14 results about "Pulsar" patented technology

The invention discloses an X-ray pulsar period and pulse time delay estimation method, and belongs to the technical field of pulsar navigation. The method comprises the following steps: through H test, according to a principle that an average integral square error between a Fourier series estimator and a real contour is minimum, searching an optimal harmonic wave truncation order under each observation; according to prior information of an observation event, adaptive selection of harmonic wave truncation orders under different data qualities is realized; re-estimating the phase of the packing data according to the equal photon intensity segmentation principle in the packing, so that the folded contour is closer to the real contour; and quantitative analysis is carried out in combination with simulation and actual measurement data, the optimal packing quantity is selected, and a folding contour with the optimal distinction degree is provided for statistical magnitude inspection. The method has the advantages of being suitable for a navigation pulsar source, high in reliability, high in environment adaptability, high in estimation precision, high in estimation stability and the like, and the X-ray pulsar navigation performance can be further improved.

The invention discloses a multi-source data fusion dynamic reference frame conversion method and a related device, and relates to the technical field of celestial body survey and space navigation, and the method comprises the steps: obtaining multi-source observation data, including pulsar timing data and VLBI absolute position measurement data; according to the multi-source observation data, a joint observation model and a high-order rotation model are established, the joint observation model is a mathematical model comprising a calendar error correction term and a coupling coefficient, and the high-order rotation model is a model which is established based on a quaternion parameterized rotation matrix and introduces a secondary correction term for nonlinear correction; on the basis of the combined observation model, a self-adaptive weighted least square algorithm is adopted, and rotation parameters are obtained through estimation; and based on the rotation parameter and the secondary correction term, performing error tracing and iterative optimization by adopting a Monte Carlo simulation method to obtain a dynamic reference framework conversion result. According to the invention, the conversion precision of the dynamic reference frame can be improved, and high-precision space reference conversion is realized.

The present invention discloses a method and system for processing real-time radio astronomy data streams based on distributed acquisition components, including: S1. Data transmission, the server receives User Datagram Protocol (UDP) data packets transmitted by a radio astronomy telescope through a network card, uses the open-source pulsar distributed acquisition component and data analysis system PSRDADA to create and manage a circular buffer, and transfers data streams between each circular buffer; S2. Data processing, utilize the unified computing device architecture (CUDA) parallel computing platform and programming model of a graphics processing unit (GPU) to write a calculation and unpacking program, thereby realizing parallel processing and data extraction of large-scale data; S3. Data writing to disk, use the data storage client of PSRDADA to write data blocks to the disk and split the data into files of arbitrary length. The present invention can efficiently and stably receive high-speed radio data streams, realize real-time processing of data, and provide a reliable solution for high-bandwidth signal transmission and processing in radio astronomy observations.

The present invention provides a combined navigation method based on pulsar / inter-satellite ranging / landmark, firstly, a state model and a measurement model of a pulsar / inter-satellite ranging / landmark combined navigation system are established, and the pulsar pulse arrival time TDOA, the inter-satellite relative position distance, and the landmark absolute position distance are obtained as the quantity measurement, and the pulsar / inter-satellite ranging / landmark combined navigation system is established by using the measurement information of the three navigation systems; the state model of the pulsar / inter-satellite ranging / landmark combined navigation system is established, the pulse arrival time TDOA is provided by pulsar navigation, the relative position information is provided by inter-satellite ranging navigation, and the absolute position information is provided by landmark navigation, and the measurement model is obtained by combining them, and the position and speed of the spacecraft are estimated by using the Unscented Kalman filter method. The present invention is aimed at the lunar exploration mission, and finally improves the accuracy of the navigation system.

The invention discloses a method and system for suppressing non-pulse noise to accurately measure pulse arrival time, and the method comprises the steps: S1, generating pulsar simulation parameters which comprise a rotation period P, a flow density S1250 and a pulse arrival phase delay standard deviation sigma delta p; s2, constructing a pulsar standard contour Q (x), and generating based on a pulse contour type Ptype, a sub-pulse number and a sub-pulse contour shape; s3, simulating multi-epoch observation data, injecting noise, adding phase delay delta p, and generating an average contour q (x); s4, judging a pulse region: positioning a candidate pulse region through baseline identification, and screening a final pulse region according to a contour type; s5, calculating a phase difference delta x between the standard contour and the average contour by using a phase gradient method; and S6, comparing a difference value between the phase difference delta x and the analog phase delay delta p, and verifying whether higher timing accuracy is obtained by removing the noise in the non-pulse region or not. The pulsar timing precision is remarkably improved by reducing noise interference in a non-pulse area, and the pulsar timing method is suitable for a high-precision scientific target.

