Aerial-space image matching is one of the significant research directions of unmanned aerial vehicles. This paper systematically constructs a framework for matching heterogeneous aerial-space images and provides an in-depth analysis of its key components. Based on literature review, this paper categorizes the key technologies of the heterogeneous image matching framework into three major types: image quality assessment technology, image preprocessing technology, and image matching technology. It summarizes the latest advancements in each of these technologies, with a particular focus on analyzing the technical differences in their application to the UAV field. Based on this, cross-comparison experiments are conducted using datasets to analyze the specific effects of each method. Finally, the paper summarizes the challenges faced in matching heterogeneous aerial and space images and provides an outlook on future research directions and development trends.

Aiming at the absolute and relative location service needs of low-altitude flight drones in complex electromagnetic environments, a three-dimensional distributed drone cooperative localization method based on high-precision ranging information is proposed. All nodes in the cluster are equipped with navigation positioning sensors with the same accuracy, and use the inertial error as a state variable, the height value of the altimeter as a height measurement and 0.1 Hz visual matching information as position and speed measurements to correct the absolute positioning error of the nodes. Use the ranging values of the nodes as cooperative measurements to correct the relative positioning error, and use the extended Kalman filter to fuse the measuring range and inertial/altimeter/vision system output. Construct the flight test scene of the 6-node drone group to complete the simulation verification of low-altitude flight scenes. Verified, through the cooperative positioning algorithm, the absolute position accuracy is improved by 61%, and the relative positioning accuracy increases by 93%, which proves the effectiveness of the cooperative localization method.

As one of the important means of data transmission between satellites, laser communication has a direct impact on the performance of the constellation system due to its fast and stable link establishment ability. The laser communication terminal relies on a high-precision optical tracking system to achieve continuous and stable pointing of the signal beam to the target satellite. However, space environmental factors can interfere with the pointing accuracy of laser terminals, and their influence can reach the level of milliarcsecond measurements. The deformation of the satellite structure caused by thermal expansion, cold contraction and stress changes during the satellite operation in orbit leads to the rigid displacement of the laser terminal pointing accuracy compared with the reference position of the satellite platform. In this paper, based on the application background of the rapid and stable chain construction of inter-satellite laser communication links, the finite element analysis method is used to study the pointing error caused by the thermally induced deformation of the laser terminal datum and the satellite platform star sensitive datum. By analyzing the installation reference error caused by the thermal deformation of satellites at different orbit altitudes, the variation law of laser communication link pointing error is obtained, which provides an analytical basis for the rapid and stable chain construction, and provides a design reference for the module layout and overall thermal control of the whole satellite.

The no-hit zone frequency hopping sequence is a sequence with zero collisions between sequences within a certain delay range, and has broad prospects in quasi-synchronous frequency hopping communication systems. To reduce frequency interference among users caused by the increase in user numbers in a frequency-hopping communication system, this article implements a no-hit zone frequency hopping sequence generation method based on matrix transformation, with variable no-hit zone range and sequence quantity, and illustrates the construction process with examples. At the same time, a high-complexity RS code was constructed as a comparison in this article, and the error rates of the two were compared through simulation under different signal-to-noise ratios and user numbers. The results showed that when accessing the frequency hopping network within the no-hit zone range, the hopping system using the no-hit zone hopping sequence had a lower error rate than the hopping system using RS code, greatly enhancing the multi-access communication capability of the hopping system.

With the ongoing advancements in equipment informatization and lightweight design, the development of navigation guidance and control (GNC) systems faces escalating complexity, while demands for system miniaturization and weight reduction grow increasingly urgent. System-in-Package (SiP), a high-density integrated packaging technology, addresses these challenges by encapsulating multiple functional chips into compact cavities, thereby achieving enhanced integration and system miniaturization. To meet the miniaturization requirements of GNC systems, this study presents a GNC information processing microsystem circuit designed using SiP technology. The circuit employs a DSP+FPGA architecture, integrates diverse interface and memory chips, and leverages mature ceramic substrate microsystem integration techniques. Comprehensive multi-physics simulations were conducted to validate the design. Experimental results demonstrate normal circuit functionality and full compliance with design specifications. Compared to the prototype verification board, the optimized circuit exhibits dimensions of 45 mm×45 mm×11 mm and a weight of approximately 60 g. Substituting traditional board-level systems with this circuit significantly improves product integration and fulfills critical miniaturization requirements for control systems.

