59results about How to "Improve capture sensitivity" patented technology

The invention discloses a GPS signal large-scale parallel quick capturing method, which comprises the following steps: configuring a large-scale parallel quick capturing module firmware comprising submodules of multiplier, data block cache, parallel part correlative processing, frequency domain transformation, postprocessing and digital controlled oscillator, code generator and the like in a system CPU; through the calling computation, converting low-medium frequency digital signals into baseband signals in a processing procedure to combine a data block; performing zeroing extension of the length and the data block on each equational data section in the data block; then based on FFT transformation computation, performing parallel part correlative PPC processing on each extended data section and local spreading codes, and performing FFT transformation on each line of a formed PPC matrix to obtain a result matrix; and performing coherent or incoherent integration on a plurality of result matrixes formed by processing a plurality of data blocks to increase the processing gain, improve the capturing sensitivity, roughly determine the code phase and the Doppler frequency of GPS signals, and achieve two-dimensional parallel quick capturing of the GPS signals. The method has high processing efficiency and high capturing speed, and can be applied to various GPS positioning navigation aids.

The invention discloses a method and a system for capturing a weak GNSS (Global Navigation Satellite System) signal under the condition of large-scale frequency deviation. The method comprises the following steps of: according to a pre-detection integration time, a carrier frequency and a sampling rate, determining a maximum carrier frequency searching step; dividing the whole frequency range to be searched into a plurality of carrier frequency units according to the maximum frequency searching step to realize rough search of the carrier frequency; mapping a received satellite signal onto each carrier frequency unit and regulating a local pseudo code rate according to the carrier frequency units so as to reduce the influence of code Doppler; calculating correlation in a flexible zero-padding mode through FFT (Fast Fourier Transform)/IFFT (Inverse Fast Fourier Transform) so as to realize code phase parallel search; and carrying out FFT operation on different correlation values corresponding to the same code phase so as to fulfill the aim of carrying out fine search on the carrier frequencies in the carrier frequency units. By the method and the system, a capturing speed and a capturing sensitivity of a receiver can be improved, so that the receiver completes the work of capturing a weak navigation signal pseudo code under the condition of the large-scale frequency deviation.

The invention discloses a circuit for rapidly capturing a long period pseudo random spread spectrum code of a satellite navigation receiver and a capturing method thereof. The circuit comprises: a data preprocessing module, a sampling data control module, a frequency mixing module, a local spread spectrum code generation module and a single capturing engine. The single capturing engine comprises:a local spread spectrum code memory, a first stage coherent integral module, a first stage coherent data memory, a second stage coherent integral module, a third stage incoherent integral module and a threshold control comparison module. An output terminal of the data preprocessing module is connected with an input terminal of the frequency mixing module through the sampling data control module. The output terminal of the frequency mixing module is connected with one input terminal of the first stage coherent integral module. The local spread spectrum code generation module is connected with another input terminal of the first stage coherent integral module. The circuit of the invention has the following characteristics that: integral gain is high; an anti-electromagnetism interference ability is strong; a capturing sensitivity is high; capturing precision is high; a capturing false alarm rate is low; a capturing speed is fast; reliability is high. And there are many other characteristics.

The invention discloses a ground-space-based integral measurement and control system applied to a terrestrial space. The system includes a ground measurement and control station; a relay satellite; anair vehicle including an upper antenna, a lower antenna, a radio frequency front end, a transceiving assembly and an air vehicle management computer, wherein the upper antenna and the lower antenna are used for receiving and transmitting of ground-base uplink and downlink signals and space-based forward and backward remote control signals; the radio frequency front end is used for performing filtering hybrid amplification on signals and outputting the signals; the transceiving assembly is used for conversion through modulation and demodulation and for receiving CCSDS remote measurement framesor acquiring positioning information according to remote measurement parameters of the transceiving assembly itself and calculating the optimal direction transmission of the space-based forward remote control signals; the air vehicle management computer is used for transmitting the received positioning information and the calculated optimal direction of the space-based forward remote control signals to the radio frequency front end for transmission switching between the upper antenna and the lower antenna and transmitting selected space-based backward remote control signals to the relay satellite. According to the invention, a ground-based and a space-based remote measurement and remote control links can be implemented at the same time and whole course coverage of flight tasks is realized.

