KR102598885B1 - Space surveillance radar for transmitting and receiving wideband signal by using phase array antenna - Google Patents

Abstract

The present invention is a space surveillance radar that monitors space and identifies space objects, and includes an antenna having a plurality of antenna elements; a transmitter for transmitting transmission signals while steering a beam through the antenna; a receiver for processing received signals received through the antenna; A delay device for generating a time delay between transmission signals to be transmitted by the transmitter and a delay device for generating a time delay between received signals processed by the receiver in accordance with the time delay between the transmission signals, including a wide band, By compensating for time delays that occur while using signals, signals can be processed stably.

Description

Phased array-based space surveillance radar for transmitting and receiving wideband signals {SPACE SURVEILLANCE RADAR FOR TRANSMITTING AND RECEIVING WIDEBAND SIGNAL BY USING PHASE ARRAY ANTENNA}

The present invention relates to a space surveillance radar, and more specifically, to a phased array-based space surveillance radar that can stably process signals by compensating for the time delay that occurs while using a broadband signal in a very large space surveillance radar.

In general, space objects such as satellites, rockets, space debris, meteorites, and asteroids are flying in space. Therefore, technologies are being developed to search for meteorites and asteroids for astronomical research purposes, or to search for and track enemy satellites and rockets for military purposes.

Previously, optical systems were developed to monitor space. The optical system includes optical equipment and drive equipment that adjusts the altitude and azimuth of the optical equipment. At this time, to increase the angle of view of the optical equipment, the size and weight increase, so the driving speed of the driving equipment slows down. Therefore, there is a problem that it is difficult to track fast-moving satellites or rockets with an optical system. Additionally, because optical equipment is affected by the weather, use may be restricted in rainy weather or at night. Accordingly, there is a problem of not being able to search or track space objects depending on the weather.

To solve the above problems, a system for monitoring space using phased array radar has recently been developed. However, during the process of beam steering with the antenna of a phased array radar, a time delay occurs between antenna elements. Therefore, there is a problem that excessive signal loss occurs.

KR 10-1584525 B

The present invention provides a space surveillance radar that can easily compensate for the time delay that occurs while using a broadband signal.

The present invention provides a space surveillance radar that can stably process signals by compensating for time delay.

The present invention is a space surveillance radar that monitors space and identifies space objects, and includes an antenna having a plurality of antenna elements; a transmitter for transmitting transmission signals while steering a beam through the antenna; a receiver for processing received signals received through the antenna; It includes a delay device for generating a time delay between transmission signals to be transmitted by the transmitter and for generating a time delay between received signals processed by the receiver in accordance with the time delay between the transmission signals.

The delay unit includes a plurality of time delay units connected in series to selectively generate a time delay between clock signals that control the operation of the transmitter and the receiver.

The delayer includes a clock signal generator for generating clock signals; a first time delay unit for generating a time delay in a first time unit between clock signals transmitted from the clock signal generator; and a second time delay unit for generating a time delay between the clock signals that have passed the first time delay unit in a second time unit shorter than the first time unit.

The delay unit further includes a third time delay unit for generating a time delay between the clock signals that have passed the second time delay unit in a third time unit shorter than the second time unit.

The first time delay unit generates a time delay at intervals of 2 nanoseconds or more and 0.5 nanoseconds or less, the second time delay unit generates a time delay at intervals of 200 picoseconds or more and 50 picoseconds or less, and the third time delay occurs. A delay occurs at intervals of 5 picoseconds or more to 1 picosecond or less.

Each of the antenna, the transmitter, and the receiver is provided in plural numbers and each is assigned channels of different frequency bands, and the delay unit is provided in plural numbers to generate a time delay for each channel.

The antenna can transmit a transmission signal in the form of circular polarization and receive a reception signal in the form of vertical polarization and horizontal polarization, respectively.

The receiver processes the received signal in the horizontal polarization form to detect a space object moving along an orbit in a first direction in space, and processes the received signal in the vertical polarization form to detect a space object moving along an orbit in the second direction. Space objects can be detected.

According to an embodiment of the present invention, time delay occurring while using a wideband signal can be easily compensated. Accordingly, signal loss due to time delay can be reduced. Therefore, signals can be processed stably from a very large space surveillance radar.

1 is a diagram showing the configuration of a space surveillance radar according to an embodiment of the present invention.
Figure 2 is a diagram showing the configuration of a transmitter and antenna according to an embodiment of the present invention.
Figure 3 is a diagram showing the configuration of a receiver and an antenna according to an embodiment of the present invention.
Figure 4 is a diagram showing the configuration of a delay device according to an embodiment of the present invention.

