Abstract: A diagonal phased antenna array for use as a wind profiler by means of Doer shift measurements comprises a plurality of Yagi-Uda antennas which are oriented in a predetermined direction such that Yagi-Uda antennas have a polarization 45.degree. offset from the principal planes of operation of the antenna array resulting in similar radiation patterns subject to a geometric taper in the array aperture with respect to the principal planes.

Abstract: A method for distinguishing between multiple noise jammer sources having different noise modulation bandwidths. Noise signals are detected by a receiver having a bandwidth substantially the same as the bandwidth of the jammer noise source. The dwell time of the noise pulses formed by the receiver provides a means for determining the noise modulation bandwidth of a noise jammer source.

Abstract: A monopulse feeder for transmission and/or reception of two separate frequency bands, the X and Ka bands, comprises a mouth section (8) and a wave guide section (9) connected to comparator circuits (5 and 6, respectively) for each frequency band. The mouth section is formed with two rectangular pairs of openings (81a, 81b and 82a, 82b, respectively) of which one (82a, 82b) is of smaller dimensions than the other (81a, 81b), and is placed between the openings of the second pair (81a, 81b). The feeder is placed at the inner focal point of a two-band Cassegrain reflector system.

Abstract: A digital MTD processor interposed between a coherent video detector and a signal extractor of a surveillance radar comprises a plurality of Doppler filters connected in parallel to the video-detector output, including a zero filter, working into respective modulus extractors connected by way of respective threshold circuits to a common OR gate. Each threshold circuit includes a fixed-threshold comparator and an adaptive-threshold comparator with inputs connected in parallel to the output of the associated modulus extractor, either of these comparators being connectable to the OR gate via a switch controlled with the aid of a rain-clutter map so that the adaptive threshold is used only during exploration of regions with heavy rain.

Abstract: A receiver for a pulsed Doppler radar system comprising, connected in series, the following elements: an IF amplifier whose band width is equal to n times the spectral width of the transmitted pulses, a coherent IF detector, an A/D coder which operates at a sampling frequency at least equal to the passband of the IF amplifier and a digital filter whose pulse response is matched to the shape of the transmitted pulses. In a variant, the receiver comprises two signal channels I and Q.

Abstract: A ground clutter suppression technique is disclosed utilizing two parallel return signal processing paths, both utilizing linear-to-logarithmic conversion capability and one having a signal delay capability for one pulse repetition. The outputs are subtracted and are subsequently compared with a factor related to the root-mean-square (rms) of two deviation inputs, one input functionally related to apparatus limitations and one deviation input functionally related to antenna position (step between samples) for each signal received. The Doppler frequency standard deviation inputs are then summed rms and used to select an amplitude standard deviation which is compared with the amplitude difference between successive return signals. Thereafter, the logic decision output is operated on utilizing a digital filter to essentially eliminate ground clutter or small variance (PRF to PRf) return signals from the display.

Abstract: The testing of radar systems is enhanced with the use of clutter generator that simulates realistic terrain echo returns which are provided in real-time. A fast array processor is used in combination with a Fourier Transform processor to produce a complex digital output having time, frequency and magnitude information corresponding to the composite echos from thousands of points. A digital-to-analog converter filters the output and a single-sideband mixer converts the digital output to a radio frequency signal.

Abstract: A factored matched filter/FFT radar Doppler processor for reducing the le of clutter components contained in radar signals. The processor includes a matched Doppler filter, having a filter response matched to the spectrum of the clutter components, through which the radar signal is passed. The filtered output of the matched filter is further filtered by a coherent integration filter to further reduce the level of the clutter components.

Abstract: An MTI radar provided with a MTI processor which includes a single erasing circuit for erasing a vector signal due to a stationary target from among all the input vector signal of reflected waves both from a moving and a stationary target; and an arithmetic circuit for removing any other variations than ones from the moving target by calculating the inner product of the post-single-erasing vector signal and a pre-erasing vector signal.

Abstract: A method is described which provides automatic self synchronization (in time) between multiple pulse repetition frequency (PRF), pulse doppler radars. The synchronization technique time aligns data within a coherent look transmission (a group of pulses--typically milliseconds). This technique substantially eliminates sensitivity losses associated with blanking false alarms or detection from interfering radars transmitting (in time) at pulse repetition intervals (PRI) different than the host radar. An implementation of this method for a 2 PRF radar waveform is described although the technique may be extended to more than 2 PRF's. The technique provides an alternative approach to pulse shaping or multiple (different) frequencies to control MI but may be used in conjunction with these techniques to minimize sensitivity losses due to interference blanking. For applications where wide angular antenna beams are required and/or multiple simultaneous radar operation is required (e.g.