阅读说明：本技术 一种被动声纳浮标多通道信号间的幅度相位误差补偿方法 (Amplitude phase error compensation method among passive sonobuoy multi-channel signals ) 是由 李昶 王英民 于 2020-11-08 设计创作，主要内容包括：本发明公开了一种被动声纳浮标多通道信号间的幅度相位误差补偿方法,首先对被动声呐浮标阵元接收到的信号进行滤波和放大,再计算信号的幅度均方根和相位均方根,找到偏离幅度均方根和相位均方根最远的通道,然后计算除最远通道外其余通道的幅度均方根和相位均方根,最后用新计算的幅度均方根和相位均方根代替原来的幅度和相位,重复以上过程,直到幅度方差和相位方差达到设定精度,完成幅度相位误差补偿。本发明能够降低被动声纳浮标的多通道接收信号之间由电路设计及器件不一致性引起的幅度和相位误差,实现更精准的方向估计的目的。(The invention discloses an amplitude phase error compensation method among passive sonar buoy multi-channel signals, which comprises the steps of filtering and amplifying signals received by passive sonar buoy array elements, calculating the amplitude root mean square and the phase root mean square of the signals, finding a channel which deviates from the amplitude root mean square and the phase root mean square furthest, calculating the amplitude root mean square and the phase root mean square of the other channels except the furthest channel, replacing the original amplitude and phase with the newly calculated amplitude root mean square and phase root mean square, repeating the processes until the amplitude variance and the phase variance reach set precision, and finishing amplitude phase error compensation. The invention can reduce the amplitude and phase errors caused by circuit design and device inconsistency among the multi-channel receiving signals of the passive sonobuoy, and realize the purpose of more accurate direction estimation.)

1. A method for compensating amplitude phase errors among multi-channel signals of a passive sonobuoy is characterized by comprising the following steps:

step 1: assuming that the signal transmitted by the target is a sinusoidal signal, noteA is the signal amplitude, ω is the signal frequency,is the signal phase; the passive sonar buoy comprises k array elements;

step 2: inputting the signals received by each array element into a preprocessing system, filtering and amplifying to form k channel output signals, and recording the k channel output signals asi is the number of channels, i is 1,2, …, k, A_iThe amplitude of the output signal for the ith channel,outputting the phase of a signal for the ith channel, wherein each channel corresponds to an array element;

and step 3: and (3) calculating:

amplitude root mean squareAmplitude variancePhase root mean square Phase varianceWherein

And 4, step 4: calculation of A_ib＝MAX{abs(A_i-A_RMS) Andib belongs to {1,2, …, k }, ic belongs to {1,2, …, k }, and the maximum difference value between the amplitude and the root mean square of the amplitude of the output signal of the ib channel and the phase of the output signal of the ic channel is obtained;

and 5: calculating the amplitude root mean square A of output signals of the rest k-1 channels except the ib channel according to the method in the step 3_RMSbCalculating the phase root mean square of the output signals of the k-1 channels except the ith channel

Step 6: let A_ibIs equal to A_RMSb，Is equal toTo obtain

And 7: and (5) repeating the steps 3 to 6 until the precision of the amplitude variance and the precision of the phase variance reach the set precision, and finishing amplitude phase error compensation.

Technical Field

The invention belongs to the technical field of signal processing, and particularly relates to a signal compensation method.

Background

The working principle of the passive sonobuoy is that the functions of detecting, identifying, positioning and the like of a target are realized by utilizing deviation comparison among underwater target signals received by a plurality of array elements. These signals mainly include parameters such as amplitude, phase and frequency, and the deviation thereof mainly consists of two parts: one part is phase deviation caused by the position of the array element, the size of the phase deviation is related to parameters such as the spacing of the array element, the working frequency and the like, and the rear end signal processing of the buoy mainly depends on the deviation to finish the detection and the positioning of a target; the other part is amplitude and phase errors caused by inconsistency of devices (such as fluctuation of resistance and capacitance values and the like) in the signal processing circuit of the preamplifier, the magnitude of the amplitude and phase errors is influenced by factors such as device characteristics, operating frequency, operating temperature and the like, and the amplitude and phase errors can interfere with the result of back-end signal processing.

At present, researches on amplitude and phase consistency of multichannel signals of a sonar buoy are few, a novel multistage amplification filtering preprocessing circuit is designed in a text of high-consistency low-noise multichannel underwater sound signal preprocessing design method by a zhahian Gem et al, a multichannel signal processing system for controlling filtering bandwidth through a CPLD is designed in a text of a multichannel sonar signal preprocessing system design by a Ming Qing et al, and the problems of amplitude and phase errors caused by inconsistency of devices to different channels are not considered in the researches. Huzhuyin et al, in the article "ranging error correction in positioning of an oblique distance measuring buoy", a method for improving measurement accuracy by installing a crystal oscillator in a buoy is provided, but the method belongs to a mechanical compensation method and is mainly effective for an active sonar buoy.

