Method for selecting weight of monobeam bathymetric instrument transmission waveform based on fuzzy function

Abstract

The application is suitable for the underwater topographic surveying technical field, and provides a TOPSIS weight selection method for a single-beam depth sounder transmission waveform based on ambiguity function, which comprises the following steps: inputting single-beam depth sounding performance prior information according to actual working conditions and index requirements of the single-beam depth sounder, wherein the single-beam depth sounding performance prior information comprises inputted working navigation speed range, maximum speed, range resolution and speed resolution; iteratively calculating ambiguity functions of each waveform in a waveform library to be selected, and obtaining parameters of the ambiguity functions, wherein the parameters comprise time delay measurement accuracy, frequency shift measurement accuracy and Q function, and the time delay measurement accuracy is half of the difference between the intersection points of the ambiguity function and the time delay axis, and the embodiment of the application can quantitatively evaluate the index of the transmission waveform in combination with the application scene, and improve the depth sounding accuracy of the single-beam depth sounder.

Description

Technical Field

[0001] This invention belongs to the field of underwater topographic surveying technology, and particularly relates to a TOPSIS weight selection method for transmitted waveforms of a single-beam echo sounder based on ambiguity functions. Background Technology

[0002] The most commonly used measurement method in underwater topographic surveying is the single-beam echo sounder (also known as an echo sounder). It has the advantages of being flexible and mobile, having stable performance, low cost, rapid technological updates, and outstanding derivative capabilities. It is widely used in my country's coastal waters, rivers, lakes, and other water bodies.

[0003] As the application scope of single-beam depth sounders continues to expand, the requirements for their depth measurement accuracy are also increasing. Selecting the transmission waveform based on the working performance requirements of single-beam depth sounders can not only improve the depth measurement accuracy and system robustness of single-beam depth sounders in a targeted manner, but also provide a theoretical basis for the optimization and design of new single-beam depth sounding transmission waveforms. At the same time, it also has important reference value for the selection of optimal waveforms for other similar active sonar equipment.

[0004] However, in existing technologies, especially in complex underwater environments, the depth measurement accuracy of existing single-beam echo sounding technology cannot meet actual needs. Summary of the Invention

[0005] The purpose of this invention is to provide a TOPSIS weight selection method for transmitted waveforms of a single-beam echo sounder based on an ambiguity function, aiming to solve the problems mentioned in the background art.

[0006] The present invention is implemented as follows: On one hand, a TOPSIS weight selection method for transmitted waveforms of a single-beam echo sounder based on an ambiguity function is provided, the method comprising the following steps:

[0007] Based on the actual working conditions and performance requirements of the single-beam depth sounder, prior information on the single-beam depth sounding performance is entered. This prior information includes the operating speed range, maximum speed, range resolution, and velocity resolution.

[0008] The ambiguity function of each waveform in the candidate waveform library is calculated through iteration, and the parameters of the ambiguity function are obtained. The parameters include time delay measurement accuracy, frequency shift measurement accuracy, and Q function. The time delay measurement accuracy is half the difference between the intersection of the ambiguity graph of the ambiguity function and the time delay axis, and the frequency shift measurement accuracy is half the difference between the intersection of the frequency shift axis. The time delay measurement accuracy, frequency shift measurement accuracy, and Q function are used as references for analyzing the waveform's time delay resolution, frequency resolution, and anti-reverberation interference capability, respectively.

[0009] Based on the performance indicators of single-beam depth sounding, a TOPSIS weighted model for selecting the transmitted waveform of the single-beam depth sounder with the parameters is established, and the final weighted result is used as the comprehensive performance indicator of the waveform.

[0010] Based on the transmitted waveform of the single-beam echo sounder using an ambiguity function, the TOPSIS weighting model is selected to complete the entire waveform selection.

[0011] As a further aspect of the present invention, the step of establishing a TOPSIS weighted model for selecting the transmitted waveform of the single-beam echo sounder based on the performance indicators of single-beam echo sounding, and using the final weighted result as a comprehensive performance indicator of the waveform, specifically includes:

[0012] The standard values ​​of the parameters are determined based on the actual working conditions and performance indicators. The standard values ​​of the time delay measurement accuracy and frequency shift measurement accuracy are obtained from the range resolution and velocity resolution working indicators of the single-beam depth sounder.