The rapid relative motion of satellites causes the burst spread-spectrum signals to produce a Doppler frequency shift. In low signal-to-noise ratio (SNR) environments, the traditional acquisition algorithms are limited in their abilities to capture large Doppler frequency shift when signals are seriously disturbed by noise. In view of the above problems, this paper designs a parallel burst spread spectrum signal acquisition algorithm based on pilot information and Partial Match Filter-Fast Fourier Transform (PMF-FFT). The algorithm utilizes pilot information and multi-path parallel processing method to achieve fast acquisition of Doppler frequency shift and PN code, which greatly reduces the acquisition time of burst signal. Firstly, the mathematical model and the acquisition loss of the algorithm are analyzed in detail. Then, the scallop loss of the acquisition system is reduced by zeroing the FFT. Finally, a method of the shortest synchronization segment based on a constant false-alarm rate and a specified detection probability is designed. The simulation results show that the acquisition probability of the proposed algorithm reaches 99 % for burst signals under the -31 dB signal-to-noise ratio when the false alarm probability is 10^-6，which verifies the feasibility of the design method.

In response to the development trend of on-board routing devices, namely the improvement of interaction rate, bandwidth increase, and lightweight design, this paper proposes a design scheme for on-board high-speed switching algorithm based on improved polling. This scheme adopts a two-level queue scheduling algorithm based on the combination of the improved RR(Round Robin) polling scheduling algorithm and PBPW (Priority-based Bandwidth Privilege with Weighting) algorithm. In the first level scheduling, priority polling scheduling is introduced to ensure that high priority data frames can be forwarded first. A cache sharing mechanism is opened to avoid congestion and resource waste to a certain extent. In the second level scheduling, thresholds are assigned to each link to avoid certain links from being unable to receive service due to hunger, while also preventing congestion issues in other links. Compared with traditional simple queue scheduling algorithms based on FIFO (First In First Out), this improved polling scheduling mechanism significantly improves the forwarding rate of on-board routers and reduces forwarding latency. In addition, priority forwarding of high priority data frames has been achieved through polling, further optimizing the performance of the router.

In this paper, we propose a novel method of attitude determination for spinning vehicles based on standalone GNSS. A baseband algorithm is first developed to resolve the shadowing effect encountered by 4-antenna receivers mounted on spinning vehicles, enabling continuous and precise signal tracking. Then the particular geometry of the 4-antenna configuration is exploited to yield differential ENU-velocity vectors from co-located antennas. By taking the inner product, the vehicle's pose information is derived from the orthonormality of rotation matrices, and yields the roll rate in the body frame. Finally, we use the roll rate to devise linearly independent differential vector pairs and solve for the rotation matrix in the linear system relating ENU velocities and body-frame velocities. The attitude information, defined by Tait-Bryan angles, can thereby be resolved. The algorithm presented is implemented in a 4-antenna real-time GNSS receiver and experiments are carried out with a spinning cylindrical platform. The results are confirmed via evaluation of the PVT results and comparisons with the platform's true attitude.

By constructing an angle tracking loop model and performing simulations in the phased array TT&C (Telemetry, Tracking and Command) system, it is used to assist in designing the parameters for the α-β filtering estimation algorithm in the angle tracking loop and the closed-loop period and delay time of the entire loop. Firstly, the equipment composition of the phased array antenna angle tracking system is introduced, and a simulation model of the angle tracking loop is constructed. Then, when the parameters of the filtering estimation algorithm and the closed-loop period and delay time of the angle tracking loop change, the step signal is used to test the dynamic response performance of the angle tracking loop, and based on this, the design parameters of each link in the loop are determined. Subsequently, constant-velocity signals and sinusoidal signals are used to simulate the maneuvering characteristics of the flight target, and the lag error of the angle tracking loop is simulated to verify whether the design parameters meet the usage requirements of the system. Finally, the sinusoidal signal is used to simulate the disturbance characteristics of the antenna carrier platform. The anti-disturbance performance of the angle tracking loop is verified through loop lag error simulation, and by simply improving the filtering estimation algorithm, the anti-disturbance performance of the loop is improved. Experimental results demonstrate that modeling and simulation of the angle tracking loop enable rapid parameter and algorithm design for all components in the loop, significantly reducing trial-and-error costs.

