JPH0779116A - Active antenna array - Google Patents

Abstract

PURPOSE: To provide many merits which can not be attained by conventional technology by integrating an active array (AESA: active electronically scanned array) to be electronically scanned in a radar induction system for a missile. CONSTITUTION: The active antenna array 58 has the prescribed number of antenna elements 60 and is used for a radar searcher. These elements 60 are respectively independently connected to plural transmitting/receiving modules 64 having the same constitution and the modules 64 are connected to cooling plates 66 for removing heat generating in operation. In an suitable embodiment, each module 64 has a rectangular prism shape housing. Phase and gain circuits to be individually controlled are stored in each housing. In another embodiment, the modules 64 are constituted of plural wafers, which have respectively corresponding identical constitution circuit function blocks as antenna elements.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION This invention relates to antenna arrays,
In particular, it relates to an antenna array incorporated in a radar guided missile or the like.

[0002]

2. Description of the Related Art Guided missiles or missile searchers (missi
In a missile system called a le seeker), an onboard radar system directs a radar beam at a target and the energy received and processed by reflecting off the target keeps the missile on the desired tracking course. There are state-of-the-art avoidance or jamming techniques that can be used on targets by avoiding or redirecting guided missile searchers or in directions other than the tracking course. In order to overcome these defensive measures or increase the success rate of target tracking, there is a need for improvement of missile search devices. The purpose of typical defense measures is to generate spurious radar return signals and confuse the missile guidance system with respect to the actual target.

The methods employed by advanced missile searchers to frustrate guided missile defenses are primarily recognizing that RF signals are received over a wide angular range, and by electronic processing of such signals. It is required that the searcher can separate the true target radar return signal and the "false" signal. Further, when used with multiple targets (multiple real targets and / or "bait" emitted from multiple radars), the searcher must be able to select a particular target located within the target population.

[0004]

[Problems to be Solved by the Invention] Gimbal search device (gimba
lled seeker) is a well-known guidance system
By mounting a high gain antenna on the gimbal assembly, the searcher can point the target over a relatively wide fixed angle or scan volume. A servo system drives the gimbal, which allows positioning of the antenna both for transmitting and receiving desired direction radar energy within the scanning volume. Due to the excessive weight, cost, volume, and mechanical complexity of such systems, alternative systems are needed. In addition, gimbal systems have traditionally been custom designed and individually manufactured for each new application.

Another type of missile searcher uses electronically scanned antenna (ESA) technology. This technique includes a large number of individual antenna elements, each antenna element having the ability to program the phase of the transmitted and received signals. In one form of ESA, known as passive ESA, high RF power is generated in a separate transmitter unit and split among multiple phase shift elements. Since the phase shift function is performed with relatively high power, the phase shifter tends to have high loss. In addition, the ESA method includes multiple full-aperture sub-arrays because all elements of the array are driven by a single transmitter and the signals received by each array element are combined before being routed to the receiver. Lack the flexibility to take full advantage of the modern signal processing techniques required for access.

A second ES called hybrid ESA
Method A uses a high power amplifier and a low noise amplifier to process the transmitted and received signals, respectively. This latter method has many problems similar to the above passive ESA,
It still does not provide sufficiently independent radiating / receiving elements in the array.

In addition to precise guidance for tracking a target, guided missiles typically have a warhead load designed to cause maximum damage to the target during an assault. Tracking requires accurate data to increase the probability of target removal, and this data is used to determine the optimal explosion point for the warhead. Current missile searchers used for guidance cannot collect the exact data needed to calculate the optimal explosion point for a missile warhead. In known systems, a second special sensor is included in the missile design to collect this necessary data. Due to such additional cost and weight of the system, as well as additional space within the missile, it is desirable to achieve this functionality with the missile searcher alone, eliminating the problems associated with separate missile searchers. It is an object of the present invention to electronically scan active electronically scanned arrays (AESAs) in missile radar guidance systems.
To provide a number of advantages that conventional techniques cannot achieve.

