Laser reference system and method of determining grade rake

Abstract

A laser reference system orients a reference plane of laser light generated by a transmitter so compensation is made for a rake angle between the first and second axes of the transmitter and an alignment axis and an axis perpendicular thereto. The transmitter includes an optical system arranged to generate a laser beam, the optical system projecting said laser beam radially along a rotational arc defined about a central rotational axis, thereby substantially defining a reference plane of laser light, and a positioning arrangement, coupled to said optical system, for adjusting the angular orientation of the optical system with respect to a first transmitter axis and with respect to a second transmitter axis. A detector is arranged to detect reception of the laser beam. The detector includes a generally vertically arranged row of detector elements. The detector further includes a transmitter for transmitting information regarding the location of said laser beam, as detected by said detector elements. The system further includes a processor adapted to receive said transmitted information from said detector regarding the location of the laser beam. The processor calculates the rake angle between the first transmitter axis and the alignment direction.