Abstract: A laser alignment system includes a transmitter and one or more receivers. The transmitter produces an alignment field by projecting laser energy in a non-planar reference cone, and the receivers locate this reference cone with photodetectors. The laser energy in the alignment field is modulated at 8 kHz and the signals produced by the photodetectors are filtered and amplified to increase the range of the system. Each receiver operates a display which indicates when it is aligned in the reference cone, and it produces an out-of-level indication when the transmitter is not properly aligned.

Abstract: A laser alignment system includes a transmitter and one or more receivers. The transmitter produces an alignment field by projecting laser energy in a non-planar reference cone, and the receivers locate this reference cone with photodetectors. The laser energy in the alignment field is modulated at 8 KHz and the signals produced by the photodetectors are filtered and amplified to increase the range of the system. Each receiver operates a display which indicates when it is aligned in the reference cone, and it produces an out-of-level indication when the transmitter is not properly aligned.

Abstract: A laser alignment system includes a transmitter and one or more receivers. The transmitter produces an alignment field by projecting laser energy in a non-planar reference cone, and the receivers locate this reference cone with photodetectors. The laser energy in the alignment field is modulated at 8 kHz and the signals produced by the photodetectors are filtered and amplified to increase the range of the system. Each receiver operates a display which indicates when it is aligned in the reference cone, and it produces an out-of-level indication when the transmitter is not properly aligned.

Abstract: A system for surveying the contour of land and for automatically determining the most efficient movement of dirt in order to obtain a desired grade utilizes a stationary transmitter which generates a rotating laser beam plane across the field to be surveyed. A receiver and a control circuit are mounted on a vehicle which is adapted to drive across the field. After providing the control circuit with certain initialization data, an operator drives the vehicle over the field in a predetermined manner to enable the control circuit to take elevational readings at selected points. After the survey has been completed, the operator can use the control circuit to display graphical information relating to the surveyed field. The operator can also utilize the control to calculate the amount of dirt which must be moved in order to obtain a desired grade on the field.