65 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.

The invention belongs to the technical field of underwater target detection, and discloses an underwater target depth coherent estimation method and system, and the method comprises the steps: receiving a single snapshot signal radiated by a target through a sensor array carried by an underwater carrier, and constructing a potential normal wave orthogonal mode space of a sound field under the condition that a sound velocity profile is known, estimating normal wave parameters (namely normal wave horizontal wave number and vertical modal function) and depth-related modal characteristics (namely modal amplitude) by using the sparsity of the sound field projected in the orthogonal modal space as a constraint, and coherently estimating the depth of the underwater target by using a modal polarity-based search method. According to the method, target depth coherent estimation is realized in a marine environment with unknown seabed sediment by using a single frequency component in a single snapshot noise signal radiated by the target, the accuracy of polarity estimation is improved by using a theoretical depth ambiguity function learned by the KAN network, and the method can be used for underwater target positioning, identification and the like. The method is suitable for carrier platforms such as vertical array subsurface buoys and vertical array buoys.

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.

The invention discloses a radar communication integrated waveform design method based on an OFDM (Orthogonal Frequency Division Multiplexing) signal. The method comprises the following steps that: a transmitting end completes constellation mapping on transmitted communication information, performs ZCT matrix reconstruction, performs serial-parallel conversion on reconstructed communication data, performs spectrum shaping on an integrated signal by adopting an improved Nyquist pulse, and transmits the integrated signal to a receiving end; and then IFFT processing, parallel-to-serial conversion, cyclic prefix addition, digital-to-analog conversion and up-conversion are carried out on the shaped data, and finally integrated waveform emission is completed. And the receiving end performs down-conversion, analog-to-digital conversion and cyclic prefix removal operation on the received signal. In the communication function, serial-to-parallel conversion, FFT processing, inverse pulse shaping, parallel-to-serial conversion, ZC matrix reconstruction solution and inverse mapping are carried out on the data without the cyclic prefix to obtain communication information. In the radar detection function, radar signal processing is performed on data without cyclic prefixes. According to the method, the correlation of OFDM integrated signals can be effectively optimized, the modulation characteristic of communication information is improved, the influence of the communication information on a fuzzy function is reduced, OFDM symbols have better correlation, meanwhile, the peak-to-average power ratio of the system is effectively reduced through pulse shaping, implementation is easy, and the comprehensive performance of the system can be remarkably improved.

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 present invention discloses a low-sidelobe FDA radar communication integrated waveform design method, comprising the following steps: constructing a signal model for the FDA radar communication integration; performing subarray delay design on the FDA radar communication integrated signal to obtain a subarray delay model; selecting a tangent frequency modulation signal as a baseband waveform to obtain a transmission signal model; obtaining an echo signal based on the transmission signal and calculating an ambiguity function; at the radar receiving end, designing an angle-time two-dimensional matched filter with time-varying characteristics based on the ambiguity function, and performing pulse compression and beamforming combined processing on the echo signal; at the communication receiving end, performing corresponding demodulation processing based on the transmission signal and analyzing the bit error rate. The present invention realizes the low-sidelobe design of the FDA radar communication integrated transmission waveform, improves the radar's range and angular resolution, and has a good communication bit error rate. It can also achieve continuous scanning of the range airspace, meeting the requirements of radar communication integrated waveform design.

The present invention relates to a distributed target detection method under a zero direct wave system, which includes: obtaining echo signals received by multiple receiving stations, sequentially performing cross-ambiguity processing on each slave station echo signal and the master station echo signal to obtain the cross-ambiguity function value corresponding to the slave station; comparing the cross-ambiguity function value with a preset first threshold value. If there is a cross-ambiguity function value exceeding the first threshold value, record the time delay corresponding to the cross-ambiguity function value, perform correction using the time delay, and perform target detection using the corrected signal. If not, construct a multi-channel time delay estimation scheme set, calculate the decision parameter corresponding to each estimation scheme, and select the estimation scheme corresponding to the maximum decision parameter as the final time delay scheme; perform correction according to the final time delay scheme, and perform target detection using the corrected signal. The present invention solves the problem that traditional target detection requires direct waves, and multiple receiving stations work together, improving the reliability.

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 present invention discloses a geometric position-related bistatic radar measurement noise covariance model. Aiming at the problem that the bistatic radar measurement noise covariance is related to the geometric position relationship between the target and the radar, a time-varying model of the bistatic radar measurement noise covariance is re-derived and constructed, accurately describing the quantitative relationship between the measurement accuracy and the geometric positions of the target, the transmitting station, and the receiving station. First, the best estimation accuracy of the signal domain time delay and Doppler frequency shift of the bistatic radar is modeled using the Cramer-Rao bound and the ambiguity function. Secondly, the time-varying correction coefficient matrix for the conversion from the signal domain to the measurement domain in the bistatic measurement form is derived. Finally, the time-varying expression of the bistatic radar measurement noise covariance is calculated. The simulation experiment verifies and analyzes that the bistatic radar measurement noise covariance is directly affected by the geometric position relationship among the target, the transmitting station, and the receiving station, and has strong practical engineering applicability.

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.