A method and device for designing integrated collision avoidance sonar signals for probing communication

Abstract

The application discloses a kind of detection communication integrated collision avoidance sonar signal design method and device, its method includes: modulating continuous frequency phase shift keying signal CFPSK, generates initial frequency and Chirp signal;Modulate continuous frequency phase shift keying signal, BPSK signal is modulated to Chirp by phase modulation two-way, then two-way signal is added, obtains final transmitting signal;After CFPSK signal is pulse width modulated, it is emitted by the transducer of collision avoidance sonar;Collecting collision avoidance sonar original echo signal, obtains original echo data;Original data collected is preprocessed, and two-way signal of virtual and real is obtained;Signal is compressed into short pulse bandwidth signal, generates the impulse response parameter of two groups of matched filters, each group is matched with virtual and real two-way signal to obtain four groups of matching results, and the final matching output is obtained from real number field to complex number field;The starting point of CFPSK signal is determined by detecting the peak position of matched filter output, and echo signal is accurately intercepted from received signal for communication decoding, and coherent detection is carried out on received signal and reference carrier.The application realizes the cooperative work of detection and communication function.

Description

TECHNICAL FIELD

[0001] The application 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 detection and communication integrated collision avoidance sonar signal design method and device. BACKGROUND

[0002] The collision avoidance sonar is a key technology widely used in underwater vehicles (such as submarines, unmanned underwater vehicles UUV), ships and ocean engineering. Its core function is to detect obstacles in the environment through sound waves and issue a warning or automatically adjust the heading when potential collision danger occurs, thereby realizing the protection of navigation safety. The collision avoidance sonar system includes one or more transmitters and receivers, which are usually installed around or at the bottom of the key parts of the carrier such as ships, submarines, etc. to effectively avoid collision. The transmitter emits a wide frequency sound wave pulse, and the sound wave propagates in the water and interacts with the seabed or underwater objects to generate a return signal. The receiver receives these return signals and then generates the position information of the underwater target through signal processing algorithms. The pure collision avoidance sonar function is single and can only be used for detection. In order to meet the demand of underwater communication, additional communication logic needs to be designed, and different spectrum resources need to be used, which is difficult to apply in scenarios where spectrum resources are scarce and equipment integration is required.

[0003] The sonar detection and communication integrated signal is a signal design combining 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 function through sound wave propagation. Target detection is the process of obtaining the distance, direction, speed, etc. of the target by processing the return signal of the sonar. The communication function is to carry data through modulation in signal transmission, and the communication information is extracted after the signal is demodulated by the receiving device, realizing the transmission of underwater information. Through the design of special signal waveform, modulation scheme and matching filter and other signal processing means, the signal can have both detection and communication functions. At present, the sonar detection and communication integrated signal plays an important role in unmanned underwater vehicles, ocean monitoring and resource exploration, military submarine communication and cooperative collision avoidance, etc.

[0004] Signal modulation and matched demodulation is the core part of sonar detection and communication integration. Chirp signal is the most common modulation signal, its wideband characteristics allow the system to obtain greater signal energy distribution without increasing the peak power, and it is widely used in detection and communication systems. Binary phase shift keying (BPSK) is a common digital modulation method, which is relatively simple to implement, and the modulation and demodulation process is 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, which is suitable for resource limited system. At the same time, the bandwidth of BPSK signal is relatively narrow, and data transmission can usually be realized by using relatively small spectrum. This makes BPSK suitable for frequency spectrum limited environment, especially in wireless communication and sonar system. The continuous frequency phase shift keying signal (CFPSK) combined with BPSK modulation and 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 the spectrum utilization, so that the system can realize the cooperative work of detection and communication function without increasing the complexity and cost. By effectively using the wideband characteristics of Chirp signal and the gain of pulse compression, the system can obtain high range resolution and long detection distance at the same time. The main method to realize pulse compression is to use a filter matched with the transmitted signal to process the received echo signal. Through matched filtering, the echo signal is compressed into a shorter pulse. SUMMARY

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

[0006] The purpose of the present application is to reduce the consumption of underwater spectrum resources, realize the high integration of detection and communication function, and provide a method for designing collision avoidance sonar signal for detection and communication integration, which can optimize spectrum utilization, improve target recognition accuracy, reduce calculation complexity and cost, and improve the efficiency and performance of the system.

[0007] To solve the above technical problems, the first aspect of the present application relates to a method for designing collision avoidance sonar signal for detection and communication integration, comprising the following steps:

[0008] Step one, modulate the continuous frequency phase shift keying signal CFPSK, first generate a Chirp signal S(t) with initial frequency f0 and frequency modulation slope k.

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

[0010] Step two, modulate the continuous frequency phase shift keying signal, the BPSK signal is modulated to the Chirp by phase modulation, and finally the two signals are added to obtain the final transmitting signal X(t).

