Photoelectric aiming device to track and look on?

Anybody has any idea how the Photoelectric aiming device works?

Naval unit conducts ship-gun live-ammunition firing

(Source: PLA Daily) 2012-04-06
http://eng.chinamil.com.cn/news-channels/photo-reports/2012-04/06/content_4827959.htm

The “Kunlun Mountain” warship of a landing ship flotilla of the South China Sea Fleet under the Navy of the Chinese People’s Liberation Army (PLA) organized