KR102365932B1 - Radar system for local oscillation frequency characteristic matching and method of driving the same - Google Patents

Abstract

The present invention relates to a radar system for matching local oscillation frequency characteristics capable of matching local oscillation frequency characteristics between a transmitter and a receiver in a radar system in which a static LoS propagation path is secured, and a driving method thereof . A reception signal matching method according to an embodiment of the present invention comprises the steps of: receiving, from the receiver, at least one or more reception baseband signals generated by converting a radio signal received by the receiver; performing range processing on baseband signals, identifying a direct path component corresponding to a radio signal received via the direct radio path from among components included in the range processing result, the direct Compensating the remaining components of the range processing result based on the path component, and performing Doppler processing based on the compensated components to determine the distance and speed of the target. can do.

Description

RADAR SYSTEM FOR LOCAL OSCILLATION FREQUENCY CHARACTERISTIC MATCHING AND METHOD OF DRIVING THE SAME

The present invention relates to an apparatus and method for matching local oscillation frequency characteristics of a radar system, and more particularly, to match local oscillation frequency characteristics between a transmitter and a receiver in a radar system in which a static LoS propagation path is secured. It relates to a radar system that can be used and a method for driving the same.

In the radar system, when the local oscillation frequencies of the transmitter and the receiver are not identical, signal detection performance is deteriorated.

For example, in a bi-static radar system, since the transmitter and the receiver are located in different places, the transmitter and the receiver independently generate a local oscillation frequency. Due to this, the ratio of the local oscillation frequencies generated by the transmitter and the receiver is different from the intended value (this will be described as a frequency difference later), and the phase noise of the local oscillation frequencies of the transmitter and the receiver are also independent. will have Accordingly, there is a problem in that signal detection performance is deteriorated due to non-uniform local oscillation frequency characteristics.

In the problem caused by the frequency difference of the local oscillation frequencies independently generated by the transmitter and the receiver, the problem can be solved by locking each local oscillation frequency to the GPS signal by applying a global positioning system (GPS) receiver. In this case, there is a problem in that a separate cost has to be paid according to the application of the GPS receiver.

In a problem caused by the independent phase noise characteristics of the local oscillation frequencies independently generated by the transmitter and the receiver, a difference in the phase noise characteristics can be reduced by applying a high-performance reference oscillator. In this case, there is a problem in that a separate cost has to be paid according to the application of the high-performance reference oscillator. In addition, even if a high-performance reference oscillator is applied, there is a problem in that it is not possible to solve all the deterioration of signal detection performance due to the independent phase noise characteristics.

An object of the present invention to solve the above problems is to provide a radar system capable of matching local oscillation frequency characteristics between a transmitter and a receiver in a radar system in which a static LoS propagation path is secured, and a method of driving the same is to provide

According to an embodiment of the present invention for achieving the above object, a received signal matching method in a radar system in which a static LoS propagation path between a transmitter and a receiver separated from each other is secured, the receiver Receiving at least one or more received baseband signals generated by converting a received radio signal from the receiver, performing range processing on the received baseband signals as many as a first set number, the Identifying a direct path component corresponding to a radio signal received through the direct radio path from among components included in the range processing result, based on the direct path component, compensation for the remaining components of the range processing result and performing Doppler processing based on the compensated components to determine the distance and speed of the target.
The identifying of the direct path component may include comparing magnitudes of detection coefficients of the components included in the range processing result, and determining a component having the largest detection coefficient among the components as the direct path component. It may be characterized in that it includes.
The performing of the compensation may include: identifying a time-varying characteristic in the direct path component; calculating a constant for offsetting the time-varying characteristic identified in the direct path component; and based on the calculated constant, the It may be characterized in that it comprises the step of performing compensation for the remaining components.
The received signal matching method may further include performing signal synchronization between the transmitter and the receiver based on the previously confirmed physical distance between the transmitter and the receiver.
According to an embodiment of the present invention, a received signal matching apparatus in a radar system in which a static LoS propagation path between a transmitter and a receiver separated from each other is secured is a processor, the processor and the electronic ( a memory (memory) for communicating electronically, and instructions stored in the memory, wherein when the instructions are executed by the processor, the instructions are received by the received signal matching device at the receiver Receive at least one or more received baseband signals generated by converting the received radio signal from the receiver, perform range processing on the received baseband signals as many as a first set number, and the range processing result Among the components included in , a direct path component corresponding to a radio signal received through the direct radio path is identified, and based on the direct path component, compensation is performed for the remaining components of the range processing result, and perform Doppler processing based on the compensated components to cause ascertaining the distance and velocity of the target.
The instructions further enable the received signal matching device to compare the magnitudes of the detection coefficients of the components included in the range processing result, and to determine the component having the largest detection coefficient among the components as the direct path component. It may be characterized in that it operates to cause.
The instructions allow the received signal matching device to determine a time-varying characteristic in the direct path component, calculate a constant for canceling the time-varying characteristic identified in the direct path component, and based on the calculated constant, the It may be characterized in that it is operative to further cause performing compensation for the remaining components.
The instructions may be operable to further cause the received signal matching device to perform signal synchronization between the transmitter and the receiver based on the previously confirmed physical distance between the transmitter and the receiver.

