RU2298267C1 - Multibeam active phased antenna array - Google Patents

Abstract

FIELD: antenna assemblies for directional radiation and reception.

SUBSTANCE: all radiated power is used in each direction (in each beam) but at different frequencies; each beam is probed within time interval depending on signal length multiplied by relative duration of probing pulse; echo signals of all beams are received simultaneously as they arrive and separated into beams by means of filters mounted at output of active phased antenna array adders. Beams are independently controlled by means of beyond-module sets of controlled phase shifters. Each set is designed for control by separate beam.

EFFECT: enhanced radiation power of each independently controlled beam, enhanced precision of measuring target angular coordinates.

1 cl, 6 dwg

Description

The present invention relates to antenna systems of directional radiation and reception - multipath active phased antenna arrays (AFAR).

The invention can be most effectively used in airborne aircraft radar systems, radio countermeasures (RPD), communication systems with moving and stationary objects on the ground, in the sea and air, or beacons.

In airborne aviation radar stations (radars), multi-beam AFAR, compared with single-beam, allows you to:

- simultaneously operate in the “air-to-surface” modes (when synthesizing an aperture, when detecting and tracking sea and ground targets, when setting active interference to ground and ship radars) and “air-to-air” (when detecting missiles and aircraft, pointing weapons at air targets when interfering with aircraft radar and homing missiles;

- N times (N is the number of rays used in a multi-beam AFAR) it is faster to inspect the designated area of responsibility.

In RPD or radio communication systems, multipath AFAR can increase the number of simultaneously suppressed radio devices or increase the number of radio communication subscribers.

т.е. два одинаковых по величине сигнала, но каждый из них в два раза меньше, чем выходной сигнал однолучевой АФАР, равный (А+В). Это означает, что коэффициент усиления двухлучевой АФАР-аналога в два раза меньше, чем в однолучевой, т.е. эффективность (коэффициент усиления) каждого луча двухлучевой АФАР будет в 2 раза меньше, чем эффективность (коэффициент усиления) однолучевой АФАР, и мощность излучения в каждом луче в этом аналоге в два раза меньше (Справочник по радиолокации под ред. М.Сколника, Сов. Радио, 1977 г., т.2, стр.201), что приводит к потере дальности действия радиосвязи, радиомаяка или системы радиопротиводействия на 40%, а РЛС - на 20%. При N-лучей уменьшение составит соответственно

и

(для РЛС) («Радиолокационные системы», Д.Бартон, Воениздат, М., 1967 г., стр. 137; Справочник по радиолокации под ред. М.Сколника, Сов. радио, 1977 г., т.1, стр.29).Multipath AFARs are known. Figure 1 presents a block diagram of a two-beam AFAR according to US patent No. 4638317 1987, which is an analogue of the proposed AFAR, where 1 are emitters connected to transceiver modules (PMT) 2, the outputs of which are connected to the inputs of the adders (in the receiving mode signals) or dividers (in the signal transmission mode) 3, the outputs of which are connected to the inputs of the adder 4, made in the form of a directional coupler, where each input signal (A and B) is divided into two equal parts, which, folding, form the total output signal of the form

those. two signals of the same magnitude, but each of them is two times smaller than the output signal of a single-beam AFAR equal to (A + B). This means that the gain of a two-beam AFAR analog is two times less than in a single-beam, i.e. the efficiency (gain) of each beam of a two-beam AFAR will be 2 times less than the efficiency (gain) of a single-beam AFAR, and the radiation power in each beam in this analog is half as much (Radar Reference edited by M. Skolnik, Sov. Radio, 1977, v.2, p. 201), which leads to a 40% loss in the range of a radio communication, a beacon or a radio countermeasure system, and a radar - by 20%. With N-rays, the decrease is respectively

and

(for radar) (“Radar Systems”, D. Barton, Military Publishing, M., 1967, p. 137; Reference to Radar, ed. M. Skolnik, Sov. Radio, 1977, v. 1, p. .29).

Since a decrease in the range of the above radio systems is unacceptable, this fact is a significant drawback of the analogue.

раза.Another analogue is the 4-beam PAR according to US patent No. 4989011, N. A. Rosen et al. from 01.29.91, which has the same drawback as the previously mentioned PAR according to US patent No. 4638317 1987 - a decrease in the gain of each beam by 4 times relative to a single-beam PAR and, accordingly, a decrease in the range of radio communications, a beacon and radio interference - 2 times, radar - in

times.

