KR20190138444A - Hopping-frequency coding based transmission and reception method and apparatus to estimate the information of a high-speed underwater vehicle in short range - Google Patents

Abstract

The present invention relates to a method for transmitting and receiving a hopping frequency based on coding, and to an apparatus thereof. According to one embodiment of the present invention, the method for transmitting and receiving a hopping frequency based on coding in an active sonar system comprises the steps of: transmitting a continuous wave signal hopping at least three frequency bands at a period shorter than the delay time of a reflected signal in a transmitter; and obtaining a frequency, a hopping time point, and a hopping frequency of a received signal from a receiver, and estimating a distance of a target and a Doppler frequency from the obtained frequency, the obtained hopping time point, and the obtained hopping frequency.

Description

Hopping-frequency coding based transmission and reception method and apparatus to estimate the information of a high-speed underwater vehicle in short range}

The present invention relates to a method and apparatus for transmitting and receiving a signal for estimating a distance and a Doppler of a target that operates at high speed in a sonar detecting apparatus for a close range.

A sonar system refers to equipment that transmits sound waves underwater and detects targets and estimates information from reflected signals. The sonar system is divided into passive sonar system which receives only the acoustic signal emitted by the target and detects the target and extracts the information, and active sonar system which transmits the acoustic signal and receives the reflected signal to detect the target and estimates the information. The present invention relates to the estimation of information of a target that is maneuvering at high speed in a short distance among active sonar systems.

Conventional representative techniques for estimating the distance and Doppler information of a target maneuvering at high speed at close range include frequency modulated continuous wave (FMCW) radar, which provides precise range of distance at close range, such as proximity fuses, level measurement systems, and collision avoidance systems. It is widely used in applications requiring measurement.

와

로 구성된 비트 신호(beat signal)를 획득하고(여기서,

와

는 송·수신 신호의 주파수 차이에 해당함), 2개의 주파수 중에서 다운 비트 주파수

를 추정하여 다음 수학식 1과 같이 지연시간을 획득한다.The FMCW radar estimates the target information at the frequency of the transmitted and received signal as follows. Mixing the transmit and receive signals to mix the two frequencies as shown in FIG.

Wow

Obtain a beat signal consisting of (where,

Wow

Corresponds to the frequency difference between the transmit and receive signals), and the down beat frequency of the two frequencies.

By estimating, obtain a delay time as in Equation 1 below.

: FM신호의 시간-주파수 기울기).(

: Time-frequency slope of the FM signal.

의 신호가 차지하는 길이 비율을 높이기 위해서 FM 신호의 송신주기

를 지연시간

보다 매우 길게 사용한다. 비트 신호에서

의 신호 길이가 길수록 높은 신호 대 잡음 비 (SNR : signal to noise power ratio)와 거리 분해능을 확보할 수 있다.In the FMCW radar, as shown in FIG.

Transmit period of FM signal to increase the length ratio occupied by

Delay time

Use very long. In beat signal

The longer the signal length, the higher the signal-to-noise power ratio (SNR) and distance resolution.

가 필수적으로 요구되고 사용 가능한 대역폭이 제한된 상황에서 신호 길이가 길어질수록 거리 분해능이 감소하고 추정치의 갱신 주기가 늘어나는 문제점이 발생한다. 뿐만 아니라, 수중 소나에서 발생하는 도플러 효과는 레이더에서 발생하는 도플러 효과보다 매우 크기 때문에 신호의 길이와 대역폭에서 무시할 수 없는 변화량이 발생한다. 수중 소나에서 발생되는 큰 도플러 효과 때문에 FMCW 소나에서는 도 1b와 같이 송수신 FMCW의 주파수 기울기와 대역폭이 달라져 일정한 주파수의 비트 신호가 발생하지 않는다. 이로 인해서 FMCW 소나에는 FMCW 레이더와 동일한 방법으로 표적의 정보를 추정할 수 없는 문제점이 있다. If the FMCW is applied to a sonar that uses sound waves that are much slower than the radar's electromagnetic waves, it will be very long for near targets.

