23 results about "Pseudorandom noise" patented technology

The invention belongs to the technical field of distributed optical fiber sensing, and relates to a phase-frequency noise suppression optical frequency domain reflection measurement method and system without an auxiliary interferometer. The measurement method comprises the following steps: acquiring positive and negative double-sideband sweep-frequency light with the same sweep-frequency range and opposite sweep-frequency directions; dividing the positive and negative double-sideband sweep frequency light into double-sideband detection light and double-sideband local oscillation light according to a preset proportion; configuring a pseudo-random noise code, and modulating the pseudo-random noise code to the double-sideband probe light to obtain spread spectrum double-sideband probe light; the spread spectrum double-sideband detection light enters the sensing optical fiber and is reflected back to the backward Rayleigh scattering light, and the backward Rayleigh scattering light and the spread spectrum double-sideband local oscillation light interfere with each other to output up-down sweep frequency beat frequency signals; separating the upper and lower sweep-frequency beat-frequency signals to obtain an upper sweep-frequency beat-frequency signal and a lower sweep-frequency beat-frequency signal; and after the upper sweep frequency beat frequency signal and the lower sweep frequency beat frequency signal are respectively decoded, a beat frequency signal is separated through band-pass filtering, the beat frequency signal is subjected to frequency mixing processing to obtain a frequency mixing signal after phase frequency noise suppression, and the frequency spectrum of the frequency mixing signal is analyzed.

The invention relates to the technical field of motion capture and space positioning, in particular to an acoustic motion capture method and system based on a receiving end synchronization mechanism. The core innovation of the method lies in that a system structure with a receiving end as a unified time reference is constructed, and asynchronous errors of a traditional transmitting end synchronization architecture are thoroughly eliminated. In order to solve the problems that signals of multiple transmitting nodes are difficult to judge at the same moment, multi-source signals are aliasing and the like, a receiving end synchronous unified time calibration mechanism is adopted, and a mixed signal scheduling scheme combining packet time division multiplexing and intra-group code division multiplexing is adopted. The system comprises a coordinator, an ultrasonic transmitting terminal, an acoustic receiving array and the like, the coordinator provides a global clock through an IEEE 1588v2 protocol and a PPS signal, the transmitting terminal transmits an ultrasonic signal with a unique pseudo-random noise code, the receiving array separates the signal through parallel matched filtering and records an accurate timestamp, and the acoustic receiving array receives the signal through the IEEE 1588v2 protocol and the PPS signal. And finally, high-precision positioning and attitude restoration are realized through a time difference of arrival algorithm, environmental parameter correction and an inverse kinematics model.

A method of determining an integer ambiguity search space includes: obtaining, at an apparatus, a code phase measurement of a satellite vehicle signal comprising a pseudorandom noise code and a carrier signal; obtaining, at the apparatus, spatial information corresponding to a wireless terrestrial signal transferred between the apparatus and a terrestrial base station; determining, at the apparatus, a satellite positioning system carrier phase integer ambiguity search space based on the code phase measurement; and constraining a size of the satellite positioning system carrier phase integer ambiguity search space based on the spatial information.

The application discloses a kind of low-orbit satellite ultra-wideband navigation signal acquisition method and system, to solve the existing low-orbit satellite ultra-wideband navigation signal acquisition method, signal can not be locked, finally lead to the technical problem of low acquisition success rate.It is to obtain the low-orbit satellite pseudo-random noise code corresponding to ka band low-orbit satellite signal and multiple low-orbit satellite ultra-wideband navigation signals;According to preset sampling rate, preset skip time, ka band low-orbit satellite signal, generate complex signal and original intermediate frequency signal;Based on each low-orbit satellite pseudo-random noise code, pseudo-code spectrum library construction is carried out, and the pseudo-code spectrum library is output;Based on the known intermediate frequency parameter of original intermediate frequency signal, determine the discrete frequency search sequence, and combine the complex signal, pseudo-code spectrum library to construct matrix, and output three-dimensional result matrix;Using three-dimensional result matrix, each low-orbit satellite ultra-wideband navigation signal is acquired and determined, and multiple acquisition successful low-orbit satellite ultra-wideband navigation signals are determined.

Techniques for direction finding and geolocation of a GPS spoofer. A methodology implementing the techniques according to an embodiment includes steering a beam in a direction selected from a search constellation and measuring a first signal power received through the steered beam. The method also includes steering a null in the selected direction and measuring a second signal power received through the steered null. The method further includes calculating a difference between the first signal power and the second signal power and estimating an angle of arrival (AOA) of the GPS spoofer signal as the selected direction if the calculated difference exceeds a threshold power value. In some such examples, the method includes accumulating signals having four similar estimated AOAs, associated with unique pseudo-random noise codes, and employing a GPS receiver to calculate a candidate position of a source of the GPS spoofer signals based on the accumulated signals.

