KR20210073130A - Beamforming test device based on live signal - Google Patents

Abstract

The present invention relates to an indoor beamforming test device based on a live signal to form an indoor test environment by using a global navigation satellite system (GNSS) signal. According to embodiments of the present invention, the indoor beamforming test device comprises: an anechoic chamber shielding electromagnetic waves in a specific frequency range; an internal GNSS antenna unit having a plurality of internal GNSS antennas forming a celestial coordinate system arranged in the anechoic chamber to generate internal GNSS signals; an external GNSS transceiver installed outside the anechoic chamber and receiving external GNSS signals from a plurality of satellites to map the received external GNSS signals to the plurality of internal GNSS antennas; and an anti-jamming receiver receiving the plurality of internal GNSS signals from the corresponding internal GNSS antennas to perform a GNSS test.

Description

Live signal-based indoor beamforming test device {BEAMFORMING TEST DEVICE BASED ON LIVE SIGNAL}

The present invention relates to a live signal-based indoor beamforming test apparatus, and more particularly, transmits a GNSS signal input from an external GNSS (Global Navigation Satellite System) transceiver to an internal GNSS antenna to perform a beamforming test indoors. It relates to a live signal-based indoor beamforming test apparatus that performs.

GNSS (Global Navigation Satellite System), developed for military purposes, is being used in various fields such as manned/unmanned aerial vehicles, drones, and automobiles. The GNSS signal transmitted from an altitude of about 20,000 km from the Earth has very low signal power, so it is vulnerable to radio interference, and if it is covered by a building or other obstacle or combined with a signal from another path, the receiver will show abnormal behavior or may lose navigation. It can be difficult to do right.

Indoor use of GNSS was almost impossible. Since it receives a signal from a satellite, the signal strength is very low, and the signal is cut off indoors, especially by windows, walls, or structures.

Beamforming is a technology that uses an array antenna to adjust the magnitude and phase of each device signal to create a beam in the direction of the satellite. This technology has been mainly used in radar. When an array antenna is used, since the beam is formed in the direction of the satellite, a gain equal to the number of antennas is obtained, which has various advantages such as signal-to-noise ratio, anti-jamming performance, and signal sensitivity improvement. However, due to the increase in the number of antennas, there are disadvantages in that hardware complexity and cost increase, such as an increase in the number of RF (Radio Frequency) components and an increase in the amount of required computation.

Registered Patent No. 10-0421802 (April 24, 2000)

An embodiment of the present invention is to provide a live signal-based indoor beamforming test apparatus capable of creating an indoor test environment using a GNSS signal.

An embodiment of the present invention is to provide an indoor beamforming test apparatus based on a live signal that receives external GNSS signals and retransmits them over a predetermined time so that an external GNSS transceiver can perform a deception test.

An embodiment of the present invention is to provide a live signal-based indoor beamforming test apparatus capable of arbitrarily classifying and changing the phase of an external GNSS transceiver outside an anechoic chamber to enable deception testing of external GNSS signals.

An embodiment of the present invention is to provide an indoor beamforming anti-jamming test apparatus based on a live signal that can create an environment similar to the outside including a jammer inside and create an indoor test environment using a real-time GNSS signal do.

In embodiments, an anechoic chamber for shielding electromagnetic waves in a specific frequency band, and an internal GNSS antenna for generating internal GNSS signals by arranging a plurality of internal Global Navigation Satellite System (GNSS) antennas forming a celestial coordinate system inside the anechoic chamber part, an external GNSS transceiver installed outside the anechoic chamber and receiving external GNSS signals from a plurality of satellites and mapping the plurality of internal GNSS antennas to the plurality of internal GNSS signals corresponding to the plurality of internal GNSS signals and an anti-jamming receiver for receiving from internal GNSS antennas and performing GNSS testing.

Among embodiments, a jammer for transmitting a jamming signal generated by an external jamming signal generator may be included therein.