In the situation where the required bandwidth is limited and the available bandwidth is limited, the longer the signal length, the smaller the distance resolution and the longer the update period of the estimate. In addition, the Doppler effect in the sonar is much larger than the Doppler effect in the radar, resulting in an insignificant amount of change in signal length and bandwidth. Due to the large Doppler effect generated in the underwater sonar, the frequency slope and bandwidth of the FMCW transmit / receive FMCW are different as shown in FIG. For this reason, there is a problem in that the FMCW sonar cannot estimate the target information in the same way as the FMCW radar.

[Prior art document number]

Prior Art 1: Korea Patent Registration 10-1049704

Prior Art 2: Korean Patent Registration 10-0532803

Prior Art 3: Korea Patent Registration 10-1175087

When estimating the distance and Doppler of a target that operates at high speed in a short distance, the present invention is suitable for a hop-frequency coding based transmission method and a signal for updating the estimate with a short period regardless of the delay time of the reflected signal and the Doppler effect. A method and apparatus for transmitting and receiving based on hopping frequency coding capable of distance and Doppler estimation are provided.

In an active sonar system according to an embodiment, a method for transmitting / receiving based on hopping frequency coding may include: transmitting, at a transmitter, a hopping frequency coding-based continuous wave signal that hops at least three frequency bands at a period shorter than a delay time of a reflected signal; Obtaining a frequency, a hop time, and a hop frequency of the Equation, and estimating a distance and a Doppler frequency of the target from the obtained frequency, the hop time and the hop frequency.

In an active sonar system, a hopping frequency coding-based transmitting / receiving apparatus includes a transmitter for transmitting a hopping frequency coding-based continuous wave signal that hops at least three frequency bands with a period shorter than a delay time of a reflected signal, a frequency of a reception signal, and a hopping time point And a receiver for obtaining the hopping frequency and estimating the distance of the target and the Doppler frequency from the obtained frequency, the time of hopping and the hopping frequency.

Another embodiment includes a recording medium recording a program for executing the transmission and reception method in a computer.

The present invention can update in real time the information of a target that starts at high speed at a short distance with a period shorter than the delay time of the reflected signal.

FIG. 1A shows a bit signal of an FMCW radar, and FIG. 1B shows a bit signal in an FMCW sonar having a large Doppler effect.
2 illustrates an example of a hopping-frequency coding based transmission signal according to an embodiment.
3 illustrates a code and state transition diagram for a case where a codeword length is 3 according to another embodiment.
4 is a diagram illustrating a code and state transition diagram when a codeword length is 5 according to another embodiment.
5A is a flowchart illustrating a transmission method according to another embodiment. 5B is a flow diagram illustrating a receiving method for obtaining distance and Doppler frequency.
6 illustrates an example of a differential average filter having a length of 2N according to another embodiment.
FIG. 7 illustrates an example of detecting a frequency hopping point with four threshold values and obtaining a hopping-frequency according to another embodiment.
8 illustrates an example of a hopping-frequency coding based transmission / reception signal and a transmission / reception time point according to another embodiment.

The terminology used in the present embodiments is a general term that is currently widely used as possible while considering the functions of the present embodiments, but may vary according to the intention or precedent of a person skilled in the art, the emergence of new technology, etc. . In addition, in certain cases, there is also a term arbitrarily selected, in which case the meaning will be described in detail in the description of the corresponding embodiment. Therefore, the terms used in the present exemplary embodiments should be defined based on the meanings of the terms and the contents throughout the present exemplary embodiments, rather than simply names of the terms.

In the description of the embodiments, when a part is connected to another part, this includes not only a case in which the part is directly connected, but also a case in which another part is electrically connected in between. In addition, when a part includes a certain component, this means that it may further include other components, not to exclude other components unless otherwise stated. In addition, the term "unit" described in the embodiments refers to a unit for processing at least one function or operation, which may be implemented in hardware or software, or a combination of hardware and software.

Terms such as “consisting of” or “comprising” as used in the present embodiments should not be construed as necessarily including all of the various elements or steps described in the specification, and some or some of them It is to be understood that the steps may not be included or may further include additional components or steps.

The description of the following embodiments should not be construed as limiting the scope of the right, it should be construed as belonging to the scope of the embodiments that can be easily inferred by those skilled in the art. Hereinafter, only exemplary embodiments will be described in detail with reference to the accompanying drawings.