Disclosure of Invention

In order to overcome the defects of the prior art, the invention provides an amplitude phase error compensation method among passive sonar buoy multi-channel signals, which comprises the steps of filtering and amplifying signals received by passive sonar buoy array elements, calculating the amplitude root mean square and the phase root mean square of the signals, finding the channel which deviates from the amplitude root mean square and the phase root mean square furthest, calculating the amplitude root mean square and the phase root mean square of the other channels except the channel furthest away, replacing the original amplitude and phase with the newly calculated amplitude root mean square and phase root mean square, repeating the processes until the amplitude variance and the phase variance reach the set precision, and finishing amplitude phase error compensation. The invention can reduce the amplitude and phase errors caused by circuit design and device inconsistency among the multi-channel receiving signals of the passive sonobuoy, and realize the purpose of more accurate direction estimation.

The technical scheme adopted by the invention for solving the technical problem comprises the following steps:

step 1: assuming that the signal transmitted by the target is a sinusoidal signal, noteA is the signal amplitude, ω is the signal frequency,is the signal phase; the passive sonar buoy comprises k array elements;

step 2: inputting the signals received by each array element into a preprocessing system, filtering and amplifying to form k channel output signals, and recording the k channel output signals asi is the number of channels, i is 1,2, …, k, A_iThe amplitude of the output signal for the ith channel,outputting the phase of a signal for the ith channel, wherein each channel corresponds to an array element;

and step 3: and (3) calculating:

amplitude root mean squareAmplitude variancePhase root mean square Phase varianceWherein

And 4, step 4: calculation of A_ib＝MAX{abs(A_i-A_RMS) Andib belongs to {1,2, …, k }, ic belongs to {1,2, …, k }, and the maximum difference value between the amplitude and the root mean square of the amplitude of the output signal of the ib channel and the phase of the output signal of the ic channel is obtained;

and 5: calculating the amplitude root mean square A of output signals of the rest k-1 channels except the ib channel according to the method in the step 3_RMSbCalculating the phase root mean square of the output signals of the k-1 channels except the ith channel

Step 6: let A_ibIs equal to A_RMSb，Is equal toTo obtain

And 7: and (5) repeating the steps 3 to 6 until the precision of the amplitude variance and the precision of the phase variance reach the set precision, and finishing amplitude phase error compensation.

By adopting the amplitude phase error compensation method among the multi-channel signals of the passive sonobuoy, the amplitude and phase errors caused by circuit design and device inconsistency among the multi-channel receiving signals of the passive sonobuoy can be reduced; by compensating the amplitude phase of each channel to the actually measured signal in advance, the variance of the amplitude phase difference between the channels is reduced, and the overall difference index is improved, so that the influence of phase errors on the direction estimation result is reduced, and the purpose of more accurate direction estimation is realized.

Drawings

FIG. 1 is a schematic diagram of an amplitude phase error compensation method according to the present invention.

Fig. 2 is a schematic diagram of the passive sonar buoy signal reception according to the present invention.

Fig. 3 is a beam pattern generated by the ideal array element spacing of the present invention.

Fig. 4 is a beam pattern formed by inserting random numbers into the array element spacing and the corresponding random array according to the first embodiment of the present invention.

Fig. 5 is a beam pattern formed by inserting random numbers into the array element spacing and the corresponding random array according to the second embodiment of the present invention.

FIG. 6 is a waveform diagram of output signals of 5 channels according to the embodiment of the present invention.

FIG. 7 is a simulation graph of waveform fitting of output signals of 5 channels according to an embodiment of the present invention.

Detailed Description

The invention is further illustrated with reference to the following figures and examples.

As shown in fig. 1, a method for compensating amplitude phase error between multi-channel signals of a passive sonobuoy includes the following steps:

step 1: assuming that the signal transmitted by the target is a sinusoidal signal, noteA is the signal amplitude, ω is the signal frequency,is the signal phase; the passive sonar buoy comprises k array elements;

step 2: inputting the signals received by each array element into a preprocessing system, filtering and amplifying to form k channel output signals, and recording the k channel output signals asi is the number of channels, i is 1,2, …, k, A_iThe amplitude of the output signal for the ith channel,outputting the phase of a signal for the ith channel, wherein each channel corresponds to an array element;the signal acquisition and analysis process can be completed by Matlab simulation of an oscilloscope and an upper computer, the data of the received signal of the whole screen is acquired in the oscilloscope and stored as a csv file, Matlab is imported and an expression is fitted outA_kTo fit the signal amplitude, ω is the signal frequency,is the fitted signal phase;

and step 3: and (3) calculating:

amplitude root mean squareAmplitude variancePhase root mean squarePhase varianceWherein

And 4, step 4: calculation of A_ib＝MAX{abs(A_i-A_RMS) Andib belongs to {1,2, …, k }, ic belongs to {1,2, …, k }, and the maximum difference value between the amplitude and the root mean square of the amplitude of the output signal of the ib channel and the phase of the output signal of the ic channel is obtained;

and 5: calculating the amplitude root mean square A of output signals of the rest k-1 channels except the ib channel according to the method in the step 3_RMSbCalculating the phase root mean square of the output signals of the k-1 channels except the ith channel

Step 6: let A_ibIs equal to A_RMSb，Is equal toTo obtain

And 7: and (5) repeating the steps 3 to 6 until the precision of the amplitude variance and the precision of the phase variance reach the set precision, and finishing amplitude phase error compensation.

