Visual-inertial combined navigation method for aircraft precision approach landing

Abstract

The invention provides a vision-inertia combined navigation method for aircraft precision approach landing. The whole approach landing process is divided into three stages, namely an initial approachstage, a precise approach stage and a precise landing stage; the method comprises the following steps of: designing corresponding constraint functions according to the navigation precision requirements of the aircraft in different stages and the characteristics of airborne measurement information, obtaining an optimal solution through a nonlinear optimization technology, and estimating the motionstate of the aircraft to navigate. The method can realize precise approach landing navigation of the aircraft without depending on the assistance of a global navigation satellite system (GNSS) under alow-visibility meteorological condition, and has high-precision, strong-real-time and autonomous navigation capability.

Description

technical field [0001] The invention belongs to the field of computer vision navigation, and in particular relates to a vision-inertial combined navigation method for aircraft precision approach and landing. Background technique [0002] The process of a fixed-wing aircraft descending from the initial approach point until it lands on the runway of the airport is called approach landing. Throughout the process, aircraft have different requirements for navigation accuracy. As the flight altitude of the aircraft continues to decrease, the distance between the aircraft and the ground facilities or obstacles of the airport is getting closer and closer, and the opportunities for avoiding ground obstacles are less, and the requirements for its own positioning accuracy are also higher. Traditional approach and landing methods include: instrument landing system-guided precision approach and landing and differential GPS-based precision approach and landing. Among them, the guidance ...

AI Technical Summary

Problems solved by technology

For example, the French Airbus Company (AIRBUS) uses a purely visual method to estimate the pose of the aircraft during approach and landing, but ignores two important facts: the visual data update rate is low, and the aircraft cannot take a complete picture when it descends below 60 feet. runway profile

The German Aerospace Research Institute (DLR) used the runway features to construct the analytical solution of the pose in the early stage, which contained many assumptions and could not be applied to practical engineering; later, SLAM was used to realize the motion estimation of the aircraft, but the positioning accuracy of SLAM in large-scale scenes is poor

The National University of Defense Technology used the ground-based camera network observation method to obtain the position information of the aircraft in the early stage, but it was unable to estimate the attitude and speed information; later, by installing an infrared light device on the runway surface, the airborne infrared camera captured the forward-looking image and extracted the target features , and then solve the aircraft pose

This is a purely visual navigation and positioning method, and its data update rate is low, which cannot meet the demand for pose state estimation when the aircraft is moving at high speed

Northwestern Polytechnical University installed a light-emitting device on the nose of the aircraft, and the ground camera array captured and extracted visual features to calculate the position information of the aircraft. This method cannot estimate the aircraft attitude information, and the data update rate is low, limited by the frame rate of the camera.

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