The external GNSS transceiver performs navigation with the C/A code of the GPS carrier of the L1 band or the C/A code of the GLONASS carrier among the external GNSS signals with respect to the external GNSS signals, and the time delay for each satellite calculated therefrom Among the external GNSS signals, the C/A code, P(Y) code, M code, and C/A code and P(Y) code band signals of the GPS carrier outside the L1 band can be retransmitted. .

The external GNSS transceiver may determine the positions of the plurality of satellites on the celestial coordinate system by analyzing an identification (ID) code for each frequency for each of the external GNSS signals.

The external GNSS transceiver may provide celestial coordinate codes for positions of the plurality of satellites to the internal GNSS antenna.

The internal GNSS antenna unit may determine signal transmission antennas among the plurality of internal GNSS antennas based on the celestial coordinate codes.

The external GNSS transceiver may arbitrarily classify and change the phase of the external GNSS signal so that a deception test is possible.

The anti-jamming receiver may convert the internal GNSS signal into a digital signal after passing it through a band pass filter determined according to the type of carrier.

The disclosed technology may have the following effects. However, this does not mean that a specific embodiment should include all of the following effects or only the following effects, so the scope of the disclosed technology should not be construed as being limited thereby.

The live signal-based indoor beamforming test apparatus according to an embodiment of the present invention may create an indoor test environment using a GNSS signal.

In the live signal-based indoor beamforming test apparatus according to an embodiment of the present invention, the external GNSS transceiver navigates the external GNSS signals and retransmits them at a predetermined time to enable a deception test.

The live signal-based indoor beamforming test apparatus according to an embodiment of the present invention may arbitrarily classify each external GNSS signal and change the phase to enable a GNSS deception test.

The live signal-based indoor beamforming test apparatus according to an embodiment of the present invention can create an indoor test environment using a real-time GNSS signal by creating an environment similar to the outside including a jammer inside.

1 is a view for explaining a live signal-based indoor beamforming test apparatus according to an embodiment of the present invention.
FIG. 2 is a view for explaining a functional configuration of an external GNSS transceiver in FIG. 1 .
FIG. 3 is a view for explaining a functional configuration of the internal GNSS antenna unit of FIG. 1 .
FIG. 4 is a view for explaining indoor coverage of an anechoic chamber of the internal GNSS antenna in FIG. 1 .
FIG. 5 is a flowchart illustrating a test process performed in the live signal-based indoor beamforming test apparatus of FIG. 1 .
6A and 6B are diagrams for explaining the sensitivity of the external GNSS transceiver by the input antenna selection unit.

Since the description of the present invention is merely an embodiment for structural or functional description, the scope of the present invention should not be construed as being limited by the embodiment described in the text. That is, since the embodiment may have various changes and may have various forms, it should be understood that the scope of the present invention includes equivalents capable of realizing the technical idea. In addition, since the object or effect presented in the present invention does not mean that a specific embodiment should include all of them or only such effects, it should not be understood that the scope of the present invention is limited thereby.

On the other hand, the meaning of the terms described in the present application should be understood as follows.

Terms such as “first” and “second” are for distinguishing one component from another, and the scope of rights should not be limited by these terms. For example, a first component may be termed a second component, and similarly, a second component may also be termed a first component.

When a component is referred to as being “connected to” another component, it should be understood that the component may be directly connected to the other component, but other components may exist in between. On the other hand, when it is mentioned that a certain element is "directly connected" to another element, it should be understood that the other element does not exist in the middle. Meanwhile, other expressions describing the relationship between elements, that is, “between” and “immediately between” or “neighboring to” and “directly adjacent to”, etc., should be interpreted similarly.

The singular expression is to be understood to include the plural expression unless the context clearly dictates otherwise, and terms such as "comprises" or "have" refer to the embodied feature, number, step, action, component, part or these It is intended to indicate that a combination exists, and it should be understood that it does not preclude the possibility of the existence or addition of one or more other features or numbers, steps, operations, components, parts, or combinations thereof.

All terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs, unless otherwise defined. Terms defined in general used in the dictionary should be interpreted as being consistent with the meaning in the context of the related art, and cannot be interpreted as having an ideal or excessively formal meaning unless explicitly defined in the present application.

1 is a view for explaining a live signal-based indoor beamforming test apparatus 100 according to an embodiment of the present invention.

Referring to FIG. 1 , a live signal-based indoor beamforming test apparatus 100 according to an embodiment includes an anechoic chamber 110 , an external Global Navigation Satellite System (GNSS) transceiver 130 , and an internal GNSS antenna unit 120 . ), an anti-jamming receiver 140 , a jamming signal generator 150 and a jammer 160 .

The anechoic chamber 110 may shield electromagnetic waves in a specific frequency range. For example, the anechoic chamber 110 may prevent a GNSS signal from the outside of the anechoic chamber 110 from being introduced into the anechoic chamber 110 and may shield not only the external GNSS signal but also other electromagnetic waves. In another embodiment, the anechoic chamber 110 may prevent internal GNSS signals from being reflected therein.

인 위치에 단일 GNSS 위성(170a)가 위치한다.The internal GNSS antenna unit 120 may generate internal GNSS signals by disposing a plurality of internal GNSS antennas in the anechoic chamber 110 . A plurality of internal GNSS antennas form a celestial coordinate system. The celestial coordinate system is a coordinate system that indicates the position of a satellite in astronomy. For example, if a single GNSS satellite 170a has an elevation of 30 degrees and an azimuth of 30 degrees, in [Figure 1]

A single GNSS satellite 170a is located at the in position.

[Figure 1]

In an embodiment, the internal GNSS antenna unit 120 may determine GNSS signal transmission antennas among a plurality of internal GNSS antennas based on celestial coordinate codes. For example, the internal GNSS antenna 120a selects an internal transmit antenna based on the ID (Identification) of the external GNSS signal for the digital IF (Intermediate Frequency) signal input from the external GNSS transceiver 130 and selects the RF (Radio Frequency) signal. ) signal, it can be converted into an internal GNSS signal and transmitted. The details of this will be described with reference to FIG. 4 .

The external GNSS transceiver 130 may be installed outside the anechoic chamber 110 and may receive external GNSS signals from a plurality of satellites and map the external GNSS signals to the plurality of internal GNSS antennas. For example, the external GNSS transceiver 130 receives the RF signal from the GNSS satellite 170 , passes through a band filter to transmit the signal to the internal GNSS antenna unit 120 , and converts an analog signal to a digital (Digital) signal. ) signal, and a signal weighted for beam steering and interference cancellation may be transmitted as the beam output signal 240 .

In one embodiment, the external GNSS transceiver 130 performs navigation with the C/A code of the GPS carrier of the L1 band or the C/A code of the GLONASS carrier among the external GNSS signals with respect to the external GNSS signals, and from Using the calculated constant time delay, the C/A code, P(Y) code, M code, and C/A code and P(Y) code of the GPS carrier outside the L1 band among the external GNSS signals are retransmitted. can do. For example, the external GNSS transceiver 130 may perform navigation by receiving a carrier wave from the GNSS satellite 170 of the L1 band, and calculate a time delay between the satellites therefrom, and GNSS in a band other than the L1 band of the satellite. The time delay calculated from the carrier signal, such as the C/A code, P(Y) code, M code of the GPS L2 carrier, and the C/A code and P(Y) code of the carrier of the GLONASS L2 band, with the L1 band signal of the satellite By applying and retransmitting , the meaconing technique, a kind of deception test, can be performed.

In an embodiment, the external GNSS transceiver 130 may include a band pass filter for controlling the influence of disturbance from being introduced into the room. For example, the external GNSS transceiver 130 passes only frequencies around 1575.42 MHz in the case of the L1 carrier of the GPS (Global Positioning System) by using the Band-Pass-Filter of the RF unit 220 . and high-frequency regions, where noise is easy to enter, may not pass.

