track and detect the object.

Abstract: An omnidirectional measurement system for a time-varying characteristic of atmospheric vapor radiation includes an antenna and calibrator assembly, a receiver assembly, a room temperature IF assembly, and a data acquisition and system control assembly. Atmospheric vapor features a wide profile and strong radiation in a frequency band of 183 GHz, and is often seen in the characteristic measurement of atmospheric vapor in high-altitude areas. The omnidirectional measurement system combines a superconductor-insulator-superconductor (SIS) mixer with high detection sensitivity in the frequency band of 183 GHz with a structure that integrates pitch scanning, omnidirectional scanning, and automatic calibration to achieve fast and high-precision omnidirectional scanning measurement of the time-varying characteristic of atmospheric vapor radiation.

Abstract: An omnidirectional measurement system for a time-varying characteristic of atmospheric vapor radiation includes an antenna and calibrator assembly, a receiver assembly, a room temperature IF assembly, and a data acquisition and system control assembly. Atmospheric vapor features a wide profile and strong radiation in a frequency band of 183 GHz, and is often seen in the characteristic measurement of atmospheric vapor in high-altitude areas. The omnidirectional measurement system combines a superconductor-insulator-superconductor (SIS) mixer with high detection sensitivity in the frequency band of 183 GHz with a structure that integrates pitch scanning, omnidirectional scanning, and automatic calibration to achieve fast and high-precision omnidirectional scanning measurement of the time-varying characteristic of atmospheric vapor radiation.

Abstract: A space debris observation method based on alternating exposure times of a charge coupled device (CCD) camera is provided. The present disclosure controls the CCD camera to acquire consecutively and alternately short-exposure and long-exposure images based on preset exposure times. The present disclosure realizes detection and astronomical positioning of low-orbit, medium-orbit and high-orbit space debris by processing short-exposure images of odd-numbered frames. The present disclosure realizes detection of medium-orbit and high-orbit space debris by processing long-exposure images of even-numbered frames, and realizes astronomical positioning of the medium-orbit and high-orbit space debris detected in a current frame through plate constant model coefficients of adjacent odd-numbered frames.

Abstract: A space debris observation method based on alternating exposure times of a charge coupled device (CCD) camera is provided. The present disclosure controls the CCD camera to acquire consecutively and alternately short-exposure and long-exposure images based on preset exposure times. The present disclosure realizes detection and astronomical positioning of low-orbit, medium-orbit and high-orbit space debris by processing short-exposure images of odd-numbered frames. The present disclosure realizes detection of medium-orbit and high-orbit space debris by processing long-exposure images of even-numbered frames, and realizes astronomical positioning of the medium-orbit and high-orbit space debris detected in a current frame through plate constant model coefficients of adjacent odd-numbered frames.

Abstract: A method for accurately and efficiently calculating a dense ephemeris of a high-eccentricity orbit is provided. With respect to the ephemeris calculation of the high-eccentricity orbit, the method constructs uneven interpolation nodes through time transformation and interpolates by an interpolation polynomial based on uneven interpolation nodes to obtain a dense ephemeris, which significantly improves the calculation efficiency and accuracy. Based on a large-scale numerical experiment, the method derives an optimal universal value (that is, 0.3) of a transformation parameter for all orbital eccentricities and various interpolation polynomials. In the case of using the optimal universal value of the transformation parameter ?, the method further verifies the Hermite interpolation polynomial as the preferable one among various interpolation polynomials.

Abstract: A method for constructing a free trajectory of a ballistic missile at a specified launch angle includes: setting of an initial state of iterations: based on geodetic coordinates of a launch point and a target point, a launch epoch and the specified launch angle, assuming that the earth does not rotate and a flight time is zero; generating a new flight time in a two-body force model by using known quantities and obtained auxiliary quantities; taking a difference between flight times obtained before and after the iterations as a condition for judging convergence; outputting designed parameters of the ballistic missile after the convergence is reached, or performing a differential correction including the J2 perturbation to improve the precision of the trajectory constructed, and taking a position error of the target point as a convergence condition of the differential correction.

Abstract: A method for accurately and efficiently calculating a dense ephemeris of a high-eccentricity orbit is provided. With respect to the ephemeris calculation of the high-eccentricity orbit, the method constructs uneven interpolation nodes through time transformation and interpolates by an interpolation polynomial based on uneven interpolation nodes to obtain a dense ephemeris, which significantly improves the calculation efficiency and accuracy. Based on a large-scale numerical experiment, the method derives an optimal universal value (that is, 0.3) of a transformation parameter for all orbital eccentricities and various interpolation polynomials. In the case of using the optimal universal value of the transformation parameter ?, the method further verifies the Hermite interpolation polynomial as the preferable one among various interpolation polynomials.

Abstract: A grating- and fiber-coupled multi-beam coherent receiving system in a mid- and far-infrared band includes a mid- and far-infrared local oscillator signal source, a phase grating, a multi-beam fiber coupling system, a 2×2 pixel mid- and far-infrared superconducting HEB mixer, a multi-channel DC bias source, a multi-channel cryogenic low-noise amplifier, and a room-temperature intermediate-frequency and high-resolution spectrum processing unit. In a 2×2 multi-beam superconducting receiving system, an echelle grating and a cryogenic optical fiber are used to distribute and couple the local oscillator signal, and the mid- and far-infrared band high-sensitivity superconducting HEB mixer is used to realize efficient local oscillator signal distribution and coupling, and ultimately achieve high-sensitivity and high-resolution multi-beam spectrum reception in the mid- and far-infrared band.

Abstract: A grating- and fiber-coupled multi-beam coherent receiving system in a mid- and far-infrared band includes a mid- and far-infrared local oscillator signal source, a phase grating, a multi-beam fiber coupling system, a 2×2 pixel mid- and far-infrared superconducting HEB mixer, a multi-channel DC bias source, a multi-channel cryogenic low-noise amplifier, and a room-temperature intermediate-frequency and high-resolution spectrum processing unit. In a 2×2 multi-beam superconducting receiving system, an echelle grating and a cryogenic optical fiber are used to distribute and couple the local oscillator signal, and the mid- and far-infrared band high-sensitivity superconducting HEB mixer is used to realize efficient local oscillator signal distribution and coupling, and ultimately achieve high-sensitivity and high-resolution multi-beam spectrum reception in the mid- and far-infrared band.