Detection and communication integrated anti-collision sonar signal design method and device

Abstract

The invention discloses a detection and communication integrated anti-collision sonar signal design method and device, and the method comprises the steps: modulating a continuous frequency phase shift keying (CFPSK) signal, and generating an initial frequency and a Chirp signal; a continuous frequency phase keying signal is modulated, a BPSK signal is divided into two paths through phase modulation to be modulated to Chirp, the two paths of signals are added, and a final transmitting signal is obtained; performing pulse width modulation on the CFPSK signal, and then transmitting the CFPSK signal through a transducer of the collision avoidance sonar; acquiring an original echo signal of the collision avoidance sonar to obtain original echo data; preprocessing the collected original data to obtain a virtual signal and a real signal; the signals are compressed into signals with short pulse bandwidth, two groups of orthogonal impulse response parameters matched with filters are generated, each group is matched with virtual and real signals to obtain four groups of matching results, and the matching results are restored from a real number field to a complex number field to obtain final matching output; the starting point of a CFPSK signal is determined by detecting the peak position output by matched filtering, an echo signal is accurately intercepted from a received signal for communication decoding, and coherent detection is performed on the received signal and a reference carrier. According to the invention, cooperative work of detection and communication functions is realized.

Description

Technical Field

[0001] The invention belongs to the field of digital signal processing and underwater detection communication, and relates to a collision avoidance sonar signal design method, in particular to a collision avoidance sonar signal design method and device integrating detection and communication. Background Art

[0002] Collision avoidance sonar is a key technology widely used in underwater vehicles (such as submarines, unmanned underwater vehicles (UUVs), ships, and marine engineering. Its core function is to detect obstacles in the environment through sound waves, and issue warnings or automatically adjust the course when potential collision risks occur, thereby ensuring navigation safety. The collision avoidance sonar system includes one or more transmitters and receivers, which are usually installed in key locations such as around or on the bottom of carriers such as ships and submersibles to effectively avoid collisions. The transmitter emits wide-frequency sound wave pulses, which propagate in the water and generate echo signals after interacting with the seabed or underwater objects. The receiver receives these echo signals and then generates the location information of the underwater target through signal processing algorithms. The simple collision avoidance sonar has a single function and can only be used for detection. In order to meet the needs of underwater communication, additional logic for communication needs to be designed, and different spectrum resources need to be used. It is difficult to apply in scenarios where spectrum resources are scarce and equipment integration requirements are high.

[0003] The sonar detection and communication integrated signal is a signal design that combines sonar detection and communication functions. The core of the sonar detection and communication integrated signal is to complete the two tasks of target detection and communication functions at the same time through sound wave propagation. Target detection is the sonar obtaining the distance, direction, speed and other information of the target by processing the echo signal. The communication function is to extract the communication information after the signal is modulated during transmission and carries data through sound wave propagation and demodulated by the receiving device, so as to realize the transmission of underwater information. By designing special signal waveforms, modulation schemes, matching filters and other signal processing methods, the signal can have both detection and communication functions. At present, the sonar detection and communication integrated signal plays an important role in the fields of unmanned underwater vehicles, ocean monitoring and resource exploration, military submarine communications and coordinated collision avoidance.

[0004] Signal modulation and matching demodulation are the core parts of the integration of sonar detection and communication. Linear frequency modulation signal (Chirp) is the most common modulation signal. Its broadband characteristics allow the system to obtain a larger signal energy distribution without increasing the peak power. It is widely used in detection and communication systems. Binary phase shift keying (BPSK) is a common digital modulation method. It is relatively simple to implement. The modulation and demodulation processes are easy to implement. The modulation process only needs to map the bit value to two phases, and the demodulation process can be completed by simple phase comparison. It is suitable for resource-constrained systems. At the same time, the bandwidth of the BPSK signal is relatively narrow, and data transmission can usually be achieved by using a relatively small spectrum. This makes BPSK suitable for environments with limited spectrum resources, especially in wireless communications and sonar systems. The continuous frequency phase keying signal (CFPSK) formed by combining BPSK modulation with the Chirp signal can be used for communication and target detection at the same time. This spectrum sharing strategy effectively reduces the occupation of spectrum resources and improves spectrum utilization, allowing the system to achieve collaborative work of detection and communication functions without increasing complexity and cost. By combining the Chirp signal with the pulse compression algorithm, the system can simultaneously obtain high range resolution and long detection distance by effectively utilizing the broadband characteristics of the Chirp signal and the gain of pulse compression. The main method to achieve pulse compression is to process the received echo signal using a filter that matches the transmitted signal. The echo signal is compressed into a shorter pulse through matched filtering. Summary of the invention

[0005] The present invention aims to overcome the above-mentioned shortcomings of the prior art and provides a method and device for designing collision avoidance sonar signals integrating detection and communication.