[0008]

[Means and Actions for Solving the Problems]
(1) Searcher power aperture product (power-aperture pr
A modular and cost-effective way to achieve (duct), (2) Integrated active / passive (ARH)
Wide bandwidth to enable guidance, (3) adaptive beamforming to enhance searcher guidance in the presence of distant stand-off jammers (SOJs), (4) enhanced for swarming targets Derivation, (5) searcher-based fusion, that is, combining the derivations to fuse functionality into a single searcher, (6) functional redundancy and real-time fitness compensation for bad elements in the array. High reliability and reduced system failure rate.

1. Modular Structure AESA consists of independent active transmit / receive modules. Each module consists of a transmitter element and a radar receiving element, which are independently adjustable with respect to phase and gain. These basic building blocks can be integrated together to form arrays of any size without undue design cost. By adopting a modular structure, an active antenna array of any size can be provided by simply assembling an appropriate number of modules.

2. A high bandwidth integrated active / passive (ARH) inductive active transmit / receive (T / R) module has a basic characteristic of wide bandwidth, operating in a bandwidth of several tens of percent. Being able to operate in such a wide bandwidth, the missile searcher is able to derive passive guidance information about various emitters due to on-board operation of the target of interest. In addition, the wide bandwidth supports active operation over a wider band, which allows for simultaneous missile or radio frequency interference (RFI).
missile movement prediction (scenar
ios) performance is improved. ECM (electronic counter measures) with a wide operating band
Performance is improved. Attempting to operate the ECM device in a wider band will dilute the jamming power received by the missile search receiver.

3. Obstacles that exist apart (SOJs: st
Adaptive beamforming to improve searcher inductiveness in the presence of and-off jammers. AESA adjusts the gain and phase of each element of the active array, manipulates nulls in real time, from the radar beam axis. Remove obstructions from missed obstacles. The reduced interference increases the probability of successful guidance to the desired target.

4. Increased Inductivity for Swarming Targets In AESA, the array can be divided into multiple sub-arrays, which are subject to appropriate signal processing
Inductivity to one of the swarming targets is improved. The separate transmission and reception allows the searcher to determine signals from multiple independent targets, with separate phase and gain adjustments for each antenna element. Moreover, its decision-making ability does not depend on the feedback signal coming from the relatively large target.

5. Searcher-based fusion, ie integration of guidance and fusion into a single searcher AESA enables the same system as the missile radar system used for target detection and tracking purposes to calculate the optimal detonation point for a missile warhead. Can be used to collect the required data. The basic features of the active T / R module design are that the fusion function combined with the radar searcher has a small blind range (that is, fast recovery after transmission) and that the target size is accurately determined.
T / R supporting waveforms to enable measurement
The wide bandwidth of the module and the fast operation for pointing the searcher beam when determining the target size.

6. Functional Redundancy and Real-time Fitness Compensation for Bad Elements in the Array AESA is typically composed of over 100 active elements. Each element is inherently highly reliable, and the failure of one element can be compensated for by adjusting the bad element to the gain and phase parameters of the element closest to the element. This feature prevents overall performance degradation when each element fails. High power searchers, which generally use traveling wave tube (TWT) technology, require pressurization of the searcher to prevent transmitter arcs and subsequent catastrophic failure. Any improper seal causes a fatal missile probe failure. Each T / R module of the present invention has a low peak power and does not need to be pressurized to prevent arcing. TWT transmitters typically require voltages as high as 10,000 volts, whereas the active T / R module uses much lower voltages. With such a high voltage of TWT, advanced manufacturing technology is required so that defects relating to the power supply do not occur. These various problems are completely overcome by using active T / R modules that use voltages on the order of tens of volts. Finally, the AESA is constructed without the moving parts that are essential to conventional gimbaled support antennas. Reliability is significantly improved by eliminating the gimbal assembly, which includes the torque motor and high power servo circuitry.

[0015]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT There are three known methods for constructing a missile searcher. That is, (1) a conventional gimballed slotted array antenna,
(2) Electronic passive scanning antenna, (3) Electronic hybrid scanning antenna.