A radar system for matching local oscillation frequency characteristics and a driving method thereof according to an embodiment of the present invention can match local oscillation frequency characteristics between a transmitter and a receiver in a radar system in which a static LoS propagation path is secured. can

A radar system for matching local oscillation frequency characteristics and a driving method thereof according to an embodiment of the present invention provide a static direct radio path between a transmitter and a receiver in a radar system in which a transmitter and a receiver must independently generate a local oscillation frequency. This is to match the characteristics of the independently generated local oscillation frequency by using it in a state in which is secured. Through this, it is possible to prevent deterioration of signal detection performance due to the frequency difference between the two local oscillation frequencies and the independent phase noise characteristics.

A radar system for matching local oscillation frequency characteristics and a driving method therefor according to an embodiment of the present invention provide for signal synchronization ( signal synchronization). More specifically, after finding out the distance between the transmitter and the receiver in advance, the signal acquisition time can be adjusted so that the detection distance of the static direct radio path in the radar system becomes the same as the distance between the transmitter and the receiver.

A radar system for matching local oscillation frequency characteristics and a driving method thereof according to an embodiment of the present invention, when measuring the distance between a transmitter and a receiver in advance with a rangefinder, apply the second embodiment of the present invention to different places Signal synchronization of the transmitter and the receiver disposed in the , and applying the first embodiment, it is possible to match the independently generated local oscillation frequency characteristics in a state in which a static direct radio path between the transmitter and the receiver is secured.

In a radar system for local oscillation frequency matching and a driving method thereof according to an embodiment of the present invention, when a GPS receiver is applied to a transmitter and a receiver, signal synchronization can be achieved using a GPS signal, and the first embodiment of the present invention By applying an example, the local oscillation frequency characteristics of the transmitter and the receiver can be matched.

In addition, in the radar system for local oscillation frequency matching and the driving method thereof according to an embodiment of the present invention, even the frequency difference between the local oscillation frequencies of the transmitter and the receiver is removed using a GPS signal, and then the first embodiment of the present invention By applying it, it is possible to prevent the deterioration of the detection performance of the radar system due to 'independent phase noise characteristics'.

Also, the distance between the transmitter and the receiver can be found by using the GPS coordinates. Therefore, when a problem occurs in the GPS signal (GPS jamming or GPS receiver failure) during operation of the radar system, signal synchronization is applied by applying the second embodiment of the present invention, and the transmitter is applied by applying the first embodiment of the present invention. and the local oscillation frequency characteristics of the receiver can be matched.

1 is a diagram illustrating a radar system for local oscillation frequency matching according to an embodiment of the present invention.
2 is a diagram illustrating a transmitter of a radar system of the present invention.
3 is a view showing a receiver of the radar system of the present invention.
4 is a diagram illustrating a signal processing method when there are two wireless paths.
5 is a diagram illustrating a method of driving a radar system for matching local oscillation frequency characteristics according to an embodiment of the present invention.

Since the present invention can have various changes and can have various embodiments, specific embodiments are illustrated in the drawings and described in detail. However, this is not intended to limit the present invention to specific embodiments, and it should be understood to include all modifications, equivalents and substitutes included in the spirit and scope of the present invention.

