Te in the neighborhood horizontal geographic frame and that in the grid frame is deduced. Flight experiments at mid-latitudes initially proved the effectiveness of your covariance transformation process. It is hard to conduct experiments inside the polar region. A purely mathematical simulation can not accurately reflect real aircraft scenarios [19]. To solve this trouble, the authors of [19,20] proposed a virtual polar-region method primarily based on the t-frame or the G-frame. In this way, the experimental data from middle and low latitude BMS-911172 Inhibitor regions can be converted for the polar area. Verification by semi-physical simulations, primarily based around the proposed process by [20], is also performed and offers much more convincing final results. This paper is organized as follows. Section 2 describes the grid-based strap-down inertial navigation technique (SINS), like the mechanization and dynamic model of your grid SINS. In Section three, the covariance transformation technique is presented. Furthermore, Section 3 also offers a navigation frame-switching system primarily based on the INS/GNSS integrated navigation system. Section four verifies the effectiveness of the proposed method by means of experimentation and semi-physical simulation. Ultimately, common conclusions are discussed in Section 5. two. The Grid SINS 2.1. Grid Frame and Grid SINS Mechanization The definition in the grid reference frame is shown in Figure 1. The grid plane is parallel for the Greenwich meridian, and its intersection using the tangent plane in the position in the aircraft could be the grid’s north. The angle N-Methylbenzamide Purity & Documentation between geographic north and grid north supplies the grid angle, and its clockwise path could be the positive path. The upAppl. Sci. 2021, 11,Appl. Sci. 2021, 11,3 of3 ofnorth delivers the grid angle, and its clockwise direction will be the positive direction. The up path of the grid frame will be the exact same as that in the regional geographic frame and types an direction in the grid frame is definitely the same as that in the neighborhood geographic frame orthogonal right-handed frame using the orientations at grid east and grid north. and forms an orthogonal right-handed frame together with the orientations at grid east and grid north.Figure 1. The definition of your grid reference frame. The blue arrows represent the 3 coordinate Figure 1. The the local geographic frame. The orange arrowsarrows represent thecoordinate axes with the axes of definition of your grid reference frame. The blue represent the 3 three coordinateframe. the regional geographic frame. The orange arrows represent the 3 coordinate grid axes of axes of the grid frame.The grid angle is expressed as located in [9]: The grid angle is expressed as located in [9]: sin = sin L sinsin =1sin sin L -cos2 L sin2 cos – cos two Lcos = sin 2(1)cos CG The path cosine matrix e= between2the G-frame as well as the e-frame (earth frame) is 1 – cos L sin 2 as found in [9]: G G G Ce = Cn Cn e The path cosine matrix C in between the G-frame and the e-frame (earth frame) (two)ecos1-cos2 L sin(1)G where n [9]: is as discovered in refers to the regional horizontal geographic frame. Cn and Cn are expressed as: e G G n (two) -C e C n C e cos sin = 0 Cn = – sin L cos – sin L sin cos L e n G exactly where n refers to the nearby horizontalcos L cos frame. sin and C n are expressed as: geographic cos L C e sin L(three)- – sin cos cos sin 0 0 G – sinCn cos sin L sin 0cos L n = – sin cos (4) Ce = L (three) 0 0 1 cosL cos cos L sin sin L The updated equations from the attitude, the velocity, along with the position in th.
