RU2562065C1 - Device for increasing range resolution - Google Patents

Abstract

FIELD: physics, navigation.

SUBSTANCE: invention relates to radar and can be used to provide high range resolution at the output of the receiving channel of a radar station. The technical result is achieved due to that the device includes a delay line, an adder, the first input of which is connected to the input of the delay line and is the input of the device, and the output is the output of the device, series-connected correlator and multiplier, the output of which is connected to the second input of the adder, and the second input of the multiplier is connected to the output of the delay line and the first input of the correlator, the second input of which is connected to the output of the adder.

EFFECT: low probability of false alarm when resolving targets.

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Description

The invention relates to radar, can be used to provide high resolution in range at the output of the receiving path of the radar station.

The known scheme matched filter for a radio pulse [Baskakov S / I. Radio engineering circuits and signals: Textbook. for universities for special. "Radio engineering". - 4th ed., Revised. and add. - M .: Higher. school, 2003 .-- 462 s / s. 435], comprising an oscillating link, a delay link, a 180 ° phase shifter, and an adder. The disadvantage of this device is the low resolution in range, since it is determined by half the pulse width at the output of the device, which is equal to two durations of the input signal.

The closest in technical essence (the prototype of the invention) is a high-frequency differentiation scheme [Theoretical basis of radar. Ed. Shirmana Y.D. Textbook for universities. M., publishing house "Soviet Radio", 1970. - 560 s /, p. 224], containing a series-connected delay line and an adder, the second input of which is connected to the input of the delay line, which is the input of the device, and the output of the adder is the output of the device.

The delay line t _s is selected from the condition

where k = 0, 1,2, ...,

f _o - carrier frequency.

The delay of the echo signal leads to the fact that the signals arrive at the inputs of the adder in antiphase, as a result of their summation, a short pulse is formed, which increases the resolution in range.

However, a change in the carrier frequency f _o (due to the instability of the transmitter, the Doppler effect when moving the target), deviation of the delay time t _s in the delay line or inaccurate knowledge of the frequency, for example, when using an extraneous transmitter, can violate the conditions of high-frequency differentiation (1 ), which will cause a decrease in the signal-to-noise ratio at the output of the device.

The technical result is to reduce the likelihood of a false alarm when resolving targets in a changing carrier frequency.

The technical result is achieved by the fact that in the high-frequency differentiation circuit containing the delay line and the adder, the first input of which is connected to the input of the delay line and is the input of the device, and the output is the output of the device, additionally connected series correlator and multiplier, the output of which is connected to the second input the adder, and the second input to the output of the delay line and the first input of the correlator, the second input of which is connected to the output of the adder.

The essence of the invention is based on multiplying the output signal of the delay line by a complex coefficient at which its phase is shifted relative to the phase of the input signal by π regardless of the carrier frequency. The formation of a complex coefficient is carried out using correlation feedback.

The structural diagram of the proposed device is shown in figure 1. The proposed device for increasing resolution in range consists of a delay line 1, a correlator 2, a multiplier 3, an adder 4 connected, as shown in figure 1.

The purpose of the circuit elements is clear from their name.

The device operates as follows.

The echo signal through the adder 4 is fed to the second input of the correlator 2, the first input of which receives an echo signal from the output of the delay line 1. The correlator 2 generates a weighting coefficient of mutual correlation of the delayed and not delayed echo signals. The echo signal from the output of the delay line 1 is multiplied in the multiplier 3 by a weight factor and fed to the second input of the adder 4, where it is subtracted from the echo signal input to the device. The duration of the signal at the output of the adder 4 is equal to the delay time in the delay line 1 and the duration of the correlator. If echo signals from two targets arrive at the input of the device, then the output increases the resolution in range, even if the delay time in the delay line 1 is not equal to the odd number of half-wavelengths of the signal 2πf _o t _s ≠ π (2k + 1), ( where k = 0, 1,2, ...; f _o is the carrier frequency; t _s is the delay time in the delay line).

Thus, the proposed device has a high resolution and provides a low probability of false alarm.

The proposed technical solution is new, since devices with high resolution and low probability of false alarm are unknown from publicly available information. The proposed technical solution is practically applicable, since standard equipment, devices and materials of widespread technology can be used for its implementation.

Claims (1)

A range resolution enhancing device comprising a delay line and an adder, the first input of which is connected to the input of the delay line and is the input of the device, and the output is the output of the device, characterized in that the correlator and multiplier are additionally connected in series, the output of which is connected to the second input the adder, and the second input of the multiplier to the output of the delay line and the first input of the correlator, the second input of which is connected to the output of the adder.

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