[0013] The parameters are positiveized based on the standard values;

[0014] The parameters that have been normalized are standardized to obtain standardized parameters;

[0015] Calculate the distances of each of the standardized parameters to their maximum and minimum values ​​to obtain the unnormalized score.

[0016] The unnormalized scores are weighted to obtain the final weighted result, which serves as a comprehensive performance index of the waveform.

[0017] As a further aspect of the present invention, the standardization of the positively oriented parameters includes:

[0018] The parameter matrix composed of the positiveized parameters is standardized.

[0019] As a further aspect of the present invention, determining the standard value of the parameter based on the actual working conditions and performance indicators includes:

[0020] The Q function is sampled within the range from 0 m / s to the maximum speed, with a sampling frequency of vmax / Δv. Within the operating speed range, Δv1 = 0.5 m / s, and outside the range, Δv2 = 1 m / s. The standard value of each parameter is taken as the maximum amplitude of the Q function at each sampling speed for each waveform.

[0021] As a further aspect of the present invention, the ambiguity function includes an ambiguity function for narrowband signals and an ambiguity function for wideband signals.

[0022] As a further aspect of the present invention, the ambiguity function of the narrowband signal is:

[0023]

[0024] In the formula, τ represents the time delay information, ξ=2v / c·f0 is the Doppler frequency shift of the signal, f0 is the center frequency of the signal, v is the velocity of motion, and c is the speed of sound in water.

[0025] As a further aspect of the present invention, the ambiguity function of the broadband signal is:

[0026]

[0027] In the formula, ζ is the Doppler compression factor, which is defined as:

[0028] As a further aspect of the present invention, the Q function can be derived from the ambiguity function, and its expression is:

[0029]

[0030] As a further aspect of the present invention, the weights of the time delay measurement accuracy and the Q function are set to 0.4, and the weight of the frequency shift measurement accuracy is set to 0.2.

[0031] This invention provides a TOPSIS weighted selection method for transmitted waveforms of a single-beam echo sounder based on ambiguity functions. The method involves inputting prior information on single-beam echo sounder performance based on the actual operating conditions and performance requirements of the single-beam echo sounder; calculating the ambiguity function of each waveform in the candidate waveform library and obtaining parameters of the ambiguity function, including time delay measurement accuracy, frequency shift measurement accuracy, and Q function; establishing a TOPSIS weighted model for single-beam echo sounder transmitted waveform selection based on the performance indicators of single-beam echo sounder, and using the final weighted result as a comprehensive performance indicator of the waveform; and selecting the TOPSIS weighted model based on the transmitted waveform of the single-beam echo sounder using ambiguity functions to complete the entire waveform selection process. This method comprehensively considers the waveform's time delay, velocity resolution, anti-reverberation interference, and anti-Doppler frequency shift capabilities, enabling targeted quantification of the evaluation indicators of the transmitted waveform in conjunction with the application scenario, improving the depth sounding accuracy of the single-beam echo sounder, and meeting practical needs. Attached Figure Description

[0032] Figure 1 This is the main flowchart of a TOPSIS weight selection method for transmitted waveforms of a single-beam echo sounder based on an ambiguity function.

[0033] Figure 2 This is a flowchart of the TOPSIS weight mode in a TOPSIS weight selection method for transmitted waveforms of a single-beam echo sounder based on an ambiguity function. Detailed Implementation

[0034] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the invention.

[0035] The specific implementation of the present invention will be described in detail below with reference to specific embodiments.

[0036] This invention provides a TOPSIS weight selection method for transmitted waveforms of a single-beam echo sounder based on an ambiguity function, which solves the technical problems in the background art.

[0037] like Figure 1 The diagram shown is a main flowchart of a TOPSIS weight selection method for a single-beam echo sounder transmitted waveform based on an ambiguity function, according to an embodiment of the present invention. The TOPSIS weight selection method for a single-beam echo sounder transmitted waveform includes:

[0038] S200: Based on the actual application scenarios of single-beam echo sounders, collect or input single-beam echo sounder performance indicators such as working environment reverberation, average sound velocity, operating speed range, maximum operating speed, frequency shift measurement accuracy, and time delay measurement accuracy according to empirical formulas.