The invention discloses a compatibility capturing method of a multi-mode GNSS (Global Navigation Satellite System) combination receiver. The capturing method comprises the following steps of: carrying out corresponding capture process on a satellite signal within coherent integration accumulation time and non-coherent integration accumulation time; adopting a fuzzy logic algorithm in the capture process, dynamically adjusting the coherent integration accumulation time and the non-coherent integration accumulation times according to a carrier-to-noise ratio and a carrier speed; and within the coherent integration accumulation time, carrying out the secondary sampling on a middle frequency signal of the acquired satellite signal, i.e. all data are decomposed into a plurality of groups, and the data points in each group are at one pseudo-random code element, and subsequently the Fourier transform, the Fourier inversion, the DCT (Discrete Cosine Transformation), the IDCT (Inverse Discrete Cosine Transform), the mode value square and threshold judgment process are carried out. With the adoption of the capturing method, the defects that signals cannot be captured as an existing capturing method is low in sensitivity and likely to be interfered are overcome, and satellite signals can be captured normally when a GNSS signal is shielded and strong environment noise exists.

The invention discloses a high-sensitivity method for capturing Beidou satellite signals. The method comprises the following steps: firstly, respectively conducting buffer memory on m single-cycle integral results of an I path and m single-cycle integral results of a Q path, and obtaining the sequence [I1, ... Im] of the single-cycle integral results of the I path, and the sequence [Q1, ... Qm] of the single-cycle integral results of the Q path; respectively conducting coherent integration on 2m-1 phase combinations which possibly exist in the m single-cycle integral results in the sequences, and obtaining 2m-1 pairs of integral branches; conducting range obtaining on the single-cycle integral results of the same phase integral branches in the I path and the Q path, and then taking the maximum value in the results as the result of the one-time multi-phase coherent integration; finally conducting noncoherent accumulation on n multi-phase coherent integration results, at last comparing the results with the threshold, and detecting the satellite signals. The invention further discloses a device for capturing the Beidou satellite signals by the adoption of the method for capturing the signals. The method and device overcome the defects that phases of single-cycle integration results are different, and the direct coherent integration can not be achieved, and have the higher satellite signal capturing sensitivity.

The invention discloses a method for rapidly capturing weak signals of a Beidou D1 satellite navigation system. The method comprises the following steps that S1, the satellite PRN numbers searched by channels are set from 1 to 6; S2, first sampling is carried out on received signals; S3, NH codes are selected for forming a matching filter to carry out relevance addition on resampling data of the received signals; S4, the results of the relevance addition in the step S3 are divided into N sections, and relevance addition is carried out on the results and local codes point by point; S5, M point FFT is carried out on the results of the relevance addition in the step S3; S6, the signal to noise ratio is calculated, whether the signals are captured or not is detected according to the threshold value of the signal to noise ratio, and if the signals are not captured, the phases of the NH codes are changed, and the step S1 to the step S6 are repeated. The method can peel NH secondary coding, achieve relevance addition of 20 ms, and improve the capacity for capturing the weak signals of the Beidou D1 satellite navigation system.

The invention discloses a satellite signal capturing method and device which achieve fast and real-time capture by a code parallel and frequency parallel search method. The satellite signal capturing method and device can be applied to military codes and civilian codes with the same rate, improve the sensitivity without increasing the resources. The whole process can be realized in a FPGA, which is beneficial to the miniaturization design of a receiver. The method of the invention is applicable to the receiver terminals of satellite navigation systems such as Beidou, GPS and the like, and has strong practicability.