The closest analogue (prototype) of the present invention is a 3-beam AFAR, a block diagram of which is presented in figure 2 in the Guide to radar ed. M. Skolnik, Owls. Radio, 1977, vol. 2, p. 188, 189, 190.

The prototype device contains:

1 - partial arrays (sublattices) of the AFAR, the number of which is equal to the number of rays, for example three. The sublattices consist of several transceiver modules (PPM), each of which contains an emitter, amplifiers, a controlled phase shifter (Active Phased Arrays, edited by D.I. Voskresensky and A.I. Kanaschenkov, ed., Radio Engineering No., M 2004, p. 19, fig. 1.3).

2 - a group of adders-dividers (first group), the number of which is equal to the number of sublattices.

3 - groups of uncontrolled phase shifters used for fixed beam separation, and the number of phase shifters in the group is equal to the number of rays.

4 - a group of adders-dividers (second group), the number of which is equal to the number of sublattices.

The adders (4) in the reception mode, coherently summing the signals of the corresponding sublattices, form at the three outputs — Out 1, Out 2, Out 3 — rays No. 1, No. 2, No. 3, respectively, stationary relative to each other, as phase shifters 3 - uncontrollable.

The controlled phase shifters PPM (intramodular) using the control signal allow you to change the position of 3 rays (3 radiation patterns) in space at the same time at the same angle.

The transmission mode in the prototype is carried out using a bridge connection. A transmitter connection diagram is shown in FIG. 2a. The signal of the transmitter 7 through divider 6 and four-arm bridges 5 (X-circulators), adders-dividers of the second group - 4, phase shifters uncontrolled - 3, adders-dividers of the first group - 2 and PPM - 1 (Fig. 2) is radiated into space by rays, motionless relative to each other.

Thus, the power radiated by the active PAR is divided equally across all 3 beams, so that in each beam this power is 3 times less than in a single-beam AFAR - A Guide to Radar Ed. M. Skolnik, vol. 2, p. 2018. All three beams change their position in space in the same way and cannot scan independently of each other, since the control phase shifters are installed only in the MRP, and the phase shifters 3 are uncontrollable.

This means that the prototype device cannot simultaneously measure the coordinates of two or N targets, for example, air and sea or several air and sea targets, which are located at different points in space and move independently. Another disadvantage of the prototype is the inability to measure the angular coordinates of the target in one of the rays in the presence of a signal reflected from the interfering target with a large effective scattering surface (EPR) irradiated by another beam, since after the adder-divider 2 part (1 / N) of the signal of the interfering target falls into the beam channel, which measures the coordinates of the target with a small EPR, for example, a tank with EPR = 10 m ² , and the interfering target is a railway bridge with EPR = 100000 m ² , located in a direction that does not coincide with the tank.

The objective of the invention is to eliminate the above disadvantages, namely, providing

- the radiation level of the signal in each of the N rays equal to the level of the emitted signal in a single-beam AFAR;

- independent control of each of the N rays;

- suppression of interfering signals entering the receiving channel of each beam, but received from targets from other directions, i.e. other rays.

This goal is achieved by the fact that in the N-beam AFAR form rays at different N operating frequencies with the help of newly introduced controlled off-module phase shifters and N newly introduced frequency filters that separate the signals of individual beams in both reception and transmission modes.

Figure 1 presents a block diagram of an analogue - 2-beam AFAR;

Figure 2 - block diagram of the prototype - transceiver 3-beam AFAR;

On figa - connection diagram of the master oscillator in the AFAR;

Figure 3 is a block diagram of the proposed multi-beam AFAR;

Figure 4 is a timing diagram of the proposed AFAR for transmission and reception (for the case of two rays);

Figure 5 - option location of targets (useful - tank and interfering - railway bridge) relative to the radiation pattern of 2 AFAR rays.

N-beam active phased antenna array (figure 3) contains: 1 - PPM with emitters controlled by phase shifters; low-noise amplifiers operating in receive mode power amplifiers operating in transmission mode; transmit-receive switches directing the signal of the master oscillators to the input of the power amplifier and then to the emitter, received signals from the ether — from the emitter — to the input of a low-noise amplifier, and the amplified received signal to the receiving channel.

The PPM scheme is described in detail in the scientific and technical literature (“Active phased antenna arrays” under the editorship of DI Voskresensky, AI Kanaschenkov, Sov. Radio, 2004, p. 19). MRPs are combined into private lattices or sublattices (Handbook of Radar, edited by M. Skolnik, vol. 2, 1977, p. 190).

