A low-cost UAV height measurement method suitable for low-altitude remote sensing monitoring of agricultural conditions

Abstract

A low-cost UAV height measurement method suitable for low-altitude remote sensing monitoring of agricultural conditions, comprising the following steps: (1) fitting the relationship curve between the image ground resolution g and the image shooting height H; (2) collecting the image (3) calculate the relational expression of this image pixel and distance D; (4) calculate the unmanned aerial vehicle camera position O a to position O in the center of each rectangular whiteboard marker 1 , O 2 , O 3 …O n The actual distance L 1 , L 2 , L 3 …L n , that is, the actual distance between the current UAV and each rectangular whiteboard marker; (5) get the ground position O directly below the UAV camera b and each rectangular whiteboard marker center position O 1 , O 2 , O 3 …O n The horizontal distance D 1 、D 2 、D 3 …D n (6) Obtain real-time UAV measurement height by weighted average. The present invention has the advantages of simple operation, cost saving and accurate measurement. The invention belongs to the field of drone remote sensing technology.

Description

technical field [0001] The invention belongs to the technical field of agricultural unmanned aerial vehicle remote sensing, and in particular relates to a low-cost unmanned aerial vehicle height measurement method suitable for low-altitude remote sensing monitoring of agricultural conditions. Background technique [0002] Traditional agricultural situation detection mainly relies on manual field surveys, which takes a long time and requires a lot of work; especially when the crops are planted with a large face value, it is difficult to obtain overall crop information. In recent years, the application of UAV low-altitude remote sensing in the field of agricultural monitoring has become more and more extensive. Agricultural situation monitoring based on low-altitude remote sensing of drones can quickly and accurately obtain remote sensing images of a large area of ​​interest, quickly monitor and extract information from a certain area, and analyze agricultural conditions, thus...

AI Technical Summary

Problems solved by technology

However, the different shooting heights of UAV remote sensing operations affect the pixel resolution of each remote sensing image obtained, affect the matching relationship between the feature points of the remote sensing image to be stitched and the reference remote sensing image, and affect the splicing effect of the remote sensing image later. In turn, it will affect the information judgment of agricultural monitoring, so it is especially important to keep the UAV remote sensing operation at the same level

Although in UAV remote sensing, there are a variety of UAV height measurement methods based on airborne laser, air pressure, inertial measurement, RTK GPS, etc., there are still deficiencies in the accuracy or cost of UAV height measurement : For example, the effective measurement distance of the laser measurement method is relatively short, and it is greatly affected by the weather, especially in cloudy conditions. Errors occur in density changes in atmospheric regions, as well as errors in temperature and humidity changes in the surrounding measurement environment. When UAVs fly at low altitudes, the air pressure resolution is seriously insufficient and the stability is poor; such as inertial measurement using gyroscopes or acceleration sensors, through The integral method accumulates the height vertically, but due to the uncertain terrain changes, the data only represents the relative height compared with the original 0 bit, which is easy to cause error accumulation and inaccurate accuracy; for example, RTK-based GPS uses carrier phase observations in real time Dynamic positioning technology provides real-time three-dimensional positioning results of the station in the specified coordinate system, and the measurement accuracy is high. However, it is necessary to use the radio data link to connect the base station and the mobile station during the measurement, and the equipment cost is too high

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