Alfred Frans Gort
Engineers at Arkins Dr, Loveland, CO

4108539, Aug 22, 1978

Nov 18, 1976

5/742938

Alfred Frans Gort - Loveland CO
Charles E. Moore - Rochester NY

Hewlett-Packard Company - Palo Alto CA

G02B 1708

350201

A tacheometer utilizes a gallium arsenide laser diode in a phase shifting distance encoder, a sinusoidal interpolator in a phase shifting shaft angle encoder, a mercury pool in a phase shifting two axis off-level encoder, a shared phase to digital decoder and a digital processor, to measure angles and distances corrected for off-level, speed of light variations, refraction and the earth's curvature. A reflecting telescope is coupled to the shaft angle encoder and is incorporated in both the phase shifting distance encoder and the alignment system. The reflecting telescope has a doublet objective lens with an embedded secondary reflective surface facing a primary mangin mirror. A biconcave element of the doublet objective lens also functions as a corrector for the secondary reflective surface. A compact objective lens system is thus realized, having minimal interference between the corrector for the secondary reflective surface and the optical path through the doublet objective lens.

4335306, Jun 15, 1982

Oct 29, 1979

6/089007

Alfred F. Gort - Loveland CO
Charles E. Moore - Rochester NY

Hewlett-Packard Company - Palo Alto CA

G01D 534

250231SE

A tacheometer includes two angle encoders each utilizing a method of eccentricity correction wherein three detectors responsive to encoded angular displacement are arranged linearly along a line passing through the desired axis of angular displacement. Two of the detectors are disposed diametrically opposite each other, at equal distances from and on opposite sides of the desired axis. In the absence of eccentricity the actual axis of angular displacement is the desired axis, and the outputs of the diametrically opposed detectors are complementary. The presence of eccentricity causes the two axes to separate, and produces a corresponding change in the outputs of the diametrically opposed detectors, rendering them non-complementary. The degree of change is measured and used to correct an angular displacement detected by the third detector, located at a different distance from the desired axis.

4346989, Aug 31, 1982

Aug 30, 1979

6/071433

Alfred F. Gort - Loveland CO
Charles E. Moore - Rochester NY

Hewlett-Packard Company - Palo Alto CA

G01C 308, G01B 1126

356 5

A tacheometer includes a distance measuring module whose output indicates the distance to a target by a phase shift in an output signal relative to a reference signal. An angle measuring module has an output that indicates angular displacement by a phase shift in another output signal relative to a different reference signal. A single phase comparison module alternately measures both phase shifts.