TDOA (Time Difference of Arrival) is a widely used passive positioning technology with high precision, strong ability of collaborating, high robustness. The issues of computational complexity and slow accuracy convergence for the positioning of moving target are addresses. Based on the positioning model in LOS (Line of Sight) environment, a positioning method suitable for a multi-station TDOA system is provided. After linearizing collaboration TDOA positioning relationship equations into a statistical estimation problem, this method online converges iteratively to solutions of targets' locations. A multiplatform collaborative positioning algorithm for different motion characteristics of the targets. Simulations results demonstrate that the provided method can achieve precise positioning. Moreover, the impact of motion patterns on positioning accuracy is analyzed, and simulation results provide guidance for system engineering design.

Taking the hydrogen-oxygen expansion cycle engine as the research object, based on the idea of modular modeling and simulation, the dynamic model of engine components is given, and the liquid rocket engine system model is constructed based on the working principle of the engine system, and the transient state of the hydrogen-oxygen expansion cycle engine is developed simulation Research. According to the simulation results and combined with the test data, the engine system model is verified and optimized, and the optimized model is simulated and calculated in the whole process of engine dynamics. The simulation results show that the main performance parameters during the dynamic change of the engine are in good agreement with the test data, which verifies the simulation model accuracy and design feasibility.

As a high-value military target, it is difficult to directly conduct damage research on real aircraft. Designing equivalent targets to replace real targets in damage tests and simulation research are important means for target vulnerability and damage. A target design method is proposed based on the damage characteristics and usage requirements of equivalent objects, with a focus on the "physical and functional" damage equivalent tecnology of aircraft components/subsystems under the threat of fragments. On this basis, a detailed design process for equivalent targets of aircraft is established by comprehensively considering the equivalence of the target's internal and external environment, as well as various factors such as processing and transportation. Then, based on the proposed method, an equivalent design target is carried out for the radar antenna cover of the early-warning-aircraft (EWA), and ground static explosion damage tests are carried out on the equivalent components. After verifying the accuracy of the simulation method with the test results, the ballistic limit velocity and corresponding critical penetration energy thresholds of diffrerent areas for the typical fragment hitting radar antenna cover are determined through impact finite element simulation, the rationality and usability of the proposed equivalent target design method is verifyed. The equivalent target design method proposed can provide support for the inspection and evaluation of the damage ability of air defense weapons and ammunition, the formulation of aircraft target damage standards, and joint combat training activitis.

In order to improve the transpiration cooling efficiency at the stagnation point of the nose cone of the near space vehicle, a wedge-shaped porous nose cone with a gradient porosity layout is proposed and the phase change transpiration cooling is experimentally and numerically investigated under different coolant injection ratio. The experimental results indicate that the gradient porosity layout can effectively improve the cooling efficiency at the stagnation point and the overall temperature uniformity of the porous surface. When the coolant injection ratio $M$ is 0.125%, the cooling efficiency at the stagnation point is increased by 52.4%, and the overall cooling efficiency is increased by 31.7%. The numerical results indicate that the gradient porosity layout increases the coolant mass flux at the leading edge and optimizes coolant distribution by moving the maximum pressure value at the stagnation point downstream. When the coolant injection ratio $M ={0.15}\%$, the coolant mass flux at the stagnation point is increased 76%. In addition, the film formed by the coolant flows out of the porous structure is more uniform.

In order to study the ability of laser-guided weapons to capture targets in various environments such as sea and land, mathematical models such as flight trajectory, backscatter and target diffuse reflection of laser-guided weapons are established, and whether the guided weapons could capture targets normally are judged by comparing the field of view, backscatter power density and target diffuse reflection power density of laser-guided weapons. Simulation calculations show that under the same conditions, the same laser weapon captures the target later at sea than in the land and other environments, the capture distance is closer, and the backscattering is more serious. Under normal circumstances, the backscattering effect of laser-guided weapons is more serious in the initial 4.4s time period of this projection, and the backscattering effect can be avoided by reducing the outlet energy of the laser irradiator or increasing the distance between the central axis of the laser-guided weapon and the optical path of the laser irradiator to more than 250m.

Focusing on the development of missile intelligent cooperation, the application of missiles in Unmanned Aerial Vehicle (UAV) swarms is focused on. The respective application characteristics of UAV swarm and missile systems are introduced, the application modes of missiles in UAV swarm are explored, the requirement on developing intelligent missile swam is analyzed. Based on the issues of observation, interaction, and collaboration in swarm intelligence, current challenges and key support technologies for missiles application in UAV swarm are analyzed. With the analysis on "MSET" and "Golden Horde" projects, the current situation and development of missiles in swam are analyzed, and the ability doubling points for the actualization of missile-UAV application are pointed out, which provides exploration for future research on intelligent missile system.

The on-orbit refueling technologies of cryogen can reduce the total mass of propellants required in rocket vehicles, allowing a significant increase in the amount of payload delivered beyond low Earth orbit. It has great potential benefits in complex space transportation systems and deep space exploration tasks. A literature investigation on the key techniques of cryogenic propellant on-orbit refueling is conducted. The existing lab-scale and full-scale experimental studies are reviewed in detail. Moreover, advantages of using on-orbit refueling techniques comprehensive analysis in future space tasks are provided. Technical suggestions on the developments for on-orbit refueling of cryogenic propellants are proposed based on this research.

The Model based Definition (MBD) technology digital process verification approach is examined. A process verification system for Design for Manufacture (DFM) is introduced. The system uses PMI, or product and manufacturing information, as a vehicle to express product processing information and dimensional information. In the concept design phase, the auto-matic process testing of the product geometry model is realized, and the viability of the product process is examined, thanks to the development of the model testing tool. The test's outcome is evaluated in accordance with the guidelines for producing liquid rocket engines. The designer can adjust and enhance the sketch of the geometry for the liquid rocket engine in light of the outcome. By using DFM, the process accessibility of the product in the design phase is improved, the design and process changes in the product manufacturing process are reduced, and the product development cycle is shortened.

To address the reentry missions with different path constraints and range requirements, a conic based bank angle is designed to enhance the lateral maneuverability, and the predictor-corrector guidance method is used to revise the bank angle profile to satisfy the range requirements. The improved artificial potential field method is used to design the lateral guidance method to satisfy the path constraints. Finally, the guidance parameters are optimized by particle swarm optimization algorithm to obtain the trajectory with the best performance. Simulation results verify that the algorithm can adapt various range requirements and path constraints, and meet the terminal constraints with high accuracy.

Interstage thermal separation is one of the core technologies in the flight process of solid rocket. The traditional "three in one" test usually includes three main subsystems: upper stage motor, servomechanism and separation system. For practical engineering development, it is costly, expensive and long cycle. It can only be used for system level performance verification test, and is not suitable for exploratory developmental test. Based on the new ground test method of cold air simulated rocket interstage separation test, combined with theoretical model, numerical simulation and ground test verification, the internal flow field in the initial pressure holding stage of interstage separation is simulated, the law of gas pressure change in interstage section is revealed, and the test mechanism of cold air simulated rocket interstage separation is expounded; Through numerical simulation analysis, the effects of different initial pressure of pressure accumulator, different volume of pressure accumulator, different pipe area and different volume of interstage section on the change of gas pressure are studied, which provides a solution for the design of interstage separation test of cold air simulation.