In this study, a method is proposed to obtain the three-dimensional attitude information of carriers based on the atmospheric polarization pattern to meet the urgent need of obtaining attitude parameters for ensuring the autonomous navigation of unmanned aerial vehicles. Initially, the atmospheric polarization mode is completely analyzed. Then, the K-means clustering algorithm is used to calculate the position of sun in space. Finally, the angle between the magnetic compass and the carrier body is used to obtain the heading information of the carrier. The navigation coordinates are transformed into a reference based on the known heading angle. First, the zenith and sun are observed to be on the same axis; thus, the zenith and sun position vectors are on the same reference and rotate together. Then, the pitch and roll angles are calculated according to the inherent height angle between the zenith and sun. Finally, the roll and pitch angle information are obtained through several conversions and calculations. The experimental results show that effective carrier attitude information can be obtained based on the position of the sun calculated in the atmospheric polarization mode, the accuracy of the simulation can reach 0.01°, whereas that of the field experiment can reach 0.1°.