Research On Electronic Units Of Spaceborne Magnetic Field Measurement Load

With the intensive exploration for satellites in outer space,more demanding requirement for magnetic field measurement device are put forward,such as wider dynamic range,higher stability and reliability etc.At the same time,magnetic field measurement device,especially used for outer space exploration,is also limited by size,weight,power consumption and intrinsic magnetic interference.The development of digital fluxgate magnetometer offers one way to solve the above problem.Because the digital fluxgate magnetometer usually digitalizes all analog signals from pre-amplifier and transfer them to digital domain for digital signal processing in FPGA,so its size,weight and power consumption can be reduced dramatically while keeping high dynamic measurement range.This thesis investigated the electronic unit for digital fluxgate magnetometer for Mars surface magnetic field measurement.Related work is summarized as follows:(1)Established a mathematical model for a single core fluxgate sensor.Through the mathematical derivation of the single-core fluxgate sensing signal,it is known that as long as the magnetic permeability of the magnetic core changes with the change of the excitation magnetic field,there will be a change in even harmonic components of the sensing signal with changes in the ambient magnetic field.This is the theoretical basis for measuring the ambient magnetic field.(2)Designed the electronic unit of the digital fluxgate magnetometer with digital closed-loop feedback structure.The hardware of the electronic unit contains power supply circuit,inductive signal acquisition circuit,DAC feedback circuit,communication interface circuit and multi-channel temperature acquisition circuit etc.(3)Completed the FPGA software of the magnetic field measurement load.The FGPA software of the magnetic field measurement load was developed by using the top-down design method.It contains the function division of FPGA of the magnetic field measurement load,the design of the top-level module,and the design of the sub-modules.The design ideas and implementation methods of each sub-module are described in detail in this article.Electronic units of space-borne magnetic field sensor load we developed,together the fluxgate sensing component,passing FPGA simulation and verification,testing and verification of the magnetic field sensor load system.The measurement results of the magnetic field sensor load system has a dynamic range of +/-65000 nT with resolution of 0.05 nT,meeting the specifications of Mars surface magnetic field measurement device.