This paper presents the design, implementation and test of a binocular measurement device for the determination of relative pose. The instrument is designed for the use with large plant parts and machinery in very harsh environments as encountered in off-shore hydrocarbon exploration, mining and tunnelling. The device is equipped with a fall-back monocular measurement procedure. This permits measurement despite the failure of one camera; however, with reduced accuracy. An algebraic formulation and derivation of the equations required to implement the auto-calibration and measurement procedure are presented. The laboratory test environment is presented, as are the results of extensive testing, which can be as summarized as follows: the root mean square measured positional error is ξx,y,z = [0.283, 0.351, 4.809] mm and the rotational measurement error of ξ φ= 0.106 ° when the measurement is performed at distances up to approximately 3.95 m.