Abstract: A new method has been developed as an attempt to improve speed and robustness of existing ISAR classification methods. The new method produces a set of silhouettes of possible models in a 3D model database. The set of silhouettes of each model views the model from various viewing angles, as the target dimensions will vary as it is viewed from different angles. The silhouettes are stored as a training set. Classification is done by comparing the silhouette of the target with the set of silhouettes in the training set. The silhouettes are calculated prior to the silhouette matching.

Abstract: A method and arrangement for finding the direction to an emitter source by determining the spatial frequency of a signal received from the source in a sensor panel and comparing the spatial frequency with the instantaneous frequency. The panel includes a first matrix of sensors and a second matrix of sensors interleaved with the first matrix. The spatial frequency is determined by comparing the signals received by the first and second sensor matrices.

Abstract: A new method has been developed as an attempt to improve speed and robustness of existing ISAR classification methods. The new method produces a set of silhouettes of possible models in a 3D model database. The set of silhouettes of each model views the model from various viewing angles, as the target dimensions will vary as it is viewed from different angles. The silhouettes are stored as a training set. Classification is done by comparing the silhouette of the target with the set of silhouettes in the training set. The silhouettes are calculated prior to the silhouette matching.

Abstract: A digitizer arrangement for converting an analogue signal into a digital signal, including a first A/D converter, said first A/D converter being arranged to convert said analogue signal into a first digital signal with a first sampling rate, the first sampling rate being lower than the frequency of the analogue signal, a second A/D converter, said second A/D converter being arranged to convert said high frequency analogue signal into a second digital signal with a second sampling rate, the second sampling rate being lower than the frequency of the analogue signal, means for combining said first and second digital signals into a third digital signal with a third sampling rate that is at least a multiple of said first and second sampling rates.

Abstract: An antenna for use in a direction finder system, said antenna including a microstrip patch layer with a stripline transmissionline layer below. The microstrip layer and the stripline layer share a common groundplane. In this groundplane is formed a number of apertures. Each aperture couples a patch to a radiation point in the stripline feed layer. The patches and transmissionlines are designed from a lossy material. The substrates in the microstrip and stripline layers may be designed from materials with lossy dielectric properties.

Abstract: A method for processing signals in a direction-finder system, including detection of pulses in the received signals, estimation of characterizing pulse parameters, sorting the pulses according to the characterizing pulse parameters, de-interleaving the received pulses into pulses coming from at least one emitter, determining emitter parameters characterizing said emitter, and comparing said emitter parameters with emitter parameters from known emitters in order to recognize and identify the emitter.