Terms such as first, second, etc. may be used to describe various elements, but the elements should not be limited by the terms. The above terms are used only for the purpose of distinguishing one component from another. For example, without departing from the scope of the present invention, a first component may be referred to as a second component, and similarly, a second component may also be referred to as a first component. and/or includes a combination of a plurality of related listed items or any of a plurality of related listed items.

When an element is referred to as being “connected” or “connected” to another element, it is understood that it may be directly connected or connected to the other element, but other elements may exist in between. it should be On the other hand, when it is said that a certain element is "directly connected" or "directly connected" to another element, it should be understood that the other element does not exist in the middle.

The terms used in the present application are only used to describe specific embodiments, and are not intended to limit the present invention. The singular expression includes the plural expression unless the context clearly dictates otherwise. In the present application, terms such as “comprise” or “have” are intended to designate that a feature, number, step, operation, component, part, or combination thereof described in the specification exists, but one or more other features It should be understood that this does not preclude the existence or addition of numbers, steps, operations, components, parts, or combinations thereof.

Unless defined otherwise, all terms used herein, including technical and 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 a commonly used dictionary should be interpreted as having a meaning consistent with the meaning in the context of the related art, and should not be interpreted in an ideal or excessively formal meaning unless explicitly defined in the present application. does not

Hereinafter, preferred embodiments of the present invention will be described in more detail with reference to the accompanying drawings. In describing the present invention, in order to facilitate the overall understanding, the same reference numerals are used for the same components in the drawings, and duplicate descriptions of the same components are omitted.

1 is a diagram illustrating a radar system for local oscillation frequency matching according to an embodiment of the present invention.

Referring to FIG. 1 , a radar system 1 for local oscillation frequency matching according to an embodiment of the present invention includes a transmitter 100 , a receiver 200 , and a signal matcher 300 . In FIG. 1 , each of the transmitter 100 and the receiver 200 separately generates a local power generation frequency.

2 is a diagram illustrating a transmitter of a radar system of the present invention.

Referring to FIG. 2 , the transmitter 100 includes a transmitter low-band unit 110 , a transmit radio frequency (RF) unit 120 , and a transmit antenna 130 .

The transmitter baseband unit 110 generates a complex baseband signal s _l (t) as shown in Equation 1 below. In addition, the transmitter baseband unit 110 transmits the generated complex baseband signal s ₁ (t) to the transmit RF unit 120 .

The transmitting RF unit 120 converts the baseband signal s _l (t) to the carrier frequency f _ct by using the first local oscillation frequency independently generated independently from the receiver 200 as shown in Equation 2 below. Generate an s(t) signal. Then, the transmit RF unit 120 transmits the generated s(t) signal to the transmit antenna 130 . In addition, the transmit RF unit 120 performs a filter function to remove a spurious signal generated during frequency conversion and an amplification function to increase the signal size. In Equation 2 below, θ _t (t) means an effect due to the phase noise of the local oscillation frequency of the transmitter 100 .

The transmitting antenna 130 converts s(t) from which the baseband signal is up-frequency-converted into a radio signal and transmits it through a radio channel.

3 is a view showing a receiver of the radar system of the present invention.

Referring to FIG. 3 , the receiver 200 includes a receiver low-band unit 210 , a reception RF unit 220 , and a reception antenna 230 .

The reception antenna 230 receives a wireless signal received through a wireless channel, converts it into a wired signal r(t), and sends it to the reception RF unit 220 .

The reception RF unit 220 down-frequency converts the reception signal r(t) using the second local oscillation frequency independently generated from the transmitter 100 as shown in Equation 4 below to obtain the r _l (t) signal. to create Then, the generated r _l (t) signal is transmitted to the receiver low-band unit 210 .

The receiver low-band unit 210 converts the r _l (t) signal into a digital signal and performs signal processing for target detection.

In Equation 4, L denotes the number of radio paths between the transmitter 100 and the receiver 200 . And, τ _n means a propagation delay time passing through each radio path. And, f _cr means the local oscillation frequency used for down-frequency conversion. And, θ _r (t) means the effect of the phase noise of the local oscillation frequency of the receiver 200 .