FIG. 1 is an exploded view of a typical gimbal radar searcher system comprised of various conventional components, the missile guiding system, generally indicated as 10. The system includes each antenna element (or slot) 14 in a general matrix arrangement at the front end, and includes various connections and electronic circuits generally identified as 16. An antenna assembly 18 having the antenna array 12 is held together with a connecting portion and an electronic circuit 16 on a pedestal 20 mounted on a gimbal. The pedestal 20 provides the ability to orient the antenna array 12 in any desired direction within a relatively wide fixed angle in a conventional manner. Servo drive 22 having control and drive electronics 24 is typically coupled to RF processor 26. In terms of use, the search assembly 10 is capable of scanning within a given fixed angle, which expands the angular range of the antenna array 12 fixed in position. Such gimbal-supported antenna array systems generally have 2-4 receive channels and are highly tuned at frequencies in a relatively narrow operating frequency range.

As shown in the radar response graph of FIG. 2, the radar echo or response 28 (sometimes called the main lobe response) received directly along the boresight of the antenna is the largest, but High power off boresight (high powe
Signal return for red off-boresight signals (ie 3
0, 32) are still important. These responses away from the mainlobe peak are called antenna sidebands or simply sidebands. Also, there is a zero receive 34, or "null" point, between adjacent lobes. In practice, a signal located as a null in the same corner or position would not be detected. These off-boresite responses have two major adverse effects: (1) When storing an interfering signal located at an off-bore sight angle having a sideband peak, the received interfering power reduces the acquisition of a radar signal returning from the target, (2) the main beam of the antenna is the target If the target return is not directly oriented to the antenna and the target return is the null of the antenna, it will be impossible to obtain the desired target return. In the case of a gimbal-supported antenna, the null is fixed and the error can be continuous in detection.

Not only are gimbal-supported antenna systems incapable of overcoming many standard defense techniques, but they also require relatively heavy components, the servomotor and a heavy yet bulky gimbal / pedestal. With the weight issue, the required size of the gimbaled support antenna system exceeds the desired limit size.

Referring now to FIG. 4, it can be seen that a so-called passive electronic scanning antenna (ESA) consists of a number of antenna elements 36. These antenna elements are arranged in the matrix 38 together with the phase controller 40, which allows the controller 40 to collectively change the phase of the signals received or transmitted by the antenna elements. This method provides a limited amount of control and processing. Since the phase shifting function is performed at high power, the phase shifter elements of device 40 generally cause large losses.

In the hybrid ESA 42 (FIG. 5), the phase control 44 provides the phase change through the antenna array 46, the low noise amplifier 48 (LNA) provides the feedback signal, and the additional separate amplifying means 50 is the mixer.
Provided to send a signal from the exciter
(Figure 4) . Each low noise amplifier 48 has a limiter 52,
It is shown including amplifier 54 and amplifier control 56 (FIG. 6). Hybrid ESAs have similar problems to passive ESAs, where the phase shifting function is implemented at high RF power.

To continue the description of the invention, reference is now made to FIGS. The desired active array is shown generally at 58 in the figure. A wideband antenna array including a plurality of antenna elements 60 is provided at the front end of the active array end. The number of these elements 60 is 100 for the purpose of explanation only. Although shown as elements of the flared-notch type, they may be of various well-known types suitable for this purpose. Each antenna element is arranged in a modular fashion rather than being secured in a single background, each module containing an antenna element. In this way, the antenna array can be made in any desired size by simply using as many antenna elements as are needed for the desired array.

A module array consisting of modules 64 and a cooling plate assembly 62 are provided directly behind the antenna array, and one module 64 is provided for each antenna element. Each module 64 has in front of it a corresponding element 60 from the broadband antenna array.
Physically and electrically connecting the module array and the cold plate assembly module to the antenna array module having a surface that can be matched with. A cooling plate assembly, shown separately as 65, may be, for example, a circulating refrigerant,
It can be constructed in a variety of different well known ways such as phase change material or heat pipes.

