1. A method of tracking a target using an unmanned aerial vehicle (UAV) having an on-board imaging device, the method comprising: a) receiving at one or more receivers, target information of the target to be tracked by the UAV, wherein the imaging device is configured to rotate around at least one axis relative to the UAV; with aid of one or more processors, b) tracking the target according to the target information while the UAV is in motion, wherein said tracking the target involves: i. assessing whether to adjust 1) the UAV, 2) the imaging device, or 3) both the UAV and the imaging device to track the target, wherein said assessing is based on a) maximum linear speed or maximum angular speed allowable for the UAV, or b) maximum angular speed allowable for the imaging device, wherein the maximum angular speed of the UAV or the maximum angular speed of the imaging device is configurable by a user of the UAV; and ii. adjusting, based on said assessing of (i), 1) the UAV, 2) the imaging device, or 3) both the UAV and the imaging device as the target is moving, such that the target stays within an image captured by the imaging device.