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Using X-ray as carrier signal to realize the high rate information transmission in a distant space is attracting the attention of researchers. The development of this technology has a positive significance for broadening the scope of use of the electromagnetic spectrum. In this paper, the novel grid control X-ray source, which consists of a traditional X-ray tube and a signal control grid, is designed to meet the requirements of X-ray communication in the simulation vacuum experimental system by means of three-dimensional electromagnetic simulation software CST particle studio. The tube potential distribution, electron trajectory, actual focal spot and the number of electrons at the anode are simulated by the computer simulation software. It works by changing the grid voltage to control the X-ray pulse emission. The data of the simulation are as follows. The actual focal spot size is 0.4 mm×4 mm, the effective gate-on voltage is 0 V, and the gate-off voltage is-10 V. X-ray tube grid-controlled characteristics are tested in experiment. The test results are well consistent with the simulation results. Finally, the digital signal transmission is successfully implemented in the X-ray vacuum experiment system.

In this paper, an X-ray communication program, which consists of a sender of grid controlled X-ray source and a receiver of X-ray single-photon detector based on micro-channel plate, is presented. With the detailed information about the signal modulation transmitter, the micro-channel-based X-ray single-photon detector as well as the signal receiving demodulator, a space audio communication system based on X-ray is built. The communication rate of more than 20 kbit/s is realized. According to the preliminary test result analyses of the X-ray space audio communication system test, the X-ray emission success rate restricts the communication speed by the influence of different X-ray intensities, signal shaping time and threshold settings respectively. Therefore, a scheme for further increasing X-ray communication performance is suggested.

In this paper a high resolution X-ray simulation source is proposed and designed to verify the navigation based on X-ray pulsar in the simulation experience system. The simulation source consists of an arbitrary signal generator and a grid controlled X-ray tube. According to the grid tube's characteristic curve, the data of the pulsar standard pulse template are converted. Then using the method of direct digital frequency synthesis, the converted data are synthesized to waveforms, called the analog modulated grid voltage. In the grid controlled X-ray tube, the grid voltage changes the number of electrons hitting on the target and controls the X-ray intensity. With an analog modulated pulse profile applied on the tube grid electrode, the tube will emit X-rays which will match photons' statistical distribution and simulate the X-ray pulsar profile extremely well. The properties of Crab pulsar simulation source are tested in X-ray pulsar navigation simulation experience system. The results of the test are as follows: Comparing the tested pulse profile with the standard pulsar profile, we have time correlation coefficient is 0.9774, and frequency correlation coefficient is 0.9853. The X-ray photon flux is 1.90 ph·cm-2·s-1, the pulsed fraction is 76.15%, and the half-width half maximum is 1.879 ms. These results show that the X-ray simulation source has several merits, such as: strong ability to simulate the X-ray, low cost and simple operation. So it is an important means for the improvement of X-ray pulsar navigation.

As an autonomous navigation method, X-ray pulsar navigation can provide position, timing and attitude information for various spacecrafts. Since the X-rays (1-20 keV) from the pulsar can not penetrate the earth atmosphere, an X-ray source in laboratory needs to be set up to test and calibrate the detector. In this paper an arbitrary X-ray pulse source to simulate the neutron pulsar signal is proposed. The main components of the simulation source are a grid controlled X-ray tube and arbitrary pulse generation electronics. With the arbitrary pulse voltage applied to the tube grid, the X-ray intensity is controlled. Through electron optics design, the tube electrode parameters are optimized. A grid controlled X-ray tube is fabricated and tested. Using a micro-channel plate detector to detect and reconstruct the generated X-ray pulses, the similarity between the accumulated profile and the original pulsar profile is better than 95%. The frequency stability of the pulsar source emulator is about 2×10-11.