During the execution of precision measurement and control tasks by ground - based equipment, in order to accurately track the angular error demodulation signal, phase and slope correction of the tracking receiver are required, and the process of obtaining the correction value is called phase calibration. Ensuring the precise phase difference calibration of the sum and difference receiving channels is a key step to meet the self - tracking requirements of the target for the angle measurement subsystem. The traditional phase calibration method for multimode feed tracking systems faces challenges such as low efficiency, susceptibility to calibration equipment failures, and the impact of field setup environments, which not only limits the smooth progress of measurement and control tasks but may also have an adverse effect on the accuracy of target tracking. This paper aims to study and analyze existing calibration methods, deeply mine the existing calibration data, and introduce the method of multiple fitting analysis of mathematical statistics to predict the phase shift value, thereby effectively enhance emergency measurement and control capability of the measurement and control equipment in practice, ensuring the continuity and accuracy of task execution.

The task volume of TT&C equipment executing satellite management tasks is increasing day by day. The daily shutdown maintenance, performance index testing and increasing workload of equipment have become contradictory. Equipment maintenance and performance index testing demand efficient automated testing methods. This article researches the integrated operation management system based on lightweight cloud, analyzes the software and hardware composition of the automated testing system, deploys automated testing software on the integrated operation management system, and improves the reliability of software operation. It has also proposed an automated testing strategy for high-density task states, optimized the automated testing process, and implemented the function of rapid and automated testing of TT&C performance indices. By testing the effective isotropic radiated power—EIRP value of the system, and applying the automated testing system in practice, the testing efficiency has been significantly improved.

The radar seeker simulation system is crucial for the process of the seeker striking the target accurately. As simulation systems become more complex and data processing demands grow, traditional serial computing methods can no longer satisfy the strict real-time requirements of radar seeker digital simulations. To address the challenge of lengthy simulation times in the radar seeker simulation process, this paper proposes a full-process digital real-time simulation method. Firstly, the core components of the traditional full-process simulation architecture—receiving and controlling system commands, simulating echo data reception, SAR imaging processing, uploading imaging results, and dynamically updating the user interface—are restructured into a pipeline-based parallelization framework. Secondly, the SAR imaging algorithm's primary steps are parallelized using the OpenMP multi-core parallel programming model on multi-core CPUs. Furthermore, the high-performance mathematical computing library FFTW3 is introduced to quickly realize the Fourier transform of the imaging algorithm to accelerate the processing speed of the SAR imaging algorithm. Finally, the simulation results show that compared with the traditional serial simulation, the acceleration ratio of the whole process design method reaches about 100 times, and the similarity of SAR images before and after acceleration is close to 1. Under the premise of consistent processing accuracy and effect, this approach enables full-process real-time simulation of the radar seeker system, showcasing promising prospects for practical engineering applications.

The annual large-scale outbreak of Enteromorpha prolifera in the Yellow Sea brings serious harm to the marine environment. Monitoring it by remote sensing technology is the most effective early warning method for dealing with the Enteromorpha prolifera disaster. In remote sensing images, Enteromorpha prolifera is mostly discrete small targets with irregular shapes, and traditional interpretation algorithms suffer from low interpretation accuracy and efficiency. To address this issue, this paper proposes a high-precision Enteromorpha prolifera detection method based on the PSPNet network, which embeds the DAM attention mechanism module to enhance the network's attention to Enteromorpha prolifera regions in remote sensing images. Then, the DBSCAN clustering algorithm is used to draw the contours of Enteromorpha prolifera regions and provide Enteromorpha prolifera interpretation results. Experimental results on MODIS remote sensing images of Enteromorpha prolifera show that the PSPNet+DAM model can achieve high-precision and high-efficiency Enteromorpha prolifera detection, and the DBSCAN clustering method can quickly generate interpreted images of Enteromorpha prolifera. The proposed framework in this paper can provide technical support for the early warning and disposal of Enteromorpha prolifera disasters.

