Research On Automatic Astronomical Measurement Technology Of Robot Based On Video Measurement

With the rapid development of surveying and mapping instruments,astronomical measurement is gradually becoming portable,intelligent and automatic.But up until now,there is no an astronomical measurement method that meets both portable and automatic requirements.New astronomical measurement systems and methods are called for to fix such deficiency.The emergence of video measurement robots(VMR)provides support to solve this limitation.Therefore,it is necessary to study the astronomical surveying mode based on the new intelligent platform.This paper demonstrates the automatic measurement technique based on VMR syste m(e.g.Leica-TS50 i total station).Following research contents and results are shown:1.In view of the fact that there has not been a summary of astronomical measurement methods in C hina,this paper summarizes the development of astronomical measurement technology,combs and generalizes the existing measurement methods and research status,introduces the representative methods of astronomical measurement in various stages,and analyses the characteristics and defects of each method.It provides a summary material for the surveyors to understand the astronomical survey,and also provides useful reference to develop future portable and automatic astronomical measurement systems.2.Describing the performance parameters of Leica-TS50 i in detail,this paper focuses on the image processing procedure based on the platform,and analyzes the image features and gray distribution of the imaging images.Firstly,the hardware specifications of Leica-TS50 i series total station are introduced in detail.With a coaxial telescope and a professional optical measurement lens,it is equipped with a CCD camera which has a wide angle camera and a long focal camera with a field angle of 19.4 /1.5 degrees respectively on the basis of a high precision total station.All these provide a possible solution to the problem that the present astronomical measurement cannot take into account the miniaturization and automation.It also provides realistic hardware support for astronomical measurement with high accuracy,speediness and automation.Then,in view of its operating platform,the key technologies used in the automatic astronomical measurement are introduced,especially the GeoCOM instructions for online control and the processing flow of the star map based on the total station video measurement.Moreover,we further analyze the characteristics of the star map,and find that it has obvious characteristics of small field,weak target,single star point and "single peak".3.A star map processing algorithm based on one dimension maximum entropy is proposed and implemented to deal with the star map taken by video measurement robot.The algorithm can make full use of the information of image grayscale,and effectively reduce the loss of image information.In view of the characteristics of "single peak" of TS50 i image,this paper discusses the image processing method of TS50 i platform.By using TS50 i to shoot the stars,we compare the maximum entropy gray level extraction method on the basis of several widely used threshold segmentation algorithms,give the distribution map of one dimension entropy under different thresholds.In addition,it is proved that the one dimensional maximum entropy method has good threshold segmentation effect for the shooting star map by the principle of region conformance and regional contrast.Compared with the true value of the star coordinates,the mean square deviation of the X axis is 0.015 pixels and the mean square deviation of the Y axis is 0.017 pixels.The experiment proves that the algorithm is accurate and reliable,which can meet the needs of high precision astronomical measurement in the field.4.A calibration method of total station built-in CCD is put forward and implemented.By using the method of simulating stars under the indoor dark conditions,the conversion model is established by obtaining the shooting star map of the simulated star.Moreover,we use least squares principle to solve transformation parameters,so as to achieve conversion between target star dial coordinates and pixel coordinates.The experimental data shows that the difference of pixel coordinates and the difference of the disk have obvious linear relationship.The calculation results show that the conversion model can realize the conversion between the difference value of the disk and the difference value of pixel coordinates accurately.TS50 i and its camera are superior to human eye observation accuracy in stability.It can replace human eye observation,and its measurement error can only be processed by fixed instrument system error.The root mean square error of horizontal and vertical direction is better than 0.7" and 0.6" respectively.According to the error propagation law and covariance analysis,the influence of the final latitude and longitude measurement results is about 0.1 ".5.A new automatic astronomical system based on video measurement is proposed and attained.Utilizing the VMR instead of classical total station as replacement,automatic CCD instead of human eyes,the measurement precision and efficiency is attained.We conduct automatic measurement over 1,300 times observation of 132 stars that are evenly distributed over all hemisphere in 12 different time period,3 days length,and in 2 disparate places.The precision of inner coincidence is optimal than 0.013 s and 0.20" respectively.Compared with the known astronomical coordinates,the external coincidence results are in accordance with the 2 times medium error of the first level measurement accuracy,and the data coincidence rate reaches 100%.In addition,Astronomical operation process and field operation time are greatly shortened.With the completion of the automatic astronomical measurement technology based on VMR,astronomical measurement instruments have also realized miniaturization,speediness,automation and intellectualization...