Measuring Absolute Delay of RNSS Signal Channel Using Digital Envelope Detection

The absolute delay caused by equipment of radio navigation satellite service (RNSS) signal channel must be calibrated in the application of positioning. The measurement accuracy of absolute delay will affect the positioning precision of RNSS user. An absolute delay measurement technique using digital envelope detection was developed for RNSS signal transmission channel. The RNSS transmission signal of navigation satellite and the one pulse per second (1PPS)generated by satellite time keeping system were sampled synchronously. With sampling data of 1PPS,the reference point of the absolute delay can be decided at first,and then sampling data of RNSS transmission signal were truncated. The truncated data were processed using digital envelop detection algorithm to search the phase converting points of RNSS signal. Finally,the absolute delay of RNSS signal transmitting channel was calculated. Uncertainty of measurement with proposed technique is lower than 0. 2 ns as the sampling frequency is 10 GHz.

Review of thrust measurement techniques for micro-thr usters

The applications of the micro-thrust e r and the challenges of micro-thrust measuring are introduced.The developments in measuring techniques for the micro-thrust are reviewed.Micro-thrust measu rements have previously been made either directly by mounting thrusters to the m easurement system or indirectly by mounting a target in the direct path of the e jected propellant.Several typical direct and indirect thrust-stands are presen ted and discussed in detail to illustrate the principles.Typical calibration me thods are also expounded.Finally,the resolution,uncertainty and thrust range of each thrust-stand are given,which may be helpful for the future thrust stan d design and micro-thrusters research.

Simultaneous Measurements of Rainfall Intensity, Low Energy Neutrons and Gamma Radiation in Sao Jose Dos Campos, SP, Brazil

The article aims to study the possible correlation between the presence and intensity of rainfall X- and T-radiation and low energy neutrons at one specific location in S[io Jos6 dos Campos, SP, Brazil. Monitoring of these parameters was carried out from end February to half of June 2013 just in Physics Department of ITA （Technological Institute of Aeronautics）. By correlating the data of measurements of intensity of X and ）,-radiations with the rainfall it has been found that this meteorological parameter had a significant influence on the background of these radiation profile. A possible reason for this fact is associated with the presence of radon gas in the environment that is dragged to the surface during the occurrences of local rainfall. In relation neutrons, it was possible to note that the rainfall has small influence on this parameter measures.

A new method of choosing scales in wavelet transform for damping identification

A systematic study of the method of selecting scales in wavelet transform for damping identification in frequency domain was carried out. A method to select the scale with the modulus at the maximum was developed by extending the range of scales. It is proved that using this method in small damping ratio and linear system, we can achieve better results in identification of the closely-spaced model.

Variable structure attitude maneuver and vibration control of flexible spacecraft

A dual-stage control system design method is presented for the three-axis-rotational maneuver and vibration stabilization of a spacecraft with flexible appendages embedded with piezoceramics as sensor and actuator. In this design approach, the attitude control and the vibration suppression sub-systems are designed separately using the lower order model. The design of attitude controller is based on the variable structure control (VSC) theory leading to a discontinuous control law. This controller accomplishes asymptotic attitude maneuvering in the closed-loop system and is insensitive to the interaction of elastic modes and uncertainty in the system. To actively suppress the flexible vibrations, the modal velocity feedback control method is presented by using piezoelectric materials as additional sensor and actuator bonded on the surface of the flexible appendages. In addition, a special configuration of actuators for three-axis attitude control is also investigated: the pitch attitude controlled by a momentum wheel, and the roll/yaw control achieved by on-off thrusters, which is modulated by pulse width pulse frequency modulation technique to construct the proper control torque history. Numerical simulations performed show that the rotational maneuver and vibration suppression are accomplished in spite of the presence of disturbance torque and parameter uncertainty.

Micro/Nano-Satellites: Opportunities and Challenges

At an accelerating development pace, Hicro-Nano Satellite technology has become one of the most ac- tive research topics in the current aerospace field. Its applications have been extended from engineering education and technology demonstration into various other fields, such as communication, remote sensing, navigation and scientific experiments just to name a few, In this paper issues raised on Micro/Nano-Satellites in recent news are reviewed and the opportunities and challenges confronting Micro/Nano-Satellites are analyzed. Then the Plicro/nano-Satellites of Na- tional University of Defense Technology, （NUDT） are briefly introduced. Finally, some suggestions on the development of Micro/Nano-Satellites in the future are proposed.

Relative navigation for satellite formation flight using a continuous-discrete converted measurement Kalman filter

The present paper develops an approach of relative orbit determination for satellite formation flight.Inter-satellite measurements by the onboard devices of the satellite were chosen to perform this relative navigation,and the equations of relative motion expressed in the Earth Centered Inertial frame were used to eliminate the assumption of the circular reference orbit.The relative orbit estimation was achieved through a continuous-discrete converted measurement Kalman filter design,in which the measurements were transformed to the inertial frame to avoid the linearization error of the observation equation.In addition,the situation of the coarse measurement period(only microwave radar measurements are available)existing was analyzed.The numerical simulation results verify the validity of the navigation approach,and it has been proved that this approach can be applied to the formation with an elliptical reference orbit.

