Study On Further Performance Improvement Of Satellite-Based Quantum Navigation And Positioning System

As a new generation technology,quantum navigation and positioning systems have been widely studied because of their unique entanglement and confidentiality.The entanglement of quantum makes it possible to compare two identical entangled photon pairs by solving the time difference of arrival between the simultaneously generated entangled photon pairs for ranging,while the traditional single-photon ranging is performed by emitting and obtaining the reflected single photon and solving the difference with the clock.Quantum navigation and positioning systems have low energy consumption,which can bring great improvements in miniaturization,duration of operation,and stealth performance of the device,and their high security may fundamentally solve the problem of transmission information disclosure.In terms of navigation and positioning,quantum entangled light offers extremely high accuracy.Since the divergence angle is smaller than that of laser,the requirements for the tracking system are relatively higher and the detection of entangled photon pairs is more difficult,so the errors at the satellite side,the ranging link and the ground side need to be analyzed to reduce the influence of external noise.The main study contents and findings of the paper include:1.Classifying quantum navigation and positioning systems and analyzing the pointing ahead angles for different cases to compare their respective characteristics.The principle of calculating and compensating the pointing ahead angle of inter-satellite links is mainly discussed.The magnitude of the pointing ahead angle of inter-satellite links is calculated by using the coordinate transformation between three systems:the satellite orbit coordinate system,the earth center inerial coordinate system and the satellite pitch coordinate system,and the coordinate transformation relationship of the ahead point in the fine tracking detector is calculated.Further improving the ranging performance of quantum navigation and positioning systems by incorporating pointing ahead angle compensation into the system,and the effect of the pointing ahead angle on the quantum reception efficiency in the link is calculated according to the quantum reception efficiency formula and the effective reflection area of the reflector.Finally,the compensation scheme is designed and the numerical simulation of satellite orbit and pointing ahead angle compensation is performed.2.A single-satellite based quantum navigation and positioning system and a singlesatellite with a ground station system are proposed to further reduce the ranging error.The single-satellite based quantum navigation and positioning system uses the time difference of arrival to obtain the entangled photon pair ranging and the output of the acquisition Tracking Pointing system to obtain the azimuth and pitch angle of the ground target relative to the satellite.Then performs coordinate conversion from the satellite pitch coordinate system to the earth center inerial coordinate system to obtain the ground target position coordinates,and solves the ground position.The positioning error of this method mainly originates from the satellite related data,the delayed distance error of the ranging link and the measurement time deviation of the ground receiver,among which the delayed distance error of the ranging link reaches the meter level and is the main error.Based on this,a single-satellite with a ground station system is proposed to further reduce the errors caused by the ranging link,which can establish separate links with the ground station and the ground target,and use the entangled photon pair ranging to obtain the arrival time difference between the two links,so that the ranging link errors can be partially offset,and finally reduce the errors caused by environmental and other factors on the positioning system.3.Based on the original visual system simulation platform,the pointing ahead simulation module and the coincidence counting simulation module are optimized to enable them to select multiple positioning methods.And a new positioning simulation module is added,which can display the position map of ground targets and satellites and their coordinates.Then we analyze the operation flow and function implementation of the whole visual system simulation platform is analyzed with a complete simulation process as an example.