For example, the characteristics of the local oscillation frequency of the transmitter 100 and the receiver 200 are the same (f _ct =f _cr , θ _t (t) = θ _r (t)), and there is only one radio path ( Assuming that L = 1), the receiver low-band signal r _l (t) can be expressed as in Equation 5 below.

The receiver low-band unit 210 extracts a propagation delay time τ ₁ by performing signal processing. In addition, the receiver low-band unit 210 converts the propagation delay time τ ₁ to the distance to the target using the propagation speed. That is, the receiver low-band unit 210 detects the distance to the target by performing range processing.

The receiver low-band unit 210 repeatedly performs range processing at regular time intervals. Thereafter, the receiver low-band unit 210 may detect the speed of the target by performing a Fourier transform on each detected distance. That is, the receiver low-band unit 210 may perform Doppler processing to detect the speed of the target.

When the target is moving, the propagation delay time τ ₁ changes with time in relation to the speed of the target (ie, τ ₁ =τ ₁ ( _t )). The characteristic is revealed only in the detection coefficient exp(-j2πf _ct τ ₁ (t)) expressed in the form of a product of the carrier frequency. That is, in multiple range processing, the same target is extracted from the same distance, but since the extracted value shows a time-varying characteristic according to the target speed, the receiver low-band unit 210 can detect the target speed using this.

4 is a diagram illustrating a signal processing method when there are two wireless paths.

4, when there is a 'frequency difference' between the local oscillation frequencies of the transmitter 100 and the receiver 200 (f _offset = (f _ct -f _cr ) ≠ 0), the receiver low-band signal r (t) can be expressed as in Equation 6 below.

The detection coefficient shows a periodic characteristic not only by the movement of the target but also by the 'frequency difference' of the local oscillation frequencies of the transmitter 100 and the receiver 200 . Therefore, an error also occurs in the detected speed of the target.

On the other hand, when the local oscillation frequencies of the transmitter 100 and the receiver 200 have 'independent phase noise characteristics' (θ _diff (t)=(θ _t (t)-θ _r (t)≠0)), The receiver low-band signal r(t) can be expressed as in Equation 7 below.

A random time-varying characteristic by 'independent phase noise characteristics' of the transmitter 100 and the receiver 200 is added to the detection coefficient. This will act as noise in Doppler processing. As described above, it can be confirmed that the signal detection performance is deteriorated when the local oscillation frequencies of the transmitter and the receiver are not identical.

first embodiment

Referring back to FIG. 1 , the signal matcher 300 corrects the phases of the detection coefficients of the static direct radio path to be the same value in the signal processing process of the receiver 200 . If a static LoS propagation path exists between the transmitter 100 and the receiver 200, the detection coefficient of the physically static direct propagation path does not have a time-varying characteristic. Therefore, if a time-varying characteristic is observed in the detection coefficient of a static direct radio path, this is a phenomenon that occurs because the first local oscillation frequency of the transmitter 100 and the second local oscillation frequency of the receiver 200 have unequal characteristics. . Based on these characteristics, the signal matcher 300 secures a static direct radio path between the transmitter 100 and the receiver 200, and in the signal processing process, the phase of the detection coefficient of the static direct radio path is the same. Correct it to be a value. When the phase of the detection coefficient of the static direct radio path is corrected to have the same value, the local oscillation frequency characteristics of the transmitter 100 and the receiver 200 can be matched.

Specifically, in a communication environment in which a static direct radio path is secured between the transmitter 100 and the receiver 200, the receiver low-band signal r1(t) can be expressed as Equation 8 below. In Equation 8, the first term denotes a received signal through the direct radio path, and the second term denotes a received signal through the remaining radio path.

As the propagation delay time of the direct propagation path is the shortest, τ ₁ has the smallest value among the propagation delay times (τ ₁ ~ τ _L ), and the detection coefficient is the largest.

Accordingly, the signal matcher 300 may multiply each range processing result by a constant for making the phase of the point having the maximum magnitude in the result of each range processing the same. Through this, the signal matcher 300 may match the characteristics of the first local oscillation frequency of the transmitter 100 and the second local oscillation frequency of the receiver 200 .

Although the signal matcher 300 is illustrated as a separate and independent component in FIG. 1 , the present invention is not limited thereto, and the signal matcher 300 may be included in the receiver low-band unit 210 of the receiver 200 .