Hereinafter, embodiments of the present invention will be described in more detail with reference to the attached drawings. However, the present invention is not limited to the embodiments disclosed below and will be implemented in various different forms. These embodiments only serve to ensure that the disclosure of the present invention is complete and to fully convey the scope of the invention to those skilled in the art. This is provided to inform you. The drawings may be exaggerated to explain the invention in detail, and like symbols refer to like elements in the drawings.

FIG. 1 is a diagram showing the configuration of a space surveillance radar according to an embodiment of the present invention, FIG. 2 is a diagram showing the configuration of a transmitter and an antenna according to an embodiment of the present invention, and FIG. 3 is a diagram showing the configuration of a space surveillance radar according to an embodiment of the present invention. This is a diagram showing the configuration of a receiver and an antenna, and Figure 4 is a diagram showing the configuration of a delayer according to an embodiment of the present invention. In the following, a space surveillance radar according to an embodiment of the present invention will be described.

The space surveillance radar according to an embodiment of the present invention is a facility for monitoring space and identifying space objects. For example, space surveillance radar is a facility installed on the ground to search and track space objects such as satellites, rockets, space debris, meteorites, and asteroids. 1 to 4, the space surveillance radar 100 includes an antenna 110, a transmitter 120, a receiver 130, and a delayer 140.

At this time, a plurality of antennas 110, transmitters 120, and receivers 130 may be provided, and channels of different frequency bands may be assigned to each. A plurality of delayers 140 may be provided to generate a time delay for each channel. Therefore, in the process of transmitting and receiving broadband signals, the time error across the entire broadband can be improved by using the delayers 140. In addition, since a plurality of delayers 140 can be provided to generate time delay for each channel, scalability of transmission and reception channels can be secured and signal-to-noise ratio (SNR) can be improved.

The antenna 110 includes a plurality of antenna elements 111. For example, the antenna elements 111 may be arranged in a 4×2 array. The antenna 110 may transmit a transmission signal in the form of Right Hand Circular Polarization and receive a reception signal in the form of Vertical Polarization and Horizontal Polarization, respectively. However, the structure in which the antenna elements 111 provided in the antenna 110 are arranged is not limited to this and may vary.

The transmitter 120 may be connected to the antenna 110 to transmit a transmission signal. Accordingly, the transmitter 120 can transmit transmission signals while steering the beam through the antenna 110. As shown in FIG. 2, the transmitter 120 includes a transmission signal generator 121, an analog converter 122, a first transmission mixer 123, a second transmission mixer 124, a phase control unit 125, and a power amplification unit. It may include unit 126.

The transmission signal generator 121 may generate a transmission signal. For example, the transmission signal generated by the transmission signal generator 121 may be in digital form.

The analog converter 122 may be connected to receive a transmission signal from the transmission signal generator 121. The analog converter 122 may be a digital-analog converter. Accordingly, the analog converter 122 can convert the transmission signal from digital form to analog form. Additionally, the analog converter 122 may operate according to clock signals transmitted by the delay 140, which will be described later. Accordingly, while the analog converter 122 operates based on clock signals, a time delay may occur between transmission signals converted by the analog converter 122 equal to the time delay between clock signals.

The first transmission mixer 123 can be connected to receive a transmission signal from the analog converter 122. The first transmission mixer 123 can receive the first local oscillation signal LO1 and mix it with the transmission signal.

The second transmission mixer 124 may be connected to receive a transmission signal from the first transmission mixer 123. The second transmission mixer 124 may receive a second local oscillation signal (LO2) having a center frequency different from the first local oscillation signal and mix it with the transmission signal. Since the transmission signal can be modulated multiple times using the first transmission mixer 123 and the second transmission mixer 124, the transmission signal can be easily modulated into a desired high frequency band with a wide bandwidth.

The phase control unit 125 may be connected to receive a transmission signal from the second transmission mixer 124. For example, the phase control unit 125 may be provided as many times as the antenna elements 111 are provided in the antenna 110, and the phase control units 125 may be connected in parallel with the second transmission mixer 124. . The phase control unit 125 can control the phase of the antenna element 111 provided in the antenna 110 so that the received transmission signal is transmitted in a determined direction.

The power amplifier (PA) 126 may be connected to receive a transmission signal from the phase control unit 125. For example, the power amplifier 126 may be provided as many as the phase control units 125, and the power amplifiers 126 may be connected to each of the phase control units 125. The power amplifiers 126 can increase the transmission power of the transmission signal and transmit the transmission signal to each of the antenna elements 111 provided in the antenna 110.