The specific embodiment is as follows:

as shown in fig. 2, taking the phase difference of the uniform line array as an example, the far-field acoustic signals received by each array element are regarded as equal to the incoming wave direction α (°), i.e. α (°) is ═ FBC. The array element spacing AB of the uniform linear array is BC, CD, DE, d (m). As known, the straight line where CF is located is the wavefront (CF ≠ BF), the acoustic path difference BF (m) ═ dcos α ═ c τ of the signals received by the adjacent array elements, where c (m/s) is the underwater sound velocity and τ(s) is the incoming wave time difference. Ideally, only the phase difference of adjacent channels needs to be measured at the output end of signal preprocessingAccording toCan obtain the phase differenceThe camber value of (1) is the time difference tau of incoming wave. Then the direction of the incoming wave in the ideal case

In actual measurement, the phase difference output at the signal processing end due to the error isWhereinI.e. an additional bias caused by the non-uniformity of the circuit device, which leads to an erroneous estimation of the incoming wave direction, i.e. the circuit device is not uniform

In order to avoid the errors as much as possible, the invention utilizes the principle that industrial devices (such as resistors, capacitors, operational amplifiers and the like) delay attenuation of signals with different frequencies is relatively stable under a certain temperature environment, measures the consistency errors of different frequencies in the working temperature range of the existing circuit design, and uses the consistency errors as the compensation basis in the working process.

Using conventional beamforming algorithms, taking a 16-element uniform linear array as an example, the array element spacing d (m) is typically half a wavelength, and the incoming wave direction is set to 20 °. And sequentially inserting a random number into the array element interval (the random number is subjected to normal distribution with the expected 0 and the variance of 0.01) so as to simulate the system error which can occur in the actual measurement.

Fig. 3 is a beam pattern generated by an ideal array element spacing, and fig. 4 and 5 are a beam pattern formed by inserting random numbers into the array element spacing and a corresponding random array. It can be seen that under the influence of systematic errors, an erroneous incoming wave direction estimation result occurs, or the incoming wave direction cannot be estimated at all. The effect of the invention can be realized by advancing each channelCompensating the actual measurement signal, reducing the variance of the amplitude phase difference between the channels, and improving the overall difference index, thereby achieving the purpose of reducingThe influence on the direction estimation result realizes the purposes of more accurate direction estimation and the like.

As shown in fig. 1, the wave front of the far-field incident signal is regarded as an equidistant plane, and the equidistant plane is received by the uniform linear array of the sonobuoy and enters the preprocessing circuit. A standard sine signal is generated from a signal generator and input into a preprocessing circuit, waveform data are collected and output through an oscilloscope, an amplitude phase difference value is fitted and analyzed and recorded in an upper computer, the difference value is used for compensating a signal to be detected, and subsequent processing is carried out.

Fig. 6 is waveform data respectively collected from 5 channels after passing through a float preprocessing circuit using a standard sinusoidal signal generated by a signal generator, with an amplitude of 0.5V and a frequency of 3kHz (ω ═ 2 π f ≈ 18850 rad/s). It can be seen that there is a significant deviation in amplitude and a small deviation in phase.

The output signals of the five channels are fitted using the cftool function fitting tool in matlab, and the resulting sine wave approximation function is shown in fig. 7.

As can be seen from FIG. 6, the output signals of the five channels are s₁＝0.5258sin(18825t+0.0816)，s₂＝0.4978sin(18825t+0.08236)，s₃＝0.5057sin(18825t+0.08225)，s₄＝0.5153sin(18825t+0.05675)，s₁＝0.5023sin(18825t+0.08798)。

The root mean square of its amplitude can be calculated as 0.509479V, variance 0.000126; the initial phase root mean square value was 0.078953 °, and the variance was 0.00015. So here the amplitude of the first path and the phase of the fourth path need to be compensated. Table 1 shows the channel parameters before compensation:

TABLE 1 parameters of each channel before Compensation

The compensation method comprises the steps of calculating the root mean square value again after removing the numerical value of the channel to be compensated, and taking the new root mean square value as the compensation standard, wherein the compensation values are respectively A' ═ A₂₃₄₅-A₁＝0.505316-0.5258＝-0.020484V，

After compensation, the new output signal should be s₁' 0.505316sin (18825t +0.0816) and s₄' -0.5153 sin (18825t +0.083587) with an amplitude rms value of 0.505316V and a variance of 4.14 × 10^-5The initial phase root mean square value is 0.083587 DEG, and the variance is 6.63 multiplied by 10^-6. Table 2 shows the channel parameters after the first compensation.

TABLE 2 parameters of each channel after first Compensation

It can be seen from the above process that when the inter-channel variance is large, the variance can be reduced by one order of magnitude by one round of compensation. If a more accurate index is needed, another channel with the maximum deviation of the root mean square value can be selected on the basis, and second round compensation is carried out, so that a smaller variance and a more tidy overall measurement value are obtained.