阅读说明：本技术 一种适用于声呐通探的一体化信号产生方法 (integration signal generation method suitable for sonar detection ) 是由 徐娜 高昱荣 凤林锋 于 2019-10-25 设计创作，主要内容包括：本发明公开一种适用于声呐通探的一体化信号产生方法,属于水声通信和探测技术领域。通过正交振幅调制方式对信源进行编码调制；在编码调制后的信源中插入导频并串并转换；进行IFFT变换；采用自适应限幅和修正的SGP联合算法抑制峰值平均功率比；并串转换；在OFDM符号的保护间隔内插入循环前缀信号；加窗函数和载频形成一体化信号。(The invention discloses methods for generating signals suitable for sonar detection, which belong to the technical field of underwater acoustic communication and detection, code modulation is carried out on an information source in a quadrature amplitude modulation mode, pilot frequency is inserted into the code-modulated information source and then is subjected to parallel-serial-parallel conversion, IFFT conversion is carried out, the peak average power ratio is restrained by adopting an adaptive amplitude limiting and correcting SGP combined algorithm, parallel-serial conversion is carried out, a cyclic prefix signal is inserted into a guard interval of an OFDM symbol, and a windowing function and a carrier frequency form signals.)

1, A integration signal generation method suitable for sonar detection, which comprises:

carrying out coding modulation on the information source in a quadrature amplitude modulation mode;

inserting pilot frequency into the information source after code modulation for parallel-serial-parallel conversion;

performing IFFT transformation;

the peak value average power ratio is restrained by adopting an SGP (serving gateway protocol) combined algorithm of self-adaptive amplitude limiting and correction;

performing parallel-serial conversion;

inserting a cyclic prefix signal into a guard interval of the OFDM symbol;

the windowing function and the carrier frequency form the integration signal.

2. The method for generating an -based signal suitable for sonar sounding according to claim 1, wherein the quadrature amplitude modulation scheme is a modulation scheme combining amplitude modulation and phase modulation, and wherein a complex envelope of QAM-OFDM signals with finite symbol length can be expressed as:

where M is the number of symbols, N is the number of subcarriers, d_m,nFor the m-th data symbol modulated on the n-th subcarrier, df is the frequency spacing between adjacent subcarrier frequencies, and 1/T is_p，T_pIs the OFDM symbol effective duration; k (t) is a window function.

3. The -based signal generation method suitable for sonar sounding according to claim 2, wherein the window function includes a rectangular window and a raised cosine window, wherein the raised cosine window is:

in the formula, T_rIs the total duration of the OFDM symbol, T_r＝T_p+T_g，T_gFor the guard interval inserted between two OFDM symbols, β is the roll-off factor, β E0, 1]。

4. The method for generating an -based signal suitable for sonar sounding according to claim 1, wherein the structure of the pilot includes comb-shaped pilots and block-shaped pilots.

5. The -based signal generation method suitable for sonar sounding according to claim 1, wherein suppressing the peak-to-average power ratio using an adaptive clipping and modified SGP combined algorithm comprises:

the amplitude limiting level is adjusted through a self-adaptive strategy to reduce the peak average power ratio, and then the novel iteration step length is utilized to carry out iterative calculation, so that the convergence speed is accelerated.

6. The method for generating an -based signal suitable for sonar sounding according to claim 1, wherein a guard interval between the OFDM symbol and the OFDM symbol is 2 to 4 times a root mean square of a delay spread.

7. The method for generating -based signals suitable for sonar detection according to claim 1, wherein the windowing function and the carrier frequency comprises:

selecting a raised cosine window with low-frequency spectrum side lobes as a window function;

and modulating the baseband signal to the carrier frequency according to actual requirements.

8. The method for generating materialized signals suitable for sonar detection according to claim 1, wherein the materialized signals are emitted into a water sound channel through a transducer for detection and communication.

Technical Field

The invention relates to the technical field of underwater acoustic communication and detection, in particular to integrated signal generation methods suitable for sonar detection.

Background

As the eyes of various countries are urgently projected to a larger ocean space, UUVs (unmanned underwater vehicles) become the key points of ocean development and research and the core of future underwater attack and combat as important means for combat and information acquisition.

In the UUV cluster cooperative detection process, the UUV in the node is extremely important for position perception and information interconnection and intercommunication of surrounding friend machines, so that the UUV needs to carry high-precision detection sonar and communication sonar.

