RU26265U1 - STROBOSCOPIC SELECTOR OF MOVING GOALS - Google Patents

Abstract

A stroboscopic moving target selector containing a time-scale converter of radio-pulse signals, consisting of a stroboscopic mixer, a memory circuit, a voltage-code converter, an inter-period compensator circuit, and a strobe radio pulse generator, the output of which is connected to the input of a stroboscopic mixer, characterized in that he introduced a scheme of auto shift with a stepwise increase in slow sawtooth voltage, the outputs of which are connected to the gene a gate pulse generator and a blanking circuit, the input of the blanking circuit being connected to the output of the inter-period compensator circuit.

Description

The utility model relates to the field of radio engineering and can be used in radar systems (radar) to isolate signals reflected from moving targets, against the background of reflections from stationary objects.

Known schemes for moving targets selection (SDC) based on interperiodic subtraction of received echo signals 1. The basic element of their implementation is a filter with a single delay (interperiodic compensator - NPC), the signal 2 {t) at the output of which is presented in the form

z (t) Zp - z.

where zo x (t) is the signal received at the input of the filter at time t, ZT x (t - T) is the signal received at the input of the filter at time t - T (T is the repetition period); T l / fnr where and is the radar pulse repetition rate. However, in the case of using “superresolution in range to obtain radar (radar) portraits of the target, a multichannel (in range) structure with a large number of memory elements N T / At and

high digitization speed (At 1-7-10 NS).

The closest in technical essence is a stroboscopic converter of the time scale of pulse signals, which allows for the observation of fast processes using low-frequency equipment 2. The frequency of the studied signal x {t), (using the complex representation 1) of the form

on the observation interval t e С, NT, where, allows you to use the difference of adjacent samples of the stroboscopic sample y (kT) - y ((k-l) T), where y (kt) ax (k AT) 1.

Here a is a coefficient taking into account the dimension; AT T - Tc, where T and Tc are the periods of the investigated and gating signals, respectively; Qd (2v / c) wo - Doppler shift of the carrier frequency WQ, v - target speed. At the output of the CNC circuit, samples will be formed

Z, y ,, - y ,, (kAT) - A ({k - DAT) - Obviously, with "super-resolution, stroboscopic samples A (kAT) Ф A ((k -1) АТ), which makes it impossible to compensate

passive interference at Qd 0.

The purpose of this utility model is to eliminate the noted drawbacks while preserving the advantages of stroboscopic processing of the reflected signals and effectively suppressing passive interference.

This goal is achieved by using an auto-shift circuit with a stepwise increase in slow sawtooth voltage (MPN), providing multiple gating of the signal at one point 2, and a blanking circuit, which suppresses the signal at the output of the PLC system for the duration of the transition process in a digital filter. The introduced elements are connected in such a way that the signals from the passive reflectors will be suppressed by the system, and the signal received from the moving target will be transmitted due to the presence of the Doppler shift of the carrier frequency.

In fig. 1 shows a functional diagram of the device. The device contains a stroboscopic mixer 1, a memory circuit 2, a voltage-code converter (ADC) 3, an inter-period compensator circuit 4, a strobe clock generator 5 controlled by an auto-shift circuit with a stepped increase in MPN b and a blanking circuit 7.

The device operates as follows. At one of the inputs of mixer 1, a periodic (with period T) sequence of studied signals x (t) is supplied, and to another, a sequence of strobe pulses (radio strobes), the temporary position of which changes by a small DT value (read step) every n (gating ratio) signal periods T,. If the input signal was received from passive reflectors (earth's surface), then samples of the form

..., ay3 ((k-l) AT), ayi (kAT), ay2 (kAT), ay3 (kAT), ayi ((k + 1) AT),

au2 ((k + l) AT), auz ((k + i) AT), ...

Here and in the future the sampling rate is taken equal

three (n 3): yi (nAT) y2 (nPAT) knots (nPAT). After passing

CPC schemes on the output of the digital filter, samples will be formed

z; 5Ck - ay, (kAT) - ay3 ((k - 1) АТ),

z О ay2 (kAT) - ay, (kAT),

  0 ay3 (kAT) - ay2 (kAT),

z, 5Ck .. ay, ((k + DAT) - ay3 (kAT),

  0 ay2 ((k + DAT) - ay, ((k + DAT),

  0 ay, ((k + DAT) - ay2 ((k + DAT)

etc. Xn О samples are formed when the strobe is shifted (during the transient in the digital filter). The blanking scheme introduced in the design is necessary to suppress the system’s output during the transition process occurring with each change in the position of the radio strokes (for periods n, 2n Зп, ...). The following values will be generated at the output of the blanking scheme:

etc. Thus, signals from passive reflectors will be completely suppressed by the system.

For a signal received from a moving target, samples will be received at the input of the digital filter

..., ac ({kl) AT) exp (j (nl) QdT), ayi (kAT) exp (j (n) QdT), ay2 (kAT) exp (j (n + 1) QdT), aus ( kAT) exp (j (n + 2) QdT), ayi ((k + l) AT) exp (j (n + 3) QdT), aug ((kfl) AT) exp (j (n + 4) QdT) , auz ((k + l) AT) exp (j (n + 5) QdT),. . .

After passing the CNC circuit and the blanking circuit, samples will be generated at the output of the stroboscopic selector

A 0.

zl ay (kAT) 1 - e - - e

zl ay (kAT) 1 -,

 - about

Z, - VJ,

Zj ay {{k + DAT) 1 - ay ((k + DAT) 1 -

At Qd const, the value of | zkl at the system output will be adequate to the radar readouts of the target portrait. Thus, the described model implements a system for selecting moving targets with the measurement of radar portraits.

Multiple gating can be implemented in an auto-shift scheme with a stepwise increase in MPN:

UMP

1Q, -,: пО, 1 f

di 1.2.

Authors: / y: / 1ё-гД. Zakharchenko

Patentee: ViViPSvbJ -L. One piece

L. N. Kut rukhi n Sources of information: Modern radar (analysis, development and design of systems). Per. from English Ed. Kobzareva Yu.B. Publishing house "Soviet Radio, 1969. - 704s. Naidenov A.I. Transformation of the spectrum of nanosecond pulses. - M .: Owls. Radio, 1973. - 180s.

Claims (1)

A stroboscopic moving target selector containing a time-scale converter of radio-pulse signals, consisting of a stroboscopic mixer, a memory circuit, a voltage-code converter, an inter-period compensator circuit, and a strobe radio pulse generator, the output of which is connected to the input of a stroboscopic mixer, characterized in that he introduced a scheme of auto shift with a stepwise increase in slow sawtooth voltage, the outputs of which are connected to the gene a gate pulse generator and a blanking circuit, the input of the blanking circuit being connected to the output of the inter-period compensator circuit.