[0011] Step three, the CFPSK signal X(t) is pulse width modulated and transmitted through the transducer of the collision avoidance sonar.

[0012] Step five, the collected original data is preprocessed, first, the original signal is quadrature demodulated, multiplied by the quadrature base with a frequency of f c , to obtain two-way signals I(t) and Q(t), and the complex domain signal is converted into two-way real domain for processing.

[0013] Among them, the center frequency of the two-way original signal after quadrature demodulation is moved to 0 and 2f c , the low-frequency components are reserved by low-pass filtering, and then the sampling points are reduced to reduce the calculation amount and prevent signal aliasing.

[0014] Step six, the signal is compressed into a short pulse bandwidth signal using pulse compression technology to obtain better range resolution, and the pulse compression is realized by using matched filtering, in order to match the real number domain data processing, generate the impulse response parameters h1(t) and h2(t) of the two sets of matched filters, each set is matched with I(t) and Q(t) signals to obtain four sets of matching results, and then the four sets of results are restored from the real number domain to the complex domain to obtain the final matching output H out .

[0015] Step seven, by detecting the peak position in the matched filter output H out , the starting point of the CFPSK signal can be determined, so that the echo signal H1(t) is accurately intercepted from the received signal for communication decoding, and the received signal and the reference carrier are coherently detected, and after mixing, the signal contains high frequency components (f0+f c ) and low frequency components (f0-f c ), the low frequency is reserved by low-pass filtering, and then the discrete signal y[n] is obtained by decimation filtering and selecting appropriate sampling points, and the phase determines the bit value contained in the signal.

[0016] The second aspect of the application relates to a collision avoidance sonar signal design device integrating detection and communication, comprising a memory and one or more processors, the memory stores executable code, and the one or more processors execute the executable code to realize the collision avoidance sonar signal design method integrating detection and communication.

[0017] The third aspect of the present application relates to a computer readable storage medium, having stored thereon a program which, when executed by a processor, implements a method for designing a collision avoidance sonar signal of integrated detection and communication.

[0018] The present application has the following beneficial effects:

[0019] 1. The method of designing a signal of integrated detection and communication is applied to a collision avoidance sonar, and through the combination of BPSK modulation and Chirp signals, compared with the traditional collision avoidance sonar which can only complete target detection, the present application enables the system to realize the cooperative work of detection and communication functions without increasing complexity and cost.

[0020] 2. The matched algorithm of pulse compression is optimized, the complex domain signal is divided into real and imaginary two paths for real domain processing, respectively matched and multiplied with the impulse response parameters of the real and imaginary two groups of matched filters to obtain four matched results, and the final matched result is obtained through complex multiplication operation splitting and combination, which can effectively reduce the calculation complexity, save resource consumption and cost. BRIEF DESCRIPTION OF DRAWINGS

[0021] Figure 1 The flowchart of the method of the present application.

[0022] Figure 2 The principle diagram of the optimized matched algorithm of the present application.

[0023] Figure 3 The structure schematic diagram of the device of the present application. DETAILED DESCRIPTION

[0024] In order to better understand the above technical solutions, the technical solutions will be described in detail below in combination with the drawings of the specification and the specific embodiments.

[0025] Embodiment 1

[0026] As shown in the drawings, Figure 1 The present embodiment relates to a method for designing a collision avoidance sonar signal of integrated detection and communication, and the implementation process specifically includes the following steps:

[0027] Step one, modulate the continuous frequency phase shift keying signal CFPSK, first generate a Chirp signal with an initial frequency f0 and a frequency modulation slope k

[0028] Wherein, 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 initial frequency f0 = 0,

[0029] The communication uses BPSK encoding Wherein a nFor the symbol data to be sent, T is the time width of the communication data symbol, rect() is a rectangular window function, and its expression is

[0030] Step two, modulate the continuous frequency phase keying signal, the BPSK signal is modulated to the Chirp in two ways by phase modulation, and finally the two signals are added to obtain the final transmitting signal X(t);

[0031] Specifically, the BPSK signal is modulated to the Chirp with a starting frequency of zero in two ways by phase modulation, and then the two CFPSK signals are modulated to the center frequency of the collision avoidance sonar system transmitting signal, and finally added to obtain the CFPSK signal with a center frequency of f c and a bandwidth of kT:

[0032]

[0033] Wherein, S0(t) and S1(t) are CFPSK signals modulated by phase:

[0034] S0(t) = sin(2π(-BW / 2 + kt / 2)t + πa(t))cos(2πf0t) (1)

[0035] S1(t) = cos(2π(-BW / 2 + kt / 2)t + πa(t))sin(2πf0t) (2)

[0036] Wherein, f0, f c is the center frequency, and BW is the bandwidth of the transmitting Chirp signal, BW = kT, k is the frequency modulation slope of the Chirp signal, and T is the time width of the transmitting signal, which is also the time width of the communication symbol.