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.

Generating a composite pseudo random noise (PRN) code is provided. The method comprises receiving a wireless transmission having a noisy received original PRN code multiplexed with navigation data. A noiseless local replica original PRN code is generated within the receiver. A noiseless local replica compressed PRN code is then generated based on the noiseless local replica original PRN code. The noiseless local replica compressed PRN code has the same length as the noiseless local replica original PRN code and a higher chip rate. A sample-to-sample multiplication operation on the noisy received original PRN code and the noiseless local replica compressed PRN code generates a noisy received composite PRN code. The received wireless transmission is then tracked according to the noisy received composite PRN code.

Techniques are provided for overcoming narrowband interference with notch filters. An example method for determining, with a receiver, a distance to a satellite vehicle includes receiving a signal from the satellite vehicle, determining one or more notch filter configurations, determining a pseudo-random noise code and a Doppler frequency associated with the signal, determining a code phase correction value based at least on the one or more notch filter configurations, the pseudo-random noise code, and the Doppler frequency, and calculating the distance to the satellite vehicle based at least in part on the signal and the code phase correction value.

The application discloses a method for enhancing random noise injection efficiency of a mechanical dithering laser gyroscope, which comprises judging the level of a pseudo-random noise signal, positively enhancing the amplitude of the random noise signal if the level of the random noise signal changes from a high level to a low level, reversely enhancing the amplitude of the random noise signal if the level of the random noise signal changes from the low level to the high level, and not changing the amplitude of the random noise signal if the level of the random noise signal does not change from the high level to the low level or from the low level to the high level; obtaining a variety of state random change noise signals according to the amplitude signal of the random change, converting the noise signals into a variety of duty cycle random change three-state square wave signals, and taking the three-state square wave signals as input signals of a dithering mechanism transfer function; the method significantly suppresses the serious attenuation phenomenon of high-frequency noise amplitude, improves the random noise injection efficiency, reduces angle random walk, and thus improves the precision of the laser gyroscope.

The application relates to a communication navigation integrated signal frame design method and device, wherein the method comprises the following steps: the occupation of traditional pilot resources is eliminated by sharing the frequency domain of a one-dimensional pseudo-random noise sequence and data symbols, so that the spectrum utilization is improved; secondly, the dynamic power distribution based on a genetic algorithm can adjust the dynamic power distribution coefficient under the conditions of signal-to-noise ratio fluctuation and terminal high-speed movement, so that the ranging error and the communication rate meet the preset requirements; in addition, the application is compatible with the signal frame structure and the standard OFDM, supports the smooth upgrading of existing communication equipment, and the introduction of the MIMO technology further expands the applicability of the system in the multi-user scene. Therefore, the problems of the existing dynamic resource allocation method, such as low resource reuse efficiency, insufficient dynamic adaptation capability and prominent performance compromise contradiction, are solved.

A method for restoring a pseudo random noise from a received binary offset carrier pseudo random noise signal. The received binary offset carrier pseudo random noise signal is filtered using a filter system to form a filtered binary offset carrier pseudo random noise signal that comprises a range of frequencies in the received binary offset carrier pseudo random noise signal. A binary offset carrier is removed from the filtered binary offset carrier pseudo random noise signal to obtain a restored pseudo random noise. The restored pseudo random noise is correlated with a local replica of the pseudo random noise.

A method for estimating delays and Doppler shifts of GNSS signals comprises obtaining respective output sequences from N correlators for a snapshot of a received GNSS signal, wherein each sequence has K values, the N correlators correspond to N different delays of a pseudorandom noise, PRN, code sequence, the K values are correlation values at K sampling time points in each sequence, N and K are positive integers. The method further comprises, for each output sequence, obtaining a frequency spectrum by computing a K-point discrete Fourier transform, DFT, of the output sequence; obtaining a N×K matrix using the N frequency spectra; determining at least one peak value in the N×K matrix; and estimating a delay and a Doppler shift of the received GNSS signal using indices of the at least one peak value in the N×K matrix.

Generating a composite pseudo random noise (PRN) code is provided. The method comprises receiving a wireless transmission having a noisy received original PRN code multiplexed with navigation data. A noiseless local replica original PRN code is generated within the receiver. A noiseless local replica compressed PRN code is then generated based on the noiseless local replica original PRN code. The noiseless local replica compressed PRN code has the same length as the noiseless local replica original PRN code and a higher chip rate. A sample-to-sample multiplication operation on the noisy received original PRN code and the noiseless local replica compressed PRN code generates a noisy received composite PRN code. The received wireless transmission is then tracked according to the noisy received composite PRN code.

