Infrared image generator of artificial space object for verifying relative navigation in rendezvous

In this paper, we propose a method of using simulated images for ground verification of navigation algorithms when an infrared camera is used as a navigation sensor for rendezvous with a non-cooperative target in orbit. The proposed simulator uses the shape model of the target object, thermal optical properties, and temperature data from an external thermal analysis tool. The simulator produces a simulated infrared image in an arbitrary position and attitude by giving the relative position and attitude to the object as the imaging conditions. The simulator can calculate the infrared radiation emitted from the object surface and that reflected by the object surface, simulate the lens and detector of an infrared camera, and convert the infrared energy into pixel values. It can simulate images closer to the actual camera output by incorporating the pixel characteristics of the camera. Since an external thermal analysis tool provides the temperature data of the target, the analysis conditions, and accuracy can be freely set by the user. The simulated image of a black body shows a brightness similar to the actual image, which is different between the center and the periphery of the image, even though the object has uniform temperature. The simulated infrared image created from the thermal analysis results of the upper stage of the rocket by the external tool is expected to be used for ground verification of navigation algorithms as a simulated image of a non-cooperative object in orbit. The simulator is fast enough to be used for real-time closed-loop testing.