Topographic Elevation Navigation and Positioning Fundamentals and Theoretical Models

Topographic elevation navigation positioning is a navigation method that uses the specificity and uniqueness of elevation differences at each point in space for positioning. Because it is a passive navigation method that does not depend on external signals, it is not easily affected by objective factors such as electromagnetic interference and weather and is valued in existing combined navigation methods. The basic principle of topographic elevation navigation and positioning is that the geographic coordinates of any location on the earth's surface can be determined singularly based on the contours or landforms of its surrounding territory. Firstly, the terrain elevation model (map) along the route is stored in the motion carrier, and when the motion carrier flies over an area with known terrain elevation, the current terrain elevation is measured by the altimetric (depth) sensor on the motion carrier, and the measured data is correlated and analyzed with the pre-stored terrain elevation model (map) to determine the corresponding grid position of the motion carrier in the terrain elevation model (map) because the terrain The latitude and longitude corresponding to the grid position in the elevation model (map) is known in advance so that the position of the motion carrier can be determined. Although the combination of inertial navigation and positioning system (INS) and satellite navigation and positioning system (GNSS) navigation can meet the requirements of high precision positioning, this combination of navigation autonomy is insufficient and easy to expose the target. The combination of INS and terrain elevation navigation and positioning meets various navigation requirements and does not depend on an artificial satellite navigation system. In addition to the navigation and positioning of motion carriers, terrain elevation positioning navigation also has many functions such as terrain tracking/terrain avoidance, rational routing, threat avoidance, obstacle alert, ground alert, target interception, marine exploitation, marine wreck salvage, and underwater launch. Terrain elevation navigation and positioning are most widely used in air vehicles and underwater vehicles because it is easier to obtain airborne terrain elevation maps, so the application of terrain elevation navigation and positioning is more mature in air vehicles; underwater artifacts are the least, and satellite positioning is limited, so it is the easiest background condition for terrain elevation navigation and positioning to work, so the academic research is focused on underwater terrain. Regardless of underwater and aviation, the basic theory of terrain elevation positioning navigation and positioning navigation methods are common, only in the means of terrain elevation map acquisition, altimetry (depth) sensors exist differently: this chapter will be developed to describe respectively.