System for deriving alignment information of a surface of a structure, the alignment information comprising a deviation of an alignment of the surface with respect to a light plane, the system comprising a plurality of light-receiver units, each light-receiver unit comprising an elongate photo sensor configured to be illuminated by the light plane and to detect an impingement position of the light plane relative to a zero position of the photo sensor, and to provide an electrical output signal indicating said impingement position, wherein the system comprises an evaluation device configured to be in wireless communication with at least one of the light-receiver units, wherein - each of the light-receiver units comprises - at least one alignment surface configured to be placed at the surface of the structure to align the light-receiver device to the surface of the structure, and - a first wireless communication interface configured to establish a wireless communication with the evaluation device and/or with the first wireless communication interface of at least one other light-receiver device of the system; - wherein each of the light-receiver units is configured to transmit data indicating or providing a crossing position value of the light plane with respect to the surface determined based on the impingement position detected by the light-receiver unit; wherein at least one of the light-receiver units (10, 10b) is configured to transmit the data to at least one other light-receiver device; and a subset of the light-receiver units (10, 10a) is configured to transmit the data to the evaluation device; and a - the evaluation device comprises - a second wireless communication interface configured to establish a wireless communication with the first communication interfaces of the subset of the plurality of light-receiver units (10, 10a) and to receive the data indicating or providing the crossing position values of each of the light-receiver units, - an evaluation unit that is configured to perform a combined analysis of the data indicating or providing the crossing position values received from the plurality of light-receiver units and to derive, based thereon, alignment information comprising the deviation of the alignment of the surface of the structure relative to the light plane, and - a display unit, wherein the evaluation device is configured to the provide alignment information on the display unit to a user of the system. - each of the light-receiver units comprises - at least one alignment surface configured to be placed at the surface of the structure to align the light-receiver device to the surface of the structure, and - a first wireless communication interface configured to establish a wireless communication with the evaluation device and/or with the first wireless communication interface of at least one other light-receiver device of the system; - at least one alignment surface configured to be placed at the surface of the structure to align the light-receiver device to the surface of the structure, and - a first wireless communication interface configured to establish a wireless communication with the evaluation device and/or with the first wireless communication interface of at least one other light-receiver device of the system; - wherein each of the light-receiver units is configured to transmit data indicating or providing a crossing position value of the light plane with respect to the surface determined based on the impingement position detected by the light-receiver unit; wherein at least one of the light-receiver units (10, 10b) is configured to transmit the data to at least one other light-receiver device; and a subset of the light-receiver units (10, 10a) is configured to transmit the data to the evaluation device; and a - the evaluation device comprises - a second wireless communication interface configured to establish a wireless communication with the first communication interfaces of the subset of the plurality of light-receiver units (10, 10a) and to receive the data indicating or providing the crossing position values of each of the light-receiver units, - an evaluation unit that is configured to perform a combined analysis of the data indicating or providing the crossing position values received from the plurality of light-receiver units and to derive, based thereon, alignment information comprising the deviation of the alignment of the surface of the structure relative to the light plane, and - a display unit, wherein the evaluation device is configured to the provide alignment information on the display unit to a user of the system. - a second wireless communication interface configured to establish a wireless communication with the first communication interfaces of the subset of the plurality of light-receiver units (10, 10a) and to receive the data indicating or providing the crossing position values of each of the light-receiver units, - an evaluation unit that is configured to perform a combined analysis of the data indicating or providing the crossing position values received from the plurality of light-receiver units and to derive, based thereon, alignment information comprising the deviation of the alignment of the surface of the structure relative to the light plane, and - a display unit, wherein the evaluation device is configured to the provide alignment information on the display unit to a user of the system.