[0039] S400: Iterates through and calculates the ambiguity function and Q function of the signals in the candidate signal library, and then obtains the frequency shift measurement accuracy and time delay measurement accuracy of each signal's ambiguity function through a two-dimensional -3dB ambiguity map. The ambiguity function for narrowband signals is:

[0040]

[0041] In the formula, τ represents the time delay information, ξ=2v / c·f0 is the Doppler frequency shift of the signal, f0 is the center frequency of the signal, v is the velocity of motion, and c is the speed of sound in water;

[0042] The ambiguity function for broadband signals is:

[0043]

[0044] In the formula, ζ is the Doppler compression factor (time compression factor), which is defined as:

[0045]

[0046] The Q function can be derived from the ambiguity function, and its expression is:

[0047]

[0048] The frequency shift measurement accuracy, time delay measurement accuracy, and the three evaluation parameters of the waveform composed of the Q function are used as references for analyzing signal speed resolution, time delay resolution, and anti-reverberation interference capability, respectively.

[0049] S600: Establish a TOPSIS weighted model for selecting the transmitted waveform of a single-beam echo sounder, corresponding to the parameters in the ambiguity function. The specific steps are as follows: Figure 2 As shown;

[0050] S1: Based on the actual operating conditions and performance indicators of the single-beam echo sounder, determine the selection of the standard values ​​x0 for each parameter: the standard values ​​for time delay measurement accuracy and frequency shift measurement accuracy are obtained from the range resolution and velocity resolution performance indicators of the single-beam echo sounder; sample the Q function within the range from 0 m / s to the maximum speed, with a sampling frequency of v. max / Δv, within the working speed range Δv1=0.5m / s, outside the range Δv2=1m / s, the standard value of each parameter index is taken as the maximum amplitude of the Q function of each waveform at each sampling speed;

[0051] S2: Based on the standard values, normalize each parameter xij' and form a new parameter matrix [xij], i.e., xij = x0 - xij';

[0052]

[0053] S3: Standardize the parameter matrix composed of the normalized parameters to eliminate the influence of the parameters. The standardized matrix is ​​Z, then we should have:

[0054]

[0055]

[0056] S4: Calculate the distances Di+ and Di- from each parameter to the maximum and minimum values, and then obtain the unnormalized score Si;

[0057]

[0058]

[0059]

[0060] S5: The weights for time measurement accuracy and Q function are set to 0.4, and the weight for frequency shift measurement accuracy is set to 0.2. The weighted result is used as the comprehensive performance index of the signal.

[0061] S800: The waveform with the largest comprehensive performance index is selected as the waveform selected based on the TOPSIS weighting method of single-beam echo sounder transmitted waveform based on ambiguity function, thus completing the entire waveform selection process.

[0062] The above embodiments of the present invention provide a TOPSIS weighted selection method for transmitted waveforms of a single-beam echo sounder based on ambiguity functions. This method involves inputting prior information on the performance of a single-beam echo sounder based on its actual operating conditions and performance requirements; calculating the ambiguity functions of each waveform in the candidate waveform library and obtaining the parameters of the ambiguity functions, including time delay measurement accuracy, frequency shift measurement accuracy, and the Q function; establishing a TOPSIS weighted model for selecting transmitted waveforms of the single-beam echo sounder based on the performance indicators of the single-beam echo sounder, and using the final weighted result as a comprehensive performance indicator of the waveform; and selecting the TOPSIS weighted model based on the transmitted waveform of the single-beam echo sounder using the ambiguity function to complete the entire waveform selection process. This method comprehensively considers the waveform's time delay, velocity resolution, and anti-reverberation interference and anti-Doppler frequency shift capabilities, enabling targeted quantification of the evaluation indicators of the transmitted waveform in conjunction with the application scenario, thereby improving the depth measurement accuracy of the single-beam echo sounder.

[0063] In order for the above methods and systems to operate smoothly, the system may include more or fewer components than those described above, or combine certain components, or different components, in addition to the various modules mentioned above. For example, it may include input / output devices, network access devices, buses, processors, and memory.

[0064] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0065] The embodiments described above are merely illustrative of several implementations of the present invention, and while the descriptions are specific and detailed, they should not be construed as limiting the scope of the present invention. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of the present invention, and these modifications and improvements all fall within the scope of protection of the present invention. Therefore, the scope of protection of this patent should be determined by the appended claims.

