###### Abstract  
This paper proposes a non-common-view axis alignment method for the alignment requirements of airborne laser communication systems. The system consists of a ground transmitting end and an airborne relay terminal. The ground transmitting end uses a camera and a pan-tilt for image tracking, while the airborne relay end uses a two-dimensional mirror to control the beam to achieve non-common-view axis alignment between the transmitting and receiving sides. The working principle and process of both the transmitter and receiver of the non-common-view axis alignment system for airborne laser communication were compared with traditional wireless optical alignment methods. The design process of the two-dimensional mirror used in this paper is introduced, the scanning trajectory of the two-dimensional mirror is simulated and analyzed according to the beam scanning principle, and the field experiment link is set up to carry out the airborne laser communication experiment. The experimental results show that when the link distance is 10 m, the tracking errors of the system in the azimuth and pitch directions are 19.02 urad and 22.35 urad respectively, and the amplitude of the electrical signal output by the signal detector is 84.0 mV; When the link distance is 20 m, the tracking errors of the system in the azimuth and pitch directions are 39.66 urad and 33.94 urad respectively, and the amplitude of the electrical signal output by the signal detector is 23.0 mV. Using this method, the alignment can be completed without data return, and the establishment of the reverse link can also be realized while the transmission link is quickly established, and there is no need for an air stability platform. The feasibility of the application of the non-common-view axis alignment method to the airborne laser communication system is verified. airborne laser communication; non-common-view axis alignment; acquisition; pointing; and tracking; two-dimensional mirror  
beam's position to shift, and even the receiving end will lose the information on the spot, eventually leading to the interruption of the communication link [7]. Therefore, an accurate and fast acquisition, pointing, and tracking (APT) mechanism is needed to assist in the establishment of airborne laser communication links [8; 9]. The APT system requires high precision and continuous alignment of the beam and can overcome the influence of mechanical vibration and the external environment on the system [10]. [PERSON] designed a full tracking controller applied to fast mirrors, using the full tracking method to effectively reduce the steady-state error of the system and expand the control bandwidth of fast mirrors [11]; [PERSON] and others proposed a beam tracking method, which uses a rotating double prism for beam tracking, and uses a fast mirror to correct the optical axis deviation of the double prism for compound tracking [12]; [PERSON] proposed a two-dimensional optical phased array mirror structure based on the Gires-Tournois (optical standing wave resonator) resonator. The high-speed phase delay generated by the resonator is used to control the beam deflection angle. The simulation results show that the structure can achieve a deflection angle of 11.2\({}^{\circ}\)[13]; [PERSON] and others proposed a high-precision tracking and aiming system applied to satellite laser communication. Through indoor simulation experiments, the alignment error value of the system was measured to be better than 10 \(\upmu\)rad [14]; [PERSON] proposed a method of alignment using a two-dimensional mirror as an actuator, and carried out far-field experiments of 1.3 km and 10.3 km. Experimental results show that this method can effectively reduce the tracking variance of the spot centroid [15]. This paper proposes a method to realize airborne laser communication by using a camera and a gimbal to track targets at the transmitter on the ground and using a two-dimensional mirror to control beam alignment at the airborne relay.