A method for the stereophotogrammetric survey of a large-dimension object is provided in which the object and a chain having two reference markers thereon spaced apart at a known distance are photographed from a height of about 30 m with two synchronized metric photographic cameras spaced apart by about 6 m. Depth measurements (Z axis) are made on a stereoscopic model reproduced by a stereoplotter at eight sets of points grouped in the eight conventional perimetral locations of photogrammetric orientation at the crests and troughs of the ripples or undulations of the water or ground, respectively. The mean of the depth measurements is calculated to determine the mean horizontal plane and the model is correctly orientated with respect to the horizontal plane by suitable rotation. The length of the chain is measured between the two reference markers on the orientated model and the ratio of the chain length measured on the model to the known length of the catenary arc between the markers is used to determine the reproduction scale.
A control unit box and one of standard point members are provided close to a connection of first and second bars. A standard plane is defined by the standard point members. A loop antenna is provided in a mount unit situated on the top surface of the control unit box. The box is positioned such that a ratio of a second distance to a first distance is less than tan 8.degree.. The first distance is from the point member to the mount unit, along the standard plane, and the second distance is from the standard plane to the top surface of the mount unit, along a direction perpendicular to the standard plane. The antenna is connected to an oscillator of 310 MHz. With respect to the antenna, the total length is approximately 0.48 m, a height from the top surface of the unit box is approximately 9.5 mm, and the inner diameter is approximately 25 mm.
The imaging system includes widely-spaced sensors on an airborne vehicle providing a base-line distance of from about five to about 65 meters between the sensors. The sensors view an object in adjacent air space at distances of from about 0.3 to 20 kilometers. The sensors may be video cameras or radar, sonar infrared or laser transponders. Two separate images of the object are viewed by the spaced sensors and signals representing each image are transmitted to a stereo display so that a pilot/observer in the aircraft has increased depth perception of the object. In effect the interpupillary distance of the human viewer is increased from the normal 5.9-7.5 cm to from about 5 to about 65 meters resulting in depth perception of objects at a distance of from about 0.3 km to 20 km or more.