[0066] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A TOPSIS weight selection method for transmitted waveforms of a single-beam echo sounder based on an ambiguity function, characterized in that, The method includes: Based on the actual working conditions and performance requirements of the single-beam depth sounder, prior information on the single-beam depth sounding performance is entered. This prior information includes the operating speed range, maximum speed, range resolution, and velocity resolution. The ambiguity function of each waveform in the candidate waveform library is calculated through iteration, and the parameters of the ambiguity function are obtained. The parameters include time delay measurement accuracy, frequency shift measurement accuracy, and Q function. The time delay measurement accuracy is half the difference between the intersection of the ambiguity graph of the ambiguity function and the time delay axis, and the frequency shift measurement accuracy is half the difference between the intersection of the frequency shift axis. The time delay measurement accuracy, frequency shift measurement accuracy, and Q function are used as references for analyzing the waveform's time delay resolution, frequency resolution, and anti-reverberation interference capability, respectively. Based on the performance indicators of single-beam depth sounding, a TOPSIS weighted model for selecting the transmitted waveform of the single-beam depth sounder with the parameters is established, and the final weighted result is used as the comprehensive performance indicator of the waveform. Based on the transmitted waveform of the single-beam echo sounder based on the ambiguity function, the TOPSIS weight model is selected to complete the entire waveform selection; Specifically, the step of establishing a TOPSIS weighted model for selecting the transmitted waveform of a single-beam echo sounder based on the performance indicators of single-beam echo sounding, and using the final weighted result as a comprehensive performance indicator of the waveform, includes: The standard values ​​of the parameters are determined based on the actual working conditions and performance indicators. The standard values ​​of the time delay measurement accuracy and frequency shift measurement accuracy are obtained from the range resolution and velocity resolution working indicators of the single-beam depth sounder. The parameters are positiveized based on the standard values; The parameters that have been normalized are standardized to obtain standardized parameters; Calculate the distances of each of the standardized parameters to the maximum and minimum values, and then obtain the unnormalized score; The unnormalized scores are weighted to obtain the final weighted result, which serves as a comprehensive performance index of the waveform.

2. The TOPSIS weight selection method for transmitted waveforms of a single-beam echo sounder based on ambiguity function as described in claim 1, characterized in that, The standardization of the positively evaluated parameters includes: The parameter matrix composed of the positiveized parameters is standardized.

3. The TOPSIS weight selection method for transmitted waveforms of a single-beam echo sounder based on an ambiguity function as described in claim 1 or 2, characterized in that, Determining the standard values ​​of the parameters based on the actual working conditions and performance indicators includes: The Q function is sampled within the range from 0 m / s to the maximum speed, with a sampling frequency of v. max / Δv, within the working speed range Δv1=0.5m / s, outside the range Δv2=1m / s, the standard value of each parameter index is taken as the maximum amplitude of the Q function of each waveform at each sampling speed.

4. The TOPSIS weight selection method for transmitted waveforms of a single-beam echo sounder based on ambiguity function according to claim 1, characterized in that, The ambiguity function includes the ambiguity function for narrowband signals and the ambiguity function for wideband signals.

5. The TOPSIS weight selection method for transmitted waveforms of a single-beam echo sounder based on ambiguity function according to claim 4, characterized in that, The ambiguity function of the narrowband signal is: ； In the formula, τ represents the time delay information, ξ=2v / c·f0 is the Doppler frequency shift of the signal, f0 is the center frequency of the signal, v is the velocity of motion, and c is the speed of sound in water.

6. The TOPSIS weight selection method for transmitted waveforms of a single-beam echo sounder based on ambiguity function according to claim 5, characterized in that, The ambiguity function of the broadband signal is: ； In the formula, ζ is the Doppler compression factor, which is defined as: .

7. The TOPSIS weight selection method for transmitted waveforms of a single-beam echo sounder based on an ambiguity function as described in claim 6, characterized in that, The Q function can be derived from the ambiguity function, and its expression is: 。 8. The TOPSIS weight selection method for transmitted waveforms of a single-beam echo sounder based on an ambiguity function as described in claim 1, 2, 4, 5, 6, or 7, characterized in that, The weights for the time delay measurement accuracy and the Q function are set to 0.4, and the weight for the frequency shift measurement accuracy is set to 0.2.

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