Extended Kalman Filter (EKF) algorithm is widely used in parameter estimation for nonlinear systems. The estimation precision is sensitively dependent on EKF’s initial state covariance matrix and state noise matrix. The grid optimization method is always used to find proper initial matrix for off-line estimation. However, the grid method has the draw back being time consuming hence, coarse grid followed by a fine grid method is adopted. To further improve efficiency without the loss of estimation accuracy, we propose a genetic algorithm for the coarse grid optimization in this paper. It is recognized that the crossover rate and mutation rate are the main influencing factors for the performance of the genetic algorithm, so sensitivity experiments for these two factors are carried out and a set of genetic algorithm parameters with good adaptability were selected by testing with several gyros’ experimental data. Experimental results show that the proposed algorithm has higher efficiency and better estimation accuracy than the traversing grid algorithm.

As a main tool for the lunar exploration and Mars landing project, the reentry capsule is responsible for the transportation of personnel and supplies, and it is very important to ensure its safety. The complex flow field caused by the shape of the large blunt cone makes it unstable in transonic and supersonic flight, so its dynamic characteristics need to be analyzed. This paper analyzes the dynamic characteristics of the reentry capsule by computational fluid dynamics (CFD) numerical simulation. The pitching combined dynamic derivative was obtained by simulation of forced pitching oscillation of the flight vehicle using the rigid dynamic grid; the time difference derivative was obtained by simulation of plunging of the flight vehicle using the rigid dynamic grid, too. The direct dynamic derivative was gained by negating the plunging derivative from sum. This paper simulates the pitching and plunging motion of NACA0012 air foil and hypersonic ballistic shape (HBS). The results of the simulation are consistent with the references. The Mars exploration rover entry capsule was simulated and analyzed to ensure a basis for the aerodynamic design and control of the reentry capsule.

The electrical system in a launch vehicle contains multiple wireless communications systems. A large number of prelaunch tests are needed to verify the correctness and reliability of electric systems at the launch site. The complex electromagnetic environment at a launch site will inevitably cause multipath effect which interfere with prelaunch tests. Theory analysis and simulation of multipath effect, combined with engineering practice, can effective identify and quickly correct abnormal situations, and identify methods and measures to eliminate the influence of mul-tipath interference .

The Chinese-French Oceanic Satellite 1 (CFOSAT-1) was successfully launched on October 29, 2018. The satellite was developed under cooperation between China and France. CFOSAT-1 realizes joint observation of sea waves and wind for the first time in the world. This paper introduces the background of the satellite, including application goals and the division of the project. The paper describes the satellite platform composition, the coverage and benefit of conducting joint observation as well as the working principle, structure and performance of the two payloads, SCAT and SWIM, and introduces the in-orbit observation results of sea wind and waves. The difficulties during the development, solutions and acquired experience for future international space cooperation are also introduced. Finally, the conclusion concerning CFOSAT-1’s contributions to sea state forecast, marine and climate research, as well as its important role in the ocean dynamic environment detection system.

The Staring Area Imaging Technology (SAIT) satellite continuously “images” the target over a certain time range, and can realize continuous imaging and multi-angle imaging of the area of interest. It has the characteristics of flexible imaging parameter setting and fast image preprocessing speed, enabling dynamic target detection and tracking, super-resolution, surface 3D model construction, night-time imaging and many other application tasks. Based on the technical characteristics of the SAIT satellite, this paper analyzes the challenges in satellite development and data processing, focuses on the quasi-realtime application of SAIT satellite data, and looks at the development trend of the SAIT satellite.

Nano and microsatellites have been widely used in communications, remote sensing, electronics, recon-naissance and other fields, and have become one of the important directions in future aerospace. On the basis of sys-tematically clarifying the concept and scope of the nano and microsatellite industry, this paper analyses the development process of the nano and microsatellite industry. Starting from the nano and microsatellite current development status, this paper summarizes the characters of nano and microsatellites industry professional entities, and then forecasts the trend for nano and microsatellites development in terms of technological development, commercial launching, invest-ment and financing channels.

Compared with the ever-changing development and changes of land communications, the development of maritime communications lags behind slightly, particularly on the offshore platform due to the complex and change-able environment, as well as the extremely difficult construction. However, the development of High Throughput Satellite (HTS) has changed the market pattern for traditional satellite communications, and its advanced technology concept ensures the rapid growth of maritime communications business. This article mainly analyzes the demand and current status of maritime satellite communications, discusses and expounds the commercial opportunities HTS satel-lites will bring to the era of maritime communications satellite.