The invention provides a capturing method of Beidou second-generation B1 signals and a system thereof. The capturing method comprises steps of 1: changing processed a B1 signal received by an antenna into a digital intermediate frequency signal; 2: receiving the digital intermediate frequency signal, peeling carrier waves, extracting and then storing data; 2: interpolating the data; 3: searching the data and peeling the carrier waves; 4: performing DFT for the data on 4 points; 5: peeling carrier waves for the data, performing FFT, then performing IFFT, obtaining related peak results, and then processing all data so as to related peak results; and 6: sequencing the related peak results, wherein if the biggest peak value is larger than a captured threshold, it shows that the B1 signal has been captured, and otherwise, the B1 signal has not been captured. The invention also provides a capturing system of the Beidou second-generation B1 signals. According to the invention, 4ms coherent integration of the B1 signals can be achieved, capturing sensitivity of the B1 signals is increased and balance between computation amount and capturing sensitivity can be obtained.

The invention discloses a method and a device for capturing GPS satellite signals, which comprises the following steps that: a GPS receiver carries out acquisition and re-sampling operations for the GPS satellite signals; the GPS receiver carries out boundary and message prediction for the acquired GPS satellite signal data; the GPS receiver carries out grouping and setting of non-coherent integration according to the predicted boundary position and message; the GPS receiver carries out computing operations of the non-coherent integration according to the finished setting mode of the non-coherent integration grouping respectively; and the GPS receiver judges the capturing result of the GPS satellite signals according to the computing results of the grouped non-coherent integration till finishing capture. Through the operation of the method, the method can effectively improve the signal integration length during GPS satellite capture, can operate across GPS navigation data, and greatly enhances the capturing sensitivity of the GPS signal receiver and the detection capacity of the weak signals. In addition, the invention also provides a corresponding realization device according to the method.

The invention provides a GNSS long code signal capturing method and device assisted by a low earth orbit satellite. The GNSS long code signal capturing method assisted by the low earth orbit satellitecomprises the following steps: acquiring GNSS baseband signals; performing frequency mixing operation; performing segment correlation operation; performing long-time coherent integration; carrying out incoherent integral operation; and performing peak detection and threshold judgment. The method and the device have the advantages that GNSS navigation signal auxiliary information, including roughDoppler information and rough code phase information, is acquired under the assistance of a low-orbit satellite, so that on one hand, the rough code phase information is used for generating sub-codesof local ranging codes and participating in related operation; it is guaranteed that the influence of bit hopping on coherent integration time is eliminated after correlation operation, high-sensitivity capturing of long codes is achieved through long-time coherent integration, and the long code signal capturing performance in the low signal-to-noise ratio environment is improved; and on the otherhand, rough Doppler information and rough code phase information of the GNSS navigation signals are utilized, the searching time of the signals in the frequency dimension and the code dimension is shortened, the capturing efficiency is improved, and rapid capturing of GNSS long code signals is achieved.

The invention discloses a bit synchronization method of satellite navigation signals, which comprises judging received satellite navigation signals and choosing a strong signal bit synchronous processing step or a weak signal bit synchronous processing step; in the strong signal bit synchronous processing step, achieving bit synchronization by comparing correlation value symbol strings with preset symbol strings; and in the weak signal bit synchronous processing step, achieving bit synchronization by utilizing related accumulated value of the satellite navigation signals continuous within 2ms. The bit synchronization method can regulate bit synchronization strategies in a self-adaptive mode. Under the condition of strong signals, the bit synchronization method can quickly achieve the bit synchronization to ensure starting time, and under the condition of weak signals, the bit synchronization method ensures reliability of the bit synchronization and shortens the time of the bit synchronization simultaneously.