[0006] The purpose of the present invention is to reduce the consumption of underwater spectrum resources, realize the high integration of detection and communication functions, and provide a collision avoidance sonar signal design method integrating detection and communication, which can optimize spectrum utilization and improve target recognition accuracy, while reducing computational complexity and cost and improving system efficiency and performance.

[0007] In order to solve the above technical problems, the first aspect of the present invention relates to a collision avoidance sonar signal design method integrating detection and communication, comprising the following steps:

[0008] Step 1: Modulate the continuous frequency phase keying signal CFPSK. First, generate a Chirp signal S(t) with an initial frequency of f0 and a frequency modulation slope of k.

[0009] Among them, the communication uses BPSK coding where a n is the symbol data to be sent, T is the communication data symbol time width, and rect() is the rectangular window function.

[0010] Step 2: Modulate the continuous frequency phase keying signal. The BPSK signal is modulated onto the Chirp in two ways by phase modulation, and then the two signals are added together to obtain the final transmission signal X(t).

[0011] Step 3: Pulse width modulation is performed on the CFPSK signal X(t) and then the signal is transmitted through the transducer of the collision avoidance sonar. Step 4: The original echo signal of the collision avoidance sonar is collected to obtain the original echo data x(t).

[0012] Step 5: Preprocess the collected raw data. First, perform orthogonal demodulation on the original signal and multiply it by the frequency f. c The orthogonal basis of is used to obtain the imaginary and real signals I(t) and Q(t), and the complex domain signal is converted into two real domains for processing.

[0013] Among them, after orthogonal demodulation, the center frequencies of the two original signals are moved to 0 and 2f c , retain the low-frequency components through low-pass filtering, and then downsample to reduce the sampling points, reduce the amount of calculation, and prevent signal aliasing.

[0014] Step 6: Use pulse compression technology to compress the signal into a signal with a short pulse bandwidth to obtain better distance resolution. Pulse compression is achieved by matched filtering. In order to match the real domain data processing, two sets of orthogonal matched filter impulse response parameters h1(t) and h2(t) are generated. Each set is matched with the I(t) and Q(t) signals to obtain four sets of matching results. These four sets of results are then restored from the real domain to the complex domain to obtain the final matching output H. out .

[0015] Step 7: Output H by detecting matched filtering out The peak position in the CFPSK signal can determine the starting point of the CFPSK signal, so that the echo signal H1(t) can be accurately intercepted from the received signal for communication decoding, and the received signal and the reference carrier are coherently detected, R(t) = H1(t)sin(2πf c t)+n(t).

[0016] Where n(t) is the noise, and the signal after mixing contains high-frequency components (f0+f c ) and low frequency components (f0-f c ) Use low-pass filtering to retain its low frequency, then use decimation filtering to select appropriate sampling points to obtain the discrete signal y[n], whose phase determines the bit value contained in the signal.

[0017] The second aspect of the present invention relates to a collision avoidance sonar signal design device that integrates detection and communication, including a memory and one or more processors, wherein the memory stores executable code, and when the one or more processors execute the executable code, they are used to implement a collision avoidance sonar signal design method that integrates detection and communication of the present invention.

[0018] A third aspect of the present invention relates to a computer-readable storage medium having a program stored thereon, which, when executed by a processor, implements a collision avoidance sonar signal design method integrating detection and communication of the present invention.

[0019] The present invention has the following beneficial effects:

[0020] 1. The integrated detection and communication signal design method is applied to collision avoidance sonar. Through the combination of BPSK modulation and Chirp signal, compared with the traditional collision avoidance sonar which can only complete the target detection function, the present invention enables the system to achieve the coordinated work of detection and communication functions without increasing the complexity and cost.

[0021] 2. Optimize the matching algorithm of pulse compression, divide the complex domain signal into two paths, real and imaginary, for real domain processing, match and multiply the impulse response parameters of the two sets of imaginary and real matching filters respectively to obtain four-way matching results, and obtain the final matching result through complex multiplication operation, which can effectively reduce the computational complexity and save resource consumption and cost. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 Flow chart of the method of the present invention.

