Research On Integration Technology Of Solid-state Magnetometer For Vehicle Magnetic Field Measurement

The magnetic field sensor based on diamond NV color center has comparable performance parameters with all-optical atomic magnetometer(SERF)and resonant magnetometer sensors in the detection of weak magnetic fields,and has the advantages of stable working performance,simple structure,and simple start-up process.Vehicles as metallic magnetic materials,their perturbations to the geomagnetic field can be detected by magnetic sensors for the purpose of obtaining the vehicle presence status,vehicle speed,and vehicle type.Currently NV magnetometers are widely used in military underground and underwater equipment detection,physical mapping of the earth’s magnetic field and biomagnetic field detection,etc.The miniaturization and integration of NV color-center based magnetometers to improve detection sensitivity is the current research and development direction.In this paper,based on the magnetic field detection technology of diamond NV color center,we design the verification experiment of color center magnetic field detection,and conduct the related research work for the miniaturization and integration of magnetometer,and the research contents are as follows.First,the magnetometer system integration design and fabrication.The photocurrent conversion circuit of the photodetector is designed,including the front transimpedance amplifier circuit,the bandpass filter circuit of the voltage signal and the design of the dual power supply circuit of the module.Using small volume microwave signal generator and Labview programming software,a microwave generator module that can realize fixed frequency modulation output and swept frequency modulation output is designed;Labview is used to write the control system upper computer program to integrate microwave control and phase-locked demodulation data analysis;a magnetic field detection system with small volume,low noise and high integration is developed.Second,the performance testing and verification of the magnetometer system.The signal output gain,output signal linearity,AC signal output characteristics,dual power quality of the photocurrent conversion circuit is tested;in the microwave module test,test the microwave source fixed frequency modulation control output and sweep frequency modulation control output capability,system control response time and other effects on the microwave control output;test the lock-in amplifier upper computer program with the internal signal generator sine cosine signal output control function The system output characteristics are tested with modulation and demodulation signal data analysis;the system inherent system noise is analyzed.Finally,the magnetic field analysis of magnetometer detection.A magnetic field detection verification platform with a miniaturized integrated magnetic field detection probe is built to calculate magnetometer performance parameters by testing simulated magnetic field variations in a laboratory environment using an integrated control system.The effectiveness of Magnetic field detectors in dynamic magnetic field detection is compared.The results show that the selfdeveloped control system is capable of detecting moving magnetic fields.In this paper,we initially realize the miniaturization and performance testing of magnetometer control system through experiments,and lay the foundation for the subsequent realization of chip-level detection probes and portable control and detection system development.By exploring the application of diamond solid-state magnetometer in vehicle magnetic field detection,we provide basic data support for the subsequent vehicle accurate magnetic field identification algorithm.