Abstract: Apparatus for detecting and determining the direction of arrival of optical radiation. The apparatus includes a first mask having one or more slit apertures, a binary encoding mask which combines the functions of angle sensing and digitizing using a so-called gray encoding scheme, and interdigitated detector(s) to produce differential electrical signals, and output processing electronics for providing a digital code or word corresponding to the angle-of-arrival of the incident radiation.

Abstract: An improved optical direction of arrival sensor in which incoming radiation passes through a cylindrical lens placed through a top mask and is focused in the gap between the lens and a detector array concentric about the back of the lens. The focal line then expands and falls on the detector array which embodies an encoding scheme. The output from the encoded detector is then processed to determine the angle of incidence of the incoming radiation with the top mask.

Abstract: An imaging coherent radiometer for detecting and determining the location and wavelength of coherent radiation or coherent lack of radiation in the presence of non-coherent ambient radiation. The apparatus includes an unequal path interferometer which divides incoming radiation containing coherent and non-coherent radiation into a first beam path and a second beam path through which a first beam and a second beam, respectively, travel. The optical path length difference between the first beam path and the second beam path are greater than the coherence length of the non-coherent radiation, but substantially less than the coherence length of the coherent radiation or coherent lack of radiation. Modulation means are provided to cause a predetermined difference in the optical frequencies between the first beam and the second beam proportional to a modulation signal. The first and second beams are then recombined into a recombined beam.