Cold atom technology, one of the quantum precision measurement technology, can carry gravity survey with high-precision, high-spatial resolution and on moving platform. In the applications of high-precision absolute gravity survey, marine & airborne gravity survey, and space gravity survey are limited by physical limits of traditional gravimeter, and it is hard to reach sub-micro Gal order and dynamic measurement, which restricts the application of gravity survey. Based on summarizing the progress of cold atom absolute gravimeter and the demand of gravity survey, this paper analyses the development tendency of gravity survey driving by cold atom technology in the future.

In order to meet the requirement of equipment maintenance support in low illumination condition at night, a visible/near infrared achromatic objective lens with large relative aperture is designed. The secondary spectrum can be well corrected in the visible/near infrared band by mean of selecting suitable optical glass materials. The designed large relative aperture objective lens has a focal length of 3.75 mm, F# of 1.2, field of view of 70.25°, distortion of -17.5% and a total length of 40 mm. The con-focal objective lens can meet the requirements of night observation without focusing in the spectral range of 486~950 nm, which provides a new technical means for the development of optical module of low-illumination night vision head-mounted system.

In order to study the distribution of stray light generated by high-order diffraction of metal grids, and then quantitatively control the diffraction energy distribution of grids at the design level, and improve the detection capability of the optical system, mathematical calculation software is used to analyze the optical wavebands of metal grids with different structural forms in this paper. The diffraction characteristics are modeled and simulated discretely, and the diffraction distribution of metal grids with different structures in the optical band is simulated and calculated discretely by using the fast Fourier transform method. The results show that the normalized energy of the +1~+3 order diffraction of the periodic grid is generally at the level of -3~-2 dB, and the ring grid is not concentrated in the axial direction, and as the diffraction order increases, the diffraction energy drops faster than square grids. The random grid has an almost completely uniform diffraction distribution, and the high-order normalized diffraction energy can be controlled at -6~-5 dB, which is much lower than that of the periodic grid. It can be used in the imaging system to reduce the stray light caused by the diffraction of the grid. The homogenization can reduce background noise and improve image quality.

Based on the theory of the atom force model in magneto-optical trap, the sub-Doppler cooling mechanism is researched under the condition that the diffracted light in the grating magneto-optical trap is nonorthogonal to the magnetic field, and the theoretical models of atomic force cooling and trapping in four beam and five beam grating magneto-optical trap are established. The scattering force of atom under the condition of grating magneto-optical trap is calculated, and the influence of grating diffraction angle on atomic cooling velocity and atomic trapping range is analyzed. The results show that the resultant force of the diffracted light and the incident light is zero at the center of the magnetic field, forming an effective potential well. The change of the polarization component of the diffracted light caused by the diffraction angle of the grating has an impact on the damping force, the restoring force and the atomic trapping velocity of the atom, and will ultimately affect the number of atoms trapped in the grating magneto-optical trap. The theoretical study provides a theoretical basis for the realization of atomic cooling and trapping in the grating magneto-optical trap and the design of the grating chip.

The haze removal methods of dynamic bad weather imaging images are studied in this paper. A fast real-time image haze removal method based on improved color homomorphic filtering and dark channel based on physical model is proposed. The algorithm is applied to static scenes and scenes with moving targets, and the operation and test results of each algorithm are compared and analyzed. It is verified that the method proposed in this paper has smaller global entropy of 7.6083, low image uncertainty and clearer texture. The average time of a single frame is 12.223 ms, which meets the requirements of real-time operation, and lays the foundation for target detection and recognition in the subsequent complex meteorological environment.

Aiming at the problems of the complex structure of the YOLOv4 target detection network, the amount of parameters and the large amount of calculation, a lightweight target detection algorithm (YOLOv4-GC) is proposed. First, the ghostnet structure is used to replace the original YOLOv4 backbone network, and the amount of calculation for acquiring redundant feature images is reduced. The depth separable convolution is used in SPP and PANet modules to reduce the calculation and parameters of the model by 82% and 80% respectively compared with the original YOLOv4. Then combined with PyConv multi-scale convolution, Py-PANet pyramid structure is designed to improve the model’s ability to extract and fuse image features. The experimental results on the Pascal VOC data set show that the amount of parameters and calculations of the model are reduced significantly under the condition that the precision of the model is assured.

High frame frequency medium wave refrigerated infrared detectors are widely used in airborne photoelectric pods, infrared warning systems and photoelectric tracking and aiming systems. The traditional medium wave cooling infrared detector of HgCdTe is limited by the integration time, and the frame frequency is generally limited by 25~100 Hz under the premise of ensuring the imaging quality. Moreover, InSb medium wave refrigerated infrared detector has good non-uniformity, low blind element rate and high frame frequency output characteristics, which can further improve the infrared system range and tracking accuracy. In this paper, a high-speed and stable image acquisition system is designed based on InSb medium wave refrigeration infrared detector, and the image output of 640×512 resolution digital video at 200 Hz is achieved. In the high frame frequency mode, the cross-talk between the detector integration time and the readout time signal is solved, and the non-uniformity of infrared image is effectively reduced. The system can further improve the frame frequency through the window setting of the detector, which can realize the infrared detection, search, identification, reconnaissance, intelligence collection, tracking and so on.