[0023] Figure 2 This is a schematic diagram of the optimized matching algorithm of the present invention.

[0024] Figure 3 It is a schematic structural diagram of the device of the present invention. DETAILED DESCRIPTION

[0025] In order to better understand the above technical solution, the technical solution will be described in detail below in conjunction with the accompanying drawings and specific implementation methods.

[0026] Example 1

[0027] like Figure 1 As shown, this embodiment relates to a collision avoidance sonar signal design method integrating detection and communication, and the implementation process specifically includes the following steps:

[0028] Step 1: Modulate the continuous frequency phase keying signal CFPSK. First, generate a Chirp signal with an initial frequency of f0 and a frequency modulation slope of k.

[0029] Where f0 is the initial frequency of the Chirp signal, k is the frequency modulation slope of the Chirp signal, that is, the frequency change rate of the signal. When the starting frequency f0 = 0, S(t) = exp[jπkt 2 ]=cosπkt 2 +j sinπkt 2

[0030] Communication uses BPSK coding where a n is the symbol data to be sent, T is the communication data symbol time width, rect() is the rectangular window function, and its expression is

[0031] Step 2: Modulate the continuous frequency phase keying signal. The BPSK signal is modulated into two channels on the Chirp by phase modulation. Finally, the two channels are added together to obtain the final transmission signal X. ( t)

[0032] Specifically, the BPSK signal is divided into two channels and modulated to a Chirp with a starting frequency of zero by phase modulation, and then the two CFPSK signals are modulated to the center frequency of the collision avoidance sonar system transmission signal, and finally the center frequency is added to obtain f c , CFPSK signal with bandwidth kT:

[0033]

[0034] Where S0(t) and S1(t) are phase modulated CFPSK signals:

[0035] S0(t)=sin(2π(-BW / 2+kt / 2)t+πa(t))cos(2πf0t) (1)

[0036] S1(t)=cos(2π(-BW / 2+kt / 2)t+πa(t))sin(2πf0t) (2)

[0037] in, is f0, f c is the center frequency, BW is the bandwidth of the transmitted Chirp signal, BW=kT, k is the frequency modulation slope of the Chirp signal, T is the time width of the transmitted signal, and also the time width of the communication code element.

[0038] Step 3: Pulse width modulated CFPSK signal X(t) is transmitted through the transducer of the collision avoidance sonar.

[0039] Step 4: Figure 2 As shown, the original echo signal of the collision avoidance sonar is collected, and the original echo data x(t) is obtained after TVG amplification and AD sampling.

[0040] Step 5: Preprocess the collected raw data. First, perform orthogonal demodulation on the original signal and multiply it by the frequency f. c The orthogonal basis is used to obtain the imaginary and real signals I(t) and Q(t), and the complex domain signal is converted into two real domains for processing.

[0041]

[0042] Among them, after orthogonal demodulation, the center frequencies of the two original signals are moved to 0 and 2f c , retain the low-frequency components through low-pass filtering, and then downsample to reduce the sampling points, reduce the amount of calculation, and prevent signal aliasing.

[0043] Step 6: Use pulse compression technology to compress the signal into a signal with a short pulse bandwidth to obtain better distance resolution. Pulse compression is achieved by matched filtering. In order to match the real domain data processing, two sets of orthogonal matched filter impulse response parameters h1(t) and h2(t) are generated. Each set is matched with the I(t) and Q(t) signals to obtain four sets of matching results. These four sets of results are then restored from the real domain to the complex domain to obtain the final matching output H. out .

[0044] Specifically, the signal is divided into two paths, virtual and real, and processed in the real domain. It is matched and multiplied with the impulse response parameters h1(t) and h2(t) of the two sets of virtual and real matched filters respectively, and then restored to the complex domain according to the complex multiplication rule to obtain the final result. For a transmitted signal X(t), the signal received by the receiving transducer after a delay of t0 can be expressed as:

[0045] H delay =X * (t0-t) (6)

[0046] Wherein, when t0=0, the impulse response h(t) of the matched filter is obtained by time deconvolution and then conjugation.

