Attitude positioning method based on optical flow camera

Abstract

The invention discloses an attitude positioning method based on an optical flow camera, relates to the technical field of unmanned aerial vehicle positioning, and is mainly used for realizing autonomous control flight of an unmanned aerial vehicle. The system structure is mainly composed of a central processing unit, an image sensing unit, an attitude sensing unit, a height sensing unit, a light supplementing unit, an early warning unit and a power supply unit. And the central processing unit is connected with the image sensing unit, the attitude sensing unit and the height sensing unit and isused for respectively carrying out optical flow algorithm processing on the image sensing data, carrying out two-dimensional speed compensation on the attitude sensing data and carrying out three-dimensional speed calculation on the height sensing data. The central processing unit is connected with the light supplementing unit and the early warning unit and controls a near-infrared light supplementing lamp and an acousto-optic early warning unit to be turned on and turned off respectively. The power supply unit supplies power to the above units. According to the method, the defects that a traditional visual positioning method is not high in precision and the accuracy drifts along with time are overcome, meanwhile, stable operation of the system under the low-brightness condition is guaranteed, and real-time monitoring and early warning are provided.

Description

technical field [0001] The invention relates to the technical field of UAV positioning, in particular to an attitude positioning method based on an optical flow camera. Background technique [0002] In recent years, with the increasing development of science and technology, UAVs have been widely used in military and civilian fields, such as air early warning and low-altitude photography in outdoor environments, intelligence reconnaissance, search and rescue in indoor environments, etc. . However, whether the UAV can perceive its own position information and speed information in real time is very important for its autonomous flight. Currently, the widely used positioning method is mainly based on the Global Positioning System (GPS) positioning method. However, in some environments where GPS signals are weak, such as between buildings or inside large buildings, traditional positioning methods cannot play a role. The vision-based positioning method does not need to rely on GP...

AI Technical Summary

Problems solved by technology

[0005] 1. The image sensor MT9V034 1 has a maximum frame rate of 60fps at the highest image resolution of 752×480. When the UAV performs high-speed flight missions in complex scenes, the microcontroller cannot accurately calculate due to the impact of low resolution. Output speed data; Affected by low frame rate, the microcontroller cannot send out speed data in real time

[0006] 2. The angular velocity data measured by the gyroscope L3GD20 2 is uncertain, and as time goes by, the gyroscope will have a steadily increasing angular velocity error, which will cause the error of the velocity data calculated by the microcontroller to compensate for the angular velocity data will become more and more Big

[0007] 3. The measurement accuracy of sonar MB1240 3 ultrasonic distance measurement is centimeter-level, which is easily affected by temperature and wind direction, and the echo interference is more in an environment with many obstacles, so that the drone cannot accurately locate the current flying height

[0008] 4. The Cortex M4F core floating-point computing performance provided by the microcontroller STM32F407 4 with a working frequency of 168MHz is not enough to support high-resolution and high-frame-rate image optical flow calculations. Currently, it can only support image resolutions up to 64*64, frame Image optical flow calculation at 30fps

[0009] 5. In the case of low brightness, the image sensor cannot perceive the surrounding environment well, which leads to the failure of the optical flow algorithm of the microcontroller and cannot give correct speed data

[0010] 6. When the system is not running normally, it is impossible to check the operation status of each unit in real time, and there is a lack of certain instructions and early warnings

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