The receiver 130 may be connected to receive a reception signal from the antenna 110. Accordingly, the receiver 130 can process received signals received through the antenna 110. For example, the receiver 130 processes received signals in the form of vertical polarization and horizontal polarization, respectively, to detect space objects moving along orbits in the vertical direction (or north-south direction) and horizontal direction (or east-west direction) in space. Each space object moving along its orbit can be detected. As shown in FIG. 3, the receiver 130 includes a low noise amplifier 131, a receiving mixer 132, a digital conversion unit 133, a first circular polarization forming unit 134, and a second circular polarization forming unit 135. It can be included.

The low noise amplifier (LNA) 131 may be connected to receive a reception signal from the antenna 110. For example, the low noise amplifier 131 may be provided twice as many as the number of antenna elements 111 provided in the antenna 110, and one antenna element 111 may be provided with two low noise amplifier units 131. is connected so that the reception signal in the form of vertical polarization and the reception signal in the form of horizontal polarization can be transmitted respectively. The low noise amplifier 131 can amplify the received signal while suppressing noise in the received signal.

The receiving mixer 132 may be connected to receive a received signal from the low noise amplifier 131. For example, the number of receiving mixers 132 may be as many as that of the low noise amplifying units 131, and the receiving mixers 132 may be connected to each of the low noise amplifying units 131. The receiving mixer 132 can receive a local oscillation signal (LO) and mix it with the received signal. The received signal may be converted to an intermediate frequency band or base band by the receiving mixer 132.

The digital converter 133 may be connected to receive a received signal from the receiving mixer 132. For example, the digital converter 133 may be provided as many as the receiving mixers 132, and the digital converters 133 may be connected to each of the receiving mixers 132. The digital converter 133 may be an analog-to-digital converter. Accordingly, the digital converter 133 can convert the received signal from analog form to digital form. Additionally, the digital converter 133 may operate according to clock signals transmitted by the delayer 140, which will be described later. Accordingly, while the digital converter 133 operates based on clock signals, a time delay may occur between received signals converted by the digital converter 133 equal to the time delay between clock signals.

The first circular polarization forming unit 134 may be connected to receive a reception signal from some of the digital converting units 133. In detail, the first circular polarization forming unit 134 may be connected to the digital converting units 133 that process received signals in the form of horizontal polarization among the digital converting units 133. The first circular polarization forming unit 134 may form a left-handed circular polarization from received signals in the form of horizontal polarization. Therefore, it is possible to detect a space object moving along an orbit in the first direction (or horizontal direction or east-west direction) in space using the left-turning circular polarization formed by the first circular polarization forming unit 134.

The second circular polarization forming unit 135 may be connected to receive a reception signal from another part of the digital converting units 133 that is not connected to the first circular polarizing wave forming unit 134. In detail, the second circular polarization forming unit 135 may be connected to the digital converting units 133 that process received signals in the form of vertical polarization among the digital converting units 133. The second circular polarization forming unit 135 may form a right-handed circular polarization from received signals in the form of vertical polarization. Therefore, a space object moving along an orbit in a second direction (or vertical direction or north-south direction) different from the first direction is detected in space using the right-handed circular polarization formed by the second circular polarization forming unit 135. can do.

The delayer 140 creates a time delay between the transmission signals that the transmitter 120 intends to transmit, and creates a time delay between the received signals processed by the receiver 130 according to the time delay between the transmission signals. You can. The delay 140 may be connected to transmit clock signals that control the operation of the transmitter 120 and the receiver 130, respectively. The delayer 140 may include a plurality of time delay units connected in series to selectively generate a time delay between clock signals. Accordingly, the delayer 140 can precisely control the time delay to be generated between clock signals. For example, the delay 140 may include a clock signal generator 141, a first time delay unit 142, and a second time delay unit 143, as shown in FIG. 4.

The clock signal generator 141 may generate clock signals. The clock signal may include clock pulses that occur periodically.

The first time delay unit 142 may be connected to receive clock signals from the clock signal generator 141. The first time delay unit 142 can selectively generate a time delay between clock signals transmitted from the clock signal generator 141 in first time units. For example, the first time delay unit 142 may include a programmable counter and may generate a time delay at intervals of 2 nanoseconds (ns) or more to 0.5 nanoseconds or less.

