49 results about "Ambiguity function" patented technology

The invention provides an intelligent door and window control method and system, and the method comprises the steps: S1, obtaining multi-source environment data; s2, inputting the multi-source environment data into a fuzzification module, and converting the multi-source environment data into a fuzzy variable through a preset ambiguity function; s3, dynamically generating an environment parameter weight vector according to the real-time scene parameters; s4, inputting the fuzzy variable and the environmental parameter weight vector into a fuzzy inference engine, executing logical operation of a fuzzy rule base, and outputting comprehensive evaluation values of window opening suitability, window closing urgency and shading demand; and S5, generating a final control instruction through a defuzzification strategy, and executing the final control instruction. According to the method, the problem of frequent invalid operation caused by fluctuation of the environmental parameters near the boundary value is solved, the environmental parameter weight vector is dynamically generated based on the time parameters, the user preset mode and the meteorological data confidence factor, adaptation to seasons, time periods, user states and other scenes is achieved, and decision logic can be flexibly adjusted according to actual requirements; and a contradictory decision under a traditional fixed rule is avoided.

The invention discloses an underwater sound double-expansion channel parameter estimation method based on Newton orthogonal matching pursuit. The method comprises the following steps: firstly, realizing frame synchronization by using a cross-correlation peak of an LFM signal and a received signal; a coarse estimation value of a Doppler coefficient is obtained on a discrete time frequency grid through an ambiguity function method by utilizing the self-correlation characteristic of m-sequence pilot frequency, multipath time delay of a channel is detected by utilizing a matched filtering peak value of a signal after frequency offset compensation, and a coarse estimation result of the channel is obtained; executing Newton iteration optimization in a continuous parameter space by adopting a Newton orthogonal matching pursuit algorithm to realize super-resolution off-grid estimation of the Doppler coefficient of the first data block; and finally, proposing an iterative block tracking strategy, initializing the compensation of the rear block through the estimated value of the front block, and updating the time-varying Doppler coefficient by using the balanced signal feedback to realize the dynamic tracking of the time-varying Doppler coefficient. According to the invention, the Doppler estimation root-mean-square error is obviously reduced, and the calculation efficiency is high.

A method of processing communication signals for use in radar sensing includes segmenting copies of a reference signal and a received echo thereof into first- and second-length segments, respectively. The first- and second-length segments are arranged in respective first and second reference and echo matrices. First and second segmented ambiguity functions based on the first and second matrix pairs are evaluated. For obtaining first and second range estimates and first and second velocity estimates for one or more targets. Any ghost signal detected is resolved, or an ambiguity order is assigned thereto if resolving is not possible. The obtained or resolved range and velocity estimates, or the estimates and the assigned ambiguity order is output, and the evaluation process is iteratively repeated until a termination criterion is met. In the second and each further iteration a respective remaining right-most non-zero columns of the echo matrices are replaced with zero-columns.

The invention relates to the technical field of synthetic aperture radars, and discloses a dechirp strip SAR waveform design method based on time domain azimuth ambiguity, and the method comprises the steps: obtaining the azimuth output maximum width and synthetic aperture length of an SAR image through calculation; respectively calculating the minimum value and the maximum value of the pulse repetition frequency through the scene size and the synthetic aperture length so as to determine the initial selection range of the pulse repetition frequency; constructing a time domain azimuth ambiguity function, presetting a time domain azimuth ambiguity value, and traversing all pulse repetition frequency values in the pulse repetition frequency initial selection range through the time domain azimuth ambiguity function to obtain a candidate pulse repetition frequency set; in the candidate pulse repetition frequency set, the minimum value of the pulse repetition frequency is used as the final pulse repetition frequency, and the technical problems that the existing time domain azimuth ambiguity is not fully constrained, so that the SAR image has fuzzy artifacts, the imaging quality is influenced and the like are solved.

