KR20140103236A - Method and apparatus for 3 dimension fmcw radar comprising multiple receiving antennas - Google Patents

Abstract

The present invention provides a three-dimensional FMCW radar method using multiple antennas. The method comprises receiving a radar return signal in fixed four receiving antennas by a target object; calculating a distance between each receiving antenna and the target object by using the received radar signal; and estimating the position of the target object by using the calculated distance and each coordinate of the receiving antenna. The position of the object is estimated by calculating the trajectory of each sphere whose radius is the calculated distance from the position of each receiving antenna to the object and using the coordinate of each receiving antenna.

Description

[0001] METHOD AND APPARATUS FOR 3 DIMENSION [0002] FMCW RADAR COMPRISING MULTIPLE RECEIVING ANTENNAS [

BACKGROUND OF THE INVENTION 1. Field of the Invention [0001] The present invention relates to a radar (Radar Detection and Ranging) for finding coordinates of a target located in a space, and more particularly, Continuous Wave RADAR ").≪ / RTI >

The existing three - dimensional radar acquires the data on the two - dimensional plane by rotating the antenna with high directivity and acquires the two - dimensional data in the same way while changing the elevation and completes the combined three - dimensional measurement. Another method is to adjust the phase of a plurality of array antennas to convert the directivity of the antenna over time to make three-dimensional measurements.

  The target is measured by placing a plurality of sensors in a space specified by the other three-dimensional measurement method, and a three-dimensional target value is obtained from each measured value. This is the case where a high-frequency signal or a laser signal is used, and a location-based service using an existing 3D sensor, a GPS (global positioning system), a mobile communication base station, and a wireless local area network (WLAN) access point (AP).

In order to implement the above-described three-dimensional radar, it is required to rotate the antenna. To this end, there is a problem that the drive unit and the physical connection of the antenna increase the cost of the antenna and shorten the service life. In addition, there is a problem in that there is a delay in the target search because the three-dimensional scan by the rotation can physically obtain the three-dimensional result after completion.

Accordingly, it is an object of the present invention to provide a method capable of implementing a three-dimensional radar while simultaneously minimizing the problems of existing three-dimensional radar by locating multiple receiving antennas in the form of a triangular pyramid in the FMCW radar and simultaneously detecting radar signals with the antenna And a device therefor.

As described above, according to the three-dimensional FMCW radar method using multiple antennas according to the embodiment disclosed herein, it is possible to acquire coordinates of a target object in three dimensions in real time without antenna rotation and beam forming algorithm There is an effect that can be done.

FIG. 1 is a layout diagram of multiple antennas embedded in a radar device according to an embodiment of the present invention.
FIG. 2 is a block diagram illustrating a structure of a three-dimensional radar using multiple antennas according to an embodiment of the present invention. Referring to FIG.
FIG. 3 shows a frequency beat signal obtained by the distance calculator of FIG. 2 according to an embodiment of the present invention .
FIG. 4 is a flowchart illustrating a three-dimensional target measurement procedure of FIG. 2 according to an embodiment of the present invention.
5 is a block diagram of a second structure of a three-dimensional radar using multiple antennas according to an embodiment of the present invention.
6 shows a frequency beat signal obtained by the distance calculator of FIG. 5 according to an embodiment of the present invention .
FIG. 7 is a flowchart illustrating a three-dimensional target measurement procedure of FIG. 5 according to an embodiment of the present invention.
FIG. 8 is a conceptual diagram for transmitting and receiving signals when a three-dimensional radar device designed according to an embodiment of the present invention is used as a terrestrial radar.
FIG. 9 shows the configuration of a bit signal reflected by two targets in FIG. 8 in a frequency spectrum.
10 is a conceptual diagram of signal transmission / reception when a radar designed according to an embodiment of the present invention is used as a ship radar.