The present invention discloses a capture method for sine binary offset carrier modulation signals. According to the capture method and apparatus, sine binary offset carrier signals are adopted as special time-division multiplexed modulation signals; under a local correlation condition, a plurality of paths of pseudo-random code signals are adopted; time division correlation-removing operation is performed on carrier-removed intermediate-frequency signals and the plurality of paths of pseudo-random code signals; the independent coherent integration values of each path are calculated; and the correlation results of all branches are combined, so that a final correlation result is obtained. With the time-division correlation method adopted, the influence of sub-peaks and zero points in an autocorrelation function can be effectively removed, and the probability of missed capture can be reduced. The capture method is similar to a traditional BPSK (binary phase shift keying) signal capture method. Compared with existing methods, the method of the invention is easier to implement and can assist in reducing system complexity. The present invention also provides an apparatus device for implementing the above method. Since cross-correlation or sideband energy loss are avoided, so that signal acquisition sensitivity can be improved. The capture method and the apparatus of the present invention therefore have high commercial value.

The invention discloses a high-sensitivity capturing method and device of a satellite navigation receiver, and relates to the field of signal processing. The device comprises the steps that a composite GNSS signal is multiplied with a local carrier of a GNSS receiver and multiplied with the data component and pilot frequency component of a local pseudocode of the GNSS receiver sequentially to perform integral operation; correlation outputs of an in-phase branch and orthogonal branch of a data channel are combined to form a multiple correlation output of the data channel, and correlation outputs of the in-phase branch and orthogonal branch of a pilot frequency channel are obtained to form a multiple correlation output of the pilot frequency channel. The method has the advantages that the capturing sensitivity of the GNSS receiver can be significantly improved from performance indicators of false-alarm possibility, detecting possibility and the like, the capturing performance improvementcan be achieved by a joint data channel and pilot frequency channel differential combined strategy compared with a traditional single-channel capturing technology, and the capturing sensitivity of the GNSS receiver in a weak signal environment is significantly improved.

The invention provides a non-ambiguity capturing method and device applicable to BOC (n, n) signals which comprises the following steps of: acquiring a digital intermediate frequency signal, mixing the digital intermediate frequency signal with a local carrier to obtain a spread spectrum signal; and performing a low-pass filter on the spread spectrum signal; extracting sampling into a segmented matched filter, wherein both the local code and the spread spectrum signal are divided into a plurality of segments, and the corresponding segment number is multiplied by two times to obtain a pluralityof points, and finally the accumulated value of the cached suitable points is FFT; comparing the obtained maximum value with the threshold, if it is greater than the threshold value, indicating thatthe signal acquisition is successful, entering into the next step of tracking; if it is less than the threshold,, indicating that the signal acquisition is not successful, feedback to extract again, and the mobile code phase is subjected to one-step serial matched filtering plus FFT operation until the acquisition is successful. The invention solves the problem that the self-correlation function of the binary offset carrier modulation technique in the prior art with a plurality of sub-peaks which in turn leads to ambiguity in signal acquisition.

The invention belongs to the technical field of satellite navigation, and discloses an L5 signal capture method and apparatus, and a computer storage medium. The method comprises the following steps:capturing Doppler frequency and a code phase of an L1 signal sent by a current satellite, and performing bit synchronization on the basis of the result, and determining a code phase search range of the L5 signal according to the bit synchronization result, so that the L5 signal can be captured and searched within a relatively small code phase search range. By adoption of the L5 signal capture method and apparatus disclosed by the invention, the problem of low capture sensitivity of the existing capture method can be solved, the L5 signal can be captured quickly, and the L5 signal capture method and apparatus are simple and feasible, and are relatively high in sensitivity.

The invention discloses a GNSS signal double-step acquisition data symbol reversal elimination method and device, and relates to the technical field of signal processing. The GNSS signal double-step acquisition data symbol reversal elimination method comprises the steps that an optimal acquisition parameter is adjusting and selected; a code phase delay hat{tau<1>}in a first step of GNSS signal acquisition is estimated; the estimated code phase delay hat{tau<1>} in the first step of GNSS signal acquisition is extracted, so that a local pseudo code of a GNSS receiver is aligned with the navigation data symbol reversal position in a GNSS received signal; and the Doppler shift hat{f<d,2>}is estimated in the second step of GNSS signal acquisition, and GNSS signal acquisition results are comprehensively optimized. The GNSS signal double-step capture data symbol reversal elimination method and device have the advantages that the CAF main peak splitting effect caused by the data symbol reversal existed in GNSS signals is effectively eliminated, and the GNSS signal acquisition sensitivity is improved; and therefore, the GNSS signal double-step acquisition method effectively solves the problem of the GNSS signal data symbol reversal, improves the GNSS signal acquisition performance, and is effectively applied to a new generation of GNSS signals.