The invention discloses a hierarchical optimization search underwater acoustic Doppler estimation method and system, and the method comprises the steps: S1, a receiving end receives an OFDM signal frame, carries out the preliminary frequency offset scanning, and obtains a preliminary Doppler frequency offset value f corresponding to the maximum value of a correlation index and a coarse Doppler estimation interval [f-1, f + 1]; s2, randomly generating a group of initial particles in the coarse Doppler estimation interval [f-1, f + 1], each initial particle representing a candidate frequency offset value; and S3, calculating the amplitude of the mutual ambiguity function of each initial particle as a fitness function for continuous iteration until a convergence condition is met, and obtaining a fine Doppler frequency offset f1. The problem of high calculation complexity can be effectively solved under the condition that Doppler estimation precision is guaranteed.

Embodiments of the present application provide a data processing method, device and equipment, the method comprising: obtaining a sequence set, the sequence set comprising a plurality of sequences, there being at least one first sequence among the plurality of sequences, the self ambiguity function of each first sequence being a thumbtack shape, the sidelobe energy of the cross ambiguity function between each first sequence and other sequences in the sequence set being less than a first threshold; transmitting a signal according to the sequences in the sequence set, the signal being used for speed measurement and / or distance measurement. The accuracy of radar measurement is improved.

The application discloses a kind of optimal matching double star SAR fusion imaging methods based on CRLB.Global navigation satellite system (GNSS) has the advantages such as all-weather operation and extensive spatial coverage, although the GNSS-R SAR technology for ground synthetic aperture radar (SAR) imaging using reflected signal of GNSS is low in cost and widely used, but because the bandwidth of GNSS signal is limited, its resolution is poor.The application establishes the SAR fusion imaging system model by multiple satellites and a single ground fixed GNSS receiver, explores the interrelation between the ambiguity function of GNSS signal and Fisher information, and deduces the system Cramer-Rao lower bound (CRLB) affected by the geometry configuration of bistatic setting.On this basis, the satellite in the optimal resolution direction for ground target is identified by using CRLB expression, and the imaging results of selected satellite are incoherently fused according to the principle that the included angle between optimal resolution directions is as close to 90 degrees as possible.Through this method, unnecessary redundant imaging processing is avoided, and imaging resources are most reasonably used.The resolution performance of the system is improved in a more efficient way.

A method and apparatus for sending a sequence, and a computing device. The method comprises: determining at least two types of reference signals; determining a number N of first sequences corresponding to the at least two types of reference signals, N being a positive integer greater than 1; determining a position sequence corresponding to the N first sequences; on the basis of the position sequence, determining positions of a number M of time units, the position sequence comprising M elements, the M elements being in one-to-one correspondence with the positions of the M time units, and M being a positive integer greater than 1 and less than or equal to N; and sending the N first sequences within the M time units, at least one first sequence being sent in each time unit of the M time units. In the described method, multiple existing types of reference signals can be reused to sense the position and speed of a detection target, and the sensing performance (i.e., the performance of an ambiguity function) can be improved while achieving integrated sensing and communication.

A signal transmission method and a communication device, a sending end device applies different sending end window functions to a plurality of symbols to be transmitted in a frequency domain spectrum shaping process. The sending end window functions corresponding to different symbols are related to the distance of a target to be perceived, so that within the distance range of the target to be perceived, the range ambiguity function of one or more symbols after applying the sending end window function has a notch or a sidelobe less than a threshold within the distance range. After the receiving end device receives the echo signal reflected by the target to be perceived, it can determine whether the target to be perceived exists according to whether the range image generated by one or more symbols has a peak or a sidelobe greater than a threshold within the distance range, thereby reducing the sidelobe level (peak) in the range image, effectively reducing the false alarm probability and the missed detection probability of the perceived target.

