3D Measurement Simulation and Relative Pointing Error Verification of the Telescope Mount Assembly Subsystem for the Large Synoptic Survey Telescope

An engineering validation of a large optical telescope consists of executing major performing tests at the subsystem level to verify the overall engineering performance of the observatory. Thus, the relative pointing error verification of the telescope mount assembly subsystem is of special interest to guarantee the absolute pointing performance of the large synoptic survey telescope. This paper presents a new verification method for the relative pointing error assessment of the telescope mount assembly, based on laser tracker technology and several fiducial points fixed to the floor. Monte-Carlo-based simulation results show that the presented methodology is fit for purpose, even if floor movement occurs due to temperature variation during the measurement acquisition process. A further research about laser tracker technology integration into the telescope structure may suggest that such laser tracker technology could be permanently installed in the telescope in order to provide an active alignment system that aims to detect and correct possible misalignment between mirrors or to provide the required mirror positioning verification accuracy after maintenance activities. The obtained results show that two on-board laser tracker systems combined with eight measurement targets could result in measurement uncertainties that are better than 1 arcsec, which would provide a reliable built-in metrology tool for large telescopes.

Development of an Accurate Video Shooting Method Using Multiple Drones Automatically Flying over Onuma Quasi-National Park

In recent years, promotional videos of mountains, seashores, and lakes have been created using drones. Shooting videos of natural landscapes with drones usually requires manual operation, and relies on the skill of the operator. However, if the intention is to shoot videos over a wide geographical area, manual operation is not sufficiently accurate. Therefore to accomplish this, and to take full advantage of the features of a drone, automatic operation is desirable. In this paper, we propose a method of safely modelling a video target and flight route. This includes planning for video shooting on the basis of a model, to realize accurate automatic video shooting of natural landscapes with drones. It was assumed that multiple drones would be operated simultaneously. Therefore, we developed an error verification method to compensate for performance differences between drones. To verify the usefulness of the method, it was used to shoot actual video images of Onuma quasi-national park in the south of Hokkaido Prefecture.

Research on Fixture Locating Error Verification Based on Statistics Method

Fixture Tolerance is one of the most important factors influencing the machined part accuracy. However caused by the manufacturing error and the assembly error of locator, the workpiece location error should not be neglected, which has led to fixture accuracy decay. A location error verification method is presented to improve the workpiece location accuracy. First, the origin of location error and the transfer process of error between locators and the workpiece are given. Second, random numbers and statistical analysis method are used to simulate locators’ errors. Finally, the location layout optimization model and the process are given. This method can be used to verify the location error and fixture design process.