The present invention relates to a method for updating information estimates in a short period, regardless of the delay time and the Doppler effect of a reflected signal, for a target that operates at high speed in a short distance. To this end, the transmitter side allocates coding to the signal and the hopping frequency that hops three frequency bands at regular intervals, and the receiver side estimates the target information using the frequency, the hopping frequency, and the frequency hopping time of the received signal.

In detail, the transmitter includes a codeword and a symbol setting step, a transmission parameter setting step, and a transmission signal generation step. The receiver side includes a frequency estimation step of the received signal, a detection and hopping-frequency classification step of the frequency hopping point, and an estimation step of the target information.

The present invention relates to a method of transmitting a signal for updating information of a target that starts at high speed in a short distance at a short cycle, and a method of processing a received signal corresponding thereto. Specifically, the transmitter transmits a hopping-frequency coding based continuous wave signal that hops three frequency bands at a period shorter than a delay time of the reflected signal. By using the frequency hopping and the corresponding coding in the transmission signal, a time point at which information can be estimated in the continuous wave can be generated, and each transmission time point corresponding to a plurality of frequency hopping time points can be known. The receiver obtains the frequency of the received signal, the time of the jump, and the hopping-frequency from a plurality of Doppler correlators. The distance information of the target may be estimated from the detected hopping time and the hopping time of the transmission signal, and the Doppler information may be estimated by comparing the estimated frequency of the received signal with the hopping frequency by comparing the frequency of the corresponding transmission signal with the hopping frequency.

Referring to FIG. 5A, the transmitting step includes setting a codeword and a symbol of step 500, setting a transmission parameter of step 502, and generating a transmission signal of step 504.

The step of setting the codeword and symbol shown in step 500 will be described.

The codeword setting step includes setting a jump-frequency, a code (Equation 2) and a codeword (Equation 3), and setting a frequency and a state (Equation 5) and a symbol (Equation 6). .

,

,

3개의 주파수 대역을

간격으로 주파수를 도약하는 신호를 생성한다. 구체적으로 도약-주파수에 대응하는 코드

, 신호의 주파수에 대응하는 상태

, 주파수 도약이 L 번 발생한 신호의 집합을 나타내는 심볼

, 송·수신 심볼에서 발생한 도약-주파수의 코드 집합을 나타내는 코드워드

, 그리고 송신신호에서 주파수 도약이 발생한 시점

를 정의한다. The hopping-frequency coding based transmission method is shown in FIG.

,

,

Three frequency bands

Generates a signal that hops frequency at intervals. Specifically, the code that corresponds to the jump-frequency

, The state corresponding to the frequency of the signal

, A symbol representing a set of signals in which frequency hopping has occurred L times

Code representing the code set of the hop-frequency generated by the Rx, Rx and Rx symbols.

And when the frequency hopping occurs in the transmission signal

Define.

은 도약-주파수

에 직접적으로 대응하는 변수로 수학식 2와 같이 정의되며, 수신신호에서 발생한 주파수 도약 시점에 대응하는 송신 시점을 획득하기 위한 목적으로 적용된다. code

Silver jump-frequency

A variable corresponding directly to Equation 2 is defined as in Equation 2, and is applied for the purpose of obtaining a transmission time corresponding to a frequency hopping time generated from a received signal.

은

범위의 정수이고

은 코드워드의 길이이며, 하나의 심볼 안에서 주파수 도약이 발생한 순서(코드워드에서는 코드의 순서)를 나타낸다. 코드워드

는 하나의 심볼에서 발생한 주파수 도약에 대응하는 L 개의 코드

의 집합이며, 수학식 3으로 정의된다. here

silver

Is an integer in the range

Is the length of the codeword and indicates the order in which frequency hopping occurs within one symbol (the order of the codes in the codeword). Codeword

Are L codes corresponding to the frequency hopping in one symbol.

It is a set of and is defined by Equation 3.

은 수학식 4와 같이 하나의 벡터로 구성될 수 있다.When frequency hopping occurs in the transmission signal

May be composed of one vector as shown in Equation 4.

