Survey system and method for identifying target

A survey system comprising:

• a survey device;
• and
• a target to be collimated by the survey device,
• wherein the survey device includes:
• a main body rotatable around a vertical axis;
• a telescope supported by the main body and rotatable around a horizontal axis;
• an imaging unit having a second angle of view wider than a first angle of view of the telescope;
• and
• a target identification unit configured to identify, based on an image captured by the imaging unit, a target image in the image,
• the target includes an emission unit configured to emit laser light, wherein the emission unit is configured to perform continuous scanning, in the vertical direction, with a fan beam having a width in the horizontal direction wider than a width in the vertical direction, and
• the target identification unit is configured to identify the target image, based on a first differential image between a first image and a second image, the first image being captured by the imaging unit during an on-period in which the laser light is emitted from the emission unit, and the second image being captured by the imaging unit during an off-period in which the laser light is not emitted from the emission unit.