The present invention discloses a parallel method and device for accelerating the search pipeline of pulsar Fourier domain, including: allocating received astronomical data to multiple parallel processes; each process includes three serial sub-threads, using the first CPU sub-thread to pre-process the allocated astronomical data, using the GPU sub-thread to read the pre-processed data and perform accelerated calculation on the GPU to obtain candidate signal data, using the second CPU sub-thread to read the candidate signal data and perform post-processing and result aggregation, while using queues and queue blocking locks of multiple parallel process architectures to synchronize the task status between sub-threads; dynamically adjusting the number of processes in the processing flow through monitoring feedback; recording the task status and the calculation results of each process in real time and handling abnormal situations. The present invention can effectively improve the pulsar binary search process, and support the use of multi-GPU parallel acceleration, greatly improving the speed of searching for this type of celestial body from FAST astronomical data.

A kind of relative navigation reference deviation calibration method of star and pulsar information fusion is disclosed, which comprises the following steps: configuring a star angular distance measuring sensor and an X-ray detector on a spacecraft; observing stars by the star angular distance measuring sensor to extract navigation information contained in two kinds of relativistic effects, i.e., star aberration caused by the movement of the spacecraft and light deflection caused by celestial gravitational field; observing pulsars by the X-ray detector to obtain pulse arrival time difference observations; combining spacecraft and earth orbit dynamics model to predict the state; processing star angular distance and pulse arrival time difference observations by an extended Kalman filter to correct the state prediction value, and obtaining the estimation of the spacecraft position and velocity, the geocenter position and velocity, and the sensor system error parameters, so as to realize the calibration of two kinds of reference deviations, i.e., earth ephemeris error and sensor system error. The present application provides a new way to improve the performance of relativistic navigation system.

The present invention provides an optimization method for establishing a comprehensive pulsar time based on Wiener filtering, wherein the reference time is TT (BIPM), and the model is fitted using existing data to obtain accurate model parameters; the reference time is changed to the monitored reference time, the timing residual before fitting is obtained and averaged within a set time length to obtain a number of residual points; all the mutual power spectra are calculated and adjusted according to the upper limit of the mutual power spectrum, and the two groups of residuals that determine the upper limit of the mutual power spectrum are filtered using the calculated mutual power spectra, and the remaining residuals are filtered using the arithmetic average of all the mutual power spectra; the correlation coefficients of each group of residuals before and after adding a tiny signal are calculated, and the normalized value of the non-correlation coefficient is used as the weight of each star; the filtering results of each star are weighted to finally obtain the comprehensive pulsar time. The present invention makes the fluctuation magnitude of the comprehensive pulsar time relative to the reference time in the correct range, and has good sensitivity to the change of the reference time.

The invention discloses a pulsar time measurement method using a multi-component template and a least square method, and the method comprises the following steps: S1, specifying a pulsar P, obtaining the average pulse contour of N times of radio observation of the pulsar P, each average pulse contour containing K data points; s2, assuming that M linearly independent pulse components exist in the pulse profile, each pulse component contains S peaks, and each peak has three parameters of position, intensity and width, and fitting to obtain a standard pulse profile of each pulse component; s3, fitting an average pulse profile obtained by observation of the pulsar by using the standard pulse profile of each pulse component to obtain a linear coefficient and a phase difference of the pulse components; and S4, calculating the pulse arrival time corresponding to the specific average pulse contour by using the phase difference. According to the invention, the effect of the least square method on the aspect of multi-parameter fitting is utilized, and the calculated amount and error of measuring the pulse arrival time by using the multi-component standard pulse profile are reduced.