While the invention is susceptible to various modifications and alternative forms, specific embodiments thereof are shown by way of example in the drawings and will herein be described in detail. It should be understood, however, that the invention is not intended to be limited to the particular embodiments, but includes all modifications, equivalents, and alternatives falling within the spirit and scope of the invention.

Terms including ordinals, such as first, second, etc., may be used to describe various elements, but the elements are not limited to these terms. The terms are used only for the purpose of distinguishing one component from another.

For example, without departing from the scope of the present invention, the first component may be referred to as a second component, and similarly, the second component may also be referred to as a first component. The term " and / or " includes any combination of a plurality of related listed items or any of a plurality of related listed yields.

When an element is referred to as being "connected" or "connected" to another element, it may be directly connected or connected to the other element, but other elements may be present in between. On the other hand, when an element is referred to as being "directly connected" or "directly connected" to another element, it should be understood that there are no other elements in between.

The terminology used in this application is used only to describe a specific embodiment and is not intended to limit the invention. The singular expressions include plural expressions unless the context clearly dictates otherwise. In the present application, the terms "comprises" or "having" and the like are used to specify that there is a feature, a number, a step, an operation, an element, a component or a combination thereof described in the specification, Should not be construed to preclude the presence or addition of one or more other features, integers, steps, operations, elements, parts, or combinations thereof.

Unless defined otherwise, all terms used herein, including technical or scientific terms, have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. Terms such as those defined in commonly used dictionaries are to be interpreted as having a meaning consistent with the meaning in the context of the relevant art and are to be interpreted as ideal or overly formal in the sense of the present invention Do not.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Reference will now be made in detail to the preferred embodiments of the present invention, examples of which are illustrated in the accompanying drawings, wherein like reference numerals refer to the like elements throughout. The description will be omitted.

The present invention eliminates the antenna driving circuit and the device in the conventional 3D radar, thereby reducing the price and enabling real-time detection. The configuration is such that a plurality of different bit signals are obtained by adding receive antennas which are distinguishable to the FMCW (Frequency Modulation Continuous Wave) radar radio circuit configuration, and a plurality of different bit signals are obtained by using the deviation .

Frequency Modulation Continuous Wave (FMCW) technology is a technology that can increase the measurement accuracy of a radar by using a wide bandwidth of a transmitter. It is used for high frequency and near field measurement. Since the FMCW radar uses a frequency change to obtain the resolution, it is possible to increase the resolution of the radar by broadening the frequency variation range of the radar transmitter.

In the present invention, the mixing of the radar transmission signal and the reception signal means a process in which a transmission radar signal and a reception radar signal are combined with each other, resulting in a radar signal having a frequency sum and a frequency difference. In the present invention, an embodiment will be described using the frequency difference.

In the present invention, in order to distinguish between a radar signal and a beat signal, a radar transmission signal radiated from a transmission antenna and a signal generated by mixing the reception signal and the transmission signal after being reflected by a target, A square wave is defined as a radar signal, and a signal is defined as a bit signal after the radar received signal is subjected to Fast Fourier Transform (FFT) processing and becomes a distinguishable frequency signal in the spectrum.

1 illustrates an antenna arrangement of a three-dimensional radar using multiple antennas built in a radar device according to an embodiment of the present invention.

As shown in FIG. 1, the antenna of the three-dimensional radar built in the radar device is configured such that three antennas 103, 105 and 107 and a single antenna 101 are configured in a triangular pyramid shape, Isotropic or Omni directional or has a wide radiation bandwidth so as to conform to the wavelength of the light. Here, an isotropic antenna means an antenna having radiating properties in all directions, and a forward antenna means an antenna having a non-directional radiation characteristic having no specific direction.

The positions of the receiving antennas 101, 103, 105, and 107 shown in FIG. 1 should be separated so as to be distinguishable from the FMCW signal processing end, and the three antennas must maintain a triangle on the shelf, The antennas 101 are arranged so as to form a triangular pyramid. The arranged antenna coordinates, together with the received bit signal, are transmitted to the signal processing device 215 of FIG.

