SU146803A1 - Method for increasing resolution of radar stations and device for its implementation - Google Patents

Description

Methods are known for increasing the resolution of radar stations operating in pulsed mode with frequency-modulated oscillations, based on reducing the duration of the probe pulses and extracting the useful signal by means of a band-pass filter from a voltage applied to the received signal and signal modulated local oscillator. However, when implementing such methods, difficulties arise associated with obtaining pulses of short duration. In addition, the use of a heterodyne method of isolating a useful signal in the case of simultaneous viewing of the entire operating range of a radar in range requires the use of a multichannel circuit.

Simplification of the method for increasing the resolution of the radar in the described invention is achieved by shortening not the probe pulses, but the pulses reflected from the target in the receiver itself using a shortening filter made in the form of a delay line (LZ) with interconnected taps from this line.

FIG. 1 shows a block diagram of the sub-part of the radar; in fig. 2 is a schematic of a shortening filter.

The signals reflected from the target are received by the antenna /, amplified in cascades of high frequency 2, converted by frequency in the conversion unit, amplified by intermediate frequency 4 stages, detected by the shortening filter 5, detected by detector 6 and (amplification at low frequency by video amplifier 7 is fed on the interface (not shown in the drawing). Due to the fact that the received signal, transmitted through a shortening filter, is converted into a pulse with a higher duration, the radar resolution is increased for a given duration probe pulse, and with a given resolution of the station it is possible to increase the range of its action.In addition, the use of a shortening filter that converts the frequency-modulated signal into a pulse of short duration, makes it possible to refuse the frequency-modulated heterodyne and to simplify the receive path circuit.

The shortening field-f includes a delay line 8 with permanent distribution and interconnected taps 9. The taps 9 can be connected to the delay line 8 by means of capacitive inductive or conductive coupling.

Applying to a shortening filter of frequency-modulated signals at the moment the signal ends at the output 10 of the filter, all half-sine waves of the pulse removed from the taps 9 are summed. Each of these half-sine waves will be delayed by the time determined by the distance 9 from the beginning of line 8- With an appropriate choice of positions taps along the length of the half-sine wave line when summing up a narrow pulse, the duration of which is significantly less than the duration of the input signal.

Subject invention

Claims (2)

1. A method for increasing the resolution of a radar station using frequency-modulated probing pulses, characterized in that, in order to shorten the duration of received reflected pulses, the receiver, for example, sequentially with intermediate frequency cascades, includes a shortening filter. 2. A filter for carrying out the method of claim 1, characterized in that it is made in the form of a delay line with interconnected discrete or continuously distributed taps performing capacitive, inductive or conductive communication with the line. / 1-r-mrr