In order to study the influence of snowfall on quantum positioning system, according to snowflake model and Mie scattering theory, the extinction coefficient of snowflake is defined, and the relationship between signal attenuation, snowfall intensity and transmission distance of quantum positioning system under different zenith angles is established. The mathematical models of positioning error, snowfall intensity and transmission distance are established through the opening angle of two quantum satellite baselines relative to users. The simulation results show that the signal of quantum positioning system attenuates with the increase of snowfall intensity and zenith angle, and the positioning error increases with the increase of snowfall intensity. Properly adjusting the opening angle can reduce the positioning error of users. Finally, the mathematical model between snowfall intensity, transmission distance and channel fidelity are established. The simulation results show that the minimum fidelity is not less than 0.9, which provides a theoretical basis for the impact of snow on quantum satellite positioning system. Therefore, in order to improve the reliability of quantum positioning system, the parameters of quantum satellite positioning system should be adjusted adaptively according to the relevant parameters of snowfall.
In order to study the influence of snowfall on quantum positioning system, according to snowflake model and Mie scattering theory, the extinction coefficient of snowflake is defined, and the relationship between signal attenuation, snowfall intensity and transmission distance of quantum positioning system under different zenith angles is established. The mathematical models of positioning error, snowfall intensity and transmission distance are established through the opening angle of two quantum satellite baselines relative to users. The simulation results show that the signal of quantum positioning system attenuates with the increase of snowfall intensity and zenith angle, and the positioning error increases with the increase of snowfall intensity. Properly adjusting the opening angle can reduce the positioning error of users. Finally, the mathematical model between snowfall intensity, transmission distance and channel fidelity are established. The simulation results show that the minimum fidelity is not less than 0.9, which provides a theoretical basis for the impact of snow on quantum satellite positioning system. Therefore, in order to improve the reliability of quantum positioning system, the parameters of quantum satellite positioning system should be adjusted adaptively according to the relevant parameters of snowfall.
In order to study the communication performance and parameter analysis of the satellite-to-earth link of the quantum satellite under the condition of forming snowfall in the stratosphere, firstly, according to the distribution function and extinction characteristics of the concentric spherical ice water condensation nuclei in the stratosphere and the snowfall, according to the Mie theory, the system environment is obtained. The extinction efficiency factor establishes the relationship between the quantum signal transmission distance and link attenuation under different system environmental levels. Further studies have been done to establish the relationship between channel capacity, survival function, bit error rate, transmission distance, and system environment level under the condition of long-distance transmission of optical quantum signals at a moderate proportion of stratus cloud and snowfall. The simulation shows that as the transmission distance and environmental level increase, the link attenuation gradually increases, the channel capacity and survival function are greatly reduced, and the bit error rate increases. Therefore, when performing satellite-to-earth link communication, the relevant parameters of quantum communication should be adjusted adaptively to reduce the influence of snowfall caused by the formation of stratus clouds and improve the transmission performance of quantum communication.
Quantum satellite communication is an essential part in building a global quantum communication network. In order to cope with the sudden interference brought by snowfall to the quantum satellite communication system, an adaptive adjustment strategy for quantum satellite communication performance based on the optimal average photon number is proposed based on the decoy state protocol and snowfall spectral distribution function for the depolarization channel characteristics. The relationship between snowfall intensity and communication elevation angle and the optimal average number of photons per pulse is established, and the bit error ratio(BER) and survival performance of the system before and after the adoption of this strategy is compared. The simulation results show that the BER of the system decreases from 0.07 and 0.085 to 0.046 and 0.064 for medium and heavy snowfall environments, respectively; if the minimum communication elevation angle is required to be 0.81, the survival capability of the system increases from 0.81 to 0.92 for heavy snowfall environment; if the channel survival capability is required to be 0.8, the minimum communication elevation angle of the satellite link can be adjusted from 26° to 18° for heavy snowfall environment. Therefore, the strategy proposed enables the system to cope with more intense snowfall, improves the transmission quality of small elevation angle communication, further reduces the BER of the quantum satellite communication system, and enhances the reliability of the system in the snowfall context.