이전의 주파수를 수학식 5와 같이 상태

로 정의하고 송신 심볼 내에 존재하는 모든

을 수학식 6과 같이 하나의 벡터로 구성하며, 상태

과 코드

의 관계는 수학식 7과 같다.Frequency hopping point

State the previous frequency as shown in Equation 5

All defined within the transmit symbol

Is composed of one vector as in Equation 6, and

And code

The relationship of is as shown in Equation 7.

은 심볼 내에서 상태

이 변하는 경우에 할당되는 코드이며, +2 또는 -2의 코드는 심볼

이 끝나고 다음 심볼

가 시작할 때 할당되는 코드이다. 송신 심볼의 시작 상태

과 마지막 상태

은 도면 3과 도면 4와 같이 항상 +1 또는 -1이며, 현재 심볼의 마지막 상태와 다음 심볼의 시작 상태는 항상 반대의 부호를 가진다. 도약-주파수 코딩 기반 신호는 주파수 도약이 발생하더라도 3개의 주파수

,

,

만 가지기 때문에, 도면 3과 도면 4와 같이 짝수 번째 상태

은 항상 0이고 홀수 번째 상태

은 +1 또는 -1이다.Code of +1 or -1 in the transmission method

Is a state within a symbol

Is a code that is assigned if it changes, and a code of +2 or -2 is a symbol

This symbol after the end

Is the code that is assigned at startup. Starting state of the transmission symbol

And last state

3 and 4 are always +1 or -1, and the last state of the current symbol and the start state of the next symbol always have opposite signs. Hopping-Frequency Coding-Based Signals Have Three Frequencies

,

,

Since only have an even numbered state, as shown in Figures 3 and 4

Is always 0 and the odd-numbered state

Is +1 or -1.

The setting step of the transmission parameter of step 502 is described.

In the setting step of the transmission parameter, the hop-frequency (Equation 8), the frequency hopping period (Equation 9), and the codeword length (Equation 10) for stably operating in the reverberation environment are set.

에 적합하게 도약-주파수

와 도약 주기

를 사용해야 한다. 그리고 코드워드의 길이

은 표적의 초기 거리

와

에 따라서 설정될 수 있다.The received signal reflected by the target which starts at high speed in the near field receives the reflected signal reflecting the large Doppler effect and the volume reverberation sound of the high power level. In order to minimize the influence of the volume reverberation sound of a high power level at a short distance, the volume reverberation band and the reception frequency band need to be separated. Therefore, the lower limit of the receiving frequency should be higher than the volume reverberation band (upper limit of the transmitting frequency).

Jump-frequency suitable for

And jump cycle

Should be used. And the length of the codeword

Is the initial distance of the target

Wow

It can be set according to.

,

,

3개의 주파수 대역을 주파수 도약 주기

간격으로 도약한다. 도약-주파수

, 주파수 도약 주기

, 그리고 코드워드 길이

은 능동 소나 시스템에서 원거리 탐색 과정으로 획득된 표적의 초기 거리

와 초기 도플러 주파수

를 기반으로 설정된다.The hopping-frequency coding based transmission signal is shown in FIG.

,

,

Frequency hopping cycle of three frequency bands

Leap at intervals. Jump-frequency

Frequency hopping cycle

, And codeword length

Is the initial distance of the target obtained by the remote search process in an active sonar system.

And initial Doppler frequency

Is set based on

보다 수신 신호의 최소 주파수

가 클 필요가 있다. 따라서 도약-주파수

는 초기 도플러 주파수

에 적합하게 수학식 8과 같이 설정한다. Maximum frequency of transmitted signal to overcome the effect of volume reverberation in near water environment

Than the minimum frequency of the received signal

Needs to be large. So jump-frequency

Initial Doppler frequency

Is set as shown in Equation 8.

와 동일하게 설정된다. 따라서 체적 잔향음의 영향을 줄이기 위해서는

를 수학식 9와 같이 설정한다.Also, the frequency band of the received volume reverberation sound is inversely proportional to the length of the correlator and the length of the correlator is the hopping period.

Is set equal to Therefore, to reduce the effect of volume reverberation

Is set as in Equation 9.