Referring now to FIGS. 8A and 8B, each antenna element is connected via a separation module 64 (generally designated as a T / R (transmit / receive) module). Each of these includes the circuit shown in FIG. In particular, the connection with the antenna element is initially made in a known manner via a duplexer 70. The duplexer 70 is a high power amplifier 72 (HP
The output radar signal from A) is connected to its associated antenna element 60 during transmission and from the same antenna element 60 to a low noise amplifier 74 (LNA) for reception. These signals are duplexing switches.
variable phase control 7 provided in series via (witch) 75
6 and variable gain control 78 connected to a common line. Thus, the amplitude and phase of each signal, when provided or received by each antenna element, can be separately controlled with respect to phase and amplitude. During transmission, the phase and gain control is performed before the high power amplifier, so the phase and gain control is performed with low power and can be achieved with low loss.

The rear of each module in the module array and cold plate assembly 62 receives RF and logic control signals from the RF and logic distribution network 80.

Finally, the adaptive processing and monopulse network circuit 82 is provided from the rear side with four main blocks, namely four main modules mounted on and electrically connected to the RF and logic control distribution network 80. In addition to making the desired electrical connections, the cold plate assembly 60 cools the backside components of the modular radar missile searcher of the present invention, namely the RF and logic distributed network network 80 and the monopulse network circuit 82.

Again referring to FIG. 7 and simultaneously FIGS. 8 (A) and 8
In (B), each T / R module 64 according to the preferred embodiment is provided in a complete unitary assembly, which has all the necessary functions and generally has a rectangular prism shape. Various functional blocks, that is, limiters, high power amplifiers, low noise amplifiers, phase and gain adjustments, interface circuits, etc. are provided in each module (that is, provided along the direction from the antenna to the circuit 82) and the assembly housing. It is arranged over a depth of 84 (FIG. 8B). Fixed cooling plate 6
6 is secured on the back surface of each module 64.

An alternative embodiment of the modular construction results from a plurality of wafer modules being sandwiched together. Each wafer has a predetermined number of identical and separated functional block elements (ie, limiters, low noise amplifiers) arranged in a matrix pattern. The wafers are connected to each other by providing the required number of connecting means on the major surface of each wafer. The cooling plate may be the same as that used in the first embodiment.

In the modular construction of each embodiment, the horizontal size is basically the same as the spacing between the antenna elements 60 as in the spacing between the modules of the first embodiment and between adjacent identical functional blocks of the second embodiment. It is important to be decided on. By correlating module size with antenna element spacing, modular arrays can be directly incorporated into the base of the antenna array one by one.

Direct Comparison of the Present Invention with the Prior Art The present invention provides numerous advantages not available with known systems. These advantages are (1) an inexpensive modular method to realize the searcher power aperture product, (2)
Broadband, which provides integrated active / passive (ARH) guidance, (3) so-called standoff jamming (SO)
Adaptive beamforming to enhance searcher guidance in the presence of Js: stand-off jammers, (4) Enhanced guidance to swarm targets, (5) Searcher-based fusion, ie guidance and fusion Including functionality into a single searcher, and (6) improved reliability and high performance degradation due to functional redundancy and real-time conformance compensation for bad elements in the array.

1. Modular Configuration In conventional radar searchers, the antenna design must be individually designed for a particular application considering factors such as center frequency, frequency band, and aperture size. The present invention comprises each active transmit / receive module, each module comprising a transmit element and a sensing radar receive element. These basic building blocks are joined together to form arrays of any size without undue cost. The cost of any type of radar missile searcher is substantially reduced because the basic components are made of modular components and the system fabrication simply requires the assembly of a certain number of modules and does not require a complete custom design. As a further result of the modular structure, the cost of recurrence or non-recurrence with each new searcher development is reduced.

Furthermore, the use of T / R modules as building blocks provides a modular method of achieving increased power aperture products. For AESA, increasing array size increases transmitter power and antenna gain at the same time. Current technology involves design efforts towards the development of high power transmitters and / or large antennas due to the significant increase in power aperture product.

2. Broadband Integrated Active / Passive (ARH) Induction Current Planar Array Antenna and Traveling Wave Tube (TW)
T) The transmitter is highly tuned to a specific frequency. Even for a relatively common band of a few percent, current systems suffer significant performance degradation at the extremes of the system's operating band frequency. On the other hand, wide band characteristics are a feature of the basic design of the active transmit / receive (T / R) of the present invention, and they can operate over an operating band of several tens of percent wide. The preferred embodiment benefits from this inherent wide bandwidth. This ability to operate in a relatively wide band elicits passive inductive information about the radiation used for protection purposes, which is generally operating in the corresponding wide band frequency range.