With the advancement of remote sensing technology, there is an increasing demand for high-resolution remote sensing images. However, due to the limitations of optical devices, insufficient sensor resolution, and factors such as satellite orbital height, the imaging equipment captured remote sensing images often cannot achieve the ideal resolution, and the imaging effect is not satisfactory, which brings great trouble to researchers in extracting and analyzing the features of remote sensing images. To solve this problem, a modular and reconfigurable system architecture is used, and a multi-row buffer pipeline mechanism is implemented based on the FPGA hardware platform to design real-time processing modules such as bilateral filtering, upsampling, and downsampling. Image pyramids and Laplacian pyramids are constructed, and image interpolation is performed layer by layer to achieve high-resolution imaging. The overall system hardware design is based on the Xilinx XC7A35T FPGA chip and its synthesis results are analyzed for performance indicators. The system has good portability. With the clock frequency of the image processing modules in the system set to 180 MHz, the delay is less than 5 ms, which can meet the real-time requirements of the system.

When a ship is sailing on the sea, the attitude of the ship changes in real - time due to the influence of the ship's own movement, wind, and waves. And it is difficult to accurately measure the ship's attitude in real - time from an aircraft. In order to solve the above problems, a pose - estimation method integrating the traditional template - matching method and the deep - learning method was designed. The deep - learning method improves the accuracy, robustness, and environmental adaptability of pose estimation, while the real - time performance of pose estimation is enhanced by combining it with the template - matching method based on contour features. Firstly, the three - dimensional model of the target ship was used to render the multi - pose images of the ship, and the ship attitude template library was established through the instance segmentation algorithm. Then, the visible - light images of the target ship were collected. The ship - matching images were obtained through the target - detection and instance - segmentation algorithms. These ship - matching images were matched with the images in the ship - attitude template database, and the attitude corresponding to the successfully - matched ship - attitude template image was the attitude of the ship. Through simulation verification, the accuracy of 3D attitude estimation could reach 1°.

The development of wireless communication technology has imposed strict requirements on antennas, including high-frequency operation, miniaturization, and strong directivity, to support higher data transmission rates in the future. Due to inherent amplitude and phase differences among channels in millimeter-wave chips and multi-antenna arrays, as well as additional amplitude and phase differences caused by factors such as temperature characteristics and aging during operation, beamforming accuracy can be significantly degraded. To mitigate the impact of inter-channel amplitude and phase differences on beam control, this paper proposes a near-field calibration algorithm based on plane wave spectrum expansion. The algorithm constructs a signal model between the antenna under test (AUT) and the probe using plane wave spectrum theory. Based on this model, a virtual signal for calibration measurement is generated and compared with the measured signal. A genetic algorithm is used to optimize the difference between the virtual and measured signals, and the initial excitations of the millimeter-wave array antenna are determined when the difference reaches its minimum. To validate the effectiveness of the proposed calibration algorithm, a four-element millimeter-wave linear array was calibrated. The probe scanning range was approximately one-third of the array aperture. The obtained amplitude calibration error range was ±0.43 dB, and the phase calibration error range was ±4.6°, achieving high-precision calibration.

This study investigates the application of flower-shaped bionic topology in phased array antenna liquid cooling systems through computational fluid dynamics (CFD) simulations and experimental validation. The phased array antenna comprises a rectangular transmitting module, 4 L-shaped receiving modules and 12 rectangular receiving modules. All these three types of liquid cooling plates are designed to form either a flower-shaped bionic topology or a fully parallel topology. Comparative analysis reveals that the flower-shaped bionic topology offers a highly efficient thermal control solution. The temperature gradient of the antenna employing flower-shaped bionic topology is significantly smaller than that of the fully parallel topology. The temperature difference between modules is controlled to ±3 ℃, representing an 8%~15% improvement over the fully parallel topology.

A D-band SIW slot antenna was proposed in this paper. The feeding network consists of a CPWG input, a CPWG-SIW transmission with the wideband and low-loss characteristics from the quasi-TEM mode to quasi-TE10 mode and a rectangular slot with functions of vertical transition, transmission and power-dividing. High-gain radiation was achieved at the SIW slot antenna with good isolation between radiation field and the feeding network. As shown in the simulation results, the bandwidth of 1×4 antenna array achieved an E-plane beam-width of 24° and an H-plane beam-width of 10° at 120 GHz. The gain is more than 18.29 dBi and the VSWR is less than 2.0 with the size of 18.73 mm×5.83 mm×0.55 mm.