는 초기 거리

에 대한 지연시간이다. 잔향음의 영향을 줄이기 위해서

는

보다 크게 설정하며, 하나의 심볼에 최소 3번의 주파수 도약을 발생시키기 위해서

보다 작게 설정한다. here

The initial distance

Is the delay for. To reduce the effects of reverberation

Is

To make it larger, to generate at least three frequency hops in one symbol

Set it smaller.

는 송신 시점의 모호성을 제거하기 위해서 pulse repetition interval (PRI)의 설정과 유사하게 지연시간

보다 길게 사용한다. 따라서 코드워드의 길이

은 수학식 10의 범위에서 홀수를 선택하여 적용된다. The length of the transmission symbol by default

The delay time is similar to the pulse repetition interval (PRI) setting to remove ambiguity at the time of transmission.

Use longer. Thus the length of the codeword

Is selected by applying an odd number in the range of (10).

A generation step of the transmission signal in step 504 will be described.

과 마지막 상태

은 항상 +1 또는 -1이며, 제한된 주파수 대역을 벗어나지 않기 위해서 짝수 번째의 상태

은 항상 0이다. 도 3과 도 4는 각각

이 3과 5인 경우에서에 코드와 상태 변환도를 나타낸 것이며, 도약-주파수 코딩 기반 신호는 코드와 상태 변환도에 맞추어 신호를 생성한다. Hop-Frequency Coding-Based Signals Are Initially Distinct to Distinguish Adjacent Symbols

And last state

Is always +1 or -1, and is even-numbered in order not to deviate from the limited frequency band

Is always zero. 3 and 4 are respectively

In the case of 3 and 5, the code and the state transition diagram are shown, and the hopping-frequency coding based signal generates the signal according to the code and the state transition diagram.

,

인 경우에서는,

이 되어야 하며, 마지막 상태

는 +1 또는 -1인 두 가지 경우가 발생한다. 이 중에서

,

,

인 경우에 대한 송신신호의 주파수는

순으로 변경되며, 코드는

,

,

(

이기 때문에 항상 +2가 된다)가 된다. For example

,

If is

Must be the last state

There are two cases where +1 or -1. among these

,

,

The frequency of the transmission signal for

In order, and the code is

,

,

(

Because it always becomes +2).

Received signal processing method for the hopping-frequency coding based signal generated by the above method, as shown in Figure 5b, the frequency estimation step of the received signal, frequency hopping point detection and hopping-frequency estimation step, and the distance and Doppler estimation It consists of steps.

A frequency estimation step of the received signal in step 506 will be described.

는 체적 잔향음의 영향이 적은 초기 도플러 주파수

대역에서 수학식 11과 같은 범위를 만족하게 설정한다. The frequency of the received signal is estimated through a filter bank comprised of multiple Doppler correlators. Doppler Correlator Frequency Range

Is the initial Doppler frequency with less effect of volumetric reverberation

The band is set to satisfy the range shown in Equation (11).

에 대한 수신 신호 길이

과 송·수신 신호의 길이 비율

를 각각 수학식 12와 13과 같이 정리하고 상관기의 길이

는 수학식 14의 범위에 적합하게 사용되며, 도플러 상관기는 수학식 15와 같다. The Doppler correlator is designed such that the operation is performed on the signal interval before and after the frequency hopping occurs. For this purpose, the initial Doppler frequency

Received signal length for

Ratio of transmission and reception signals

Are plotted as Equations 12 and 13, respectively, and the length of the correlator

Is suitably used in the range of Equation 14, and the Doppler correlator is shown in Equation 15.

: 샘플링 주파수)(

: Sampling frequency)

은 수신신호의 추정된 주파수이며, 수학식 16과 같이 최대 상관정도를 가지는 상관기의 주파수에 해당한다. Output of filter bank consisting of multiple correlators

Is an estimated frequency of the received signal and corresponds to the frequency of the correlator having the maximum correlation degree as shown in Equation 16.

: 수신 신호)(

: Received signal)

The detection of the frequency hopping point and the hopping-frequency separation step of step 508 are described.