The output of each of the sublattices of the PPM - 1 is connected to the microwave adder / divider of the first group - 2 using the microwave path, made in the form of a waveguide, strip line, or fiber optic line.

Microwave adder / divider - 2 can be performed similarly to the adder / divider of the prototype.

The outputs of the microwave adders / dividers - 2 of the first group are connected to the inputs of the respective adders / dividers 4 (second group) through additionally introduced controlled out-of-module phase shifters 3. The output of each adder / divider of the second group 4 is connected to the corresponding input of the additionally introduced filters 5. The output of each of the filters 5 is connected to the first input of the corresponding receive-transmit switch 6, and the second inputs of these switches are connected to the corresponding outputs of the multi-frequency (N-frequency) master oscillator (3G) 7, and the frequency of the signal at each output of 3G 7 is set equal to the operating frequency of the corresponding filter 5, connected via its receive-transmit switch 6 to this 3G output 7. The output of each switch 6 is connected to the input of the operating frequency receiver of the corresponding beam.

In the proposed N-beam AFAR, the circuit of which is shown in FIG. 3, the power radiated by each beam to the radiation level of a single-beam AFAR is increased due to the radiation of the total power of all APMs during the probe pulse in one of the beams (see FIG. 4) on the corresponding frequency.

Independent control and focusing of each beam is carried out using the additionally introduced extra-modular controlled phase shifters - 3.

Multipath AFAR works as follows.

In the transmission mode, the 3G 7 master oscillator that generates N-frequency microwave signals, each of which is designed to form a single beam, is connected using the receive-transfer switch 6 with one of the outputs to the corresponding ith filter 5, the frequency of which (F _i ) corresponds to the frequency at which one of the - rays (1 ... N) of the AFAR is formed.

From the output of the ith filter filter 5 of the signal with a frequency F, it is supplied to the corresponding microwave adder / divider (second group) 4, with which the signal power is distributed to the inputs of the microwave adder / dividers (first group) 2 through non-modular controlled phase shifters 3 used for simultaneous control of all beams at once (if necessary).

Using controlled non-modular phase shifters in accordance with digital control signals - 4- or 5-bit words of transistor-transistor logic (TTL) of level U (Θ ^o _N ), the direction of each beam is established. The number of inputs of each microwave adder / divider 2 is equal to the number of generated beams.

With the output of all the microwave adders / dividers 2, the signals at the frequency F _i are fed to the inputs of the PMF 1 during the duration of the emitted pulse τ _i (see Fig. 4 - Timing diagram of the 2-beam AFAR in the coordinates F _c - signal frequency, t - time), and are received during t _ave.i (for example, the signal of the first beam with a frequency of F ₁ from the adder / divider ∑ _{1 of the} second group 4 is fed to the inputs of PPM-1 during the duration of the emitted signal τ _1. In the PPM signals are amplified, and all power (without loss of division by rays) is radiated into space in the direction of only the first beam, which is determined by intramodular phase shifters.

The next pulse, for example, of duration τ _{2 with} frequency F _{2 is} supplied from the master oscillator 7 through the second switch 6, the second filter 5 to the input of the second adder / divider 4 through the time interval ΔT + τ ₁ · Q (Fig. 4), where Q is the duty cycle signal τ ₁ - the duration of the previous pulse at a frequency F ₁ .

The second adder / divider 4 distributes the signal at a frequency of F ₂ at the inputs of controlled out-of-module phase shifters 3 (setting the phase distribution at the inputs of the PPM for the beam).

After the controlled phase shifters 3, the signals are fed to the inputs of the adders / dividers 2, in which they are combined and fed to the input of each PPM 1.

With the output of each PPM 1 through the emitter, the signal is emitted. In this case, the radiation direction (beam No. 2) is determined by the extra-modular controlled phase shifters 3. Thus, all the rays are focused in a given direction using the intra-modular controlled phase shifters, and each of the rays 1 ... N (independently) using the extra-modular controlled phase shifters 3.