The detection communication integration technology is applied to radar at first, in the 60 th 20 th century, Mealey proposes an idea of realizing a communication function on radar, communication data is modulated by using pulses of radar to realize a one-way communication system, in 1975, Fiden et al use different PRFs (pulse repetition frequencies) to represent different communication data to realize a data transmission function of a radar system, subsequently, the U.S. navy develops a large amount of basic research on the aspect, issues a preliminary technical report on an advanced multifunctional radio frequency test platform, marks a conceptual integration of multifunctional electronic equipment and shifts to an implementation stage, a detection communication integration working system can be divided into a time division system, a frequency division system, a beam splitting system and a full sharing system 4.

Disclosure of Invention

The invention aims to provide methods for generating integration signals suitable for sonar penetration detection, so as to solve the problem that the existing OFDM signals are poor in practice when used for sonar penetration detection integration, and verify the feasibility of the OFDM signals as the integration signals of the sonar penetration detection.

In order to solve the above problems, the present invention provides methods for generating -based signals suitable for sonar detection, comprising:

carrying out coding modulation on the information source in a quadrature amplitude modulation mode;

inserting pilot frequency into the information source after code modulation for parallel-serial-parallel conversion;

performing IFFT transformation;

the peak value average power ratio is restrained by adopting an SGP (serving gateway protocol) combined algorithm of self-adaptive amplitude limiting and correction;

performing parallel-serial conversion;

inserting a cyclic prefix signal into a guard interval of the OFDM symbol;

the windowing function and the carrier frequency form the integration signal.

Optionally, the quadrature amplitude modulation scheme is a modulation scheme combining amplitude modulation and phase modulation, and the complex envelope s (t) of the QAM-OFDM signal with the length of finite symbols can be represented as:

where M is the number of symbols, N is the number of subcarriers, d_m,nFor the m-th data symbol modulated on the n-th subcarrier, df is the frequency spacing between adjacent subcarrier frequencies, and 1/T is_p，T_pIs the OFDM symbol effective duration; k (t) is a window function.

Optionally, the window function includes a rectangular window and a raised cosine window, where the raised cosine window is:

in the formula, T_rIs the total duration of the OFDM symbol, T_r＝T_p+T_g，T_gFor the guard interval inserted between two OFDM symbols, β is the roll-off factor, β E0, 1]。

Optionally, the structure of the pilots includes comb pilots and block pilots.

Optionally, the step of suppressing the peak-to-average power ratio by using an SGP combined algorithm with adaptive clipping and correction includes:

the amplitude limiting level is adjusted through a self-adaptive strategy to reduce the peak average power ratio, and then the novel iteration step length is utilized to carry out iterative calculation, so that the convergence speed is accelerated.

Optionally, the guard interval between the OFDM symbol and the OFDM symbol is 2 to 4 times of a root mean square of the delay spread.

Optionally, the windowing function and the carrier frequency include:

selecting a raised cosine window with low-frequency spectrum side lobes as a window function;

and modulating the baseband signal to the carrier frequency according to actual requirements.

Optionally, the echo signal is transmitted into the underwater acoustic channel by a transducer for detection and communication.

The invention provides methods for generating signals suitable for sonar sounding, which comprises the steps of coding and modulating an information source in an orthogonal amplitude modulation mode, inserting pilot frequency into the coded and modulated information source, performing parallel-serial-parallel conversion, performing IFFT (inverse fast Fourier transform), restraining a peak average power ratio by adopting an adaptive amplitude limiting and correcting SGP (generalized minimum-power-point) combined algorithm, performing parallel-serial conversion, inserting cyclic prefix signals into a guard interval of an OFDM (orthogonal frequency division multiplexing) symbol, and forming signals by using a windowing function and carrier frequency.

Drawings

FIG. 1 is a schematic flow chart of an integration signal generation method suitable for sonar detection according to the present invention;

FIG. 2 is a schematic diagram of a range ambiguity function for an OFDM signal;

FIG. 3 is a velocity ambiguity function diagram for an OFDM signal;

FIG. 4 is a diagram illustrating bit error rates for different paths;

fig. 5 is a schematic diagram of the bit error rate for different doppler spectra.

Detailed Description

The present invention provides a method for generating signals suitable for sonar detection , which is further detailed in with reference to the accompanying drawings and the specific embodiments.