Research On The Measurement Of The Landing Position Of Helicopter Based On Close-range Photogrammetric Technology

At present, the landing position of helicopter is measured by the method of eye-measurement, which has a low precision and a bad measurement environment. It is emergent to find a new method to replace it. At recent years, the close-range photogrammetric technology is widely used in many fields as a non-contact and high-accuracy method of measurement. In this paper, based on the close-range photogrammetric technology, a new method of measurement for the landing position of helicopter is proposed so as to achieve a high precision and a good measurement environment.The main work and the results obtained are as follows.(1) The basic theory of the close-range photogrammetric technology is studied, including its co-linearity equation and the method of Direct Linear Transformation. The general method of the technology is analyzed and its geometric model is built up. Then, some contrast experiments research are done to find the factors affecting the precision of the measurement.(2) Based on the plane measurement and the geometric model, an iterative algorithm of the cylinder measurement is proposed to make the measurement of cylinder as convenient as the plane's and keep a certain precision.(3) A measurement system is built up to measure the landing position of helicopter. The measurement results are compared with that of eye-measurement, and the source of error is analyzed.The analytical and the experimental results indicate that the application of the close-range photogrammetric technology into measuring the landing position of helicopter can not only get a high precision but also improve greatly the measurement environment and the automation level.