5 is a diagram illustrating a method of driving a radar system for local oscillation frequency matching according to an embodiment of the present invention.

5, on the assumption that Doppler processing is performed using N range processing results in the signal processing process of the receiver 100, the signal matcher 300 performs the first local oscillation of the transmitter 100 Matching the frequency and the characteristics of the second local oscillation frequency of the receiver 200 is an example.

The receiver 200 may receive a radio signal transmitted through a radio channel to obtain a signal (S10).

Subsequently, the receiver low-band unit 210 may set the number of times the range processing is performed to 0 ( S20 ).

Subsequently, the receiver low-band unit 210 may perform range processing to detect the distance to the target ( S30 ).

Subsequently, the receiver low-band unit 210 may search for the position of the target having the largest size in the range processing result, that is, the distance of the target (S40).

Then, the signal matcher 300 multiplies each range processing result by a constant for making the phase of the point having the maximum magnitude in the result of each range processing the same (S50).

Next, the signal matcher 300 determines whether the number n of the range processing is performed is a preset reference number N (S60).

As a result of the determination in S60, if the number of times (n) that the range processing is performed is less than the preset reference number (N), the process returns to step S30 to repeatedly perform range processing.

Meanwhile, as a result of the determination in S60, when the number of times (n) that the range processing is performed is the preset reference number (N), the receiver low-band unit 210 performs Doppler processing to detect the speed of the target. It can be done (S70).

The radar system for local oscillation frequency matching and the driving method thereof according to the embodiment of the present invention described with reference to FIG. 5 , assumes that the signal synchronization of the transmitter 100 and the receiver 200 coincide. That is, it means that the start time of the transmission signal transmitted from the transmitter 100 coincides with the start time of the signal acquisition of the receiver 200 . However, it is not limited thereto, and even if the start time of the transmission signal transmitted from the transmitter 100 and the start time of the signal acquisition of the receiver 200 do not match, even if the difference is within the error tolerance range, the above-described local oscillation frequency matching is performed. The radar system and its driving method can be equally applied.

second embodiment

The signal matcher 300 may synchronize signals between the transmitter 100 and the receiver 200 and match local oscillation frequency characteristics of the transmitter 100 and the receiver 200 .

Specifically, when a static direct radio wave path exists between the transmitter 100 and the receiver 200 , the physical distance between the transmitter 100 and the receiver 200 may be calculated in advance. Here, when calculating the physical distance between the transmitter 100 and the receiver 200, the following three methods may be used.

1) The physical distance between the transmitter and the receiver can be calculated using an optical rangefinder, etc.

2) In the transmitter and the receiver to which the GPS receiver is applied, the physical distance between the transmitter and the receiver may be calculated based on the respective GPS coordinates.

3) The receiver low-band unit 210 may perform range processing by operating the transmitter and the receiver to which the GPS receiver is applied, and may calculate a physical distance between the transmitter and the receiver based on the result of the range processing.

If you know the physical distance between the transmitter and the receiver, you can know where the static direct propagation path should appear in the range processing result. Accordingly, the signal acquisition timing in the receiver 200 may be adjusted so that the position where the maximum magnitude occurs in the range processing result value coincides with a previously known position. Through this, signal synchronization between the transmitter 100 and the receiver 200 may be matched.

If the distance between the transmitter and the receiver is measured in advance with a rangefinder, the radar system can be configured without applying a GPS receiver between the transmitter and the receiver. By applying the second embodiment of the present invention, the signals of the transmitter and the receiver arranged in different places are synchronized, and by applying the first embodiment, they are independently generated in a state in which a static direct radio path between the transmitter and the receiver is secured. It is possible to match the local oscillation frequency characteristics of the transmitter and the receiver.

When a GPS receiver is applied to a transmitter and a receiver, signal synchronization can be achieved using a GPS signal, and local oscillation frequency characteristics of the transmitter and receiver can be matched by applying the first embodiment of the present invention. In addition, after removing even the difference between the local oscillation frequencies of the transmitter and the receiver using the GPS signal, the performance degradation of the radar system due to the 'independent phase noise characteristic' can be prevented by applying the first embodiment of the present invention. . In addition, in the above situation, since the distance between the transmitter and the receiver can be found using, for example, GPS coordinates, when a problem occurs in the GPS signal (GPS jamming or malfunction of the GPS receiver) during operation of the radar system, the second aspect of the present invention By applying the embodiment, signal synchronization can be applied, and the local oscillation frequency characteristics of the transmitter and the receiver can be matched by applying the first embodiment of the present invention.