This invention discloses a method and system for determining the current time using radio observations of multiple pulsars, comprising the following steps: S1. Correcting the deviation between the local clock time and the absolute time to within a set threshold; S2. Selecting N radio pulsars, where N is greater than or equal to 4, and continuously observing the selected radio pulsars using a radio telescope to obtain observation data; S3. Processing the observation data to generate the observed pulse profile; calculating the pulsar pulse phase φ. i S4. Calculate the standard pulse profile P k With the observed pulse profile P' k The relative phase deviation δφ between i Calculate the relative phase deviation δφ with error S5. i With phase φ i deviation Δφ i S6. The deviation δT between the telescope's local clock time and absolute time is calculated, thereby determining the absolute time. This invention eliminates the need to synchronize the local clock with the absolute time of a certain time standard. It can obtain absolute time with an accuracy on the order of tens of microseconds by analyzing observed pulsars, and significantly reduces calculation time.

The invention relates to the technical field of astronomy and computer communication, in particular to a method for constructing a propagation time difference model for a pulsar to reach a spacecraft and a solar system centroid, which comprises the following steps of: establishing a rotation matrix through a Kepler law and an angular momentum conservation law on the basis of orbit parameters corresponding to the spacecraft when a photon reaches a detector; obtaining a three-dimensional position coordinate and a velocity vector of the spacecraft relative to the earth; simulating different photons through a Monte Carlo algorithm to examine a geometric propagation time delay model; the right ascension and declination and the time difference between the MJD and epochs are updated by considering the influence of pulse self-motion and are substituted into a geometric propagation time delay model and a gravitational red shift time delay model. And then, respectively establishing a Shapio time delay and a narrow relativistic dynamic clock slowdown effect. Geometric propagation time delay and gravitational red shift time delay which consider the influence of pulse self are added into a total time delay module; according to the method, the propagation time difference of the photons of the pulsar reaching the spacecraft and the solar system mass center can be accurately calculated.

The invention discloses an autonomous navigation method based on the atmospheric absorption effect of an X-ray source, and belongs to the technical field of autonomous navigation of aircrafts. The method comprises the following steps: firstly, establishing a relation model of the tangency point height and the X-ray atmospheric transmittance in an occultation observation state, then calculating the X-ray atmospheric transmittance at the current moment to obtain the corresponding tangency point height, and combining the predicted speed and position information of the aircraft at the current moment, and carrying out information fusion through Kalman filtering to realize autonomous navigation of the aircraft. The X-ray pulsar navigation detector is used for detecting strong-flow X-ray sources including pulsar and direct-flow X-ray stars, the defect that the number of strong sources in X-ray pulsar navigation is insufficient is overcome, the number of navigation sources is increased, and the precision and real-time performance of X-ray pulsar navigation are improved.

The invention provides a pulse phase estimation method based on photon TOA point cloudization. The method comprises the following steps: step 1, cutting a photon TOA sequence into a plurality of sections by taking a pulsar pulse period as a segmentation interval, endowing each section with Y-axis coordinates at equal intervals, aligning starting points to realize point cloudization, and normalizing and converting a point cloud time axis into a phase axis; 2, performing point cloud registration on the photon TOA point cloud and the standard point cloud by adopting a kernel density estimation method, and outputting a translation amount as a pulse phase estimation value; compared with a conventional cross-correlation phase estimation method based on an epoch folding algorithm, the method can guarantee the estimation speed while greatly improving the estimation precision, is high in anti-noise capability, is not sensitive to observation duration, and is of great significance to real-time estimation of the pulse phase of an on-orbit spacecraft.

The invention relates to the technical field of radio astronomy, and discloses a radio astronomy signal radio frequency interference elimination method, which comprises the following steps: S1, a preprocessing step; s2, an independent component analysis step; s3, a signal separation step; and S4, a post-processing step. According to the radio astronomical signal radio frequency interference elimination method, a radio signal is expressed as a linear combination of random variables, and a source signal meets a specific condition; the fast independent component analysis estimates negentropy by maximizing non-Gaussian property, and separates out independent components; a threshold value does not need to be preset in the process, so that the problem of data loss or noise residue caused by improper threshold value selection is avoided; in addition, as the observation data is directly processed through rapid independent component analysis instead of depending on feature selection, the method is more stable when facing a time-varying celestial body such as a pulsar; finally, pulsar signals and radio frequency interference signals are identified and separated by calculating the column standard deviation and the median value of the hybrid matrix A, and generation of high-quality observation results is ensured.