High Dynamic Range Digital Fluxgate Magnetometer

In this paper, we present an advanced fully digital solution of a fluxgate magnetometer with both demodulation and compensation carried out by a low-cost field programmable gate array (FPGA). For feedback operation, we avoid using a costly precise digital-to-analog converter, instead employing an FPGA to generate a hybrid pulse width modulation sigma-delta signal. Even with only a few additional components to process such signals, we were able to achieve excellent linearity, noise, and stability, as supported by measurements. On the front-end side only one pick-up signal preamplifier is necessary, greatly reducing the number of analog circuits needed. This can be an advantage in radiation-hazard sites like space missions, as there are fewer radiation-susceptible parts that can degrade. We provide a short description of the entire setup—electronics, fluxgate sensor construction, and final power budget—and a parameter summary in the conclusion.