Subjects: Geosciences >> Space Physics submitted time 2017-01-22
Abstract： In order to analyze the radiative transfer characteristics of planetary atmosphere in the microwave and sub millimeter wave bands, the absorption coefficient of the gases included in planetary atmosphere are calculated by using line-by-line integration method. Based on the parameters of gas molecules in HITRAN database, such as the transition frequency, line strength and so on, the absorption feature of every gas molecule in the 1-3THz frequency range is simulated and compared with the existing atmospheric radiative transfer model of the Earth. As an example, the radiation transport characteristics of Earth’s and Mars’ atmosphere are analyzed and the brightness temperature of Earth’s atmosphere radiative transfer is simulated by using radiative transfer equation. The work in this article provides the model and theoretical basis for the selection of detection frequency band of planetary atmospheric composition and for the retrieval of atmosphere profiles.
Peer Review Status:
Awaiting Review
Subjects: Geosciences >> Space Physics submitted time 2017-01-22
Abstract： Microwave interferometer is an efficient tool for non-intrusively diagnosis of electron density of plasma, which can be used for the measurement of plume of helicon plasma thruster. Four different numerical Abel inversion algorithms, including the discretization method, the cubic spline interpolation method, the Hankel-Fourier transform method and the Nestor-Olsen method, are used to retrieved the plume density profile that is detected by microwave interferometry for the cases with and without noise. After analysis of the effect of sampling density on the retrieval error, the smoothing and interpolating solution is proposed to mitigate the under-sampling related problem. As a summary, the procedures of the retrieval and processing are proposed. Two principle verification experiments with microwave network analyzer have been done. In the first experiment, a circular pipe is measured as a axial symmetrical target, which simulates the plume, and the retrieval results match well with the shape of the pipe. In the second experiment, spatial resolved integrated phase shifts are retrieved by Abel algorithm. The radial electron density profile within the plume is calculated. The experiments and their results verify the performance and validity of both the system design and the retrieval algorithm.
Peer Review Status:Awaiting Review
Subjects: Geosciences >> Space Physics submitted time 2016-05-13
Abstract： A measurement and control system of three-dimensional(3D) position information of electrostatic levitation based on position sensitive detector(PSD) is setup and structure of PSD and position measurement and control principle of electrostatic levitation are analyzed.Output signal of PSD is processed by STC12C5A60S2 MCU,corresponding relationship between suspension sample position information and output voltage of PSD is obtained,and communication between MCU and upper PC,data analysis and processing,and position control on levitation sample are realized.Use zirconium materials to carry out suspension experiment and test results indicate that the system can realize non-contact measurement of sample position information and stable suspension of sample,and it has advantages of stable operation and reliable detecting data,and so on,and this measurement system laid foundation for material suspended heating and undercooling research.
Peer Review Status:Awaiting Review
Subjects: Geosciences >> Space Physics submitted time 2016-05-13
Abstract： To meet the needs of image stabilization system of domestic solar observatory imaging instrument, a position sensitive detector(PSD)-based electronics system design for high-precision sun sensor is proposed.Concrete measures are put forward to improve the sensitivity and reduce system noise.At presemt,level of the system noise is lower than 4 nA,and has high resolving power of 0.3 in center area of working scope,can cooperate with tip-tilt mirror to make up this system image stabilization system, which serve for Kua Fu and SPORT project and other solar imaging instruments which has high resolution imaging demand.
Peer Review Status:Awaiting Review
Subjects: Geosciences >> Space Physics submitted time 2016-05-13
Abstract： To solve the problem that data handling system for sounding rockets lacks feasibility, and increasing requirements on expansibility and reliability of data handling system, a general and extensible data handling system is proposed. This system uses TMS570LS3137 produced by TI as CPU, and has abundant interfaces, such as IIC, CAN, Ethernet and SD card. EMIF interface provides external modules with addressing space. For software, muC/OS-II is ported to system and combines with drivers to complete invoking multitask. This system can satisfy various testing task and has high value in aerospace applications.
Peer Review Status:Awaiting Review
Subjects: Geosciences >> Space Physics submitted time 2016-05-13
Abstract： The production and measurement system of uniform axial hypomagnetic field based on Silicon Labs C8051F005 micro-processor is designed for the research on biological effects of the hypomagnetic field. A new structure for producing uniform axial hypomagnetic field is suggested according to the principle of magnetic field generated by Helmholtz coil. MAX038 is used for hardware circuit to generate the alternating magnetic field. The magnetic field can be accurately measured by magnetoresistive sensor, the data of which are transferred to the host computer via serial port, and then displayed graphically in real time. The uniformity of the magnetic field generated with the new structure is experimentally demonstrated to be better than that generated with Helmholtz coil. Experiments show that the magnetic field intensity is proportional to the current, and has the well controllability. The frequency of alternating magnetic field can be controlled by simple parameter setting.
Peer Review Status:Awaiting Review
Subjects: Geosciences >> Space Physics submitted time 2016-05-13
Abstract： GMSK modulation plays an important role in space telecommunications. Local oscillator phase noise has significant influence on GMSK demodulation system. Some characteristics of phase noise and its math expressions on both time and frequency domains are analyzed. Furthermore, the simulated phase noise sequence is added to the GMSK modulation system to show how the different levels of phase noise affect the demodulation performance. The conclusions have deep reference value to optimize the GMSK demodulation system. This method to analyze phase noise and its effect can be extended to any modulation system.
Peer Review Status:Awaiting Review
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