| Choosing polar routes during ultra long-distance flight can not only shorten the voyage and reduce fuel consumption,but also improve the business load and improve the passenger experience.It is an effective way in line with the airlines' pursuit of profit maximization and the current social concept of "green and low-carbon" development.However,due to the non applicability of the conventional navigation coordinate system,the single and limited navigation mode,the decline of the performance of the navigation system in the polar region,and the vulnerability of the satellite navigation system to interference caused by the complex environment in the polar region,there are some deficiencies in the navigation support ability in the polar flight process at this stage,which limits the further development of the polar route and brings some risks to the polar flight.In order to solve the above problems,based on the full investigation and study of the complexity of polar environment and polar navigation related technologies,this thesis proposes to draw the celestial navigation system(CNS)into the civil aviation navigation system,and to make it forms an airborne INS/GNSS/CNS integrated navigation system with the existing inertial navigation system(INS)and global navigation satellite system(GNSS).Meanwhile,The grid coordinate system is studied and adopted to replace the conventional north-east-up geographic coordinate system as the navigation coordinate system of the polar region,and a new integrated navigation system including fault detection module and information fusion module is designed.The fault detection algorithm and information fusion algorithm of INS/GNSS/CNS integrated navigation system are analyzed and studied in detail.The performance of the relevant single algorithm and the overall algorithm of INS/GNSS/CNS integrated navigation system are verified by simulation,Finally,the hardware in the loop simulation system experiment is used to further verify the system algorithm.This thesis mainly studies the following aspects:(1)The complex environment and possible navigation risks in the region during polar flight are analyzed in detail.The related research on improving navigation support capability in polar regions at home and abroad is expounded.The principle and characteristics of CNS applied in aviation field are introduced.The grid coordinate system and the mechanical arrangement and error equation of INS in this coordinate system are studied.An INS/GNSS/CNS integrated navigation system including fault detection and information fusion technology is proposed.(2)The fault detection algorithm of integrated navigation system is studied.This thesis expounds the GA-BP neural network model,studies the algorithm flow and related technology of the model,puts forward the simulation data generation method,and designs the simulation test.The simulation shows that the fault detection algorithm can accurately identify the fault of the integrated navigation system.(3)The information fusion algorithm of integrated navigation system is studied.The centralized Kalman filtering algorithm is selected and studied,and the simulation experiment is designed.The simulation shows that compared with INS/GNSS integrated navigation system,the INS/GNSS/CNS integrated navigation system studied in this paper not only has the attitude error of about 15.2% of the latter,but also improves the position accuracy by about 10% in normal operation.When GNSS fails,it can still be kept within 300 m within 1 hour.The simulation verifies the performance of the information fusion algorithm.(4)The simulation experiment and the experiment based on the integrated navigation hardware in the loop simulation system are designed to verify the overall performance of the system.It shows that the INS/GNSS/CNS integrated navigation system and its algorithm can improve the navigation support ability of polar flight. |
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