Magnetic Anomaly Detection Based On SQUID

Magnetic detection is a powerful means of anti submarine anti mine.With the rapid development of magnetic sensor technology,it has gradually become one of the most dependent technologies of information-based weapon and equipment.It is widely used in military,biological medical,nondestructive testing and other fields.Compared with traditional sonar detection,the technology based on magnetic anomaly detection has many advantages,such as better activity and concealment.Its principle is to get information of the size,position and even shape of the magnetic target by detecting the change of the magnetic field under the action of the magnetic material.The magnetic anomaly information is extremely weak.SQUID is a conversion component of magnetic flux to voltage,using the weak connection Josephson effect of superconducting ring.It can convert a small change in a magnetic field into a measurable voltage.In this paper,DC-SQUID is used as a magnetic anomaly signal detection device,and the front-end system of magnetic anomaly signal detection with very high receiving sensitivity can be realized.The main contents and contributions of this paper are summarized as follows:1.By Using ANSYS Maxwell,the marine and submarine models is established,the three component value of the ocean magnetic field and the gradient value are extracted,and quantitatively analyzing the marine magnetic anomaly information.2.Based on the requirements of magnetic anomaly signal detection front-end syst em for DC-SQUID model.With the help of WRspice,four DC-SQUID models and th eir characteristic curves of the I_C-Φand V-Φwere simulated,thus a appropriate DC-SQUID model was chosen for the system.3.The external antenna is used as the core to construct the magnetic signal sensing loop and the key parameters of DC-SQUID are set up.In the design of SQUID chip,dua l crystal YBCO superconducting thin film is used as the main structure.4.In the presence of the zero flux locking theory,the working process and principle of the magnetic anomaly signal detection system based on DC-SQUID are described.Analysis of the circuit structure of the system and noise generation.5.Based on the theory of zero flux locking,the circuit model of front-end system of magnetic anomaly signal detection was completed by DC-SQUID.The system is simulated by superconducting circuit simulation software and its transient response was analyzed.