The optical phased array controls the emission beam by adjusting the phase of the array antenna to change the wave-front, thus achieving control over the emission beam. Optical phased array technology has great potential applications in areas such as laser radar, laser communication, high-brightness laser generation, and synthetic aperture detection. This article reviews the re-search progress, advantages, and disadvantages of liquid crystal phased arrays, micro-electro-mechanical system phased arrays, and optical waveguide phased arrays. It also delves into the optical waveguide phased array technology in laser radar, proposing break-through directions for this technology.

This paper introduces the composition, major function, and technical specifications of a high integrated eight-channel Ka-band low noise down-converter module. An eight-channel Ka-band low noise down-converter module is designed, and the imple-mentation method of the circuit is proposed. The isolation, amplitude imbalance, noise figure (NF), and combined frequency interfer-ence are also analyzed. The measured results of the module are as follows: NF is lower than 2.3 dB, the converter gain is more than 35 dB, and the amplitude imbalance is lower than ±0.5 dB. The isolation of multi-channel is more than 60 dB. The module has the advantages of a small size, high output power, high reliability, and good consistency. It has been successfully applied in TT&C.

Clouds and precipitation are vital to the global water and energy cycle and act as crucial elements in maintaining the Earth's energy balance. Spaceborne cloud and precipitation radars can actively detect clouds and precipitation and obtain three-dimensional structural information of cloud and precipitation globally all day and night,effectively filling the shortcomings of pas-sive detection by meteorological satellites. Firstly, the demand analysis is conducted on spaceborne cloud and precipitation radars,summarizing the shortcomings of cloud and precipitation detection capabilities of current Chinese meteorological satellites. Then,the development status of spaceborne cloud and precipitation radars at home and abroad is introduced, and the problems that China's spaceborne cloud and precipitation radars need to be solved are summarized. Finally, we give the main direction of the development of spaceborne cloud and precipitation radars in China in the future.

From March 27-29, 2021, a large-scale and prolonged dust pollution event occurred in the north of China. This study analyzed the optical properties, vertical distribution, and transport patterns of dust aerosols using data from MODIS and ground-based lidar (AMPLE-001), combined with the HYSPLIT model. Additionally, hourly data from the China Environmental Monitoring Station and aerosol optical depth (AOD) data from MCD19A2 and AERONET were used to verify the accuracy of the ground-based lidar measurements. The key findings are as follows: ① The dust was primarily transported at an altitude of 4 km over the northern Gobi Desert, and mixed with local pollutants and then settled. ② During the dust event, particulate matter concentrations surged dra-matically. PM₁₀ concentrations peaked at over 2 492.65 μg/m³, while PM_2.5 reached a maximum of 236.48 μg/m³. The highest record-ed AOD was 4.1, with dust pollution being most severe in the southern and eastern parts of Beijing, Tianjin, and Hebei. ③ In terms of accuracy validation, comparisons between AOD values from sun photometers and lidar showed a strong correlation, with a corre-lation coefficient of 95.63%. Similarly, the PM₁₀ and PM_2.5 data from ground-based lidar were highly consistent with official monitor-ing data, with correlation coefficients of 85.93% and 98.47%, respectively. These results validate the detection capability and accura-cy of the AMPLE-001 ground-based lidar system.

Aiming at the issue of poor stability of visual localization and mapping (SLAM) methods during dynamic low-altitude flight of unmanned aerial vehicles (UAVs) in the absence of navigation signals, this paper proposes a UAV visual localization method based on edge features, which generates the edge features by downsizing the traditional feature extraction algorithm and finally completes the position estimation by nonlinear optimization. A convolutional neural network is employed to match edge fea-tures between consecutive key frames, yielding an edge feature reprojection error function, and finally the position estimation is com-pleted by nonlinear optimization. The experimental results demonstrate that compared to the state-of-the-art ORB-SLAM3 algo-rithm, the proposed method reduces localization time by 31% on the dataset and improves localization accuracy by 15.04% in low-texture scenes. Flight experiments further indicate a significant enhancement in the accuracy and stability of UAV localization.

