This paper presents the development of a low cost miniature navigation system for autonomous flying rotary-wing unmanned\naerial vehicles (UAVs). The system incorporates measurements from a low cost single point GPS and a triaxial solid state\ninertial/magnetic sensor unit. The navigation algorithm is composed of three modules running on a micro controller: the sensor\ncalibration module, the attitude estimator, and the velocity and position estimator. The sensor calibration module relies on a\nrecursive least square based ellipsoid hypothesis calibration algorithm to estimate biases and scale factors of accelerometers and\nmagnetometers without any additional calibration equipment. The attitude estimator is a low computational linear attitude fusion\nalgorithm that effectively incorporates high frequency components of gyros and low frequency components of accelerometers and\nmagnetometers to guarantee both accuracy and bandwidth of attitude estimation. The velocity and position estimator uses two\ncascaded complementary filters which fuse translational acceleration, GPS velocity, and position to improve the bandwidth of\nvelocity and position. The designed navigation system is feasible for miniature UAVs due to its low cost, simplicity, miniaturization,\nand guaranteed estimation errors. Both ground tests and autonomous flight tests of miniature unmanned helicopter and quadrotor\nhave shown the effectiveness of the proposed system, demonstrating its promise in UAV systems.
Loading....