RU142313U1 - Doppler Transmitter Radar - Google Patents

Abstract

1. Radar with a Doppler transmitter containing an antenna, the input-output of which is connected to the input-output of the antenna switch, the input of which is connected to the output of the transmitter, and the output is connected to the input of the receiver, characterized in that at least the first and the second converters connected in series with the receiver, a frequency standard, the output of which is connected to the second input of the first converter, and to the second input of the second converter, a search circuit and an electronic key configured to connect Ia transmitter input to the output of the second inverter, or the output of the search circuit having an input connected to the output receiver, and a first input of the first inverter, a first output of which is connected to the first input of the second preobrazovatelya.2. The radar according to claim 1, characterized in that the receiver comprises a filter and an amplifier connected in series, each of the converters is equipped with a multiplier and a filter connected in series, and the transmitter has an amplifier. The radar according to claim 2, characterized in that it is equipped with a random combination generator (HSC), a synchronizer with a memory, the first input of which is connected to the output of a random combination generator (HSC), a selector, a quadrator and a detection channel, connected in series between the antenna switch and the receiver the output of which through a series-connected filter and detector, which are a shaper of correlation maxima, is connected to the first input of the computing means, the second and third inputs of which о are connected to the second outputs of the first and second converters, and

Description

The proposed utility model relates to the field of radar and is intended for use in radar stations or radars with a Doppler transmitter, as well as in specific tracking systems.

The main difference between the proposed radar with a Doppler transmitter and current radars with a Doppler transmitter is the use of ultra-long sounding signals in it.

Currently, various radars with a Doppler transmitter are known, as well as radars with a Doppler transmitter, however, they do not have sufficient accuracy and reliability of measurements, they have rather complicated schemes for their implementation, which use quite expensive equipment.

So known radar, containing a FM signal transmitter, a transmitting antenna, a receiver of the FM signal reflected from the target signal with an amplifier, an ADC, a processor that performs the conversion of time / frequency, and the connected control device [US patent No. 59972223, MKI G01S 13 / 34].

The disadvantage of this radar is the insufficient range.

Also known is a radar for measuring small distances to an object, containing a parallel-connected receiving antenna, a mixer, a first low-pass filter and an amplifier-limiter, as well as a series-connected microwave frequency-controlled oscillator, a directional coupler, a transmitting antenna, a frequency-voltage converter and a height meter with a variable scale, as well as an amplifier with automatic gain control, the first and second logic circuit And, the first and second counters of the number of pulses, and e digital adder [RF applications from №94037470, IPC G01S 13/34].

This radar has increased accuracy and reliability of measuring small distances to the object, but it has a greater range.

Closest to this invention by technical essence are a target tracking method and a monopulse radar device that implements this method according to the RF patent for IZ No. 2338219, IPC G01S 13/44, selected as a prototype.

A monopulse radar that implements this method comprises a monopulse antenna system, the first input-output of which is connected to the second input-output of the antenna switch, an exciter, quadrature-phase detectors of the sum and difference channels, a synchronizer, a transmitter connected to the antenna switch, and a modulated shaper connected in series signal shaper reference signal, and on-board computer.

This device provides the ability to track both the target signal and the noise source of interference while increasing the radar potential of the target signal by suppressing the mirror noise band at the video frequency, however, this device does not provide sufficient radar range, sufficient noise immunity, and measurement accuracy current coordinates and parameters.

The technical task of the proposed utility model is the creation of such a radar with a Doppler transmitter in which its range would be significantly increased, noise immunity and accuracy in measuring current coordinates and parameters would be increased, the possibility of reconnaissance of the structure of the probing signal would be excluded, with a significant simplification of the radar circuit and a corresponding reduction in equipment volume and its value.

The technical task of the proposed utility model is achieved due to the fact that the radar with a Doppler transmitter contains an antenna, the input-output of which is connected to the input-output of the antenna switch, the input of which is connected to the output of the transmitter, and the output is connected to the input of the receiver, has at least the first and second converters connected in series with the receiver, a frequency standard whose output is connected to the second input of the first converter, and to the second input of the second converter, search circuit and the electronic key is adapted to connect the transmitter input to the output of the second inverter, or the output of the search circuit having an input connected to the output of the receiver and the first input of the first inverter, a first output of which is connected to the first input of the second inverter.

Preferably, the radar with a Doppler transmitter contains a filter and an amplifier connected in series, each of the converters has a multiplier and a filter connected in series, and the transmitter has an amplifier.