The methods according to the present invention may be implemented in the form of program instructions that can be executed by various computer means and recorded in a computer-readable medium. The computer-readable medium may include program instructions, data files, data structures, etc. alone or in combination. The program instructions recorded on the computer-readable medium may be specially designed and configured for the present invention, or may be known and available to those skilled in the art of computer software.

Examples of computer-readable media include hardware devices specially configured to store and carry out program instructions, such as ROM, RAM, flash memory, and the like. Examples of program instructions include not only machine language codes such as those generated by a compiler, but also high-level language codes that can be executed by a computer using an interpreter or the like. The hardware device described above may be configured to operate as at least one software module to perform the operations of the present invention, and vice versa.

Although described with reference to the above embodiments, those skilled in the art will understand that various modifications and changes can be made to the present invention without departing from the spirit and scope of the present invention as set forth in the claims below. will be able

Claims (8)

A method for matching a received signal in a radar system in which a static LoS propagation path between a transmitter and a receiver separated from each other is secured, the method comprising:
receiving, from the receiver, at least one or more reception baseband signals transmitted by the transmitter to detect a predetermined target and generated by converting a radio signal received by the receiver;
matching frequency characteristics of the transmitter and the receiver by repeatedly performing compensation for components included in a range processing result for the received baseband signals a first set number of times; and
performing Doppler processing based on the components compensated according to the matching step to confirm the distance and speed of the target;
The matching step is
performing range processing on the received baseband signals;
checking a direct path component received through the radio wave direct path without passing through the target from among the components included in the range processing result; and
and performing compensation on the remaining components of the range processing result based on the direct path component. The method according to claim 1,
The step of identifying the direct path component is,
comparing magnitudes of detection coefficients of the components included in the range processing result; and
and determining a component having the largest detection coefficient among the components as the direct path component. The method according to claim 1,
The step of performing the compensation is
identifying time-varying characteristics in the direct path component;
calculating a constant for offsetting the time-varying characteristic identified in the direct path component; and
and performing compensation on the remaining components based on the calculated constant. The method according to claim 1,
Based on the previously confirmed physical distance between the transmitter and the receiver, the method further comprising the step of performing signal synchronization between the transmitter and the receiver, the received signal matching method. As a reception signal matching device in a radar system in which a static LoS propagation path between a transmitter and a receiver separated from each other is secured,
processor;
a memory in electronic communication with the processor; and
including instructions stored in the memory;
When the instructions are executed by the processor, the instructions cause the received signal matching device to
receiving, from the receiver, at least one or more reception baseband signals generated by converting a radio signal transmitted by the transmitter to detect a predetermined target and received by the receiver;
matching the frequency characteristics of the transmitter and the receiver by repeatedly performing compensation for components included in a range processing result of the received baseband signals for a first set number of times for a first set number of times; And
performing Doppler processing based on components compensated through matching to the frequency characteristic to cause ascertaining a distance and speed of a target,
Matching the frequency characteristics is,
perform range processing on the received baseband signals;
check a direct path component received through the radio wave direct path without passing through the target, among components included in the range processing result; And
and performing compensation on the remaining components of the range processing result based on the direct path component. 6. The method of claim 5,
The commands are the received signal matching device,
comparing magnitudes of detection coefficients of the components included in the range processing result; And
and operable to further cause the component having the largest detection coefficient among the components to be determined as the direct path component. 6. The method of claim 5,
The commands are the received signal matching device,
identifying time-varying characteristics in the direct path component;
calculating a constant for canceling the time-varying characteristic identified in the direct path component; And
and operative to further cause performing compensation on the remaining components based on the calculated constant. 6. The method of claim 5,
The commands are the received signal matching device,
Based on the previously confirmed physical distance between the transmitter and the receiver, the reception signal matching apparatus characterized in that it further operates to cause signal synchronization between the transmitter and the receiver.

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