Projection system

A projection system, comprises:

• a control module configured to issue a first control command and a second control command;
• a projection tube;
• an aiming driver, electrically connected to the projection tube, and configured to:
• in response to the first control command, control a projection viewing-line of the projection tube to be aligned with a calibration point;
• an observation device;
• and
• an observation driver, electrically connected to the observation device, and configured to:
• in response to the second control command, control an observation viewing-line of the observation device to be aligned with the calibration point;
• wherein the projection tube and the observation device are controlled asynchronously;
• wherein the observation device is further configured to obtain a calibration distance between the projection tube and the calibration point along the observation viewing-line;
• the control module further configured to obtain a deviation angle between the projection tube and a target point according to a target distance between the target point and the projection tube along the observation viewing-line, the calibration distance and a separation distance between the projection tube and the observation device along a separation direction.