[0037] Step three, pulse width modulate the CFPSK signal X(t) and transmit it through the transducer of the collision avoidance sonar.

[0038] Step four, as shown in Figure 2 , collect the original echo signal of the collision avoidance sonar, and obtain the original echo data x(t) after TVG amplification and AD sampling.

[0039] Step five, pre-process the collected original data, first orthogonal demodulate the original signal, multiply by the orthogonal base with a frequency of f c , obtain the virtual and real two-way signals I(t) and Q(t), and convert the complex domain signal into two-way real domain for processing

[0040]

[0041] Wherein, the center frequency of two original signals after orthogonal demodulation is moved to 0 and 2f c The low-frequency component is reserved by low-pass filtering, and then the sampling points are reduced by downsampling to reduce the calculation amount and prevent signal aliasing.

[0042] Step six, using pulse compression technology to compress the signal into a short pulse bandwidth signal to obtain better range resolution, using matched filtering to realize pulse compression, in order to match the real number domain data processing, generate two sets of matched filter impulse response parameters h1(t) and h2(t) Orthogonal, each group is matched with I(t) and Q(t) signal to get four sets of matching results, and then restore the four sets of results from the real number domain to the complex domain to get the final matching output H out .

[0043] Specifically, the signal is divided into virtual and real two paths for real number domain processing, respectively matched with virtual and real two sets of matched filter impulse response parameters h1(t) and h2(t) Multiplication, and then restored to the complex domain according to the complex multiplication law to get the final result. For a transmitted signal X(t), the signal received by the receiving transducer after time delay t0 can be expressed as:

[0044] H delay =X * (t0-t) (6)

[0045] In the formula, when t0=0, the time deconvolution of the matched filter impulse response h(t) is obtained, and then the conjugate is taken.

[0046]

[0047] Because the signal starting frequency is moved to zero frequency by orthogonal demodulation and low-pass filtering during signal preprocessing, the impulse response function h(t) is:

[0048]

[0049] Then the signal is converted from the complex domain to the real number domain, and the matched filter impulse response function is split into two virtual and real orthogonal functions:

[0050]

[0051] Then linearly convolve the two signals I(t) and Q(t) after signal preprocessing with the two impulse response functions to obtain four components of pulse compression:

[0052]

[0053] The four-way signal is re-converted into a complex domain signal to obtain a matching result, and a target obstacle map can be drawn according to the peak position, and the echo signal is intercepted at the peak value point for communication demodulation,

[0054] H out = [I(t) + jQ(t)] * [h1(t) + jh2(t)] = H1(t) - H4(t) + j[H2(t) + H3(t)] (15)

[0055] Step seven, the starting point of the CFPSK signal is determined by detecting the peak position in the matched filter output H out , and the echo signal H1(t) is accurately intercepted from the received signal for communication decoding. The received signal is coherently detected with the reference carrier, and after mixing, the signal contains high frequency components (f0+f c ) and low frequency components (f0-f c ). The low pass filter is used to retain the low frequency, and then the decimation filter is used to select appropriate sampling points to obtain the discrete signal.

[0056]

[0057] The phase of the signal πa(nT) determines the bit value contained in the signal, and the communication information transmitted by the target is obtained.

[0058] Embodiment 2

[0059] As shown in Figure 3 , the embodiment relates to a detection and communication integrated collision avoidance sonar signal design device, which comprises a memory and one or more processors, the memory stores executable code, and the one or more processors execute the executable code to implement the detection and communication integrated collision avoidance sonar signal design method of embodiment 1.

[0060] Embodiment 3

[0061] The embodiment relates to a computer readable storage medium, which stores a program, and the program is executed by a processor to implement the detection and communication integrated collision avoidance sonar signal design method of embodiment 1.

[0062] Finally, it should be noted that the specific scheme and embodiment described above in conjunction with the figure are only a preferred embodiment of the present application, and those skilled in the art can make some changes and changes to the described technical content without departing from the technical scope of the present application. The modifications and modifications made without departing from the spirit and principles of the present application should be within the scope of the technical scheme of the present application.

