Improved Attitude Determination for Unmanned Aerial Vehicles with a Cross-Shaped Antenna Array

Abstract

Accurate estimation of the attitude of unmanned aerial vehicles (UAVs) is crucial for their control and displacement. Errors in the attitude estimate may misuse the limited battery energy of UAVs or even cause an accident. For attitude estimation, proprioceptive sensors such as inertial measurement units (IMUs) are widely applied, but they are susceptible to inertial guidance error. With antenna arrays currently being installed in UAVs for communication with ground base stations, we can take advantage of the array structure in order to improve the estimates of IMUs. In the state-of-the-art attitude estimation algorithm, the first crucial step is phase delay estimation, which directly affects the attitude estimation performance. In this paper, by exploiting the parallelogram shape of the crossshaped antenna array, a 2-D unitary ESPRIT is used for phase delay estimation to achieve high attitude accuracy as well as computational efficiency. Moreover, we relax the known yaw to unknown case by adding an additional pair of antennas along the normal direction of the body-wing plane. The extension from one frequency bin to the case of multiple frequency bins is also included. Simulations show the feasibility of our proposed solution for different SNR levels as well as multipath scenarios.