The quantum positioning system has the characteristics of high precision and high security. When the optical quantum signal propagates in the atmospheric space, it will attenuate to a certain extent due to the change of atmospheric visibility. The simulation results show that when the transmission distance is <?TeX 40km ?> and the baseline satellite's opening angle relative to the user is 30°, when the haze particle concentrations are <?TeX 0.3mg/m3 ?> and <?TeX 0.5mg/m3 ?> respectively, the positioning errors are 3.64 cm and 11.09 cm respectively. When the opening angle is adjusted to 45°,and the concentration of haze particle concentrations are <?TeX 0.3mg/m3 ?> and <?TeX 0.5mg/m3 ?> respectively, the positioning errors are 1.68 cm and 3.95 cm respectively. It can be seen that the increase of the concentration of haze particles will lead to a decrease in visibility, which in turn leads to an increase in the error of the quantum positioning system. Properly adjusting the opening angle can improve the accuracy of the quantum positioning system.
In quantum satellite communication, when the optical quantum signal is transmitted between satellite and ground links, it will be affected by various natural environments.At the same time, haze has become one of the largest environmental problems in the world.Therefore, it is of great significance to study the communication performance of quantum satellites in haze atmosphere.In this paper, according to the scale distribution and vertical spatial concentration change of large aerosol haze particles, the extinction characteristic model of large aerosol haze particles and the attenuation model of atmospheric haze particle concentration and transmission height on quantum satellite ground link are established.Some important performance parameters in quantum satellite communication are analyzed for amplitude damping channel, depolarization channel and phase damping channel respectively, It includes the quantitative relationship between channel capacity, quantum fidelity, quantum bit error rate and entanglement and large aerosol haze particle concentration and transmission height.The simulation results show that with the increase of transmission distance and haze particle concentration, the channel capacity, quantum fidelity and entanglement of quantum satellite communication in different channels will decrease, and the bit error rate will increase.Therefore, the impact of large haze environment on quantum satellite communication should be fully considered in the actual process of quantum satellite communication, Adaptive adjustment of relevant parameters to ensure the normal operation of quantum satellite communication.
Abstract Soot aerosol is an important part of atmospheric aerosol, which has important influence on the propagation of quantum signal. In order to study the influence of soot aerosol on satellite-ground quantum communication, according to the size distribution parameter and extinction coefficient of the soot aerosol, the influence of the concentration of the soot aerosol particles and the transmission distance on the attenuation of the link is analyzed. The simulation experiments of channel capacity, channel fidelity and channel bit error rate (Ber) are carried out with amplitude-damped channel. The simulation results show that the soot aerosol concentration increases from 2.1×10 6 / m 3 to 3.2 10× 6 / m 3 , the link attenuation factor increases from 0.3dB/ km to 0.46dB/ km, the fidelity decreases from 0.98 to 0.97, and the bit error rate increases from 0.0087 to 0.0122 at a transmission distance of 3km . hhen the transmission distance is 6km and the particle concentration is 2.1×10 6 / m 3 , 2.7 10× 6 / m 3 and 3.9×10 6 / m 3 , the channel capacity increases from 1.078 to 1.0809, and then decreases to 1.0804. Therefore, the soot aerosol has influence on the performance of satellite-ground quantum communication, and the degree of influence is different. In order to ensure the reliability of quantum communication between satellite and ground, the parameters can be adjusted to ensure the normal transmission of quantum signal.
Quantum satellite communication is a communication method with strong security and large coverage area, and it has become a hot research topic at home and abroad. The successful launch of the quantum satellite has laid an important foundation for future integrated quantum communication. When further studying the communication performance between quantum satellite-ground links, it is found that atmospheric particulate matter has a significant impact on quantum satellite communication performance. In this paper, by analyzing the extinction characteristics of atmospheric particles, a mathematical model of particle concentration, transmission distance and satellite-earth quantum energy is established, and the influence of atmospheric particles on communication parameters, bit error rate and entanglement degree is analyzed. The simulation results show that with the increase of particle concentration, the performance indicators of quantum satellite communication are affected to a certain extent. As the concentration of particulate matter in the atmosphere continues to decrease, the energy of the optical quantum signal continues to increase, and the quantum bit error rate increases with the increase in the concentration of atmospheric particulate matter and the transmission distance. The degree of quantum entanglement decreases with the increase of the particle size of atmospheric particles, and increases with the increase of visibility. The luminosity of light quantum will decrease with the increase of transmission height and the increase of surface particle concentration. By studying the optimization and adjustment strategy of quantum signal based on fidelity quantum relay satellite, simulation ensures the feasibility of this strategy. It is observed that the research in this paper can provide the necessary theoretical reference for the development of quantum space-ground integrated communication network.