과 4개의 문턱값을 활용한다. 차분 평균 필터

은 주파수 도약이 발생하지 않는 시간에서는 0에 근접한 값을 가지고 주파수 도약이 발생하는 시점에서는 도약-주파수를 가지는 신호

을 안정적으로 생성하기 위해서 적용된다. 4개의 문턱값은 4개의 도약-주파수

,

,

,

의 발생 시점을 탐지하고 도약-주파수를 구분하기 위해서 사용된다. In this step, the difference average filter

And four thresholds. Differential average filter

Is a signal that has a value close to zero at the time when no frequency hopping occurs and has a hopping-frequency when the frequency hopping occurs.

It is applied to generate stably. Four thresholds are four jump-frequency

,

,

,

It is used to detect the time of occurrence and to distinguish jump-frequency.

은 도 6과 같이 길이가 2

이며, 크기가

과

인 두 구간으로 구분되는 함수이다. 잡음 환경이 열악해지거나 도약 주파수에 비해서 도약 주기가 짧을수록

의 길이를 길게 사용할 필요가 있으며, 잔향음의 파워가 반사신호의 파워보다 매우 큰 환경에서는 충분한 길이의

을 적용하는 것이 안정적으로 도약-주파수를 추정하는 데 도움이 된다.

의 출력 신호

은 도 7과 같이 주파수의 도약이 발생하는 시점에서

,

,

,

의 값을 가진다. 이 과정에서는 표 1과 도 7과 같이 4개의 문턱값

,

,

,

로

을 5개의 구간으로 분할하여서 주파수 도약이 발생한 시점

를 탐지하고 각 구간의 도약-주파수

와 할당된 코드

를 얻는다. 이 단계의 최종 출력은 주파수 도약의 탐지된 시점

, 도약-주파수

, 그리고 코드

이다. 여기서, 예시적으로 5개의 구간으로 분할하여 주파수 도약이 발생한 시점을 탐지하는 것을 설명하였지만, 그 구간의 개수에 한정되는 것은 아니다.Differential average filter

Has a length of 2 as shown in FIG.

Is the size

and

This function is divided into two intervals. The worse the noise environment or the shorter the period of hopping relative to the hopping frequency,

It is necessary to use the length of. If the power of the reverberation sound is much larger than the power of the reflected signal,

Applying this helps to estimate the hop-frequency stably.

Output signal

Is the time when the frequency leap occurs as shown in FIG.

,

,

,

Has the value In this process, four threshold values are shown in Table 1 and FIG.

,

,

,

in

Is divided into 5 sections and frequency hopping occurs

Detects the leap-frequency of each interval

And assigned code

Get The final output of this stage is the detected point of frequency hopping

, Jump-frequency

, And code

to be. Here, for example, it has been described to detect the time when the frequency hopping occurs by dividing into five sections, but is not limited to the number of sections.

의 구간

Interval Detection Jump-frequency

code

<

On -2

-2

≤

<

On -

-One

≤

<

Off 0 none

≤

<

On

One

≤

On 2

2

An estimation step of the target information of step 510 will be described.

을 사용하면 도 8과 같이 두 번째 심볼의 송신 시점

이전에 첫 번째 심볼의 반사신호가 수신된다(

<

). 주파수 도약 시점이 정상적으로 탐지되어

,

,

를 모두 획득하면

번째 주파수 도약 시점에서의 거리

와 도플러 주파수

는 다음 수학식 17 및 18과 같이 계산된다. Codeword Lengths According to Equation 10

When is used, the transmission time of the second symbol as shown in FIG.

Previously the reflected signal of the first symbol is received (

<

). Frequency hopping point is detected normally

,

,

Once you get all of

Distance at the first frequency hopping

Doppler Frequency

Is calculated by the following equations (17) and (18).

( c is the speed of sound waves)

은 필터 뱅크의 출력으로 추정된 수신신호의 주파수이고,

는

구간에서 송신신호의 주파수이다. 최종적으로 수신 코드워드

과 송신 코드워드

가 동일하다면 거리 및 도플러 추정이 정상적으로 수행되는 것이다. here

Is the frequency of the received signal estimated at the output of the filter bank,

Is

The frequency of the transmission signal in the interval. Finally receive codeword

And transmit codewords

If is equal, the distance and Doppler estimation is normally performed.

