Abstract: Before a temperature characteristic of a band gap reference circuit is tested, temperature dependencies of a reference voltage and an absolute temperature proportional voltage for a plurality of samples are measured. When the temperature characteristic is tested, based on a difference ?Vref between the reference voltage of the band gap reference circuit at a predetermined temperature and a median value of the reference voltages of the plurality of samples, a difference ?Vptat between the absolute temperature proportional voltage of the band gap reference circuit at a predetermined temperature and a median value of the absolute temperature proportional voltages of the plurality of samples is calculated.

Abstract: In a survey system in which guide light is emitted from the side of a target, and, on the side of a surveying instrument, a telescope is directed roughly toward the target by receiving the guide light so as to shorten the time required for automatic collimation, the automatic collimation of the surveying instrument can be reliably performed by removing guide light reflected by reflective objects such as windowpanes. The target has a guide light remitter that emits guide light The guide light transmitter includes a light source, a polarizing plate that changes light emitted from this light source into linearly polarized light, and a quarter-wave plate that changes this nearly polarized light into circularly polarized guide light The surveying instrument includes a direction detector and a collimation preparing means. The direction detector includes a quarter-wave plate and a polarizing plate.

Abstract: In a survey system in which guide light is emitted from the side of a target, and, on the side of a surveying instrument, a telescope is directed roughly toward the target by receiving the guide light so as to shorten the time required for automatic collimation, the automatic collimation of the surveying instrument can be reliably performed by removing guide light reflected by reflective objects such as windowpanes. The target has a guide light remitter that emits guide light The guide light transmitter includes a light source, a polarizing plate that changes light emitted from this light source into linearly polarized light, and a quarter-wave plate that changes this nearly polarized light into circularly polarized guide light The surveying instrument includes a direction detector and a collimation preparing means. The direction detector includes a quarter-wave plate and a polarizing plate.