Optical alignment compensation system for a gas detection system

An optical alignment compensation system (50) for a gas detection system for detecting a gas, the optical alignment system (50) comprising:

• an array (51) of transceiver pairs (51a, 51b, 51c), wherein each transceiver pair (51a, 51b, 51c) is configured to transmit and receive light (52) with an optical spectrum in an absorption region of the gas (53) to be detected;
• a retroreflector (54) arranged at a nominal position and configured to reflect the light (52);
• an optical element (55) arranged and configured to direct the light (52) from at least one of the transceiver pairs (51a, 51b, 51c) along an optical path through the gas (53) to the retroreflector (54), to receive the light (52) reflected by the retroreflector (54) along the optical path, and to direct the reflected light (52) to the respective transceiver pair (51a, 51b, 51c);
• and
• a control unit (56) configured to select one of the transceiver pairs (51a, 51b, 51c) for transmitting and receiving the light (52), wherein the control unit (56) is configured to perform a search algorithm to identify the transceiver pair (51a, 51b, 51c) that receives the reflected light (52) with the highest signal response and to select said transceiver pair (51a, 51b, 51c),
• wherein the search algorithm comprises
• a brute-force interrogation of transceiver pairs (51a, 51b, 51c) in conditions of lower signal response of the reflected light (52) received by the transceiver pairs (51a, 51b, 51c),
• a gradient descent based interrogating of transceiver pairs (51a, 51b, 51c) in conditions of higher signal responses of the reflected light (52) received by the transceiver pairs (51a, 51b, 51c).