The invention discloses a constant modulus waveform design method based on a penalty flow pattern optimization strategy, which relates to the technical field of radars, and comprises the following steps: for the problem of joint design of a constant modulus waveform and a filter of local fuzzy function shaping in single-input single-output radar system modeling, designing a constant modulus waveform and a filter; solving the problem of joint design of modeling based on a flow pattern accurate penalty method, and constructing an accurate penalty mechanism item for performing penalty optimization on a spectrum constraint condition; a plurality of inequality constraints are constructed into subitems of a target function through an accurate penalty function to eliminate the inequality constraints, and then a problem is projected to a CCM to obtain an equivalent complex quaternary unconstrained problem; the complex quaternary unconstrained problem is solved through a conjugate gradient method in a flow pattern space. The method provided by the invention shows better practicability in the aspects of radio frequency interference resistance, spectrum utilization, target detection and the like.

The embodiment of the invention provides a communication method and device, which are used for reducing the detection complexity while ensuring the detection performance of a PSS (Power System Stabilizer). According to the embodiment of the invention, the synchronization signal is generated based on the generalized Golay sequence, or the sequence used by the synchronization signal in the embodiment of the invention can be the generalized Golay sequence. A generalized Golay sequence element value set is {1,-1} and has a nested structure, and multiplication complexity required by related detection can be converted into addition complexity during detection, so that the detection complexity can be reduced. Moreover, the anti-frequency offset capability is generally evaluated by a fuzzy function sidelobe value, and the larger the fuzzy function sidelobe value is, the weaker the sequence anti-frequency offset capability is. In order to ensure the anti-frequency offset capability of the synchronization signal, the sidelobe value of the self-ambiguity function of the sequence used by the synchronization signal in the embodiment of the invention is relatively small, so that the anti-frequency offset capability of the synchronization signal is relatively strong, and the detection performance of the synchronization signal can be ensured.

This invention discloses a signal Doppler tolerance and sidelobe optimization method based on a weighted ambiguity function template. The method includes determining a discrete ambiguity function based on a two-dimensional ambiguity function of a continuous signal and a radar transmitted signal; obtaining matched filtering results for signals with different Doppler frequency shifts and determining the main lobe and sidelobe positions based on the Doppler frequency shift results; for the Doppler frequency shift case, establishing a cost function for Doppler tolerance optimization and a weighted cost function for joint optimization of Doppler tolerance and sidelobe based on the main lobe and sidelobe positions, respectively; setting the weight coefficients of the weighted cost function according to signal characteristic requirements to obtain the target cost function; and using simulation parameters for iterative updating to obtain the optimization result. This invention can improve signal Doppler tolerance while reducing signal sidelobes, significantly improving the practicality of random noise signals; and it allows for setting weight coefficients according to signal characteristic requirements to adjust the optimization ratio of signal Doppler tolerance and sidelobe, providing strong flexibility.

The invention discloses an anti-interference communication perception integrated waveform optimization method, and belongs to the field of wireless communication. The implementation method comprises the following steps: a transmitter generates a basic pseudo-random noise PRN code and generates a plurality of CSK symbols through cyclic shift, and a CSK modulation signal adopts a multi-system coding mode to enable data bits to correspond to various different code sequences, so that signal modulation is realized, and modulated communication information data is obtained; on the basis of a code shift keying CSK signal and a radar linear frequency modulation signal, a common-inductance integrated waveform is designed, the distance resolution and the detection distance of the radar can be improved on the premise of not increasing peak power, and CSK high-order modulation has higher frequency band utilization rate, high reliability and strong anti-interference capability; besides, the sidelobe level of the fuzzy function of the optimized anti-interference and inductance integrated waveform is lower, so that the dual targets of efficient communication and accurate perception can be realized in an integrated system, and excellent communication and radar performance is achieved.

