Abstract: A celestial navigation system includes an optical device for receiving light from a celestial object, a spectrometer for measuring a spectrum of the light in sufficient detail to identify absorption and/or emission features, and a processor for processing the spectrum to match the spectrum, or a processed version thereof, against a set of reference spectra information in a database, a device for measuring the pointing direction of the optical device and a clock. The matching may be on a maximum likelihood basis. The system is thus able, on identification of a single star, and, using commonly available navigational almanacs, to calculate a geographical position. Celestial navigation takes place even when only one celestial object (that is also within the database) is visible, although improved accuracy may be obtained with multiple observations. Advantageously, the database includes stars of the K and/or M type, that have more characteristic spectral content.

Abstract: A celestial navigation system includes an optical device for receiving light from a celestial object, a spectrometer for measuring a spectrum of the light in sufficient detail to identify absorption and/or emission features, and a processor for processing the spectrum to match the spectrum, or a processed version thereof, against a set of reference spectra information in a database, a device for measuring the pointing direction of the optical device and a clock. The matching may be on a maximum likelihood basis. The system is thus able, on identification of a single star, and, using commonly available navigational almanacs, to calculate a geographical position. Celestial navigation takes place even when only one celestial object (that is also within the database) is visible, although improved accuracy may be obtained with multiple observations. Advantageously, the database includes stars of the K and/or M type, that have more characteristic spectral content.

Abstract: Apparatus for scanning a moving object includes a visible waveband sensor 12 oriented to collect a series of images of the object as it passes through a field of view 16. An image processor 14 uses the series of images to form a composite image. The image processor 14 stores image pixel data for a current image and a predecessor image in the series. It uses information in the current image and its predecessor to analyse images and derive likelihood measures indicating probabilities that current image pixels correspond to parts of the object. The image processor 14 estimates motion between the current image and its predecessor from likelihood weighted pixels. It generates the composite image from frames positioned according to respective estimates of object image motion. Image motion may alternatively be detected by a speed sensor such as a Doppler radar 200 sensing object motion directly and providing image timing signals.

Abstract: A system for stabilizing video signals generated by a video camera which may be mounted in an unstable manner includes a digital processing means for manipulation of each incoming image that attempts to overlay features of the current image onto similar features of a previous image. A mask is used that prevents parts of the image that are likely to cause errors in the overlaying process from being used in the calculation of the required movement to be applied to the image. The mask may include areas where small movements of the image have been detected, and many also include areas where image anomalies including excess noise have been detected. The invention also discloses means for dealing with wanted movements of the camera, such as pan or zoom, and also discloses means for dealing with the edges of video signals as processed by the system. A method is also disclosed.