In another embodiment, the external GNSS transceiver 130 may perform front-end filtering. The front-end filtering uses a band filter with a sharp cut-up characteristic that suppresses jamming signals other than the satellite navigation signal band and passes only the satellite navigation signal. For example, the RF unit 320 of the external GNSS transceiver 130 may use a band pass filter as a band filter having a sharp cut-up characteristic. A band filter having a sharp cut-up characteristic is concerned about insertion loss. If a cavity filter is used, the insertion loss can be reduced and the stop-band signal of the band filter can be strongly suppressed. In addition, the external GNSS transceiver 130 may perform frequency down-conversion at the filter stage. When the frequency down-conversion is performed, a narrowband filtering effect can be expected, and filtering before and after a local oscillator can be performed. Narrowband filtering at the down-conversion stage suppresses out-of-band jamming signals to improve reception performance, and reduces Nyquist through IF and A/D (Analog to Digital) conversion. ) Enables sample signal processing.

In an embodiment, the external GNSS transceiver 130 may determine the positions of the plurality of satellites on the celestial coordinate system by analyzing the ID codes for each frequency for each of the external GNSS signals. Even in the same frequency band, an external GNSS signal can be received based on a CDMA (Code Division Multi Access) method. For example, the external GNSS transceiver 130 has information of a Gold Code consisting of 1023 bits of a GPS satellite, and when an external GNSS signal is input, the position of the satellite is determined based on the information of the Gold code carried on the carrier. can decide

In an embodiment, the external GNSS transceiver 130 may provide celestial coordinate codes for positions of a plurality of satellites to the internal GNSS antenna unit 120 . For example, the external GNSS transceiver 130 may provide information of the Gold code of the GPS satellite to the internal GNSS antenna unit 120 , and the internal GNSS antenna unit 120 receives from the external GNSS transceiver 130 . An internal antenna may be determined based on the antenna selection command 340 based on information of one Gold code.

The external GNSS transceiver 130 may arbitrarily classify each of the external GNSS signals so that a deception test is possible and change the phase. For example, the external GNSS transceiver 130 may cause the anti-jamming receiver 140 to mistake an incorrect location for its current location by opening the satellite navigation information, manipulating the internal information with other information and re-emitting it.

In an embodiment, the external GNSS transceiver 130 may steer a signal in a similar direction when receiving an external GNSS signal from a similar direction or when satellite signal information obtained from external information is in a similar direction. For example, when the external GNSS transceiver 130 receives a plurality of signals from a plurality of similar-direction GNSS satellites 170b, the beam-former 230 combines a plurality of signals in a similar direction into one in the anechoic chamber 110. It can be transmitted to the internal internal GNSS antenna unit 120 .

In one embodiment, the external GNSS transceiver 130 includes an array antenna unit, an RF unit, a beamforming unit, an input antenna selection unit, and a beam steering and interference cancellation weight generation unit, and the RF unit receives digital IF ( Intermediate Frequency) signal. This will be described in more detail with reference to FIG. 2 .

The anti-jamming receiver 140 may perform GNSS testing by receiving a plurality of internal GNSS signals from corresponding internal GNSS antennas. For example, the anti-jamming receiver 140 is configured as an array antenna to receive signals from multiple directions indoors and outdoors in the same direction, and performs beamforming in the corresponding direction to improve signal-to-noise ratio performance.

The jamming signal generator 150 is a device for generating a waveform that is an electronic signal. For example, the jamming signal generator 150 may generate a continuous signal and may generate a sine wave, a square wave, a triangle wave, a pulse wave, a ramp wave, and may generate a frequency/period, amplitude magnitude, phase/delay, initial DC ( Direct Current) value can be adjusted. Also, the jamming signal generator 150 may generate an analog signal, a digital signal, an ideal signal, a distorted signal, a standard signal, and a user-defined signal. Also, the jamming signal generator 150 may generate a signal of an additive white Gaussian noise (AWGN) channel.

