为解决四旋翼无人机在飞行时实时姿态测量的问题, 提高姿态估计精度, 设计了一种基于STM32的梯度下降姿态估计系统。该系统以STM32F427微处理器为主控制器, MPU6000和LSM303D作为姿态传感器, 实现了对姿态传感器数据采集以及姿态解算。系统对加速度计、磁罗盘进行预处理, 利用梯度下降滤波的方法估计误差四元数, 从而修正陀螺仪积分误差, 实现了姿态角的精确估计。最后, 通过搭建的飞行实验平台, 与Pixhawk飞控进行姿态角比较分析, 实验结果表明：采用梯度下降法的姿态估计系统能够稳定有效地估计无人机的姿态, 满足四旋翼无人机的飞行要求。

In order to solve the problem of real-time attitude measurement of quad-rotor UAVs in flight and improve the accuracy of attitude estimation, a gradient-descent attitude estimation system based on STM32 is designed.The system takes STM32F427 microprocessor as the main controller, MPU6000 and LSM303D as the attitude sensor, and realizes data acquisition of the attitude sensor and attitude calculation.The accelerometer and magnetometer are pre-processed by the system, and the error quaternion is estimated by using the method of gradient descent filtering, and thus the integral error of the gyroscope is corrected and the accurate estimation of the attitude angle is realized.Finally, a comparison is made with the attitude angle of Pixhawk flight control system by using the established flight experiment platform.The experimental results show that the attitude estimation system using the gradient descent method can estimate the attitude of UAVs effectively and stably, which can meet the flight requirements of quad-rotor UAVs.