Claims

1. A method for designing a collision avoidance sonar signal for integrated communication and detection, characterized by, It comprises the following steps: Step one, modulate the continuous frequency phase shift keying CFPSK signal, generate a linear frequency modulation signal with initial frequency f0 and frequency modulation slope k, and divide it into two paths to be used as the carrier of the subsequent communication signal, when the initial frequency f0=0, it is converted into two paths of virtual and real; Step two, the communication signal is modulated onto the linear frequency modulation signal in two paths by phase modulation, and finally the two signals are added to obtain the final CFPSK signal X(t); Step three, the continuous frequency phase shift keying signal X(t) is pulse width modulated and transmitted through the transducer of the collision avoidance sonar; Step four, collect the original echo signal of the collision avoidance sonar to obtain the original echo data x(t); Step five, the original data collected for pretreatment, first to the original signal quadrature demodulation, multiplied by the frequency of f c quadrature basis, get virtual real two-way signal I(t) and Q(t), the complex domain signal into two real domain for processing, quadrature demodulation after the center frequency of two original signal is moved to 0 and 2f c , by low-pass filter to retain low frequency components, then down sampling to reduce the sampling points; Step six, using pulse compression technology to compress the signal into a short pulse bandwidth signal to obtain better range resolution, using matched filtering to realize pulse compression, in order to match the real number domain data processing, generate the impulse response parameters h1(t) and h2(t) of two sets of matched filters, each set is matched with I(t) and Q(t) signal respectively to obtain four sets of matching results, and then restore the four sets of results from the real number domain to the complex number domain to obtain the final matching output H out ; Step seven, the start point of the continuous frequency phase keying is determined by detecting the peak position in the matched filter output H out , and the echo signal H1(t) is accurately cut from the received signal for communication decoding. The received signal is coherently detected with the reference carrier, After mixing, the signal contains high frequency components and low frequency components, use low pass filter to retain the low frequency, and then through decimation filter, select the sampling points to obtain the discrete signal: The phase of the discrete signal determines the bit value contained in the signal.

2. The method of designing a collision avoidance sonar signal for integrated communication and detection of claim 1, wherein In the step one, first generate Chirp signal with initial frequency f0 and frequency modulation slope k wherein f0is the initial frequency of the Chirp signal, k is the frequency modulation slope of the Chirp signal, i.e. the rate of change of the frequency of the signal, and when the initial frequency f0= 0, The communication uses BPSK encoding where a n is the symbol data to be transmitted, T is the time width of the communication data symbol, and rect() is a rectangular window function whose expression is 3. The method of designing a collision avoidance sonar signal for integrated communication and detection of claim 1, wherein In step two, the continuous frequency phase shift keying signals S0(t) and S1(t) are modulated onto the center frequency of the collision avoidance sonar system transmission signal in two paths, the specific steps are as follows: 2.1 The communication signal is modulated onto the linear frequency modulation signal with zero initial frequency in two paths, and then the two CFPSK signals are modulated onto the center frequency of the collision avoidance sonar system transmission signal, 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) Where, BW is the bandwidth of the transmitted linear frequency modulation signal, BW=kT, k is the frequency modulation slope of the Chirp signal, and T is the time width of the transmitted signal, which is also the time width of the communication symbol; 2.2 Adding the two signals gives a CFPSK signal with a center frequency of f c = f0+ BW / 2, and a bandwidth of BW. Simplify using the identity of the triangle, so the above transmission 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 of designing a collision avoidance sonar signal for integrated communication and detection of claim 1, wherein In step five, the expressions of the virtual and real two paths of signals I(t) and Q(t) are: 。 5. The method of designing a collision avoidance sonar signal for integrated communication and detection of claim 1, wherein In step six, the signal is divided into virtual and real two paths for real number domain processing, respectively multiplied by the impulse response parameters h1(t) and h2(t) of the virtual and real two sets of matched filters, and then restored to the complex domain to obtain the final result according to the complex multiplication rule.

6. The method of designing a collision avoidance sonar signal for integrated communication and detection of claim 5, wherein, The specific process of step six includes: 6.1 For a transmitted signal X(t), the signal received by the receiving transducer after a time delay t0 can be represented as: H delay = X * (t0-t) (6) When t0=0, the time deconvolution of the impulse response h(t) of the matched filter is obtained, and then the conjugate is taken: Because the signal is moved to zero frequency by orthogonal demodulation and low pass filtering during signal preprocessing, the impulse response function h(t) is: The complex domain is converted to the real domain, and the impulse response function of the matched filter is split into two orthogonal functions of virtual and real: 6.2 Linear convolution of the two signals I(t) and Q(t) after signal preprocessing with the two impulse response functions can obtain four components of pulse compression: The four-path signal is converted into a complex domain signal again: H out = [I(t) + jQ(t)] * [h1(t) + jh2(t)] = H1(t) - H4(t) + j[H2(t) + H3(t)] (15) The matching result is obtained, and the target obstacle map is drawn according to the peak position, and the echo signal is intercepted at the peak value point for communication demodulation.

7. A device for designing a collision avoidance sonar signal for integrated communication, characterized in that An apparatus includes a memory having executable code stored therein and one or more processors that execute the executable code to implement the method of any of claims 1-5.

8. A computer-readable storage medium, characterized in that, A non-transitory computer-readable medium having stored thereon a program that, when executed by a processor, implements the method of any of claims 1-5.

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