A communication method and apparatus are used for improving communication performance. The method may include determining a first signal and transmitting the first signal. Wherein the first signal is determined based on a first sequence, and the first sequence is determined based on a base sequence and an extended sequence; the base sequence is a ZC periodic continuation sequence; the expansion sequence is a cyclic shift sequence, and the fuzzy function of the first sequence is equal to zero in the maximum delay spread and maximum Doppler spread range, or the expansion sequence is a cubic polynomial index sequence, and the fuzzy function of the second sequence is equal to zero in the maximum delay spread and maximum Doppler spread range. The fuzzy function of the first sequence is smaller than or equal to a fuzzy function threshold value within the maximum delay spread and the maximum Doppler spread range. The first sequence is constructed through the base sequence and the extended sequence, so that the first sequence can be used for various physical channels and physical signals, the first signal is transmitted based on the first sequence, and the communication performance can be improved.

A communication method and apparatus are used for improving communication performance. The method comprises the following steps: a first communication device determines a first signal and sends the first signal; wherein the first signal is determined based on a first sequence, and the first sequence is determined based on a base sequence and an auxiliary sequence; wherein the base sequence is an ideal autocorrelation function sequence, the auxiliary sequence is a cyclic shift sequence, and the fuzzy function of the first sequence is equal to zero in the maximum delay spread and maximum Doppler spread range; or, the base sequence is an optimal self-ambiguity function sequence, the auxiliary sequence is a quadratic polynomial exponential sequence, and the ambiguity function of the first sequence is smaller than or equal to an ambiguity function threshold within the maximum delay spread and maximum Doppler spread range. The first sequence is constructed through the base sequence and the auxiliary sequence, so that the first sequence can be used for various physical channels and physical signals, the first signal is transmitted based on the first sequence, and the communication performance can be improved.

The invention belongs to the field of radio detection, particularly relates to a signal and data processing method for a multi-base incoherent scatter radar, and aims to solve the problem of failure of a conventional signal and data processing method for the multi-base incoherent scatter radar. The method comprises the following steps: dividing a detection distance range of a multi-base incoherent scatter radar beam into a plurality of detection distance doors, and calculating a signal autocorrelation function of each detection distance door; after time correction is carried out on the signal of the receiving station, an observation system equation constant is determined based on antenna gains of the transmitting station and the receiving station and the detection co-body height in combination with radar transmitting power; fitting the signal autocorrelation function according to the spectrum fuzzy function and the plasma scattering theory power spectrum function in combination with the observation system equation constant and the statistical error of the signal autocorrelation function, and performing inversion to obtain the ionosphere parameter of each detection range gate. The method is applied to a multi-base incoherent scattering radar, and an effective ionosphere multi-parameter result is obtained.

An MIMO array sparse rapid design method of a fuzzy function generator based on deep learning comprises the following steps: firstly, directly learning a fuzzy function mapping relation corresponding to virtual array configuration and an incident angle by using a deep learning model so as to replace a traditional analysis fuzzy function calculation process depending on a manifold matrix; and then performing efficient performance evaluation on the candidate sparse array based on the fuzzy function generator, and obtaining a sparse array structure meeting the requirements of high resolution and low sidelobe in combination with an optimization strategy. By means of the technology, acceleration of more than 35 times can be achieved on the premise of not explicitly calculating the fuzzy function, the fuzzy function prediction root mean square error (RMSE) lower than 0.1 is kept, and therefore the sparse array design time is greatly shortened. Experiments on a 2T4R K-band MIMO radar prove that the designed array achieves 10 dB sidelobe level in a 100-degree field of view, the angular resolution is improved by about 32.8%, and the effectiveness and engineering application value of the method in high-resolution MIMO sparse array design are proved.