LM-3B Launches Tiantong 1 Satellite

China Launched its first satellite for mobile communications on a LM-3B launch vehicle from the Xichang Satellite Launch Center at 0：22 on August 6,2016.The Tiantong 1 satellite was developed by the China Academy of Space Technology under CASC to provide all-weather,all-time stable and reliable mobile communications services to China and surrounding regions as well as to the Middle East,Africa,

The Creative Application of DIY Manufacturing Technology in Remote Sensing Satellite

Based on the concept of DIY, this paper demonstrates the essential potential of DIY manufacturing technology in the application of space equipment. According to the future space technology development trends, the future spacecraft DIY idea and system standard are proposed. The standardized, modularized and serialized micro/nano-satellite DIY products are introduced. Finally, a commercial remote sensing satellite system based on spacecraft DIY is designed and its application prospect is analyzed.

Study on Potential Application of “Space Ginseng Yeast” in Cosmetics

Through the in vitro cell-based assay, a series of experiments to investigate the efficacy of "space ginseng yeast", which were obtained from space breeding technology and modern fermentation engineering were conducted in order to provide theoretical basis and scientific guide for the potential applications in cosmetic areas from various aspects. The results have shown that this active ingredient can improve the proliferation, colony forming efficiency and Scratch repair ability of human primary keratinocytes. Moreover, it can significantly increase the expression of Perlecan which is key protein in the basal layer of the skin. Meanwhile, "space ginseng yeast" can help the cell morphology recovery and improve Perlecan, collagen I and elastin expression on the fibroblasts after heavy ion irradiation. All of these results showed that the "space ginseng yeast" displays potential applications on skin regeneration in cosmetic industry.

A LM-4C Launches the GF-3 Satellite

The GF-3 satellite was successfully launched at 06：55 Beijing time on August10 using a LM-4C launch vehicle from the Taiyuan Satellite Launch Center.The launch was the 233rd flight of a LM family launch vehicle and the carrier rocket LM-4C was developed by the Shanghai Academy of Spaceflight Technology.

Digital Assembly Technology Applied for Large Rocket Sections Assembly and Mating

Tianjin Aerospace Long March Rocket Manufacturing Co.,Ltd.under CASC successfully completed the digital assembly of the first-stage hydrogen tank and oxygen tank and the inter-tank section of the LM-5 launch vehicle for its maiden flight.It is the first time that indigenous developed equipment,for digital assembly,was used formally in product assembly,

China Will Launch 14 Meteosats over the Next Ten Years

It was announced at the Symposium for FY Satellite Development that by2025,China will launch 14 more meteorological satellites,developed by CASC,into orbit.The 14 satellites include one FY-2 satellite,four FY-3 satellites,three FY-4 satellites,two precipitation measurement radar satellites,one earlymorning-orbit satellite,one geostationary atmospheric microwave sounding satellite,

China's First HTS Broadband Satellite Communications System Construction Initiated

China Aerospace Science and Technology Corporation（CASC）and the People’s Government of Shenzhen Municipality co-hosted a ceremony for the contract signing of the high-throughput broadband satellite project and for the establishment of a joint venture on July23,marking the formal start of the construction of China’s first high-throughput broadband satellite communication system.

3 m Twin-Segment Solid Rocket Engine Tested Successfully

On August 2,a twin-segment solid rocket motor of the largest diameter,grain mass and thrust in China completed its ground test firing with success.The3 m solid motor was independently developed by the Academy of Aerospace Solid Propulsion Technology（AASPT）under CASC.

500-ton LOX/Kerosene Engine Joint Test Achieved Success

Recently,the first gas generator-turbopump joint test for the 500-ton LOX/kerosene engine was completed with success.The engine developed independently by the Academy of Aerospace Liquid Propulsion Technology（AALPT）will be used for the heavy-lift rocket.The 500-ton LOX/kerosene engine has the thrust of the largest ever developed by China and in the foreseeable future.

Promotion and Application Prospects of Disruptive Technology in Future Development of Space Industry

Space is a high-tech field integrating materials, electronic information, manufacture, energy, medicine ana other disciplines. A number of disruptive technologies in various fields will have an important influence in areas such as space industry, scientific research on space and even military space. This article focuses on disruptive technologies exerting enormous influence in the space field based on the qualitative and quantitative research of disruptive technolo- gies. The research and application for disruptive space technology is expected to greatly improve the emciency of space system, significantly reducing research cost, and to promote a great improvement of space technology level,

Diagnosis and Treatment Value of Ultrasound for Hepatobiliary and Pancreatic Disease

As an innovative technology, ultrasound has been applied to agriculture, medical, military, aerospace, machinery and other fields widely, as well as the medical industry, such as ultrasound diagnosis, ultrasound therapy. Ultrasonic technology has many advantages, and it certainly will promote the progress in medical area as a new method.