acquiring accelerometer signal data and gyroscope signal data of the smart watch;

estimating a tilt angle of the smart watch by using the accelerometer signal data and correcting the gyroscope signal data by using the tilt angle; and

calculating angle value information of the smart watch by using the corrected gyroscope signal data and estimating a coordinate point;

wherein estimating the tilt angle of the smart watch by using the accelerometer signal data and correcting the gyroscope signal data by using the tilt angle comprises following sub-steps:

recording X, Y, and Z axis data of the accelerometer signal data as a_x, a_y, a_z, respectively, and recording X, Y, and Z axis data of the gyroscope signal data as g_x, g_y, g_z, respectively;

calculating an energy value e=a_x²+a_y²+a_z² of the accelerometer signal data, initializing an energy count c=0, and setting an energy threshold e_threshold and an energy count threshold c_threshold;

judging whether the energy value e of the accelerometer signal data is less than or equal to the energy threshold, and if the energy value e of the accelerometer signal data is less than or equal to the energy threshold, updating energy count information c=c+1: judging whether the energy count c is greater than or equal to the energy count threshold c_threshold, and if the energy count c is greater than or equal to the energy count threshold c_threshold, updating tilt angle information represented by

correcting gyroscope V-axis and z-axis angular velocity signal data by using the updated tilt angle information, represented by =g_y×cos θ+g_z×sin θ, =g_y×(−sin θ)+g_z×cos θ, wherein is the corrected gyroscope y-axis angular velocity signal data, and is the corrected gyroscope z-axis angular velocity signal data.