In addition, the wideband nature of the preferred embodiment provides enhanced performance in mobility planning in the environment of multiple missiles or high radio frequency interference RFI in flight at the same time. The wide operating bandwidth also allows for some similar electronics (E
CM) provides higher performance. Operating the ECM device in a wide band tends to dilute the jamming power in the missile search receiver.

3. Adaptive beamforming for enhanced search guidance in the presence of distant obstructions (SOJs) Traditional gimbals Many alternatives have fixed antenna sideband response, which is different from the various counter defense techniques available. Cannot be modified in real time. One prior art solution to this problem is to adjust the geometry of the missiles by adjusting their geometry relative to the sources of interference and placing them within the nulls of the antenna. However, this treatment often reduces overall missile performance. On the other hand, in the preferred embodiment, the gain and phase of each element of the active array can be adjusted, and the off-a
xis) Remove disturbances from distant obstacles. All this can be accomplished without changing the flight path of the missile. The reduced interference increases the success induction rate for the desired target.

4. Improved Guidance for Swarming Targets Conventional gimbal-supported searchers have limited performance for swarming targets, and antenna arrays typically have four antennas.
It is divided into four quadrants, and each quadrant is combined together and processed, or processed separately. The largest of the three targets is successfully judged in this way. On the other hand, in the preferred embodiment, the array is divided into a plurality of sub-arrays, which may be provided with appropriate signal processing to achieve improved guidance for a particular target located within the swarm of targets. The number of sub-arrays, which is determined by the size of the array and the complexity of the supply network, can theoretically be any size within the packaging constraints required for signal processing. The separate transmit and receive capabilities and phase and gain control of each antenna element allows the searcher to determine signals received from multiple independent targets. Moreover, by utilizing modern signal processing techniques, decision making is not dependent on feedback coming from relatively large size targets.

5. In the case of conventional gimbal support arrays that combine searcher-based fusion, guidance and fusion functions into a single searcher, it is virtually impossible to incorporate the fusion and guidance functions into a single searcher. The limiting factors are the blind spot range of the high-power searcher, the limitation of the operating band, and the inability to determine the optimum explosion point by positioning the beam at a rate consistent with the attempt to manipulate the target. . In the present invention, the same missile radar used to direct and track a target can be used to collect the data needed to calculate the optimum explosion point for a missile warhead. The unique features of the active T / R design that enable the fusion function to be combined with the radar searcher are the T / Rs that support the waveform with a small blind spot range (short recovery time after transmission).
The module has a high bandwidth, which allows the target size to be accurately measured, and is an agile operation that directs the searcher beam to determine the target size.

6. Improved Reliability and Excellent Deterioration of Unnecessary Rate Comparing FIGS. 1 and 7, it can be seen that the use of the present invention in place of a conventional gimbal-supported pedestal system results in a significant hardware reduction. More specifically, FIG.
As shown in FIG. 6, the equipment particularly required for the conventional missile searcher having a gimbal antenna is indicated by the shaded reference numeral 86.
It is an item arranged in the functional block of. Compared to FIG. 9, the gimbal torque motor, servo electric circuit, and other mechanical components necessary for the operation of this conventional system have been removed, and the parts are lightweight and relatively inexpensive electronic components and 8
It is occupied by the circuit indicated by the dotted line 8 in FIG. In both cases, the remaining circuit parts (ie, parts other than 86 and 88) are the same for the gimbal support and the present invention.

In conventional gimbaled support arrays, guided missiles are unable to successfully accomplish their mission due to one of the many performance demanding components failing.
Since the AESA is generally composed of more than 100 identical active modular elements, the overall performance degradation due to any one element is prevented. The reliability of the searcher system is improved because each element is basically highly reliable and the failure of one element can be compensated for by adjusting the gain and phase of the element most adjacent to that element. Sex is further enhanced. This feature provides a very effective defect rate reduction.

