Abstract: A computer method for accurate target tracking by a faster method for hit-to-target data association. The method involves using an approximation of a weighted centroid of hits to update the calculated tracks. The result, while losing theoretical accuracy since it approximates the calculation, produces fast calculations. Further, the calculated result has sufficient accuracy for most practical applications.

Abstract: The disclosed apparatus provides a point optical radiation source (i.e. point light source), at one or more distant points, the three-dimensional coordinates of which are to be measured relative to a known frame of reference. Each point light source emits light waves of a known wavelength which are received by the front plate of a multiple-beam interferometer means having a known angle of light acceptance. With respect to the light waves transmitted by each point light source and received by the interferometer means, a set of non-localized multiple-beam interference fringes are created within the interferometer means. A photo-electric detection means is provided a known distance from the back plate of the multiple-beam interferometer means and is positioned so that the interferometer means and photo-electric detection means have a common optical center axis.

Abstract: An apparatus is provided for use in optically determining distance and velocity relating to an object. The apparatus includes an optical radiation source that emits a first optical radiation signal of a modulating amplitude. The amplitude modulation of the first optical radiation signal is swept over a predetermined frequency range in a predetermined time period. Common optical components are employed to direct the first optical radiation signal towards the object, and to receive a portion of the first optical radiation signal that reflects off of the object. A portion of the first optical radiation signal is internally reflected by one of the common optical components to obtain a second optical radiation signal. An optical heterodyne detector optically mixes the received first and second optical radiation signals to produce an electrical output signal. The frequency of the electrical output signal is measured, and the frequency measurements are used to determine first and second frequency components.

Abstract: An apparatus is provided for use in determining the distance and velocity of a distant object. The apparatus employs a low energy optical radiation source that emits identical external and internal radiation signals whose wavelengths are swept. The wavelength sweep is induced by varying the magnitude of an electrical input supplied to the optical radiation source. An external ranging system employs common optical means, including polarizing means, to direct the external signal towards a distant object, and to receive a portion of that signal which reflects off of the object. First optical heterodyne means are provided to mix the reflected external signal and a local oscillator signal derived from the external optical radiation signal, to produce an output signal. Means are provided to determine representative values of the frequency of that output signal. An internal processing system directs the internal signal into an optical delay means of a known length.