The application discloses a moving target echo interference suppression method of a full-duplex sensing integrated system, and comprises the following steps: S1. signal transmission and reception are performed to suppress static self-interference signals; S2. OFDM radar processing based on a periodogram is performed on the signals after self-interference suppression to obtain an initial ambiguity function, and delay / Doppler information of moving target echoes is extracted; S3. targets are numbered according to target echo power, and a termination threshold is set; S4. the absolute value of the ambiguity function is compared with the termination threshold; S5. reconstruction of the first target echo is performed to obtain the first iteration signal; S6. the ambiguity function of the first iteration is obtained; S7. steps S4-S6 are repeatedly executed until the maximum value of the absolute value of the ambiguity function is smaller than the termination threshold, and finally, the output signal is obtained. The application enables the receiver to suppress static self-interference of the same frequency at the same time, and to decouple moving target echo signals and uplink communication signals of the same frequency at the same time, so as to extract sensing information and uplink communication information.

The invention provides an ISAC sequence generation method and device, and relates to the technical field of communication perception integration, and the method comprises the steps: obtaining a sequence length N and a sequence set size M, N being an odd number, M being a positive integer, and M being less than or equal to N; according to the sequence length N and the sequence set size M, sequence generation processing is carried out, a sequence set is obtained, the sequence set comprises M sequences, the length of each sequence ui is N, and the value of a sequence element ui (n) is an exponential function of a unit root omega N of modulus N. The sequence set in the application has a similar thumbtack type fuzzy function. In communication, the designed sequence can be used as a pilot frequency sequence of multiple users to realize channel estimation or synchronization; in the radar, the designed sequence set can be used for target perception.

The present invention provides a high-orbit ship target imaging resolution analysis method, comprising constructing a simplified high-orbit echo ambiguity function; constructing a sway model of a sinusoidal variation of the ship target rotation angle; obtaining a rotation matrix based on the constructed sine variation of the ship target rotation angle sway model; taking the derivative of the rotation matrix to obtain the ship sway angular velocity; substituting the obtained ship sway angular velocity into the constructed simplified high-orbit echo ambiguity function to obtain an updated high-orbit echo ambiguity function; and determining the high-orbit ship target imaging resolution based on the updated high-orbit echo ambiguity function. The method of the present invention uses the ambiguity function as an analysis tool to simplify the high-orbit SAR imaging ambiguity function; uses the rotational angular velocity formed by the ship sway as a resolution evaluation condition, integrates the ship sway motion into the ambiguity function, and intuitively provides the high-orbit ship target imaging resolution evaluation result.

The invention provides a time frequency estimation method based on SSA-VMD denoising, and relates to the technical field of passive positioning signal processing. The method comprises the following steps: acquiring a reference signal and an echo signal of a radiation source through a receiving station, optimizing key parameters (IMF number K and secondary penalty factor alpha) of variational mode decomposition (VMD) by using a sparrow search algorithm (SSA), and decomposing the signal through the optimized VMD algorithm to obtain an intrinsic mode function; the method comprises the following steps of: constructing an observation matrix and separating a signal source by taking the time difference as input of ICA (Independent Component Analysis), distinguishing useful signals and noise by combining permutation entropy (PE) and completing signal reconstruction, and finally realizing joint estimation of time difference and frequency difference based on a cross-ambiguity function. The method solves the problems of poor stability and poor signal denoising effect of traditional VMD parameter selection under a low signal-to-noise ratio, improves the accuracy and reliability of time-frequency estimation, and is suitable for a passive positioning system in a complex noise environment.

The invention particularly relates to a time-space-frequency combined target depth estimation method based on deep sea sound field interference. The method comprises the steps of multi-moment broadband beam forming, depth mapping of a glancing angle-time history chart, depth mapping of a frequency-glancing angle spectrogram and construction of a target depth ambiguity function. According to the method, a target beam output signal on a glancing angle-time history graph is decomposed into an eigenmode with the maximum variance contribution rate by using a complementary set empirical mode decomposition algorithm, and a new ambiguity function is constructed by using a target depth ambiguity sequence / plane obtained by mapping the eigenmode and a frequency-glancing angle spectrum respectively. And long-time continuous depth estimation of the underwater target can be realized under the condition that environmental parameters are completely unknown.

