Ability Statement: Not applicable. Conflicts of Interest: The authors declare no conflict of interest.
applied sciencesArticlePolar Region (S)-(-)-Phenylethanol Metabolic Enzyme/Protease integrated Navigation Strategy Based on Covariance TransformationYongjian Zhang, Lin Wang , Guo Wei and Chunfeng Phenyl acetate medchemexpress GaoCollege of Advanced Interdisciplinary Studies, National University of Defense Technologies, Changsha 410073, China; [email protected] (Y.Z.); [email protected] (G.W.); [email protected] (C.G.) Correspondence: [email protected]: Aircraft flying the trans-arctic routes normally apply inertial navigation mechanization in two distinctive navigation frames, e.g., the nearby geographic frame plus the grid frame. Having said that, this transform of navigation frame will cause filter overshoot and error discontinuity. To solve this difficulty, taking the inertial navigation system/global navigation satellite technique (INS/GNSS) integrated navigation technique as an example, an integrated navigation technique based on covariance transformation is proposed. The connection of the method error state amongst different navigation frames is deduced as a means to accurately convert the Kalman filter’s covariance matrix. The experiment and semi-physical simulation benefits show that the presented covariance transformation algorithm can efficiently resolve the filter overshoot and error discontinuity brought on by the modify of navigation frame. Compared with non-covariance transformation, the program state error is thereby decreased considerably. Keywords and phrases: covariance transformation; integrated navigation; polar regionCitation: Zhang, Y.; Wang, L.; Wei, G.; Gao, C. Polar Area Integrated Navigation Technique Based on Covariance Transformation. Appl. Sci. 2021, 11, 9572. https://doi.org/ ten.3390/app11209572 Academic Editors: Kamil Krasuski and Damian Wierzbicki Received: eight June 2021 Accepted: 12 October 2021 Published: 14 October1. Introduction Taking into consideration that the distance of a fantastic circle flight route is shorter, applying trans-arctic routes can accomplish great savings in flying time when aircraft make transcontinental flights. As a result of demands of flight safety, each and every aircraft ordinarily utilizes an INS/GNSS integrated navigation program to supply high-precision navigation information. The INS/GNSS integrated navigation method has broad improvement prospects. Prior literature [1] proposed an integrated navigation scheme based on INS and GNSS single-frequency precision point positioning, which can be expected to be an benefit for low-cost precise land vehicle navigation applications. Many researchers [2,3] have discussed the application of GNSS/INS on railways. Conventional INS/GNSS-integrated navigation algorithms are based on a north-oriented geographic frame. Having said that, as the latitude increases, the classic algorithms shed their efficacy inside the polar area because of the meridian convergence. To resolve this problem, when the aircraft is in the polar area, pilots usually strategy their route primarily based on polar-adaptable coordinate frames, like the Earth-centered Earth-fixed frame (e-frame) [4], transversal Earth frame (t-frame) [5,6], pseudo-Earth frame [7], wander frame [8] and grid frame (G-frame) [9,10]. While these coordinate frames are adaptable to polar regions, they cannot achieve productive global navigation individually because a number of them have specific mathematical singularities, like the t-frame, pseudo-Earth frame, wander frame, and G-frame. These coordinate frames are usually adopted only in the polar reg.