The jammer 160 may receive a jamming signal from the jamming signal generator 150 and transmit the jamming signal to the inside of the anechoic chamber 110 .

FIG. 2 is a view for explaining a functional configuration of the external GNSS transceiver 130 in FIG. 1 .

2, the external GNSS transceiver 130 includes an array antenna 210, an RF unit 220, a beam former 230, an input antenna selection unit 250, and a beam steering and interference cancellation weight generation unit ( 260) may be included.

The array antenna 210 is a kind of input unit and performs a function of receiving an external GNSS signal.

The RF unit 220 processes the RF signal received by the array antenna 210 into a digital IF signal. The RF unit 220 may pass only the external GNSS signal and remove noise based on the frequency band of the external GNSS signal received using a band-pass filter. For example, the RF unit 220 may be set to pass only a band around 1227.6 MHz when an indoor experiment is performed on the L2 carrier of the GPS.

The RF unit 220 may amplify the processed signal using a bandpass filter using an amplifier to minimize noise. For example, the RF unit 220 converts the weak RF signal input to the array antenna 210 into a digital signal using a low noise amplifier, and can amplify the signal by minimizing noise. have.

The RF unit 220 may transform the amplified signal into an IF signal using a mixer. In addition, the RF unit 220 may perform a pre-processing process of converting the converted IF signal into a digital signal using an analog-to-digital converter.

The input antenna selection unit 250 may select the number of antennas arranged in the external GNSS transceiver 130 . When the number of array antenna selections increases, the sensitivity of the external GNSS transceiver 130 increases as shown in FIG. 6B . For example, the input antenna selector 250 may arbitrarily adjust the number of array antennas selected according to the nature of the beamforming test.

The beam steering and interference cancellation weight generation unit 260 may combine external GNSS signals according to the input antenna selection of the input antenna selection unit 250 and may perform anti-jamming through generation of weights. For example, the beam steering and interference cancellation weight generator 260 uses a Minimum Variance Distortionless Response (MVDR) algorithm to maintain a constant gain with respect to an external GNSS signal incident from a specific direction while maintaining a constant gain with respect to an external signal in another direction. By giving a small weight (nulling), it is possible to increase the signal to noise ratio (SNR) while minimizing the output power of the array.

FIG. 3 is a view for explaining a functional configuration of the internal GNSS antenna unit 120 in FIG. 1 .

Referring to FIG. 3 , the internal GNSS antenna unit 120 may include a transmit antenna selection unit 310 , an IF/RF unit 320 , and a transmit amplifier 330 .

The transmit antenna selector 310 receives the beam output signal 240 from the external GNSS transmit/receive unit 130 and determines a transmit antenna according to the antenna selection command 340 according to the indoor test configuration.

The IF/RF unit 320 converts the IF signal into an analog signal using a digital-to-analog converter and converts it into an RF signal using a bandpass filter and a mixer.

The transmit amplifier 330 may adjust the signal output level from the IF/RF unit 320 . For example, the transmit amplifier 330 may be configured as a power amplifier, and a gain value may be adjusted according to the configuration of the anechoic chamber 110 and the number of internal GNSS antenna units 120 .

FIG. 4 is a view for explaining indoor coverage of the anechoic chamber 110 of the transmitting antenna in FIG. 1 .

A7 transmission antenna coverage 410 covers the range of 45 to 90 degrees in azimuth and 0 to 30 degrees in elevation. For example, the A7 transmitting antenna transmits the input received from the external GNSS transceiver 130 when the satellite direction is 70 degrees in azimuth and 10 degrees in embossing.

FIG. 5 is a flowchart illustrating a test process performed in the live signal-based indoor beamforming test apparatus 100 of FIG. 1 .