The present application belongs to the technical field of underwater target detection, and discloses a water target depth coherence estimation method and system. A sensor array carried by a waterborne body receives a single snapshot signal of target radiation. In the case where the sound velocity profile is known, a potential normal wave orthogonal mode space of the sound field is constructed, and then the sparsity of the sound field projection in the orthogonal mode space is used as a constraint to estimate the normal wave parameters (i.e. normal wave horizontal wave number and vertical mode function) and depth-related mode characteristics (i.e. mode amplitude). The depth of the underwater target is coherently estimated by using a mode polarity search method. The present application uses a single frequency component in the single snapshot noise signal of target radiation to realize target depth coherence estimation in a marine environment where the seabed is unknown. The accuracy of polarity estimation is improved by using a KAN network learned theoretical depth ambiguity function, and the present application can be used for underwater target positioning, identification, etc., and is suitable for vertical array subsurface platforms, vertical array floating platforms, etc.

A communication method and apparatus, for use in improving the communication performance. The method comprises: a first communication apparatus determines a first signal and sends the first signal. The first signal is determined on the basis of a first sequence, and the first sequence is determined on the basis of a base sequence and an auxiliary sequence; the base sequence is an ideal autocorrelation function sequence, the auxiliary sequence is a cyclic shift sequence, and an ambiguity function of the first sequence is equal to zero in the range of maximum delay spread and maximum Doppler spread; or, the base sequence is an optimal self-ambiguity function sequence, the auxiliary sequence is a quadratic polynomial exponential sequence, and the ambiguity function of the first sequence is smaller than or equal to an ambiguity function threshold in the rage of maximum delay spread and maximum Doppler spread. The first sequence is constructed by means of the base sequence and the auxiliary sequence, so that the first sequence can be used for various physical channels and physical signals, and then the first signal is transmitted on the basis of the first sequence, such that the communication performance can be improved.

The invention discloses a nonlinear frequency modulation waveform reaching a lower bound of a peak sidelobe ratio and a parameter design method of the nonlinear frequency modulation waveform. The nonlinear frequency modulation waveform is composed of a head section, a middle section and a tail section. Wherein the head section and the tail section are fixed frequency waveforms with the same time width, the frequencies of the head section and the tail section are the minimum frequency and the maximum frequency of the nonlinear frequency modulation waveform respectively, the time width T0 of the head section and the tail section meets the condition that T0 is larger than or equal to 1 / (2B), and B is the bandwidth of the nonlinear frequency modulation waveform; the middle section is a frequency modulation waveform of which the bandwidth is not greater than B; and the local side lobe peak level of the normalized distance dimension fuzzy function AF (tau, 0) of the nonlinear frequency modulation waveform is not greater than-20 log10 (piBT) dB. The NLFM waveform designed by the invention has a low side lobe, the PSLR of the waveform distance dimension fuzzy function can reach the PSLR lower bound of-20log10 (piBT) dB and is lower than the PSLR lower bound of other existing NLFM waveforms, the strong target side lobe level in matched filtering output can be reduced, and the shielding effect on an adjacent weak target is reduced.

The application discloses a time-frequency difference parameter estimation algorithm based on RANSAC-WLS in a strong interference environment and belongs to the technical field of signal processing and target positioning. Firstly, a narrowband cross ambiguity function and a two-dimensional Fourier transform are used to extract candidate energy points; a RANSAC algorithm is used to construct a straight line model, iteratively screen an inlier point set, and effectively peel off interference outliers; based on the inlier points, a weighted least square method is used to optimize and solve ridge line parameters, and the bias influence of interference on estimation is eliminated; finally, combined with ridge line prior information, one-dimensional fine search is carried out through a wideband cross ambiguity function, and final time difference and scale difference are obtained. The application realizes effective discrimination of target features in a high interference environment, improves the algorithm theory breaking point to about 50%, and significantly enhances the robustness and accuracy of parameter estimation.

