48 results about "Pseudorandom noise" patented technology

A satellite constellation system includes a plurality of satellites, wherein each satellite is configured to orbit in one of a plurality of orbital planes of the satellite constellation system at an altitude range corresponding to low earth orbit (LEO), wherein each of the plurality of orbital planes includes a corresponding one of a plurality of satellite subsets of a plurality of satellites, wherein a first orbital plane of the plurality of orbital planes corresponds to a first coverage area facilitated by a plurality of navigation signals transmitted by ones of the plurality of satellites in the first orbital plane, wherein the plurality of navigation signals transmitted by the ones of the plurality of satellites in the first orbital plane each have a first primary pseudo-random noise (PRN) code; and wherein a second orbital plane of the plurality of orbital planes corresponds to a second coverage area facilitated by a plurality of navigation signals transmitted by ones of the plurality of satellites in the second orbital plane, wherein the plurality of navigation signals transmitted by the ones of the plurality of satellites in the second orbital plane each have a second primary PRN code.

Techniques for executing privacy-preserving aggregation queries on a database table include receiving a query, obtaining the true output, and generating deterministic pseudorandom noise based on the query and current database state. This noise is added to the true output to create a privacy-protected result. For subsequent queries, this process is repeated, potentially with updated state data, ensuring that privacy protection adapts to changes in the underlying data. The approach maintains consistency for repeated queries on unchanged data while providing fresh noise when data changes. It balances privacy protection with data utility, allowing for various query types while guarding against privacy attacks. The techniques include displaying the noisy output to a user interface. The techniques offer adaptive privacy protection, query flexibility, and efficient resource utilization, making them suitable for dynamic data environments requiring both privacy and analytical capabilities.

The invention discloses a method and a system for capturing an ultra-wideband navigation signal of a low-orbit satellite, which are used for solving the technical problem that the existing method for capturing the ultra-wideband navigation signal of the low-orbit satellite is easy to cause that the signal cannot be locked, and finally the capturing success rate is low. The method comprises the following steps: acquiring ka-band low-orbit satellite signals and low-orbit satellite pseudo-random noise codes corresponding to a plurality of low-orbit satellite ultra-wideband navigation signals; generating a complex signal and an original intermediate-frequency signal according to a preset sampling rate, preset skipping time and the ka-band low-orbit satellite signal; constructing a pseudo-code spectrum library based on the pseudo-random noise codes of the low-orbit satellites, and outputting the pseudo-code spectrum library; determining a discrete frequency search sequence based on known intermediate frequency parameters of the original intermediate frequency signal, performing matrix construction in combination with the complex signal and the pseudo code spectrum library, and outputting a three-dimensional result matrix; and capturing and judging the ultra-wideband navigation signals of the low-orbit satellites by adopting the three-dimensional result matrix, and determining a plurality of successfully captured ultra-wideband navigation signals of the low-orbit satellites.

A method (20) of identifying an authentic navigation signal comprises detecting (21), in a sampled navigation signal, a plurality of correlation peaks for a pseudorandom noise code replica associated with a respective navigation beacon. Navigation messages (123) associated with the plurality of the correlation peaks are decoded (22). The navigation messages are authenticated (23). Based on a plurality of the navigation messages being found authentic, a range criterion is applied (25) to ranging measurements (124) determined from correlation peaks associated with the authentic navigation messages. The correlation peak associated with one of the authentic navigation messages passing the range criterion is selected as an authentic correlation peak. A device for identifying an authentic navigation signal comprises processing circuitry configured to carry out the above method.

A server for hybrid federated learning with trusted execution environment (TEE) client devices and non-TEE client devices may determine an initial set of global model weights associated with a desired machine learning algorithm, transmit the initial set of global model weights to a plurality of client devices, the plurality of client devices including a plurality of TEE client devices and a plurality of non-TEE client devices, the initial set of global model weights enabling each of the plurality of client devices to generate encoded gradient information based on data collected by each respective client device and pseudo-random noise generated by the respective client device, receive the encoded gradient information from each of the plurality of client devices, and determine an updated set global model weights based on the encoded gradient information.

A modem is configurable on a satellite, user terminal or gateway generates a radio frequency (RF) signal using an orthogonal frequency division multiplexing (OFDM) protocol including a radio frame including one or more bursts. A burst of the one or more bursts includes a first portion including burst detection data, a second portion including channel characteristic estimation data, a third portion including payload data, and fourth and fifth portions including pilot data. The first portion in a time domain is included in the burst prior to the second, third, fourth, and fifth portions. The first portion can include a pseudo-random noise sequence inserted in the time domain. The same physical modem can be configured to transmit signals on an uplink or downlink between a user terminal and a satellite or on the uplink or downlink between the satellite and the gateway.

The invention relates to a method for navigating a vehicle (6) by tracking GNSS signals with spoofing detection by means of a GNSS receiver having a plurality of channels, wherein a first GNSS signal is tracked on a first channel and then checked for plausibility on a second channel, comprising the following steps: a) searching for a second GNSS signal which should contain the identical pseudo random noise code as the first GNSS signal, b) checking the plausibility of the first GNSS signal as an authentic GNSS signal if no second GNSS signal has been found, or carrying out the following sub-steps if a second GNSS signal has been found: i) comparing the first and the second GNSS signal with one another, and ii) checking the plausibility of the first or the second GNSS signal as the authentic GNSS signal on the basis of the comparison result.

