With the development of space laser communication and the planned deployment of satellite Internet constellations, there is a growing demand for microminiature laser communication terminals. To meet the requirements of size, weight and power (SWaP), miniaturized terminals require smaller drive components to complete on-orbit scanning and capture, which must be fast and efficient to enable satellite laser communication networks. These miniaturized laser communication terminals are highly susceptible to the impact of the initial pointing accuracy of the laser beam and microvibrations of the satellite platform. Therefore, this paper proposes a laser scanning-capture model based on a Micro-electromechanical Systems (MEMS) micromirror that can provide a fast, large-scale scanning analysis. A scanning overlap factor is introduced to improve the capture probability under the influence of microvibrations. Finally, experimental analysis was carried out to verify the effectiveness of the proposed model, which can establish a theoretical basis for future ultra-long-distance microspace laser communication.

In intersatellite laser communications, the centroiding accuracy of a laser spot is crucial for maintaining steady communication links. However, the systematic error introduced by discrete sampling restricts further improvement of centroiding accuracy when choosing algorithms that are widely used in engineering. Additionally, the ultrahigh computational complexity and multiple-step iterations of the Gaussian fitting (GF) algorithm are unsuitable for real-time implementation, even though the algorithm can achieve the highest centroiding accuracy. In this study, we propose a laser spot centroiding algorithm based on template correlation to simultaneously satisfy the requirements of real-time performance and accuracy. The proposed algorithm evaluates the central location of a laser spot by obtaining the index of the maximum Pearson correlation coefficient (PCC). Simulations performed under different conditions reveal that the proposed algorithm is robust against the interference of background noise and the bad pixels. Moreover, experimental verification is performed based on the implementation on a Field-Programmable Gate Array (FPGA) in real-time, meanwhile its accuracy is on the same level as that of the GF algorithm and better than those of other widely-used algorithms. Therefore, the proposed algorithm is suitable for accurate real-time locating of laser spots in engineering applications of the intersatellite laser communications

As a typical active noise control algorithm, FxLMS is widely used in the field of audio denoising. In this paper, an audio denoising coprocessor based on RISC-V custom instruction set extension was designed, and the idea of software and hardware co-design was adopted; based on the traditional pure-hardware implementation, the accelerator optimization design was carried out, and the accelerator was connected to RISC- V core in the form of coprocessor. Meanwhile, the corresponding custom instructions were designed, the compiling environment was established, and the library function of coprocessor acceleration instructions was established by embedded inline assembly. Finally, the ANC system was built and tested based on E203-SoC, and the test data was collected by audio analyzer. The results showed that the audio denoising algorithm could be realized by combining heterogeneous SoC with hardware accelerator, and the denoising effect was about 8dB. The number of instructions consumed by testing custom instructions for specific operations was reduced by about 60%, and the operation acceleration effect was significant.

With the growing demand for high-efficiency and secure information transmission, ultra-long-range optical communication has demonstrated significant potential. This paper proposes a method for establishing ground-based fixed-point ultra-long-range atmospheric optical communication links, aiming to overcome challenges such as atmospheric turbulence, transmission loss, and environmental interference. Through theoretical analysis and experimental validation, we developed a high-precision optical communication terminal installation model, determined the terminal’s optical axis direction via stellar calibration, and established a coordinate transformation model from geodetic coordinates to initial pointing angles. By analyzing initial pointing errors, we designed a laser link scanning strategy to compensate for uncertainties in the initial pointing region. The feasibility of this approach was verified through near-field validation and a long-distance link acquisition experiment exceeding 100 km. Experimental results demonstrated successful 100 km/100 Gbps ultra-high-speed optical communication. This breakthrough study is expected to play a critical role in future space-localized optical communication networks.