The Ordrat - Ordnance Dial Reader and Translator

The Ordnance Dial Reader and Translator is an electronic data reduction machine designed specifically for the purpose of automatically reading the azimuth and elevation dial images of cinetheodolite films as produced in ballistic measurements of guided missile test flights. The data is applied to the machine in the form of 35 mm film records which may be either the double frame or single frame type. The machine handles double frame records at the rate of 10 dial images per second and the single frame records at the rate of 20 images per second. The time code, the degree values and the vernier readings of the dials are processed through the machine, translated into digital form and recorded on six channels of a standard digital computer tape. The magnetic tape is prepared in such a form as to be immediately applied to a digital computer of the type ERA-1103. Preparation of films for automatic reading requires only a minor modification of the theodolites. It is necessary to replace the existing glass circles and reticle plates with coded units especially engraved for automatic reading. The performance of the machine in digitizing the vernier reading is equivalent to that achieved by visual readers, the three sigma spread being approximately ±6 seconds of arc in reading the half degree intervals.