The application provides a long-distance acoustic positioning method and system based on a moving object, comprising: generating an acoustic pulse signal by modulating a preset pseudo-random noise model and sending it outward; receiving the acoustic pulse signal by a matching filter in a preset microphone, performing Doppler distortion compensation, and detecting an obvious correlation peak; taking the position of the correlation peak as the time when the acoustic pulse signal reaches the microphone, and calculating the relative time delay of the pulse arrival of the diagonal microphone; based on the relative time delay of the pulse arrival of the diagonal microphone, establishing a three-dimensional coordinate system through the moving object, determining the coordinate positions of the microphone and the moving object in the three-dimensional coordinate system; and positioning the moving object based on the coordinate positions of the microphone and the moving object in the three-dimensional coordinate system. The application solves the problem that the existing moving object is difficult to accurately position, and realizes accurate positioning through an acoustic pulse signal.

This invention relates to the field of federated learning technology, specifically to a decentralized training method based on a secure federated generative adversarial network (GAN) framework. First, a decentralized secure federated GAN framework is constructed, introducing an encrypted model sharding method. Parameter encryption transmission and storage are achieved through vertical sharding, DH key exchange, and pseudo-random noise. Simultaneously, a dual-metric dynamic reputation and anti-poisoning aggregation mechanism are employed, combined with similarity verification, reputation voting, and weighted aggregation to isolate malicious clients. Finally, decentralized iterative training is used, and a sample visualization graph is generated after convergence. Experimental results show that the framework of this invention can still converge stably with a malicious client ratio of 10%–40%, achieving a main task accuracy of 0.89 on the MNIST dataset and 0.67 on the Fashion-MNIST dataset. The backdoor attack success rate is suppressed to below 20%, while achieving end-to-end privacy protection, eliminating single points of failure, and balancing model performance and scalability.

The application relates to a communication and sensing integrated waveform optimization method for anti-interference, and belongs to the wireless communication field.The application is characterized in that: a transmitter generates a basic pseudo-random noise (PRN) code, and generates a plurality of CSK symbols through cyclic shift; a CSK modulated signal uses a multi-ary coding mode, so that data bits can correspond to a plurality of different code sequences, thereby realizing signal modulation and obtaining modulated communication information data; a communication and sensing integrated waveform is designed based on a code shift keying (CSK) signal and a radar linear frequency modulation signal, the distance resolution and the detection distance of the radar can be improved without increasing the peak power, the CSK high-order modulation has higher frequency band utilization, higher reliability and stronger anti-interference capability; in addition, the sidelobe level of the fuzzy function of the optimized anti-interference communication and sensing integrated waveform is lower, so that the dual targets of efficient communication and accurate sensing can be realized in the integrated system, and the communication and radar performance is excellent.

The invention discloses a time-frequency synchronization method and system for orthogonal frequency division multiplexing transmission of an unmanned aerial vehicle, and belongs to the field of communication. The method comprises the steps of obtaining a baseband receiving signal transmitted by an unmanned aerial vehicle end; the baseband receiving signal is generated according to a superposed signal generated by a pseudo-random noise sequence and a preset power distribution factor; generating a synchronization function according to the baseband receiving signal and a preset local time domain training sequence; performing coarse estimation on the phase difference between the cyclic prefix and the symbol main body according to the symbol starting point at the moment when the peak value of the synchronization function exceeds the preset threshold value to obtain coarse estimation frequency offset, performing coarse compensation correction on the baseband receiving signal, and performing fine estimation on the subcarrier phase rotation amount by the baseband receiving signal after coarse compensation to obtain fine estimation frequency offset; and performing frequency offset correction on the baseband receiving signal according to the total frequency offset obtained by adding the coarse estimation frequency offset and the fine estimation frequency offset. According to the invention, the problem that broadband offset coverage and high synchronization precision cannot be satisfied simultaneously in the prior art is solved.

The invention relates to a method for estimating delay and Doppler shift of global navigation satellite system signals. A method of estimating delays and Doppler shifts of a GNSS signal includes obtaining respective output sequences from N correlators for snapshots of a received GNSS signal, where each sequence has K values, the N correlators corresponding to N different delays of a pseudorandom noise (PRN) code sequence, the K values being correlation values at K sampling time points in each sequence, n and K are positive integers. The method further comprises: for each output sequence, obtaining a spectrum by calculating a K-point discrete Fourier transform (DFT) of the output sequence; obtaining an N * K matrix by using the N frequency spectrums; determining at least one peak value in the N * K matrix; and estimating the delay and Doppler shift of the received GNSS signal using an index of the at least one peak in the N * K matrix.

