Pure Geomagnetic Homing Navigation On Earth Surface

As a passive, stable, cheap resource, geomagnetism has already been used in navigation systems. But up to now, it is either only an assistant for other navigation methods, or it requires large amount of pre-stored geomagnetism data. This paper did some research on pure geomagnetic navigation in analogy with pigeon homing.On 2-D Cartesian plane,it utilizes the Jacobian determinant to simplify measurements, and it applies linear approximation and iteration to search for destination. Moreover, it improves the algorithm to eliminate the distance's measurement.Then it extended navigation to spherical surface, using dynamic north pole instead of fixed north pole, and uses geodesic line instead of straight line segments.To verify the algorithm, this paper did some simulations with World Magnetic Model. Tests are based on truncated data, which has verified that 2-D pure geomagnetic navigation can be done on idealized spherical surface as long as we have magnetic sensors with enough accuracy.Then, a signal conditioning circuit for a magnetic sensor is designed. VHDL codes are designed for a SPI controller to read data from ADC, a controller for numeric display. The codes are tested on a FPGA development board.Finally, the robotic movement control block is added, and the system diagram is proposed in addition with very detailed steps converted from algorithms.