2 is a block diagram illustrating a structure of a three-dimensional radar using multiple antennas built in a radar device according to an embodiment of the present invention.

2, the structure of a three-dimensional radar device including multiple antennas includes a signal generator 201, a transmitter 203, a transmission antenna 221, four reception antennas 223, 225, 227, and 229, Four receivers 209, four mixers 211, four distance calculation units 213, and a signal processing unit 215.

The broadband radar signal generated by the signal generator 201 is subjected to analog signal processing in the transceiver unit 203 for long distance transmission and then radiated toward the space by one antenna 221.

The analog signal processing includes amplification of a signal and filtering for setting a band, a function for keeping a transmission signal constant, and a function for monitoring a radiation signal.

The radiated radar transmission signal reaches the target object and is reflected by the target object, and the reflected radar signal returns to the radiated distance and arrives at the radar. A radar signal between the transmitter and the target is characterized by a delay as long as it is between the radar and the target object when received, and the radar signals received from the four receivers have differential delays.

1, when a plurality of antennas are configured in a triangular pyramidal shape as shown in FIG. 1, the positions of the antennas can be distinguished from each other, and a target frequency band (frequency sweep range or frequency bandwidth) It should be wide enough to acquire azimuth and angle to the object and may have a frequency step of less than 1Hz to have a higher resolution within a given frequency variation range.

The radar received signal arriving at the receiving antenna 223 is transmitted to the radar receiver 209 and is subjected to analog signal processing and then applied to the mixer 211. The mixer 211 transmits the difference between the transmission signal input to the transmission side and the reception signal input from the radar receiver 209 to the distance calculation unit 213.

The distance calculation unit 213 converts the received radar received signal into a digital signal through filtering and amplification, and performs an FFT (Fast Fourier Transform) process. The FFT-processed radar received signal has a frequency value proportional to the distance between the receiving antenna and the target. The frequency calculated by the distance calculation unit 213 is characterized in that a target at a close distance is output at a low frequency and a target at a far distance is output at a high frequency .

The radar reception signals arriving at the remaining reception antennas 225, 227 and 229 are mixed with the radar reception signal and the transmission signal 203 generated by the signal generator 201, as in the reception antenna 223, And obtains a bit signal 301 on the frequency spectrum, thereby calculating distance values between the reception antennas 225, 227, and 229 and the target object, respectively.

The obtained four distance values are transmitted to the signal processing unit 215 for obtaining the coordinates of the target object together with the antenna coordinate values of the respective reception channel antennas 223, 225, 227, and 229. The signal processing unit 215 draws the trajectory of four spheres or spheres having the calculated distance value as a radius on the space centered on the received antenna coordinates. In the present invention, the point at which the four drawn spheres meet is calculated with respect to the target object and the altitude.

3 shows a frequency beat signal in the distance calculator of FIG. 2 according to an embodiment of the present invention .

3, the radar signals reflected on the target object in the structure of FIG. 2 are respectively received through four receiving antennas 223, 225, 227 and 229, and the received signals are received by a radar receiver 209 And then converted into a difference component of the two signals by being combined with the transmission signal in the mixer 211 and output.

The distance calculator 213 performs FFT processing on the signals output from the mixer to generate frequency bit signals 301, 303, 305, and 307, respectively. Since the frequency bits obtained in the distance calculation unit 213 are proportional to the distance between the radar and the target object, the distance from the signal processing unit 215 to the target object is used to calculate the distance.

In FIG. 3, the frequency bits 301, 303, 305, and 307 correspond to the relative positions or coordinates of the respective receiving antennas with respect to the target object, and the variation width 309 of the frequency bits is proportional to the interval between the receiving antennas. For example, if the signal received from the antenna closest to the target object is located at 301, the signal received at the second nearest antenna is located at 303, and the signal received from the antenna at the farthest distance among the triangular prisms shown in FIG. 1 is located at 307 do.