Various aspects of the present disclosure generally relate to wireless communication Some aspects more specifically relate to ambient device random access message transmissions. A network node may transmit, and an ambient device may receive, configuration information that indicates a minimum permitted duration and a maximum permitted duration for transmitting a random access message. A reader device may transmit a query message to the ambient device. The ambient device may transmit, and the reader device may receive, a random access message that includes a pseudorandom noise sequence and a redundancy sequence. The redundancy-sequence may include a portion of the pseudorandom noise sequence. A duration of the redundancy sequence may be in accordance with the minimum permitted duration and the maximum permitted duration. For example, the duration of the redundancy sequence may be equal to the maximum permitted duration subtracted by- the minimum permitted duration.

The invention discloses an RFSoC (radio frequency system-on-chip) low-delay optimization method oriented to a communication sensing integrated system. The method comprises the following steps: firstly, establishing a transmitting link and a receiving link of an OFDM (orthogonal frequency division multiplexing) communication system in a programmable logic PL of an RFSoC; data interaction with a processing system PS is realized by adopting an AXI-based streaming interface; a pseudo-random noise PN sequence is inserted into the initial position of a transmission link in a time division multiplexing mode, and cooperative operation of communication and sensing is achieved; carrying out pipelined delay optimization processing on the transmitting link; dMA data path optimization is carried out on a data transmission path on the PS side, and system-level data paths and signal interface modes of an OFDM transmitting link and an OFDM receiving link are optimized on the PL side. According to the method, the parameterization relationship between communication and sensing performance is constructed, so that the system can select proper PN code configuration according to application requirements, and the performance balance between the communication and sensing functions is realized.

The present application belongs to the field of distributed optical fiber sensing technology, and relates to a phase frequency noise suppression optical frequency domain reflectometry method and system of an auxiliary-free interferometer. The measurement method comprises: obtaining positive and negative double sideband swept light with the same sweep range and opposite sweep directions; dividing the positive and negative double sideband swept light into double sideband probe light and double sideband local light according to a preset ratio; configuring a pseudo-random noise code and modulating the pseudo-random noise code to the double sideband probe light to obtain spread spectrum double sideband probe light; the spread spectrum double sideband probe light enters the sensing optical fiber to reflect back the back Rayleigh scattering light, the back Rayleigh scattering light interferes with the spread spectrum double sideband local light to output up and down sweep beat signals; the up and down sweep beat signals are separated to obtain up sweep beat signals and down sweep beat signals; after decoding the up sweep beat signals and the down sweep beat signals respectively, the beat signals are separated by band pass filtering, the beat signals are mixed to obtain mixed signals after phase frequency noise suppression, and the frequency spectrum of the mixed signals is analyzed.

The application provides a method for calibrating inter-stage gain error of a pipeline ADC, a circuit thereof and the pipeline ADC. The method comprises the following steps: simultaneously injecting pseudo-random noise jitter in opposite directions from a sub-ADC and a sub-DAC; determining an actual gain coefficient of a pipeline stage to be calibrated based on a sampling signal interval division mode of the pipeline stage to be calibrated; and extracting the inter-stage gain error. When the pseudo-random noise jitter in opposite directions is simultaneously injected from the sub-ADC and the sub-DAC, the residual voltage is maintained at ±1 / 2*V ref Therefore, the requirement for linearity of the amplified signal of the pipeline stage to be calibrated can be greatly reduced. For a high-precision ADC, a better inter-stage gain calibration effect is achieved. Meanwhile, on the basis of completing the inter-stage gain calibration, the method for calibrating the inter-stage gain error can achieve a better spectrum scattering effect and improve the overall dynamic range of the pipeline ADC by simultaneously injecting the pseudo-random noise jitter in opposite directions from the sub-ADC and the sub-DAC.

The present application relates to the technical field of action capture and spatial positioning, in particular to an acoustic action capture method and system based on a receiving end synchronization mechanism. The core innovation is to build a system architecture with the receiving end as the unified time reference, completely eliminating the asynchronous error of the traditional transmitting end synchronization architecture. To solve the problems of difficult determination of multiple transmitting node signals at the same time and signal aliasing of multiple sources, a unified time calibration mechanism of receiving end synchronization is adopted, combined with a hybrid signal scheduling scheme of grouping time division multiplexing and intra-group code division multiplexing. The system includes a coordinator, an ultrasonic transmitting terminal, an acoustic receiving array and other components. The coordinator provides a global clock through the IEEE 1588v2 protocol and PPS signal, the transmitting terminal transmits ultrasonic signals with a unique pseudo-random noise code, the receiving array separates the signals through parallel matched filtering and records accurate time stamps, and finally realizes high-precision positioning and attitude restoration through the time difference of arrival algorithm, environmental parameter correction and inverse kinematics model.