One embodiment of the present invention can also be implemented in the form of a recording medium containing instructions executable by a computer, such as a program module executed by the computer. Computer readable media can be any available media that can be accessed by a computer and includes both volatile and nonvolatile media, removable and non-removable media. In addition, computer readable media may include both computer storage media and communication media. Computer storage media includes both volatile and nonvolatile, removable and non-removable media implemented in any method or technology for storage of information such as computer readable instructions, data structures, program modules or other data. Communication media typically includes computer readable instructions, data structures, program modules, or other data in a modulated data signal such as a carrier wave, or other transmission mechanism, and includes any information delivery media.

The above description of the present invention is intended for illustration, and it will be understood by those skilled in the art that the present invention may be easily modified in other specific forms without changing the technical spirit or essential features of the present invention. will be. Therefore, it should be understood that the embodiments described above are exemplary in all respects and not restrictive. For example, each component described as a single type may be implemented in a distributed manner, and similarly, components described as distributed may be implemented in a combined form.

The scope of the present invention is shown by the following claims rather than the above description, and all changes or modifications derived from the meaning and scope of the claims and their equivalents should be construed as being included in the scope of the present invention. do.

Claims (10)

A method for transmitting / receiving based on hopping frequency coding of an active sonar system,
At the transmitter, transmitting a hopping frequency coding based continuous wave signal that hops at least three frequency bands at a period shorter than a delay time of the reflected signal; And
And obtaining a frequency, a jump time, and a hop frequency of the received signal from the receiver, and estimating a distance and a Doppler frequency of a target from the obtained frequency, the jump time and the hop frequency. The method of claim 1,
The transmitting step,
Setting a codeword and a symbol;
Setting a transmission parameter; And
And generating a transmission signal based on the set codeword, symbol, and transmission parameter. The method of claim 2,
The step of setting the codeword and symbol,
Defining a frequency of the transmission signal as a state, defining a hopping frequency as a code, and defining a code included in one symbol as a codeword;
Setting the first and last states of the symbol to have a value of +1 or -1 and the even state to zero; And
The magnitude of the hopping frequency between the states in the symbol and

And the jump-frequency between the symbols

Transmitting and receiving method comprising the step of setting. The method of claim 3, wherein
The setting step of the transmission parameter,
Setting a jump-frequency as in Equation 8;
Setting a frequency hopping period as shown in Equation 9 below; And
And a step of setting a length of a codeword as in Equation 10 below.
[Equation 8]

[Equation 9]

[Equation 10]

The method of claim 1,
The estimating step,
Estimating a frequency of the received signal;
Detecting the frequency hopping point and classifying the hopping frequency; And
Hopping frequency coding-based transmission and reception method comprising the step of estimating the information of the target. The method of claim 5,
The frequency estimation step of the received signal,
Constructing a Doppler correlator only for the frequency range of Equation 11 and estimating the frequency of the received signal; And
And generating an output signal in the form of a function of time on the estimated frequency of the received signal.
[Equation 11]

The method of claim 5,
The detecting and hopping-frequency classification step of the frequency hopping time,
Applying a differential average filter to detect the frequency hopping point;
Four threshold values for the output signal to which the difference average filter is applied

,

,

,

Dividing the data into at least five sections based on the result; And
*? * ”Is output when the frequency hopping is not detected, and when the frequency hopping is detected

, Jump-frequency

, code

Hopping frequency coding-based transmission and reception method comprising the step of outputting. The method of claim 5,
The information estimating step of the target,
Frequency hopping time of the transmission signal as shown in Equation 17

Frequency hopping point of the received signal with

Estimating the distance of the target by using; And
And estimating a Doppler frequency as shown in Equation 18.
[Equation 17]

Equation 18

(

Is the frequency of the estimated received signal,

Is

Is the frequency of the transmission signal in the interval) A recording medium having recorded thereon a program for executing a method according to any one of claims 1 to 8 on a computer. A hopping frequency coding-based transceiver of an active sonar system,
A transmitter for transmitting a hopping frequency coding based continuous wave signal that hops at least three frequency bands at a period shorter than a delay time of the reflected signal; And
And a receiver for obtaining a frequency, a hop time, and a hopping frequency of a received signal, and estimating a distance and a Doppler frequency of a target from the obtained frequency, the hopping time, and the hopping frequency.

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