In this case, the sphere drawn around the bit 301 of the antenna nearest to the target among the antennas arranged in the radar has the smallest size, and the sphere drawn around the bit 303 of the second nearest antenna The second smallest size. In the same way, the size of the third and fourth sphere is determined.

The position of the bit signals 301, 303, 305 and 307 shown in FIG. 3 in the frequency domain corresponds to the positions of the reception antennas 223, 225, 227 and 229 and the target object to be searched, The positions may be mutually varied.

FIG. 4 is a flowchart illustrating a three-dimensional target measurement procedure using multiple antennas built in a radar apparatus in FIG. 2 according to an embodiment of the present invention.

As shown in FIG. 4, the signal generated by the signal issuing unit 201 is subjected to analog signal processing for long-distance radiation in the transmitter 203, then radiated into space (S401) through a transmission antenna 221, (S403), and receives the reflected signal (S405) from the receiving antennas 223, 225, 227, and 229. A distance value between the transmitting / receiving antenna and the target is obtained from the received signal (S407). The position of the target is estimated (S409) using the distance value S407 and the antenna coordinate values S411 obtained above.

5 is a second block diagram of a 3D radar using fixed multiple antennas according to an embodiment of the present invention.

5, the structure of the three-dimensional radar using fixed multiple antennas includes a signal generator 501, a transmitter 503, a transmission antenna 521, four reception antennas 523, 525, 527, and 529, Four delay elements 505, a power combiner 507, a mixer 509, a distance calculator 511, and a signal processor 513. Here, the time delay 505 for distinguishing the receive antennas may be obtained by changing the arrangement of the antennas so that the four antennas have different predetermined delays.

FIG. 5 shows a second structure of the fixed three-dimensional radar. As shown in FIG. 2, it is composed of one transmitting antenna and four receiving antennas, but coordinates of each receiving antenna are not transmitted to the signal processor 513 . Instead, the receive antennas 523, 525, 527, and 529 are each connected to and power coupled to a power combiner 507, each with a known predetermined delay 505. The combined signal is mixed with the transmission signal 503 so that the difference between the two signals is output from the mixer 509. The output signal is subjected to FFT processing by the distance calculation unit 511, It appears in the frequency domain with four bit signals as shown.

Unlike the structure of FIG. 2, the obtained four bit signals have a characteristic 609 of frequency deviation according to the positions of the respective receiving antennas 523. 525, 527 and 529 and a delay 505 located at the receiving end of each radar receiving antenna. (601, 603, 605) according to the frequency deviation (601, 603, 605).

5 differs from the method of FIG. 2 in that the radar reception signals are subjected to FFT processing together with the delay values of the respective antennas in the distance calculation unit 511, and the signals (FIG. 6) The location information on the < RTI ID = 0.0 > Separately, without information on the coordinates of the receiving antenna It is possible to estimate the position of the target object with only the received frequency bit spectrum.

2 and 5, the transmission antennas 221 and 521 may be used in combination with the antenna 101 of FIG. 1 in a layout. In this case, a transmission / reception signal separation circuit such as a circulator may be applied.

FIG. 6 shows frequency bit signals obtained by the distance calculator of FIG. 5 according to an embodiment of the present invention .

6 shows a case where a radar signal reflected from a target object is received through four receiving antennas 523, 525, 527, and 529, respectively, and a signal combined at a power combiner 507 through different known delays FFT processing is performed in the distance calculator 511 and converted into a frequency bit signal, and the converted bit signal is used to calculate the distance to the target object. Since the obtained frequency bit signal has a characteristic proportional to the distance between the radar and the target object, it is possible to calculate the position of the target using this.

6, the signals received through the four reception antennas 523, 525, 527 and 529 are supplied to one distance calculation unit 511 together with respective known delay values, 525, 527, and 529 from the known delay value because they are FFT-processed and converted into frequency bit signals.

