Patent ID: 7345748

Claim:
A survey system comprising a target for collimation and a surveying instrument provided with an automatic collimation device that causes a collimation axis of a telescope to automatically coincide with the target, wherein said target has a guide light transmitter that emits guide light, said surveying instrument including a direction detector that detects a direction of said guide light transmitter by receiving the guide light and a collimation preparing means for directing said telescope toward said target based on an output signal emitted from said direction detector before actuating said automatic collimation device, said guide light transmitter emitting circularly polarized guide light, said direction detector including a polarization changing portion for changing said circularly polarized guide light into linearly polarized guide light and a polarizing plate for giving a polarization plane that coincides with said linearly polarized guide light into which said circularly polarized guide light has been changed by said polarization changing portion.