In a preferred and practically feasible version, with a new structure of probing signals, the PN MSK radar with a Doppler transmitter is equipped with a random combination generator (GSK), a synchronizer with a memory, the first input of which is connected to the output of a random combination generator (GSK), a selector, a quadrator, and a channel detection, connected in series between the antenna switch and the receiver, the output of which is through series-connected filter of the driver and the detector, which are correlation maxima, connected to the first input of the computing tool, the second and third inputs of which are connected to the second outputs of the first and second converters, and the fourth input of the computing tool is connected to the input of the search circuit and the detection channel, while the transmitter is equipped with a PSP signal modulator, the first input of which connected to the output of the synchronizer, the second input is connected to the output of the electronic key, and the output of the PSP modulator is connected to the input of the transmitter amplifier, the detection channel contains an adder, two circuits in parallel between it and the receiver from the first narrow-band filter and the first detector, as well as from the second narrow-band filter and the second detector, connected by the outputs of the detectors to the first and second inputs of the adder, while the receiver has two frequency dividers, a delay circuit, the second adder and several multipliers, configured to match the LFD with the SRP, and connected between the delay circuit and the second adder in such a way that the outputs of the receiver multipliers are connected to odes of the second adder, the output of which is connected to the filter input, the first inputs of the receiver multipliers are connected to the outputs of the delay circuit, and the second inputs of the receiver multipliers are connected to the first outputs of the frequency dividers, the inputs of which are connected to the first inputs of the first and second converters, the first of which additionally contains a chain of the second multiplier and the second filter connected in series, and the second also further comprises a chain of the second multiplier and the second connected in series Filtering, wherein the first and second outputs of the frequency reference connected to the second input of the second multipliers of the first and second converters, and filters the outputs of the first and second converters connected to the inputs of the second multipliers of the first and second converters and to inputs of the second and third computing means.

The protected novelty of a radar with a Doppler transmitter is to compensate for the Doppler frequency offset of the signal reflected from the target by changing the frequency of the probe signal of the transmitter strictly by the current value of the Doppler frequency offset of the reflected signal, but with the opposite sign

f _{d otr} = | -f _{d out} |

For a more complete disclosure of the invention, the following is a description of specific possible options for its implementation with the corresponding drawings.

FIG. 1 is a structural diagram of a radar with a Doppler transmitter.

FIG. 2 is a structural diagram of a radar with a Doppler transmitter with PN MSK signals.

FIG. 3 - structure of frequency changes (Doppler and compensating).

FIG. 4 - PN MSK signal structure.

FIG. 5 - quadratic spectrum of PN MSK signal.

FIG. 6 is an isometric view of the PN MSK signal. A radar with a Doppler transmitter comprises a transmitter 1, which may include an amplifier 1.2 (Fig. 1). The output of the transmitter 1 is connected to the input of the antenna switch 2, the input-output of which is connected to the input-output of the antenna 3, and the output of the antenna switch 2 is connected to the input of the receiver 4, which may contain a filter 4.1 and a rectifier 4.2, the output of which is connected to the first input of the first converter 5.1, the second input of which is connected to the output of the frequency standard 6, the output of which is connected to the second input of the second converter 5.2, the first input of which is connected to the output of the first converter 5.1. The output of the second converter 5.2 is connected to the input of the electronic key 8, the second input of which is connected to the output of the search circuit 7, the input of which is connected to the output of the receiver 4 and the first input of the first converter 5.1, and the output of the electronic key 8 is connected to the input of the transmitter 1. In this case, the first converter has a multiplier 5.1.1 and a filter 5.1.2, and the second converter has a multiplier 5.2.1 and a filter 5.2.2.

Radar with a Doppler transmitter operates as follows.

In the initial state, the search circuit 7 generates a signal with a frequency f ₀ that varies linearly within the entire Doppler frequency range. This signal from the output of the search circuit 7 through the electronic key 8 is fed to the input of the transmitter 1. There it is amplified, and through the antenna switch 2 it enters the antenna 3 and is emitted. When the target appears, within the directional pattern of the antenna 3, there comes a moment when, reflected from the target, a signal with a frequency f ₀ + f _{D is} received by the antenna 3, and from its output, through the antenna switch 2 goes to the input of the receiver 4, amplifies in it, and enters the input of the first converter 5.1, in which the frequency is converted from the signal reflected from the target with a frequency f ₀ + f _D. In the first converter 5.1, to the second input of which a signal with a frequency f _{0 is} constantly supplied from a frequency standard 6, the frequency of the input signal is converted, and a signal with a frequency f ₀ + f _D -f _{0 is formed} , that is, a signal with a frequency f _D that is received to the first input of the second Converter 5.2, to the second input of which is fed continuously from the standard frequency 6 signal with a frequency f ₀ . In the second converter 5.2, the input signal with a frequency f _{D is} converted into an output signal with a frequency f ₀ + f _D , which is sent through an electronic key 8 to the transmitter 1, and then through the antenna switch 2 to the antenna 3 to transmit it as a probe signal after which there is a continuous maintenance of the equality of frequencies f _D = | -f _D | closed loop of the system, in which the instantaneous change in the frequency of the doppler of the transmitter 1Δf is compensated by the corresponding change in the frequency of the transmitter 1, resulting in the closure of the feedback system loop formed by the transmitter 1, in which its radiation frequency is controlled.