In the reception mode, multipath AFAR operates as follows. The echo signals at the emitted frequencies F ₁ and F _{2 (N)} are reflected from targets and other objects and are received by the emitters of the entire AFAR aperture, then they are fed to the MRP _i 1 (Fig. 3), where they are amplified, phase shifts are obtained on controlled intramodular phase shifters, arrive at the inputs of the adders / dividers 2. After the microwave adders / dividers 2, the signals are fed to the inputs of the adders / dividers 4 through controlled non-modular phase shifters 3. The signals at frequencies F ₁ ... F _n (rays 1 ... N) will be phased using corresponding non-modular phase shifters 3 at the inputs with ummatators / dividers 4: signals at a frequency of F ₁ (beam 1) - ∑ ₁ ; at the frequency F _N (beam N) - ∑ _N. In this case, the signals of all beams (1 ... N) will be received almost at the same time interval O ... t _pN (Fig. 4), but at different frequencies. At the input of each adder / divider ∑ _i 4 there will be (in the presence of reflecting objects in the direction of all beams) signals of all (1 ... N) frequencies, but only signals of one frequency (one beam) will be phased at the input of each adder / divider 4 corresponding to this frequency.

The signals from the output of each adder / divider ∑ _i 4 (phased and unphased) are fed to the input of the corresponding frequency filter 5, in which the unphased signals, i.e. signals whose frequency does not correspond to the operating frequency of a given filter (signals of other beams) are suppressed, since the passband of the filter is chosen narrower than the minimum frequency difference of the signals generated by the master oscillator.

Signals with a frequency corresponding to the frequency of this filter pass to its output without attenuation and go to the input of the receiving device of this beam through the receive-transmit switch 6. For example, signals of beam 3 with a frequency of F ₃ through the third switch go to the input of the receiver connected to the output of this switch. Thus, at the output of each input filter 5, a corresponding independently controlled beam is formed whose signal frequency F _i is equal to the operating frequency of the i-th filter 5. Signals of other frequencies will be suppressed. In this case, errors in measuring the angular coordinates will be absent, because interfering signals of other directions (rays) will be suppressed by the newly introduced filters by an amount equal to the square of the level of the side lobe (UBL) of the measuring beam.

, с которого принимается эхо-сигнал от мешающего объекта Ц₂, облучаемого сигналом с частотой F₂ (главным лепестком луча 2) и сигналом с частотой F₁ (боковым лепестком с УБЛ=-30 дБ) луча 1.5 shows the angular direction

, from which an echo signal is received from an interfering object C ₂ irradiated with a signal with a frequency of F ₂ (main beam of beam 2) and a signal with a frequency of F ₁ (side lobe with UBL = -30 dB) of beam 1.

, фиг.5).At the output of the first filter 5 (FIG. 3), a signal with a frequency of F ₂ will be suppressed, and a signal with a frequency of F ₁ received by the side lobe (UBL = -30 dB) of beam 1 will pass through switch 6 to the receiver of beam 1, but will be attenuated by 60 dB (10 ⁶ times -30 dB - UBL exposure and - 30 dB - UBL reception). This means that the error in measuring the angular coordinate of target Ts ₁ due to interfering Ts ₂ will be practically absent, i.e. its value will not exceed 0.0001% of the angular distance between C ₁ and C ₂ - (

5).

It follows that the proposed technical solution ensures the achievement of the technical result:

- suppression of interfering signals whose angular position does not correspond to the direction of the beam, with which the angular coordinates of the useful target are measured, which practically eliminates the error in measuring the angular coordinates of the target in the presence of interfering ones.

The proposed technical solution ensures the achievement of a technical result in comparison with the prototype, which consists of:

1. In increasing the radiation power level in each of the N rays to the radiation power level of a single-beam AFAR by using separate frequencies to form each beam and additionally introduced filters.

2. In providing independent control of each of the N beams due to the introduction of controlled non-modular phase shifters.

3. In eliminating errors in measuring the angular coordinates of the target by suppressing interfering signals in additionally introduced filters.

Claims (1)

Multipath (N is the number of rays, where N = 2, 3, ...) an active phased array antenna containing sublattices consisting of emitters, transceiver modules, adders, the output of each of which is connected to the input of the first adder / power divider of the first group , the number of outputs of which is equal to the number of rays (N) and each output of each of these adders / dividers is connected to the input of the corresponding adder / divider of the second group, the transmit-receive switches, the output of each of which is connected to the input of the receiver, respectively beam, characterized in that each of the N outputs of each of the adders / dividers of the first group is connected to the input of additionally introduced controlled out-of-module phase shifters, the output of each of which is connected to the input of the corresponding adder / divider of the second group, the output of each of which is connected to the input an inserted frequency filter, the output of which is connected to the first input of the receive-transmit switch, of each beam, and the second input of this switch is connected to the corresponding output of the multi-frequency deleterious oscillator.

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