The second time delay unit 143 may be connected to receive clock signals from the first time delay unit 142. The second time delay unit 143 may selectively generate a time delay between clock signals transmitted from the first time delay unit 142 in a second time unit shorter than the first time unit. For example, the second time delay unit 143 may be provided with a tapped delay line and may generate a time delay at intervals of 200 pico seconds (ps: Pico Second) or more to 50 pico seconds or less. there is. Therefore, the first time delay unit 142 generates a time delay in units of 1 nanosecond, and the second time delay unit 143 generates a time delay in units of 100 picoseconds, thereby creating a desired time delay between clock signals. It can be generated precisely. The clock signals that have passed through the second time delay unit 143 are transmitted to the analog conversion unit 122 of the transmitter 120 or the digital conversion unit 133 of the receiver 130, and are converted into the analog conversion unit 122 and the digital conversion unit. The operation of (133) can be controlled.

At this time, the delay 140 may further include a third time delay unit 144. The third time delay unit 144 may selectively generate a time delay between clock signals transmitted from the second time delay unit 143 in a third time unit shorter than the second time unit. For example, the third time delay unit 144 may include a digital time delay element and may generate a time delay at intervals of 5 picoseconds or more to 1 picosecond or less. Therefore, a time delay of 3 picoseconds is additionally generated between the clock signals that have passed through the first time delay unit 142 and the second time delay unit 143, thereby further increasing the desired time delay between the clock signals. It can be generated precisely. When the third time delay unit 144 is provided, the clock signals passing through the third time delay unit 144 are converted to the analog conversion unit 122 of the transmitter 120 or the digital conversion unit 133 of the receiver 130. It can be transmitted to control the operations of the analog converter 122 and the digital converter 133. When the first time delay unit 142, the second time delay unit 143, and the third time delay unit 144 are provided, the value of the implemented time delay can be calculated using the formula below.

Calculation formula: t _d = n·△t ₁ + m·△t ₂ + k·△t ₃

Here, t _d is the total sum of the time delays generated by the first time delay unit, the second time delay unit, and the third time delay unit, and n is the first time delay unit to set the degree to which the first time delay unit generates the time delay. It is a natural number including 0 input to the time delay unit, △t ₁ is the first time unit, and m is 0 input to the second time delay unit to set the degree to which the second time delay unit generates time delay. is a natural number containing, △t ₂ is the second time unit, k is a natural number including 0 input to the third time delay unit to set the degree to which the third time delay unit generates time delay, and △t ₃ is the third time unit. The values of n, m, and k can be set by the operator. Therefore, since the degree of generating time delay can be precisely set in three time units, the desired time delay can be accurately generated.

Meanwhile, the process by which the space surveillance radar 100 transmits a transmission signal will be described with reference to FIGS. 1, 2, and 4. First, the transmission signal generator 121 generates digital transmission signals. Transmission signals are delivered to the analog conversion unit 122 and converted into analog form. At this time, clock signals that control the operation of the analog converter 122 may be transmitted to the analog converter 122. Clock signals may be generated in the clock signal generator 141 and transmitted to the analog converter 122 through time delay units connected in series. For example, the clock signals include a first clock signal, a second clock signal having a time delay from the first clock signal equal to the first time delay generated by the first time delay unit 142, and a second time delay unit 143. A third clock signal having a time delay from the second clock signal equal to the second time delay generated by the third clock signal, and a fourth clock signal having a time delay from the third clock signal equal to the third time delay generated from the third time delay unit 144. It may include a clock signal. Accordingly, the analog converter 122 operates based on clock signals and generates a first transmission signal, a second transmission signal having a first transmission signal and a first time delay, and a third transmission signal having a second transmission signal and a second time delay. A transmission signal and a fourth transmission signal having a third time delay from the third transmission signal may be generated. However, the time delay between clock signals is not limited to this and can be set in various ways.

Next, the transmission signals are sequentially delivered to the first transmission mixer 123 and the second transmission mixer 124 with a time delay. The first transmission mixer 123 and the second transmission mixer 124 can mix the first local oscillation signal and the second local oscillation signal with the received transmission signals, respectively, and modulate them into a high frequency band.

Next, the phase control unit 125 can control the phase of the antenna element 111 provided in the antenna 110 to set the transmission signal to be transmitted in a specified direction. Accordingly, while steering the beam, transmission signals can be sequentially transmitted through the antenna 110 according to time delay. For example, transmission signals can be sequentially transmitted into the sky while steering the beam from south to north. At this time, before transmitting the transmission signal through the antenna 110, the transmission power of the transmission signal can be increased by the power amplifier 126. Therefore, the transmission signal can be stably transmitted to distant space objects.

Meanwhile, the process by which the space surveillance radar 100 receives a reception signal will be described with reference to FIGS. 1, 3, and 4. First, received signals reflected from space objects are received by the antenna 110, and the antenna 110 can transmit the received signals to the receiver 130. In detail, each antenna element 111 of the antenna 110 may receive a received signal in the form of vertical polarization and horizontal polarization and transmit it to the receiver 130.

