TRACK DISPLAYING DEVICE

PURPOSE:To reduce consumption of power necessary for degaussing by providing a moving distance detecting means, a course detecting means and a degaussing instruction signal generating device which determines a shift of a moving body exceeding a prescribed moving distance and a prescribed angle and generates a degaussing instruction signal. CONSTITUTION:A program to be executed by CPU 1 is written before hand in ROM 2, and RAM 3 is used as a working area on the occasion of storing a course taken at the time of the previous degaussing and calculating the amount of shift of the course etc. and for other purposes, while VRAM 4 stores display data. A video output circuit 5 converts an output signal of the VRAM 4 into a video signal and outputs it to CRT 6. A display control circuit 7 estimates a read-out address of the VRAM 4 in accordance with a raster scan of the CRT 6. A degaussing circuit 9 makes a degaussing current flow through a degaussing coil incorporated in the CRT 6, and the CPU 1 gives it a degaussing instruction signal through an interface 8. A position measuring device 11 is constructed of a loran C receiver and others and determines the position of a moving body as data on the latitude and longitude. The CPU 1 is connected to the bus line of these elements and exercises general control over the whole of a track displaying apparatus.