Memory navigation theory is one of homing pigeon navigation theories, and it is the research result of homing pigeon enthusiasts in China based on summarizing practical experience in recent years. Carrier pigeons have a good memory, which is recognized by carrier pigeon lovers as practical experience. It is one of the applications of Ovi Map. Ovi Map is a voice package. You can make your own voice into the command sound of navigation. It's also easy to do, step by step.