title: Weak beacon detection for air-to-ground optical wireless link establishment.
abstract: In an air-to-ground free-space optical communication system, strong background interference seriously affects the beacon detection, which makes it difficult to establish the optical link. In this paper, we propose a correlation beacon detection scheme under strong background interference conditions. As opposed to traditional beacon detection schemes, the beacon is modulated by an m-sequence at the transmitting terminal with a digital differential matched filter (DDMF) array introduced at the receiving end to detect the modulated beacon. This scheme is capable of suppressing both strong interference and noise by correlation reception of the received image sequence. In addition, the DDMF array enables each pixel of the image sensor to have its own DDMF of the same structure to process its received image sequence in parallel, thus it makes fast beacon detection possible. Theoretical analysis and an outdoor experiment have been demonstrated and show that the proposed scheme can realize fast and effective beacon detection under strong background interference conditions. Consequently, the required beacon transmission power can also be reduced dramatically.
authors.affiliation: Department of Electronics, School of Electronics Engineering and Computer Science, Peking University, Beijing 100871, PR China.
authors.forename: Yaoqiang
authors.initials: Y
authors.lastname: Han
authors.forename: Anhong
authors.initials: A
authors.lastname: Dang
authors.forename: Junxiong
authors.initials: J
authors.lastname: Tang
authors.forename: Hong
authors.initials: H
authors.lastname: Guo