Regarding the compensation of geomagnetic navigation magnetic interference for low-altitude unmanned aerial platforms, this paper, based on the theory of magnetic dipoles, analyzes the relationship between the magnetization coefficient of the platform’s cabin materials and the resulting interference magnetic field. An equivalent magnetic dipole model of the interference sources within the platform cabin is established. The magnetic fields around the aluminum alloy cabin tube of a sounding rocket and a rectangular permanent magnet were measured, verifying the effectiveness of the equivalent magnetic dipole model. Using a differential measurement method based on recursive least squares, a simulation study of a multi-magnetic dipole equivalent model for multiple interference sources was conducted, demonstrating that the platform’s magnetic interference can be estimated in real-time using this method.