The instantaneous change in the Doppler frequency Δf (Fig. 3) is compensated by the corresponding change in the frequency of the transmitter 1, i.e. f _D (t) = | -f _D (tT), where Τ is the transit time of the emitted signal to the target and vice versa.

The result of organizing such a closed system feedback loop is the forced compensation of the Doppler frequency shift, i.e. the target from which the reflected signal is received “as if ceases to move” in space on the basis of the absence of a Doppler frequency shift in its signal, and, as a result, the working conditions of a narrow-band receiver at a constant frequency f ₀ arise.

The application of the above radar with a Doppler transmitter allows you to:

- firstly, to realize the potentially limiting radar energy potential due to narrowing the receiver bandwidth to the theoretically minimal one (instead of the total, at which the receiver band should be expanded to take into account the dynamic component of the spectrum in the input signal), i.e. the signal energy is maximum, and the noise energy is minimal, and all the information properties of the signal are preserved (the dynamic component of the spectrum generated by the movement of the target, and manifested in the Doppler frequency shift, is compensated);

- secondly, in the spectral and correlation Fourier transforms conditions arise for a significant increase in the limits of integration (accumulation of signal energy), and, consequently, an additional increase in the energy parameters of the radar, since on the given time scale, the “time defect” caused by different time (frequency) reference systems is eliminated;

- thirdly, such a compensation structure for building a radar (radar) provides the reception of signals from only one target, because signals reflected from all other objects (including reflections from local objects of the underlying surface, passive and active noise and other stationary and moving objects with a frequency different from the compensation transmitter, will not pass through the narrow-band filter of the receiving system;

- fourthly, the non-sensitivity of the radar receiver (radar) to all reflected signals, with the exception of one tracked target, significantly relieves the computing and indicator means of the radar.

In the simplest version of the radar described above with a Doppler transmitter (radar), the structures of the signals used and a number of other details were not specified. Therefore, the main task of the simplest radar presented was the problem of setting forth a new method of Doppler radar, which can be adapted to specific conditions (ground, ship, aircraft, space, etc.)

The second embodiment of a radar with a Doppler transmitter (Fig. 2), with the restructuring of the carriers emitted by the transmitter, using a new structural principle, is specified in terms of the use of new PN MSC signals (Pseudo Noise Minimum Shift Keying) of wideband noise-like discrete signals with a minimum phase shift and an index of frequency manipulation D = 2 _∧ fT _d = 0.5. Their structure in the time and spectral regions is depicted in FIG. 4 and 5, and in FIG. 6 is an isometric view of the PN MSC signal. In their essence and properties, these signals significantly exceed the widely used PCM, not to mention obsolete ones like AM, LFM, etc. Their main difference and advantage over the known signals is that the envelopes of the time function, the envelopes of the spectrum, and correlation functions are smooth curves without side lobes of FIG. 4 (provided that there is a sufficiently large amount of N, and almost when the maximum level of the side lobe is no more than the nominal noise level), therefore, the uncertainty function has a single maximum in the center of the plane.

The second embodiment of a radar with a Doppler transmitter (Fig. 2) contains, in addition to the first embodiment of a radar with a Doppler transmitter, a synchronizer 24 with a memory 23, the first input of which is connected to the output of a random combination generator (HSC) 25, a selector 9, a square 10, and detection channel 4.1 connected between the antenna switch 2 and the receiver 4, the output of which through a series-connected filter 21 and a detector 22 is connected to the first input of the computing means 26, while in series filter 21 and detector 22 are a correlation maximum shaper. The second and third inputs of the computing means 26 are connected to the second outputs of the first 5.1 and second 5.2 converters, and the fourth input of the computing means 26 is connected to the input of the search circuit 7, while the transmitter 1 is equipped with a PSP signal modulator 1.1 and an amplifier 1.2. The first input of the modulator of the SRP signals 1.1 is connected to the output of the synchronizer 24, the second input is connected to the output of the electronic key 8, and the output of the modulator of the SRP signals 1.1 is connected to the input of the amplifier of the transmitter 1.2. Detection channel 4.1 comprises a first adder 15, two circuits connected in parallel between it and the receiver from the first narrow-band filter 11 and the first detector 13, as well as from the second narrow-band filter 12 and the second detector 14, connected to the first and second inputs of the first adder 15.