[0047]

[0048] Since the signal starting frequency is moved to zero frequency through orthogonal demodulation and low-pass filtering during signal preprocessing, the impulse response function h(t) is:

[0049]

[0050] Then convert the signal from the complex domain to the real domain, and the impulse response function of the matched filter is split into two orthogonal functions:

[0051]

[0052] Then, the two preprocessed signals I(t) and Q(t) are linearly convolved with the two impulse response functions to obtain the four components of pulse compression:

[0053]

[0054] The four-way signals are reconverted into complex domain signals to obtain matching results. The target obstacle map can be drawn according to the peak position, and the echo signal can be intercepted from this peak point for communication demodulation.

[0055] H out =[I(t)+jQ(t)]·[h1(t)+jh2(t)]=H1(t)-H4(t)+j[H2(t)+H3(t)] (15)

[0056] Step 7: Output H by detecting matched filtering out The peak position in the CFPSK signal can determine the starting point of the CFPSK signal, so that the echo signal H1(t) can be accurately intercepted from the received signal for communication decoding, and the received signal and the reference carrier are coherently detected.

[0057] R(t)=H1(t)sin(2πf c t)+n(t) (16)

[0058] Where n(t) is the noise, and the signal after mixing contains high-frequency components (f0+f c ) and low frequency components (f0-f c ) Use low-pass filtering to retain its low frequency, then use decimation filtering to select appropriate sampling points to obtain a discrete signal:

[0059]

[0060] The phase πa(nT) of the signal determines the bit value contained in the signal and obtains the communication information transmitted by the target.

[0061] Example 2

[0062] like Figure 3 As shown, this embodiment relates to a collision avoidance sonar signal design device integrating detection and communication, including a memory and one or more processors, wherein the memory stores executable code, and when the one or more processors execute the executable code, it is used to implement a collision avoidance sonar signal design method integrating detection and communication of Example 1.

[0063] Example 3

[0064] The present embodiment relates to a computer-readable storage medium having a program stored thereon. When the program is executed by a processor, a collision avoidance sonar signal design method integrating detection and communication of embodiment 1 is implemented.

[0065] Finally, it should be noted that the specific scheme and embodiment described above in conjunction with the illustrations are only a preferred implementation of the present invention. Technical personnel in this profession can make slight changes and modifications to the technical content described without departing from the technical scope of the present invention. However, modifications and deformations made without departing from the spirit and principles of the present invention should fall within the scope of the technical scheme of the present invention.

Claims

1. A method for designing collision avoidance sonar signals integrating detection and communication, characterized in that: The steps include: Step 1: modulate the continuous frequency phase keying CFPSK signal to generate a linear frequency modulation signal with an initial frequency of f0 and a frequency modulation slope of k and divide it into two paths used as carriers of subsequent communication signals. When the starting frequency f0=0, it is converted into two virtual and real paths; Step 2: The communication signal is modulated into two linear frequency modulation signals by phase modulation, and then the two signals are added together to obtain the final CFPSK signal X(t); Step 3, pulse width modulating the continuous frequency phase keying signal X(t) and transmitting it through the transducer of the collision avoidance sonar; Step 4: Collect the original echo signal of the collision avoidance sonar to obtain the original echo data x(t); Step 5: Preprocess the collected raw data. First, perform orthogonal demodulation on the original signal and multiply it by the frequency f. c The orthogonal basis is used to obtain the virtual and real signals I(t) and Q(t). The complex domain signal is converted into two real domains for processing. After orthogonal demodulation, the center frequencies of the two original signals are moved to 0 and 2f c , retain the low-frequency components through low-pass filtering, and then downsample to reduce the sampling points; Step 6: Use pulse compression technology to compress the signal into a signal with a short pulse bandwidth to obtain better distance resolution. Pulse compression is achieved by matched filtering. In order to match the real domain data processing, two sets of orthogonal matched filter impulse response parameters h1(t) and h2(t) are generated. Each set is matched with the I(t) and Q(t) signals to obtain four sets of matching results. These four sets of results are then restored from the real domain to the complex domain to obtain the final matching output H. out ; Step 7: Output H by detecting matched filtering out The peak position in the waveform is used to determine the starting point of continuous frequency phase keying, so as to accurately extract the echo signal H1(t) from the received signal for communication decoding and perform coherent detection on the received signal and the reference carrier. After mixing, the signal contains high-frequency components and low-frequency components. Use low-pass filtering to retain its low frequency, and then use extraction filtering to select sampling points to obtain a discrete signal: The phase of a discrete signal determines the value of the bits it contains.

