Sensitivity of a 3-Dimensional Position and Attitude Measurement Device using 4 LED’s on the Apices of a Tetrahedron and a PSD

Abstract

It is known that the position and the attitude of a little plate can be calculated from a picture of more than 4 specific spots on the plate. Usually, 4 LED’s are arranged at the corners of a 2-dimensional square. However, calculated results are shown to be too sensitive to erroneous reading of the picture. This paper proposes an arrangement of 4 LED’s at the apices of a tetrahedron or similar 3-dimensional arrangement. The sensitivities are compared for 2-dimensional and 3-dimensional arrangements of 4 LED’s.