A runaway speed of servo system is an ordinary fault. It will strike and damage the mechanical limit in an axis system with limited rotation. The optical machine structure and the cable would be destroyed. Currently, a traditional software spacing is used to restrain runaway speed in servo control system, but it is limited. Software spacing will be invalid when control software crash. In order to solve the runaway problem, the causes and the principles of runaway speed of servo system are analysed in this paper. Several new methods to avoid runaway speed are presented. Especially, the bottom hardware circuit design to avoid runaway speed is effective and reliable. It is an effective method to avoid runaway speed of servo system and has been validated in the application of optical-electronic equipments.

Long wave infrared thermal imager based on TDI (Time Delay Integration) mechanism is widely used in military, aviation and aerospace fields. Through optical scanning, large imaging field of view and high spatial resolution can be achieved simultaneously. The detector of the long wave infrared thermal imager based on TDI mechanism adopts TDI working mode. Due to the problem of matching accuracy between TDI and optical scanning, when imaging a scene, the edge of the scene often has uneven sawtooth, which affects target extraction and recognition and reduces the image appearance. In this paper, the phenomenon of aliasing in the scene image caused by the mismatch between the scanning field of view and the optical field of view is analyzed, and a method to eliminate sawtooth by converting the spatial physical interval of the pixel distribution on the detector into a time delay is proposed. The method of time to space can effectively eliminate the sawtooth of the scene image, restore the details of the small target edge, greatly improve the image appearance, and the method has been widely used in IRST systems, infrared photoelectric systems and other equipment.

Multi-star simulator is a device that can simulate the position, magnitude and spectral information of multiple stars in the sky in a test chamber, used to complete indoor testing and calibration of star sensors. The design of the single star simulator and bracket that form a fixed distributed multi-star simulator for the test requirements of the star sensor equipment is described in detail in the article, as well as the detection instruments and methods used to test the stability of the simulated star angle position of the multi-star simulator and the error of the simulated star angle position caused by translation. The test results show that the performance indicators of the multi-star simulator meet the design requirements and can be used for indoor dynamic and static performance test of the star sensor.

The ECEF is an important reference system for the conversion of the geographical horizontal system and the astronomical inertial system and the measurement of the earth's motion parameters. The research on the error characteristics of inertial navigation under ECEF is still insufficient, and the astronomical/inertial combination mechanism is still unclear. The ECEF inertial navigation calculation and arrangement, the derivation of the inertial navigation error equation, the analysis of the inertial navigation error characteristics, and the astronomical/inertial integrated navigation principle are derived according to the inertial navigation error law, and the astronomical/inertial integrated navigation algorithm under ECEF is realized. The simulation results show that the astronomical/inertial integrated navigation algorithm based on the ECEF system can effectively suppress the oscillation amplitude of the inertial navigation position error, and provide an effective idea for the navigation information guarantee of sea and air platforms.

In view of the sensitive characteristics of cold atom inertial measurement equipment to low-frequency vibration, it is necessary to analyze the environmental vibration characteristics, especially the use requirements of extracting and analyzing the low-frequency environmental vibration characteristics. A new spectrum transformation method which can adjust the resolution of data near each frequency point after frequency domain transformation is summarized. At the same time, this method can not only effectively deal with the problem of spectrum aliasing, but also effectively reduce the impact of unreasonable weighted transformation on analog signal spectrum analysis. The spectrum transformation method is used to analyze the actual measurement data to determine the effectiveness of the method.

For conventional phase measuring deflectometry, the measurement principle based on the law of reflection makes it difficult to perform full-aperture measurements of the radius of curvature (ROC) of large dynamic curvature value. Therefore, the traditional monoscopic deflectometry combined with a planar mirror measurement method is proposed. However, the measurement method of the existing method requires the plane mirror mounted on the monitor to be strictly tilted at 45° and the angle of 45° with the camera optical axis in the horizontal direction, which undoubtedly makes the experimental setup more difficult to align. Therefore, the calibration of entrance pupil center of the imaging lens method is proposed in this paper. In the experiment, only the translation of the display is needed to obtain the position of entrance pupil center of the imaging camera lens, without the need to accurately align the posture of the camera and the plane mirror. Finally, a convex spherical optical element with a mean ROC of 8.262 mm is measured in the experiment, and the mean ROC at each point is measured to be 8.321 mm with a PV of 0.212 mm, with a relative error of 0.71% about. Compared with existing normal incident optical paths, the adjustment process is less difficult, but the measurement accuracy of components is still high, which verifies the feasibility of the method.

Aiming at the situation that the oil canvas needs to be disassembled when detecting the surface topography of the deformed oil painting in the traditional method, a method for nondestructive detection of the three-dimensional topography of the oil painting surface is proposed. The absolute phase distribution of the oil painting surface is obtained by the three-dimensional detection technology of structured light, the least squares method is used to fit the quadratic surface as the reference surface, and the difference between the absolute phase and the reference surface is used as the actual phase to obtain the height distribution of the oil painting surface. The test results show that the method can realize non-destructive testing without dismantling the oil painting canvas. It has an ideal detection effect for oil paintings with different degrees of deformation.

