RU2708765C1 - Radio fuse with linear frequency modulation signal - Google Patents

Abstract

FIELD: radar ranging.

SUBSTANCE: invention relates to the field of radar equipment and can be used in devices with continuous frequency-modulated probing signals for fixing a predetermined range to an object when approaching it. Radio fuse with linear frequency modulation of the signal comprises series-connected first sawtooth voltage generator, autodin-based transceiver module, phase detector, signal analyzer and actuator. Additionally, a synchronizer, a second sawtooth voltage generator, a pseudorandom sequence generator, first and second switches, wherein the output of the synchronizer is connected to the inputs of the first and second sawtooth voltage generators, the first input of the phase detector and the input of the pseudorandom sequence generator. Outputs of the first and second sawtooth voltage generators and the pseudorandom sequence generator are respectively connected to the first, second and third inputs of the first switch, the output of which is connected to the input of the transceiver module, which output is connected to the first input of the signal analyzer and the input of the phase detector, the output of which is connected to the first input of the second switch, and the output of the pseudorandom sequence generator is also connected to the second input of the second switch. First and second outputs of the second switch are connected to the second and third inputs of the signal analyzer, respectively. Device can be used in non-contact detonators, in range sensors, altitude sensors etc.

EFFECT: invention increases noise immunity of the device from the action of relay interference stations.

1 cl, 3 dwg

Description

The invention relates to the field of radar technology and can be used in devices with continuous frequency-modulated probing signals for fixing a predetermined range to the object when approaching it. The device can be used in proximity fuses, range sensors, height sensors above the surface of the Earth, etc.

Known radar devices using linear frequency modulation of radiation, have a selection of signals in range to the location object and the speed of convergence with it.

The closest analogue, taken as a prototype of the claimed invention, is a short-range radar device with a continuous frequency-modulated probing signal [I.M. Kogan. Near radar (theoretical basis). M, "Owls. radio ”, 1973.], using the spectral method of signal processing. The device comprises a transceiver with a channel for separating the harmonic of the modulation frequency and a channel for isolating the Doppler frequency signal, the output of which is connected to a signal analyzer. The device also contains an actuator.

In such devices, the operating range is set by choosing the value of the frequency modulation band and the harmonic number, on which the signal reflected from the location object is processed.

The disadvantage of this device is the periodicity of the spatial selection function, due to the periodicity of the temporal function of linear frequency modulation, and, as a result, the vulnerability to relay interference [A.I. Paly. Electronic warfare. M., Military Publishing, 1989]. This means that when the interference is delayed for a time equal to (or a multiple of) the modulation period, the relay interference will have all the signs of a useful signal from the target and cause a false response of the product.

As a measure of protection against this, the use of random (or pseudo-random) functions for modulating the parameters of the probing signal can be considered [Modern radar (analysis, calculation and design of systems). Per. from English under the editorship of Kobzareva Yu.B. Publishing House "Soviet Radio", 1969]. There are examples of the use of pseudorandom sequences in the form of phase-shift keying (FCM) radiation. In simple miniature short-range near-radar devices of mass application, in which autodyne-type transceiver modules are used, phase-shift keying is not possible, since this will require separate emitting and receiving antennas with a sufficient mutual isolation coefficient no worse than 70 ... 80 dB, a coherent microwave generator with a phase manipulator, a device for delaying the reference signal, a microwave mixer for the signals of the reference and reflected from the location object. Given the tight overall and energy limitations of the radio fuse, the option of phase-shift keying is not possible.

Therefore, an option is proposed to use a pseudo-random function, in which the elements of the code sequence are pulses with linear frequency modulation of radiation, characterized by a set of parameters:

- steepness and sign (increasing or decreasing) of linear frequency modulation;

- constant (within a given pulse with linear frequency modulation) carrier frequency offset.

The objective of the invention is a significant increase in the period of the spatial selection function of a radar device using linear frequency modulation of radiation.

The technical result is an increase in the noise immunity of the device from the action of relay interference stations.

The proposed device contains a transceiver module, two sawtooth voltage generators, two switches, a synchronizer, a pseudo-random sequence generator and a signal analyzer.

The device and principle of operation of the proposed device are illustrated by illustrations:

FIG. 1. Block diagram of the fuse. On the block diagram are indicated:

1 - synchronizer,

2 - the first sawtooth voltage generator,

3 - second sawtooth voltage generator,

4 - pseudo-random sequence generator,

5 - the first switch

6 - transceiver module,

7 - phase detector

8 - the second switch,

9 - signal analyzer,

10 - actuator.

FIG. 2. The signal reflected from the target at the output of the transceiver module.

FIG. 3. The result of the action of relay interference at the output of the transceiver module.

The operation of the device is as follows. The first switch 5, controlled by a pseudo-random sequence generator 4, connects to the input of the frequency modulation of the transceiver module 6 the output of one of two sawtooth voltage generators (2 or 3).

As a result, the transceiver module 6 emits a pseudo-random sequence of signals with various parameters. The signals reflected from the location object from the output of the transceiver module are detected by a phase detector 7 and sent by the second switch 8 to the first or second input of the signal analyzer 9. Thus, the pseudorandom stream of received signals with different parameters is divided into two signal streams with identical parameters in each stream. The signals in each stream are similar to signals in traditional near-radar systems with regular linear frequency modulation. In FIG. 2 shows a view of a signal reflected from a target at a range of operation. Under the action of relay interference, an external signal that does not correspond to the signal currently being emitted is supplied from the output of the transceiver module to the third input of the signal analyzer. In FIG. 3 you can see how the difference frequency (the beat frequency of the emitted pulse and the pulse of organized relay interference), at the beginning of the pulse close to the frequency deviation, decreases to the middle of the pulse, passes through the zero value and then increases again. In this case, the signal analyzer identifies the interference and blocks the actuation mechanism.

Claims (1)

A radio fuse with linear frequency modulation of a signal, comprising a first sawtooth voltage generator, a transceiver module based on an autodyne, a phase detector, a signal analyzer and an actuator, characterized in that the synchronizer, a second sawtooth voltage generator, a pseudo-random sequence generator, are additionally installed in the radio fuse and second switches, and the synchronizer output is connected to the inputs of the first and second saw saw generators different voltages, the first input of the phase detector and the input of the pseudo-random sequence generator, and the outputs of the first and second sawtooth voltage generators and the pseudo-random sequence generator are connected respectively to the first, second and third inputs of the first switch, the output of which is connected to the input of the transceiver module, the output of which is connected to the first the input of the signal analyzer and the input of the phase detector, the output of which is connected to the first input of the second switch, and to the second input of orogo switch is also connected pseudorandom sequence generator output, said first and second outputs of the second switch are respectively connected to second and third inputs of a signal analyzer.

Images