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.

The application provides an OFDM underwater acoustic communication method based on a pseudo-random noise sequence, compared with existing TDS-OFDM and DPN-OFDM, due to the existence of CP in the PN-CPOFDM frame structure design, the influence of inter-symbol interference (ICI) on OFDM symbols is greatly weakened, therefore, the bit error rate performance of the PN-CPOFDM is superior to that of TDS / DPN-OFDM; the application simulates an actual underwater acoustic channel by using BELLHOP underwater acoustic channel simulation software, under the condition of a lower signal-to-noise ratio, the bit error rate performance of DPN-OFDM is equivalent to that of TDS-OFDM, when the signal-to-noise ratio is larger, the bit error rate performance of DPN-OFDM is superior to that of TDS-OFDM, and the bit error rate performance of the modulation scheme is improved with the increase of the signal-to-noise ratio, and the bit error rate performance of the modulation scheme is always superior to that of the former two modulation technologies, which further verifies the performance of the technical scheme.

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.

The invention relates to a communication and navigation integrated signal frame design method and device, and the method comprises the steps: eliminating the occupation of a conventional pilot frequency resource through the frequency domain sharing of a one-dimensional pseudo-random noise sequence and a data symbol, and enabling the frequency spectrum utilization rate to be improved; secondly, dynamic power distribution based on the genetic algorithm can adjust a dynamic power distribution coefficient in a signal-to-noise ratio fluctuation scene and a terminal high-speed moving scene, and it is ensured that a ranging error and a communication rate meet preset requirements; in addition, the method is compatible with a signal frame structure and standard OFDM, and supports smooth upgrade of existing communication equipment, and the introduction of the MIMO technology further expands the applicability of the system in a multi-user scene. Therefore, the problems that an existing dynamic resource allocation method is low in resource reuse efficiency, insufficient in dynamic adaptive capacity, prominent in performance compromise contradiction and the like are solved.

A first electronic device for performing channel sounding includes a transceiver configured to communicate with a second electronic device, one or more processors, and memory. The memory is configured to store instructions that, when executed by one or more processors, cause the first electronic device to receive a channel sounding signal generated from the second electronic device based on a sounding sequence and artificial noise symbols, subtract artificial noise symbols from the channel sounding signal to reconstruct the sounding sequence, calculate a travel time between the first electronic device and the second electronic device based on the sounding sequence, and determine a distance between the first electronic device and the second electronic device based on the travel time.

A method and apparatus for fast searching GNSS signals performed on a GNSS receiver includes the steps of receiving a signal having a known pseudo random noise code. State information of a code generator is stored when a pseudo random noise code is generated. Several NCO, including a Doppler NCO are used to search GNSS signal for several supposed Doppler's simultaneously. A search window associated with the received signal is reviewed a first time to identify a source of the received signal. After it is determined if a source of the received signal can be identified, the state information is loaded into the code generator prior to reviewing the search window a second time etc. Search windows is shifting by all length PRN Code. The loading of state information allows sequential review of the search window without re-adjustment of a fast search module which speeds the process of analyzing the received signals.

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 present application discloses a satellite locking method, device, equipment and storage medium, which relates to the navigation field and is applied to a controller. The method includes: determining a first ranging code and a first pseudo-random noise code of a satellite to be locked, and sending the first ranging code to a code comparator; obtaining a code coincidence signal, where the code coincidence signal is a signal generated by the code comparator when the first ranging code is consistent with a ranging code to be compared in a ranging code list to be compared; determining a target satellite signal based on the code coincidence signal, demodulating the target satellite signal to obtain a target message, and determining a second pseudo-random noise code of the target satellite signal based on the target message; where the second ranging code is the ranging code to be compared in the ranging code list to be compared that is consistent with the first ranging code; determining whether the second pseudo-random noise code is consistent with the first pseudo-random noise code, and when they are consistent, determining the satellite of the target satellite signal as the target satellite to perform a satellite locking operation. The present application realizes accurate locking of a satellite.

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.

A method and apparatus for performing a fast search for GNSS signals on a GNSS receiver includes the step of receiving a signal having a known pseudo-random noise code. When the pseudo-random noise code is generated, state information of the code generator is stored. A plurality of assumed Doppler in a GNSS signal is searched simultaneously using a plurality of NCOs including Doppler NCOs. A first check is performed on a search window associated with the received signal to identify a source of the received signal. After determining whether the source of the received signal can be identified, the state information is loaded into a code generator prior to a second check of the search window, and the like. The search window shifts the full length PRN code. The loading of the state information allows for sequential check of the search windows without the need to readjust the fast search module, which accelerates the process of analyzing the received signals.

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.

A method and apparatus for fast searching GNSS signals performed on a GNSS receiver includes the steps of receiving a signal having a known pseudo random noise code. State information of a code generator is stored when a pseudo random noise code is generated. Several NCO, including a Doppler NCO are used to search GNSS signal for several supposed Doppler's simultaneously. A search window associated with the received signal is reviewed a first time to identify a source of the received signal. After it is determined if a source of the received signal can be identified, the state information is loaded into the code generator prior to reviewing the search window a second time etc. Search windows is shifting by all length PRN Code. The loading of state information allows sequential review of the search window without re-adjustment of a fast search module which speeds the process of analyzing the received signals.