Showing papers on "Moving target indication published in 1980"

Apparatus and method for classifying moving targets

Abstract: Method and apparatus for passive classification of moving targets which uses pulse Doppler radar wherein in addition to the primary Doppler echo the radar echo signals of the moving targets also contain periodically repeating Dopplers side line frequencies which can be utilized for classification of the targets. These Doppler side lines occur because of the periodic change of reflectivity of the target as, for example, due to rotating parts on the target and in the invention are investigated by means of spectral analysis for identification of the target. For example, land vehicles, wheeled and track vehicles can be easily distinguished with the invention and a first rough evaluation and in a fine detail evaluation, can be classified for every target type.

A method in a tracking radar to attain a large unambiguous range for detected targets by means of radar pulses with high repetition frequency

Abstract: The invention relates to a method for a tracking radar which transmits radar pulses towards a certain target whose target range from the beginning is known. The carrier frequency of the transmitted radar pulses are during the target tracking varied from one pulse to the next following, so that a pulse series including a certain number M of carrier frequencies is treated. The number M is chosen with reference to the continuously measured target range and as long as this range is less than a certain value. If the target range exceeds this value the number M of carrier frequencies is changed and a new pulse series including this new number is transmitted. The unambiguous range to the followed target becomes dependent on the frequency repetition frequency in the transmitted pulse series instead of the PRF of the radar.

Radar Target Detection and Map-Matching Algorithm Studies

Abstract: Results of a study of adaptive threshold target detection and map-matching algorithms are presented. Log threshold processing is shown to be preferred over linear threshold processing when the clutter data surrounding the target cell is contaminated by other targets, decoy corner reflectors, or bright clutter cells. Whereas previous studies have resorted to extensive Monte-Carlo simulations of log threshold algorithms, the results were obtained using a novel analytical approach based upon Parseval's theorem.

Pulse doppler radar receiver - has device which forms mean value of interferences and displays them differently from moving targets

Abstract: The radar receiver has a moving target indicator filter and interference suppression circuits whose outputs are connected to an indication and/or evaluation device. A device consisting of a mean value forming stage for the interference signals in the range channels, and an amplitude-time conversion stage, represents magnitude and direction of interference signals. It displays them differently from the moving targets. It is mounted at the output of the MTI filter (8) with a rectifier (9), independently from a succeeding evaluation circuit, e.g. CFAR, integration and counting stages. A comparator is used to divert signals to the sensitivity time control (STC).

Signal-to-noise losses associated with hardware-efficient designs of moving target indicators

Abstract: In many radar systems the signal processor contains a moving target indicator which is implemented by either an infinite or finite impulse response digital filter. The finite impulse response configuration is most often used, and there are two major implementation alternatives: the moving window (or sliding window) and the fixed window (or block window) methods. The hardware requirements and the signal-to-noise characteristics for various implementations of moving and fixed window moving target indicators are determined and compared. It is demonstrated that the moving window configuration produces correlation of noise samples which is not present in fixed window systems. Equations are given that relate the effective number of outputs from these systems when the same number of input samples are used. It is shown that a square-law detector, or a linear detector, does not alter the relative performance of the moving and fixed window moving target indicator systems. A tabulated result is given that compares hardware (i.e., memories, adders, multiplexers, multipliers, multiplication speed) for the moving and fixed window systems. One significance of this effort is that it allows a tradeoff to be made between the better signal-to-noise improvement for the moving window system and the less complex hardware requirements of the fixed window system.

Radar apparatus having spaced transmitting and receiving antennae

Abstract: In radar apparatus, to reduce long range clutter and chaff returns, a bistatic radar system is used with spaced directional transmitting and receiving antennae (10,12 in Figure 1), the directional patterns overlapping but with the null 18 on one side of one directional pattern being substantially parallel to the null 19 on the other side of the other directional pattern whereby signals from targets, clutter, etc. beyond a predetermined range Ro dependent on the directional patterns and antenna spacing are substantially reduced. The invention is particularly applicable to short range radars with a high repetition rate and especially to radars with moving target indication.

Design Considerations for the Infrared Airborne Radar (IRAR) MTI Subsystem.

Abstract: : A design for a moving target indication (MTI) subsystem for the infrared airborne radar (IRAR) is investigated A Doppler MTI system incorporating heterodyne detection and a cw CO2 laser is determined to be the most suitable approach Numerous analyses of topics including field-of-view coverage, Doppler resolution, signal-to-noise ratio, clutter effects, etc are presented which serve to define component specifications and processing requirements The potential architecture of the MTI system is discussed and the impact of developing technologies on system and component design is estimated (Author)