Therefore, the signal processor 513 can finally calculate the position of the target object by using the frequency bits calculated by the distance calculator 511 without any separate coordinate information for each of the reception antennas 523, 525, 527 and 529 have.

FIG. 7 is a flowchart illustrating a three-dimensional target measurement procedure using multiple antennas built in a radar apparatus in FIG. 5 according to an embodiment of the present invention.

7, the signal generated in the signal generator 501 is radiated (S701) through the transmitter 503, the signal radiated into the space is reflected by the target (S703), and the reflected signal (S705). A distance value between the transmitting / receiving antenna and the target object is obtained from the received signal (S707). The position of the target is determined using the distance values and the antenna coordinate values obtained in the step S709.

FIG. 8 is a conceptual diagram of signal transmission / reception when a radar device designed according to an embodiment of the present invention is used as a ground-based radar. FIG. 8 shows a case where a three-dimensional radar using fixed multiple antennas finds two targets on the ground, and three-dimensional coordinates can be obtained by triangulating the three antennas.

As shown in FIG. 9, the present invention can find the coordinates of the target through the distance calculation and coordinate determination procedures of FIGS. 4 and 7 for two or more targets. In the case of the embodiment of FIG. 9, the antenna 101 of FIG. 1 forming the triangular pyramid may be limited to a transmitting antenna.

FIG. 9 shows the configuration of a bit signal reflected by two target objects in a frequency spectrum as shown in FIG. When the position of the reception antennas is close to the target object, the signal group 901 reflected by the target object has a frequency value 905 proportional to a close distance, and the position of the reception antennas is distant from the target object The signal group 903 reflected by the target object has a frequency value 907 that is proportional to a long distance.

9 shows a bit signal configuration in a case where a three-dimensional FMCW radar with multiple antennas has a plurality of targets, in which two groups 901 and 903 of received bit signals are represented on frequency, The method for determining the coordinates is to calculate the distance to the received frequency bit 901 by performing a process of drawing a sphere or calculating a deviation of bit signals with respect to the frequency reception bit 901, Orientation and coordinate values are determined, and the same process is repeated for the reception frequency bit 903.

10 is a conceptual diagram of signal transmission / reception when a radar designed according to an embodiment of the present invention is used as a ship radar. FIG. 10 shows a case in which a three-dimensional antenna using fixed multiple antennas is operated as a shipboard radar. In the present invention, three-dimensional antennas having a forward characteristic are used to transmit and receive radio waves. You can determine the position of the target by drawing a circle with.

Data can be acquired by increasing the number of antennas of the radar designed for the area (space) where the radar is installed or the size of the ship or the aviation body to four or more, or by increasing the distance between the antennas.

101; Triangular-pyramid antenna
103, 105, 107; Triangularly arranged antenna
109; Triangle bottom triangle
201; Broadband signal generator
203; Radar signal transmitter
207; Receiving antenna
209; Radar signal receiver
211; A mixer for extracting a frequency difference between a transmission signal and a reception radar signal
213; Take the FFT of the two signal differences to obtain the bit signal and calculate the distance
215; A signal processor; Determine the 3D coordinates of the target with four antenna coordinates and four bit signals
223, 225, 227, 229; Receive channel
301; The received four bit signals
302; The difference between the transmitted signal and the received signal frequency
401, 304, 405, 407; The received four bit signal configuration
S501; Broadband signal transmission
S503; Reflection of signal by target
S505; Reception of reflection signal
S507; Obtain distance value for each channel
S509; Determination of the coordinates for the target
601; Broadband signal generator
603; Radar signal transmitter
621, 6133, 225, 227; Receive channel
607; Receiving antenna
609; Delay element
611; Combine the radar signals of channels 621, 623, 625, 627
613; A mixer for extracting a frequency difference between a transmission signal and a reception radar signal
615; FFT of two signal differences to obtain four bit signals and calculate distance
617; A signal processor; Determine the 3D coordinates of the target with four antenna coordinates and four bit signals
701; The distance in the spectrum of the received bit signal
702; Distance in received bit spectrum by delay element
S801; Broadband signal transmission
S803; Reflection of signal by target
S805; Reception of reflection signal
S807; Obtain distance value for each channel
S809; Determination of the coordinates for the target
901, 903, 905, 907; Antenna with triangular arrangement
909; Antenna laying cable
1001; antenna
1003; The radar signal receiving unit and the signal processing unit
1005; User interface
1201; Bit signal by target 1
1203; Bit signal by target 2