In order to improve the rate accuracy and rate stability of the laser gyro test turntable, a fixed angle time measuring device is developed in this paper. The device uses the high-precision clock as the reference to uniformly encode the axis angle data of the turntable, and generates degree pulse and cycle pulse signals. The clock pulse is counted with the degree pulse as the fixed angle interval, and the time code of the fixed angle interval is read by the computer. The computer calculates the rate accuracy and rate stability according to the requirements of the national standard. This technology can effectively eliminate the errors caused by the rate accuracy and rate stability of the laser gyro test turntable, and improve the rate accuracy and rate stability of the laser gyro test turntable. After using this technology, the rate accuracy and rate stability error of the laser gyro test turntable are reduced to one tenth of the original.

According to the actual needs of environmental monitoring about power equipment, the technology of the temperature sensing about fiber sensor array is carried out in this paper. An interferometric sensing probe with polarization-maintaining fiber as the sensing unit is proposed. Firstly, a mathematical analysis model of the sensing system is established, and an interference optical path is constructed to explore the influence of the length of the optical fiber sensor probe and wavelength of light source on the temperature measurement range. Secondly, on the basis, the sensor package based on the capillary glass tube is completed and system prototype is built. Finally, the temperature test experiment and sensor repeatability experiment are carried out. The experimental results show that under the same light source with the same wavelength, the shorter the length of sensing probe, the greater the range of the temperature measurement has, and when the sensing probe is 1cm, the temperature measurement error is about 0.37 ℃, and the accuracy is about 0.3 ℃. This research has reference value for the application of optical fiber temperature sensing technology in power and other industries.

In order to realize the optimal route planning and promote the energy-saving and loss reduction of overhead ground wire, the energy-saving grounding technology of overhead ground wire of transmission line based on multi-objective evolutionary algorithm is studied. Aiming at the lowest risk of geological disasters and the highest operation safety factor of overhead ground wire route, an optimization model of overhead ground wire route of transmission line is established. The multi-objective evolutionary algorithm is used to solve the model and obtain the route optimization scheme. The energy-saving grounding technology of single circuit or multi circuit overhead ground wire is selected according to the actual geological conditions. The experimental results show that the proposed technology can obtain the optimization scheme of overhead ground wire route of transmission line in line with the objective function and constraints. The energy-saving grounding mode is selected as two overhead ground wires of single circuit line, the pitch of each section of overhead ground wire is 6.4 km, and the grounding point is selected at the middle point of each section of ground wire. Compared with the previous year, the power loss of this grounding mode is reduced by 60% ~ 69%, and the energy-saving effect is outstanding.

In order to achieve high-precision photoelectric parameter measurement of laser seeker, a weak signal amplification technology based on avalanche photodiode (APD) avalanche amplification effect and a full waveform acquisition technology based on field programmable gate array (FPGA) are proposed. The measuring device performs photoelectric conversion and multistage amplification for weak pulse laser echo, and then realizes analog-to-digital conversion through high-speed AD, and the FPGA stores and processes the full waveform signal, which is then transferred to the upper computer. Finally, the standard energy meter is used to build a metering calibration optical path to calibrate the energy of the measuring device. The measuring device realizes the measurement of 1 064 nm pulsed laser energy with pulse width of 10~100 ns and energy range of 40 fJ~1.1 pJ. The measurement repeatability is not more than 2%, which basically meets the test requirements.

Nowadays, with the rapid development of social economy, the scale of power grid is increasing, the capacity of power grid is increasing, and the problem of power loss is becoming more and more serious. In order to make rational and efficient use of power, the research on abnormal power consumption is very important. Aiming at the problem of abnormal power consumption, this paper preprocesses the power consumption data of a regional power grid logically, and uses heuristic algorithm to build two targeted heuristic models. The data collected from the detection instruments deployed in the power grid are used for experimental verification. The relative anomaly index in the case of abnormal power consumption is 6~10 times larger than that in the normal case. Combined with the heuristic algorithm, it can better identify and detect the abnormal power consumption phenomenon of the power grid, and verify the effectiveness of the proposed method.

Although live working in the process of power grid operation and maintenance ensures the uninterrupted operation of power grid, it also increases the risk of operators and mechanical equipment compared with traditional methods. Real time and accurate monitoring of the electric field environment and real-time alarm to power personnel when the electric field is too strong are of great significance to the safety of power personnel. Taking 110 kV transmission line as an example, the influence of live working human body on the measurement of high voltage power frequency electric field under the limit safety distance by finite element method is studied in this paper. The differences of electric field measurement with and without human body in the upper, lower and side directions are compared, and the differences of electric field in different body parts of live line workers are calculated. The maximum difference of electric field measurement with or without human body in the three directions can reach 183.08%. Therefore, the electric field alarm device should consider the influence of human body on electric field distortion and the monitoring direction and position of human body to correct the alarm threshold.