The invention discloses a spaceborne automatic gain switching phase-locked receiver comprising a normal receiver body and an automatic gain amplifying device. The automatic gain amplifying device is arranged in front of the automatic gain amplifying device, and the automatic switching method is applied to the output power. Before received signals are locked, the automatic gain amplifying device is controlled to output small power, the loop phase discrimination gain is small, the loop bandwidth is small, and the signals are easy to lock; after the signals are locked, the automatic gain amplifying device is controlled to output large power, the loop phase discrimination gain is large, the loop bandwidth is large, the loop steady-state phase error is small, signal tracking is maintained easily, and the tracking sensitivity of the phase-locked receiver is improved. The large and small power output switching of the automatic gain amplifying device is controlled automatically through a switch according to locking indication signals. The phase-locked receiver is obtained through analog devices completely, circuits are simple and reliable, the steady-state phase error can be reduced, the loop dynamic performance and the receiver sensitivity can be improved, and the phase-locked receiver is particularly adaptive to the field of deep space exploration.

The invention discloses a high-performance capturing and judging method for an intersatellite link wireless signal of navigation satellites, and the method comprises the steps: S1, carrying out the digital orthogonal demodulation of a received signal, and obtaining a complex number baseband signals composed of I/Q signals; S2, carrying out the resampling of the complex number baseband signals, obtaining detection statistical quantities through coherent integration, detection and incoherent integration, searching the maximum value of all detection statistical quantities, recording the grid position of the maximum value, adjusting the searching range after the first detection, carrying out multiple detection, and verifying the consistency of the grid positions of the maximum value; S3, judging whether the capturing is successful or not according to the verifying result. The method is adapted to the intersatellite time-variant characteristics, improves the capturing sensitivity, and achieves the quick capturing.

The invention discloses a high-dynamic satellite signal capturing method and system based on code Doppler compensation, and the method comprises the steps: sequentially carrying out the correlation integral calculation, buffering processing and frequency spectrum shifting of the storage data of a to-be-captured satellite signal, meeting the requirements of a high-dynamic Doppler frequency coveragerange, reducing the correlation peak attenuation caused by Doppler, and reducing resource consumption of subsequent incoherent accumulation; enabling the frequency spectrum shifted data to enter an FFT module, and calculating an integral value, Doppler frequency and incoherent accumulation times on a preset numerical code phase respectively; utilizing the Doppler frequency, the incoherent accumulation times, the integral value on the preset numerical code phase and the preset integral time to calculate the offset and dislocation incoherent accumulation of the related peaks, thereby reducing the energy dispersion, enhancing the capture sensitivity in the high-dynamic environment, and reducing the average capture time by half. The increase of code phase search times caused by dislocation incoherent accumulation is compensated, and the capture speed, capture sensitivity and resource consumption are balanced.

The invention discloses a satellite navigation signal capturing method and device; wherein the method comprises the steps: carrying out the correlation of a digital intermediate frequency signal X anda local complex carrier signal, and generating a zero intermediate frequency complex signal S; performing correlation operation on the zero intermediate frequency complex signal S and local codes ofdifferent initial phases to obtain a correlated signal Y; performing piecewise integration on the signal Y to generate an integrated signal Yr; randomly sampling the signal Yr to obtain a signal Ys; knowing the observation matrix phi s and the signal Ys, and generating a frequency signal theta by adopting a fast Bayesian compressed sensing reconstruction algorithm; when the frequency signal thetameets a preset threshold range, judging that signal capture succeeds; the frequency offset searching range and searching precision are improved, and the capturing sensitivity is high.