Referring to FIG. 5 , the testing process of the live signal-based indoor beamforming test apparatus 100 includes receiving external GNSS signals from a plurality of satellites outside the anechoic chamber that shields electromagnetic waves in a specific frequency band (S510), Changing the external GNSS signal into a digital IF signal having at least one number in the RF unit (S520), the digital IF signal is output as one beam output signal through the beam forming unit (S530), the beam output signal is anechoic The step of being input to the internal GNSS antenna unit inside the chamber (S540), the internal GNSS antenna unit converting the digital IF signal into an RF signal based on the satellite direction information according to the real-time GNSS signal and transmitting it (S550) and the internal GNSS signals It may include receiving from the corresponding internal GNSS antennas (S560).

Although the above has been described with reference to preferred embodiments of the present invention, those skilled in the art can variously modify and change the present invention within the scope without departing from the spirit and scope of the present invention as set forth in the claims below. You will understand that it can be done.

100: Live signal-based indoor beamforming test device
110: anechoic chamber 120: internal GNSS antenna unit
120a: internal GNSS antenna 130: external GNSS transceiver
140: anti-jamming receiver 150: jamming signal generator
160: jammer 170: GNSS satellite
170a: single GNSS satellite 170b: multiple pseudo-directional GNSS satellites
210: array antenna 220: RF unit
230: beam former 240: beam output signal
250: input antenna selection unit
260: beam steering and interference cancellation weight generation unit
310: transmit antenna selection unit 320: IF / RF unit
330: transmit amplifier 340: antenna selection command
410: A7 transmit antenna coverage
500: a test process performed in an indoor beamforming test apparatus

Claims (8)

An anechoic chamber for shielding electromagnetic waves in a specific frequency band;
an internal GNSS antenna unit for generating internal GNSS signals by disposing a plurality of internal Global Navigation Satellite System (GNSS) antennas forming a celestial coordinate system inside the anechoic chamber;
an external GNSS transceiver installed outside the anechoic chamber and receiving external GNSS signals from a plurality of satellites and mapping the external GNSS signals to the plurality of internal GNSS antennas; and
and an anti-jamming receiver configured to receive the plurality of internal GNSS signals from corresponding internal GNSS antennas and perform GNSS testing.
According to claim 1,
A live signal-based indoor beamforming test apparatus, characterized in that it includes a jammer inside for transmitting a jamming signal generated by an external jamming signal generator.
According to claim 1, wherein the external GNSS transceiver unit
The external GNSS signals are navigated with the C/A code of the GPS carrier of the L1 band or the C/A code of the GLONASS carrier among the external GNSS signals, and the external GNSS signals are transmitted using the time delay calculated therefrom. A live signal-based indoor beam characterized in that it retransmits the C/A code, P(Y) code, M code, and C/A code and P(Y) code band signals of the GLONASS carrier other than the L1 band. Foaming test device.
According to claim 1, wherein the external GNSS transceiver unit
A live signal-based indoor beamforming test apparatus, characterized in that the positions of the plurality of satellites are determined on the celestial coordinate system by analyzing ID (identification) codes for each frequency for each of the external GNSS signals.
According to claim 1, wherein the external GNSS transceiver unit
A live signal-based indoor beamforming test apparatus, characterized in that providing celestial coordinate codes for the positions of the plurality of satellites to the internal GNSS antenna unit.
According to claim 1, wherein the external GNSS transceiver unit
A live signal-based indoor beamforming test apparatus, characterized in that the external GNSS signal can be arbitrarily classified and phased to enable deception testing.
The method of claim 5, wherein the internal GNSS antenna unit
A live signal-based indoor beamforming test apparatus, characterized in that determining GNSS signal transmission antennas among the plurality of internal GNSS antennas based on the celestial coordinate codes.
The method of claim 1, wherein the anti-jamming receiver
A live signal-based indoor beamforming test apparatus, characterized in that the internal GNSS signal is passed through a band pass filter determined according to the type of carrier and then converted into a digital signal.

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