The invention relates to the technical field of underwater acoustic signal processing, in particular to a deep sea target sound source positioning system and method, and aims at solving the problem that a traditional DOA estimation positioning method has large errors. The invention provides a deep-sea target sound source positioning system and method. The method comprises the following steps: S1, performing two-dimensional plane conventional beam forming processing on a received deep-sea target signal to obtain a receiving arrival angle of the deep-sea target signal; s2, receiving arrival angle information according to the receiving arrival angle of the deep sea target, and reversely constructing a target position fuzzy surface in combination with an acoustic propagation model; s3, constructing a multi-path delay inequality fuzzy surface based on the propagation delay inequality of the receiving angle of arrival of the deep sea target among the multi-path paths; and S4, performing joint matching on the target position fuzzy surface in the S2 and the multi-path delay inequality fuzzy surface in the S3, and determining the accurate position of the target through a fuzzy function intersection point. According to the positioning system and method for the deep sea target sound source, the positioning precision is improved, and the error influence is reduced.

The embodiments of the present application relate to the field of communication technology, and in particular to a method for jointly estimating time and frequency differences between multi-antenna signals in a distributed system. The method comprises: optimizing and solving a variational mode decomposition algorithm using a QPSO algorithm to obtain an optimal solution for the number of decomposition layers and an optimal solution for a penalty factor; performing variational mode decomposition on a received signal based on the optimal solution for the number of decomposition layers and the optimal solution for the penalty factor to obtain multiple IMF components; calculating the variance contribution rate of each IMF component respectively, and filtering out IMF components whose variance contribution rate is less than a first preset threshold; performing wavelet threshold processing on each retained IMF component; performing signal reconstruction based on each IMF component after wavelet threshold processing, calculating the conjugate ambiguity function of the reconstructed received signal, and performing peak detection on the conjugate ambiguity function to estimate the time delay difference and frequency difference between multi-antenna signals in the distributed system. The method can achieve high-precision joint estimation of time and frequency differences.

A communication method and apparatus, which are used for improving communication performance. The method may comprise: determining a first signal, and sending the first signal, wherein the first signal is determined on the basis of a first sequence, and the first sequence is determined based on a base sequence and an extension sequence; the base sequence is a ZC periodic extension sequence; if the extension sequence is a cyclic shift sequence, the ambiguity function of the first sequence is equal to zero within the ranges of a maximum delay spread and a maximum Doppler spread; alternatively, if the extension sequence is a cubic polynomial exponential sequence, the ambiguity function of the first sequence is less than or equal to an ambiguity function threshold within the ranges of the maximum delay spread and the maximum Doppler spread. A first sequence is constructed on the basis of a base sequence and an extension sequence, such that the first sequence may be used for various physical channels and physical signals, and thus a first signal is transmitted on the basis of the first sequence, and the communication performance can be improved.

The invention discloses a cognitive sonar waveform design method using ambiguity function constraint, and belongs to the technical field of sonar target detection. According to the method, on the basis of a traditional water injection algorithm, a Q function representing reverberation output intensity is introduced to serve as a constraint condition on the target of maximizing the signal to interference and noise ratio (SINR); by deriving frequency domain expressions of a broadband ambiguity function, a narrowband ambiguity function and a Q function, constructing a nonlinear non-convex optimization model including SINR maximization, an equivalent bandwidth constraint (constant alpha), a Q function constraint (constant beta) and a transmitted waveform energy constraint (Ex); a fmincon solver (interior point method) in MATLAB is combined with a MultiStart global search mechanism to solve the model, and an optimal solution is selected through multiple times of random initialization to avoid initial value sensitivity. According to the waveform generated by the method, the Q function value at the Doppler frequency shift of the target can be reduced while the relatively high SINR is maintained, reverberation is effectively inhibited, and the shallow sea slow target detection performance is improved.