The invention discloses a satellite signal acquisition method and a satellite signal acquisition apparatus applying the related method. According to the satellite signal acquisition method and the apparatus, the calculation amount in a satellite signal acquisition process is effectively reduced, and the acquisition sensitivity is improved. The satellite signal acquisition method specifically comprises the following steps: generating a local carrier; down-converting an input satellite signal; generating a pilot channel and a data channel spreading code, respectively; completing pilot channel signal and data channel signal acquisition; inverting a sign of an imaginary part of pilot channel acquisition data; exchanging real and imaginary parts; obtaining a data channel acquisition result copy; accumulating the data channel acquisition result copy and the data channel acquisition result; subtracting the data channel acquisition result copy and the data channel acquisition result; and selecting a maximum value to perform acquisition judgment.

The embodiments of the invention provide a positioning signal generating method and device. The method comprises the steps of: according to the acquired spread spectrum code rate and information rate, a sending end acquiring a ratio of the spread spectrum code rate to the information rate; obtaining a first spread spectrum code length according to the acquired first spread spectrum codes; then obtaining the number of the first spread spectrum codes and a second spread spectrum code length according to the ratio and the first spread spectrum code length, and generating second spread spectrum codes according to the second spread spectrum code length and the first spread spectrum codes; further, generating target spread spectrum codes according to the number of the first spread spectrum codes, the first spread spectrum codes and the second spread spectrum codes, wherein the length of the target spread spectrum codes is equal to the ratio; and performing spread spectrum modulation on a preset number of bits of navigation message by using the target spread spectrum codes to generate a positioning signal. By using the method and the device, the positioning signal generated by using the target spread spectrum modulation navigation message is easily captured, and the capturing sensitivity to GNSS (Global Navigation Satellite System) is improved.

The invention discloses a method and a device for capturing navigation signals. The method comprises steps: to-be-processed data segments are selected, the to-be-processed data segments are delayed sequentially for a delay step, and N data groups are obtained; the coherent integral value of each data group is acquired, and the first largest coherent integral value, a left neighbor coherent integral value and a right neighbor coherent integral value are determined; when the absolute value of the difference between the left neighbor coherent integral value and the right neighbor coherent integral value is smaller than or equal to a threshold value, the first largest coherent integral value is determined to be the coherent integral value not including navigation data bit hopping and can be used for capturing and deciding the navigation signals; and when the absolute value of the difference between the left neighbor coherent integral value and the right neighbor coherent integral value is larger than the threshold value, through comparing the left neighbor coherent integral value and the right neighbor coherent integral value, a fine searching direction is determined, and through the fine searching, the coherent integral value not including the navigation data bit hopping is determined. Thus, the computational efficiency during the navigation signal capturing process can be improved, and the signal-to-noise ratio gains are improved.

The invention belongs to the technical field of satellite navigation, and discloses an inter-symbol difference and code parallel GPS weak signal capturing method and system. Comprising a digital down-conversion module, a code merging module, a data storage module, a Doppler stripping module, a data folding module, a step-by-step matching coherence module, an inter-symbol difference module, a Doppler compensation module, a step-by-step coherence module, a step-by-step incoherence module, a peak value judgment module, a Purler search completion judgment module, a Doppler regulation and control module and a result output module. According to the high-orbit GPS signal capturing method based on inter-symbol difference and code parallelism, a rapid and efficient capturing algorithm is provided for a navigation receiver; an inter-symbol difference algorithm is adopted to avoid the influence of navigation data jump on the coherent integration duration, and the capture sensitivity of the GPS signal is improved by improving the coherent integration duration. According to the invention, a step-by-step coherent algorithm and a step-by-step incoherent algorithm are adopted, so that rapid acquisition of signals with different intensities is realized, and the first positioning time of a navigation receiver is shortened.