Next, the low noise amplifier 131 of the receiver 130 can amplify the received signal while suppressing noise in the received signal. The received signal that has passed through the low noise amplifier 131 may be mixed with the local oscillation signal in the receiving mixer 132 and converted into an intermediate frequency band or base band.

Next, the received signals are transmitted to the digital conversion unit 133 and converted into digital form. At this time, clock signals that control the operation of the digital conversion unit 133 may be transmitted to the digital conversion unit 133. Clock signals may be generated in the clock signal generator 141 and transmitted to the digital converter 133 through time delay units connected in series. For example, clock signals matched to the clock signals transmitted to the analog converter 122 may be transmitted to the digital converter 133. Accordingly, while the digital converter 133 operates based on clock signals, it can differentially generate time delays according to the order in which the received signals are received in accordance with the time delays that occur between transmitted signals. In other words, a time delay may occur between received signals in accordance with the time delay generated between transmitted signals. However, the time delay between clock signals is not limited to this and can be set in various ways.

Next, the received signals in the form of horizontal polarization are received from the first circular polarization forming unit 134 to form a left-handed circular polarization, and the receiving signals in the form of vertical polarization are received from the second circular polarization forming unit 135. Circular polarization can be formed. Therefore, using left-handed circular polarization, a space object moving along an orbit in the first direction (or horizontal or east-west direction) in space is detected, and using right-handed circular polarization to detect space objects moving in the second direction (or, It can detect space objects moving along an orbit (vertical or north-south direction). Accordingly, space objects moving along orbits in various directions can be easily detected and tracked.

In this way, the time delay that occurs when using a wideband signal can be easily compensated for by precisely generating a time delay between the transmission signals and by generating a time delay in the reception signals according to the time delay between the transmission signals. Therefore, signal loss due to time delay can be reduced. Accordingly, signals can be processed stably from a very large space surveillance radar.

As such, in the detailed description of the present invention, specific embodiments have been described, but various modifications are possible without departing from the scope of the present invention, and various combinations between the embodiments are also possible. Therefore, the scope of the present invention should not be limited to the described embodiments, but should be determined by the claims described below as well as equivalents to these claims.

100: Space surveillance radar 110: Antenna
120: Transmitter 130: Receiver
140: delayer 141: clock signal generator
142: first time delay unit 143: second time delay unit
144: Third time delay unit

Claims (8)

As a space surveillance radar that monitors space and identifies space objects,
An antenna having a plurality of antenna elements;
a transmitter for transmitting transmission signals while steering a beam through the antenna;
a receiver for processing received signals received through the antenna;
A delay device for generating a time delay between transmission signals to be transmitted by the transmitter, and a delay device for generating a time delay between received signals processed by the receiver in accordance with the time delay between the transmission signals,
The antenna, the transmitter, and the receiver each have a plurality and are respectively assigned channels of different frequency bands,
The delay device is a space surveillance radar provided with a plurality of delay devices to generate a time delay for each channel. In claim 1,
The delay period is,
A space surveillance radar including a plurality of time delay units connected in series to selectively generate a time delay between clock signals that control the operation of the transmitter and the receiver. In claim 2,
The delay period is,
A clock signal generator for generating clock signals;
a first time delay unit for generating a time delay in a first time unit between clock signals transmitted from the clock signal generator; and
A space surveillance radar including a second time delay unit for generating a time delay between the clock signals that have passed the first time delay unit in a second time unit shorter than the first time unit. In claim 3,
The delay period is,
The space surveillance radar further includes a third time delay unit for generating a time delay in a third time unit shorter than the second time unit between the clock signals that have passed the second time delay unit. In claim 4,
The first time delay unit generates a time delay at intervals of 2 nanoseconds or more and 0.5 nanoseconds or less, the second time delay unit generates a time delay at intervals of 200 picoseconds or more and 50 picoseconds or less, and the third time delay occurs. It is a space surveillance radar that generates time delays at intervals of 5 picoseconds or more to 1 picosecond or less. delete The method according to any one of claims 1 to 5,
The antenna is,
It is a space surveillance radar that can transmit signals in the form of circular polarization and receive signals in the form of vertical and horizontal polarization, respectively. In claim 7,
The receiver is,
The reception signal in the horizontal polarization form is processed to detect a space object moving along an orbit in a first direction in space, and the vertical polarization form reception signal is processed to follow an orbit in a second direction different from the first direction. A space surveillance radar that can detect moving space objects.

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