2. A collision avoidance sonar signal design method integrating detection and communication as claimed in claim 1, characterized in that: In the step 1, a Chirp signal with an initial frequency of f0 and a frequency modulation slope of k is first generated. Where f0 is the initial frequency of the Chirp signal, k is the frequency modulation slope of the Chirp signal, that is, the frequency change rate of the signal. When the starting frequency f0 = 0, S(t) = exp[jπkt 2 ]=cosπkt 2 +j sinπkt 2 ; Communication uses BPSK coding where a n is the symbol data to be sent, T is the communication data symbol time width, rect() is the rectangular window function, and its expression is 3. The method for designing a collision avoidance sonar signal integrating detection and communication as claimed in claim 1, characterized in that: In the step 2, the continuous frequency phase keying signals S0(t) and S1(t) are modulated to the center frequency of the collision avoidance sonar system transmission signal in two ways. The specific steps are as follows: 2.1 The communication signal is divided into two paths through phase modulation and modulated into a linear frequency modulation signal with a starting frequency of zero, and then the two CFPSK signals are modulated to the center frequency of the transmission signal of the collision avoidance sonar system. S0(t)=sin(2π(-BW / 2+kt / 2)t+πa(t))cos(2πf0t) (1) S1(t)=cos(2π(-BW / 2+kt / 2)t+πa(t))sin(2πf0t) (2) Among them, BW is the bandwidth of the transmitted linear frequency modulation signal, BW=kT, k is the frequency modulation slope of the Chirp signal, T is the time width of the transmitted signal, and also the time width of the communication code element. 2.2 Add the two signals to get the center frequency f c =f0+BW / 2, CFPSK signal with bandwidth BW: Using trigonometric identities to simplify, the above transmit signal result becomes: X(t)=sin(πkt 2 +πa(t))cos(2πf0t)+cos(πkt 2 +πa(t))sin(2πf0t) =sin(2πf0t+πkt 2 +πa(t)) (4)。 4. The method for designing a collision avoidance sonar signal integrating detection and communication as claimed in claim 1, characterized in that: In step 5, the expressions of the virtual and real signals I(t) and Q(t) are: 。 5. The method for designing a collision avoidance sonar signal integrating detection and communication as claimed in claim 1, characterized in that: In step six, the signal is divided into two paths, real and imaginary, and processed in the real domain. The signals are matched and multiplied with the impulse response parameters h1(t) and h2(t) of the two sets of imaginary and real matched filters respectively, and then restored to the complex domain according to the complex multiplication rule to obtain the final result.

6. The method for designing a collision avoidance sonar signal integrating detection and communication as claimed in claim 5, characterized in that: Step 6 The specific process includes: 6.1 For a transmitted signal X(t), the signal received by the receiving transducer after a time delay t0 can be expressed as: H delay =X * (t0-t) (6) When t0 = 0, the impulse response h(t) of the matched filter is obtained by time deconvolution and then conjugation: Since the signal starting frequency is moved to zero frequency through orthogonal demodulation and low-pass filtering during signal preprocessing, the impulse response function h(t) is: When the complex domain is transformed into the real domain, the impulse response function of the matched filter is split into two orthogonal functions: 6.2 The two pre-processed signals I(t) and Q(t) are linearly convolved with the two impulse response functions to obtain the four components of pulse compression: Convert the four signals back into complex domain signals: H out =[I(t)+jQ(t)]*[h1(t)+jh2(t)]=H1(t)-H4(t)+j[H2(t)+H3(t)] (15) After the matching result is obtained, a target obstacle map is drawn according to its peak position, and the echo signal is intercepted at this peak point for communication demodulation.

7. The method for designing a collision avoidance sonar signal integrating detection and communication as claimed in claim 1, characterized in that: In step 7, the formula for coherent detection of the received signal and the reference carrier is: Where n(t) is the noise, and the signal after mixing contains high-frequency components (f0+f c ) and low frequency components (f0-f c ), the formula for obtaining the discrete signal is: The phase of a discrete signal is πa(nT).

8. A collision avoidance sonar signal design device integrating detection and communication, characterized in that: It comprises a memory and one or more processors, wherein the memory stores executable codes, and when the one or more processors execute the executable codes, they are used to implement a collision avoidance sonar signal design method integrating detection and communication as described in any one of claims 1-5.

9. A computer-readable storage medium, characterized in that: A program is stored thereon, and when the program is executed by a processor, a collision avoidance sonar signal design method integrating detection and communication as described in any one of claims 1-5 is implemented.

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