Claims (13)

Receiving a radar reflection signal by a target object with four fixed receiving antennas;
Calculating a distance from the position of each of the four fixed receive antennas to the target object using the received radar signal; And
Estimating a position of the target object using the calculated distance and coordinates of each of the receive antennas; , ≪ / RTI &
The position estimation may be performed by calculating the trajectory of each sphere whose radius is the distance to the object calculated at the position of each of the four fixed receive antennas and estimating the position of the object using the coordinates of the position of each of the receive antennas Dimensional FMCW radar using multiple antennas. The method according to claim 1,
Wherein the radar signal has a wide frequency band so that coordinates of a receiving antenna can be distinguished. The method according to claim 1,
Wherein the radar signal utilizes a frequency of 1 Hz or less to widen the utilization of the signal generator in a low frequency band where it is difficult to secure a wideband frequency. The method according to claim 1,
Wherein the radar signal uses a broadband signal generator or a DDS (Direct Digital Synthesis) signal generator. The method according to claim 1,
Wherein the fixed four receiving antennas are constituted by three antennas which are triangularly arranged at a predetermined interval on the circumference above the antenna shelf and one antenna which forms a triangular pyramid in association with the three antennas. Three - Dimensional FMCW Radar Method Using Antenna. The method according to claim 1,
Wherein the received radar signal is a radar signal that is radar transmission signal radiated from one antenna and is reflected by a target object to reach the fixed four receiving antennas. The method according to claim 1,
Wherein the received radar signal is a signal in which a radar transmission signal and a fixed four reception antenna signals are mixed. The method according to claim 1,
The received radar signal is received through the four receive antennas and subjected to FFT processing to be converted into a frequency beat signal, and the converted frequency beat signal is used to calculate a distance to the target object Dimensional FMCW radar using multiple antennas. The method according to claim 1,
Wherein the received radar signals are received through four receive antennas and are respectively coupled to the power combiner through different time delays and then sequentially FFT-processed into a frequency beat signal. 3D FMCW radar using multiple antennas. 10. The method of claim 9,
The position information of each receive antenna is extracted from the signal that is subjected to the FFT processing sequentially and converted into a frequency bit signal. Using the converted frequency beat signal and the extracted position information of each received antenna, Wherein the distance to the target object is used for the calculation of the three-dimensional FMCW radar using the fixed multi-antenna. The method according to claim 1,
Wherein the calculated four distances are used as radii for calculating the trajectory of four spheres around four antenna coordinates, respectively. The method according to claim 1,
And estimating the position of the object using the trajectory of the sphere, wherein the positions of the trajectories of the four calculated spheres overlap each other as the position of the object. A receiver for receiving a radar reflection signal by a target object with four fixed receiving antennas;
Calculates a distance from the position of each of the fixed four reception antennas to the target object using the received radar signal,
A controller for estimating a position of the target object using the calculated distance and the coordinates of each of the receive antennas; , ≪ / RTI &
The controller estimates a position of each of the four receiving antennas by calculating a trajectory of each sphere having a radius to an object calculated at a position of each of the fixed four receiving antennas and calculating a position of the object using coordinates Dimensional FMCW radar apparatus using fixed multi-antennas.

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