Further, in conventional high power gimbal supported searchers using traveling wave tube (TWT) technology, the searcher is typically pressurized to prevent transmitter arcs and subsequent catastrophic failures. Need to In this case, a poor seal results in a missile finder failure, and thus the missile is unable to accomplish its mission. In the modular system described above, each T / R module has a low peak power, so no pressurization is needed to prevent arcing. Active T / R modular technology has a TWT of about 10,
It operates at a much lower voltage than it does at 000 volts. In such a high voltage operation of TWT, an extremely advanced manufacturing technique is required so that a power supply failure does not occur.

Although the present invention has been described in terms of a preferred embodiment, those skilled in the art will be able to make various modifications to the present invention within the scope of the above description and claims.

[Brief description of drawings]

FIG. 1 is a development view of a general antenna assembly having a conventional array and a servo drive device.

FIG. 2 is a graph of antenna gains received along boresight and located on each boresight side.

FIG. 3 is a schematic functional block diagram showing various devices required for a general slotted array antenna missile radar searcher.

FIG. 4 is a schematic functional block diagram showing various devices required for a general passive ESA missile radar searcher.

FIG. 5 is a schematic functional block diagram showing various devices required for a missile radar searcher of a general hybrid ESA.

6 is a diagram showing a configuration of the low noise amplifier of FIG.

FIG. 7 is a development view of an active array searcher according to the present invention.

FIG. 8 is a functional block diagram of an active array according to the present invention.

FIG. 9 is a schematic diagram of a search device according to the present invention.

[Explanation of symbols]

 12 ... Antenna array 14 ... Antenna element 16 ... Connection part and electronic circuit 18 ... Antenna assembly 20 ... Gimbal support pedestal 22 ... Sabo mechanism drive part 24 ... Control and drive electronic circuit 26 ... RF processor 60 ... Antenna element 62 ... Module array and Cooling plate assembly 64 ... Module 66 ... Cooling plate 80 ... RF and logic distributed network 82 ... Compatibility processing and monopulse network circuit

Front Page Continuation (72) Inventor Robert El Tomanek, California 91307, USA, West Hills, Jarrad Way 23681 (72) Inventor Timothy El Boland United States, California 93010, Camarillo, San Miguel・ Drive 152

Claims (10)

[Claims] 1. A plurality of antenna elements having a common transmission / reception direction and arranged in one plane, and antenna modular transmission / reception circuit means provided in each antenna element and connected to one plane of the antenna element. An active antenna array comprising: 2. The active antenna array according to claim 1, wherein each of the modular circuit means includes a separating means for separating a radar signal transmitted and received by the antenna element. 3. Each module circuit means comprises a plurality of wafers, each wafer including a plurality of identical functional block circuits arranged in a single matrix, the functional block circuits for different wafers having selectively different structures. 3. The plurality of wafers are respectively connected to one functional block circuit of each wafer, and are linearly arranged with respect to one functional block circuit of an adjacent one wafer. Active antenna array. 4. The modular transmission / reception circuit means includes:
The active antenna array according to claim 1, further comprising means for absorbing heat. 5. An active antenna array with variable transmit power and variable antenna gain, which achieves a predetermined power and antenna gain, and a predetermined number of modular antenna elements arranged at regular intervals, physical and electrical. Each connected to one antenna element,
An active antenna array comprising: a plurality of transmitting / receiving circuit modules having the same configuration; and cooling plate means physically connected to the circuit module to form a unit configuration of the circuit module and the antenna element. 6. The active antenna array according to claim 5, wherein each of the circuit modules includes a rectangular prism-shaped housing that houses each of the transmission / reception circuits of the connected antenna elements. 7. The active antenna array according to claim 6, wherein the circuit modules have the same configuration. 8. The active antenna array according to claim 5, wherein each of the circuit modules can adjust a phase and a gain separately. 9. The active antenna array according to claim 8, wherein each of the circuit modules is secured in a different antenna element. 10. Each circuit module includes a duplexer, the duplexer being connected to an antenna element,
The interconnection from the antenna element to a high power amplifier and a low noise amplifier is performed, and the high power amplifier and the low noise amplifier are respectively connected to a variable phase control unit and a variable gain control unit connected in series. Active antenna array.