Research On SINS/GPS Navigation For Small-sized Unmanned Helicopter

Due to the advantages of small size, vertical taking off and landing ability, hovering ability, maneuverability, excellent concealment performance, low cost and no casualties, the study of small-sized unmanned helicopter (SSUH) has been one of the most interesting research fields in the world. And navigation system is the key component of SSUH, it provides flight control system with necessary attitude, velocity and position estimations which directly affect the flight control performance.Compared with the fixed-wing vehicle, SSUH has the properties of slower speed, high response and small dynamic scope of attitude, and strapdown inertial navigation system(SINS) and global position system(GPS) are shown to complement each other, so we design SINS/GPS integrated navigation for SSUH. The main work in details is as follow:This paper first elaborated the basic theories of navigation of SSUH. With analyzing the difference of attitude methods and nolinear characters of SINS/GPS integrated navigation, we decide to use double simples rotation vector of quaternion and extended kalman filter to calculate attitude, velocity and position information. After analyzing the complex and accuracy of system, we build the simplified model of multi-sensors. We get the differential equation of strapdown inertial navigation system(SINS), and use double simples rotation vector of quaternion to get attitude with the purpose to avoid the singularity points. After that, we use iterative equations to estimate velocity and position.SINS will have a bias error with the accumulation of time, so we found an error model of integrated navigation system which uses system's errors as state variable. Then we use extended kalman filter to modify SINS. Because the angular rate of gyroscope is very important, so the model has used time-varying drift of gyroscope as state variable. SSUH need accuracy yaw to realize dynamic flight model, so we use magnetometer which is a part of input of observation.We get the simulate model of integrated navigation system, and set the parameters with the reference of multi-sensors. Then we did the simulate experiments which have proved the SINS/GPS integrated navigation can give control system of SSUH with high accuracy. It can satisfy the demands of SSUH.Finally, we design an embedded system which include integrated navigation and servo control system. We get multi-sensors' information with ARM. After emendation and synchronization, ARM transmits it to PC 104 which use extended kalman filter to get navigation information. And the servo control system has a high accuracy of servo control, especially it can control the engine speed with a constant speed which is very important for the flight of SSUH.