The receiver 4 contains a delay circuit 18 with taps, a second adder 20, several multipliers 19 (19-1,9-n, 19-n-1), made with the possibility of matching LFD with the SRP, and connected between the delay circuit 18 and the second adder 20 as well as two frequency dividers 16 and 17, connected by outputs to the second inputs of the multipliers 19, and inputs to the first 5.1 and second 5.2 converters, the first of which additionally contains a chain of series-connected second filter 5.1.3 and the second multiplier 5.1.4, and the second additionally contains a chain of succession the second filter 5.2.3 and the second multiplier 5.2.4.

The principle of operation of the second embodiment of the radar with a Doppler transmitter shown in FIG. 2 is similar to that described for the first embodiment of the radar. The only difference is the need to adapt the simplified single-channel and single-frequency version of the receiver, the Fourier scheme of time convolution to dual-frequency PN MSK signals, as well as to protect the new principle of detecting a quadratic signal by bursts of the spectrum at doubled LFDs.

A distinctive feature of the second variant of the radar is the structure of the detection channel 4.1, in which, when the signal frequency is squared (doubled), the spectrum regular components appear in the PN MSK signal structure, which theoretically leads to the appearance of components in it that contain 50% of the input signal energy (Fig. four).

Using this property to detect a signal, the sensitivity threshold significantly decreases and the s / w ratio increases sharply, which is not taken into account in standard technical calculations. However, the absence of an explicit dependence of the amplitude of the residual side lobes in the spectrum expression on the number of discretes makes it necessary to impose an additional condition: so that the maximum amplitude of the side lobe of the spectrum does not exceed the minimum noise level.

The structure (combinatorics of the PSP) of the probing signal is protected by using the GSK 25, the basis of which is a noise generator, so even the hardware designer cannot predict the structure of the next combination of the PSP.

The readiness for the Fourier operation of convolution in time during the entire sending is provided by the memory circuit 23 as part of the synchronizer 24.

As is obvious to those skilled in the art, this utility model is easy to develop in other specific forms without going beyond the essence of this utility model.

Moreover, the present embodiments should be considered merely illustrative, and not limiting, and the volume of the utility model is represented by its formula, and it is assumed that it includes all possible changes and the equivalence domain of the claims of this utility model.

Claims (3)

1. Radar with a Doppler transmitter containing an antenna, the input-output of which is connected to the input-output of the antenna switch, the input of which is connected to the output of the transmitter, and the output is connected to the input of the receiver, characterized in that at least the first and the second converters connected in series with the receiver, a frequency standard, the output of which is connected to the second input of the first converter, and to the second input of the second converter, a search circuit and an electronic key configured to connect Ia transmitter input to the output of the second inverter, or the output of the search circuit having an input connected to the output of the receiver and the first input of the first inverter, a first output of which is connected to the first input of the second inverter. 2. The radar according to claim 1, characterized in that the receiver comprises a filter and an amplifier connected in series, each of the converters is equipped with a multiplier and a filter connected in series, and the transmitter has an amplifier. 3. The radar according to claim 2, characterized in that it is equipped with a random combination generator (HSC), a synchronizer with a memory, the first input of which is connected to the output of a random combination generator (HSC), a selector, a quadrator and a detection channel, connected in series between the antenna switch and a receiver, the output of which through a series-connected filter and detector, which are a shaper of correlation maxima, is connected to the first input of the computing means, the second and third inputs of which connected to the second outputs of the first and second converters, and the fourth input of the computing tool is connected to the input of the search circuit and the detection channel, while the transmitter is equipped with a PSP signal modulator, the first input of which is connected to the output of the synchronizer, the second input is connected to the output of the electronic key, and the output the PSP signal modulator is connected to the input of the transmitter amplifier, the detection channel contains the first adder, two connected in parallel between it and the receiver, chains from the first narrow-band filter and of the detector, as well as from the second narrow-band filter and the second detector, connected by the outputs of the detectors to the first and second inputs of the first adder, the receiver has two frequency dividers, a delay circuit, a second adder and several multipliers made with the possibility of matching the LFD with the SRP and connected between the delay circuit and the second adder so that the outputs of the receiver multipliers are connected to the inputs of the second adder, the output of which is connected to the filter input, the first inputs of the receiver multipliers connected to the outputs of the delay circuit, and the second inputs of the receiver multipliers are connected to the first outputs of the frequency dividers, the inputs of which are connected to the first inputs of the first and second converters, the first of which additionally contains a chain of series-connected second multiplier and a second filter, and the second also additionally contains a chain from a series-connected second multiplier and a second filter, while the first and second outputs of the frequency standard are connected to the second inputs of the second multipliers the first and second converters, and the outputs of the filters of the first and second converters are connected to the inputs of the second multipliers of the first and second converters and to the second and third inputs of the computing means.

Images