The Surface Water and Ocean Topography (SWOT) satellite is a new generation ocean observation satellite. It is used to provide a new method for wave detection by adopting the synthetic aperture radar (SAR) observation system at a small inci-dence angle. Based on previous studies on SAR wave spectrum inversion, the applicability of the wave spectrum inversion algorithm for SWOT satellite data is studied. The effects of wind speed, wind direction, and main wave direction on wave spectrum inversion are discussed. The effective wave height of the inversion is verified using the ERA5 dataset from the European Center for Mediumrange Weather Forecasts (ECMWF). The results show that the root mean square errors (RMSE) of the effective wave height inver-sion are 0.30 m, 0.19 m, and 0.64 m at wind speeds of 7-9 m/s, 9-11 m/s, and >11 m/s, respectively. The scatter indices (SI) are 16.74%, 7.03%, and 19.61%, respectively. It can be proven that the SWOT satellite, as a small incidence angle SAR, has the poten-tial to invert wave spectra and wave parameters.

The paper provides a brief overview of the development of terahertz technology and its advantages in various appli-cation scenarios, including high resolution and strong anti-stealth characteristics in radar. Regarding terahertz atmospheric transmis-sion characteristics, the paper focuses on the basic principles of the MPM and provides an overview and comparison of mainstream atmospheric transmission models like the ATM model and AM model. At the same time, this paper also introduces recent research developments and progress on terahertz atmospheric transmission characteristics domestically and internationally. Finally, this paper summarizes the development of terahertz technology and offers prospects for its applications.

The high-precision navigation of the remote sensing instruments onboard FengYun-4 (FY-4) geostationary meteoro-logical satellite is the basis for instrument calibration, product retrieval, and quantitative application. The geosynchronous interfero-metric infrared sounder (GIIRS) onboard FY-4 satellite, the new generation geostationary meteorological satellite in China, is the first hyperspectral vertical detector operating in the geostationary orbit in the world. In the process of hyperspectral detection, it is key to keep the "resident" observation target stable with high precision. The FY-4 satellite uses an advanced three-axis stable attitude control platform, which brings great flexibility to earth observation and great challenges to the high-precision navigation of the GIIRS. The stability of the high-precision observation target requires the cooperation of satellite platform, attitude control, the instru-ment and the ground system, which process is very complicated. Based on the introduction of the detection principle and working mode design of the GIIRS, the key technology of satellite-ground integrated navigation is researched. The resident accuracy as well as the navigation accuracy are tested and analyzed using the measured data from the GIIRS in orbit. The results show that the GIIRS achieves a resident accuracy of 1/10 pixel and a navigation accuracy of 1 pixel, laying a good foundation for quantitative applications including numerical weather prediction.

Considering cost and integration constraints, traditional phased array antennas are usually single-polarized or time-multiplexed polarized and do not finely regulate the polarization form when transmitting or receiving signals, which constrains the polarization domain efficiency of phased array antennas. To address this issue, this paper is based on heterogeneous fully polarized phased arrays and jointly regulate their beam pointing and polarization parameters, in an attempt to achieve the full polarization ap-plication of phased array antennas at a lower cost. Firstly, the concept of heterogeneous fully polarized phased arrays is proposed;then, the mathematical model for the joint regulation of beam pointing and polarization parameters of heterogeneous fully polarized phased arrays is established; finally, a joint regulation method is proposed and mathematically simulated. The simulation results dem-onstrate the correctness and effectiveness of the joint regulation method for beam pointing and polarization parameters of heteroge-neous fully polarized phased arrays.

DRO orbit in cislunar space is a kind of periodic orbit with great value and mission potential. The scientific exploration satellite on DRO orbit has the requirement of timely down-transmission of critical buret data of scientific payload and global coverage of measurement and control management. This paper analyzes the basic capability of BDS-3 global short message. The cis-lunar space TT&C data transmission scheme and TT&C data transmission process are designed based on the BDS-3 global short message, and the key technologies are analyzed. The research and analysis show that the cislunar space TI&C data transmission scheme based on the BDS-3 global short message can make up for the gap of ground-based TT&C, and realize the low-cost TT&C data transmission in all weather and all day.