97results about How to "Improve capture speed" 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 double-antenna A-GNSS receiving machine system. The double-antenna A-GNSS receiving machine system utilizes double antennae to perform positioning, the auxiliary antenna is arranged in the open sky to be positioned so as to extract code phases and carrier wave Doppler values in satellite signal digital channels, calculating satellite signal navigation message information and then utilizing the auxiliary information to assist baseband processing of a target antenna receiving signal. In the baseband processing process of the target antenna receiving signal, the code phase values and the carrier wave Doppler values are set according to the auxiliary information, the capture process and the frequency pulling process of a receiving machine system can be omitted, and tracking process is directly performed after code phase pulling. The coherent integration time is prolonged by eliminating the bit influence during tracking, the tracking accuracy and the sensitivity are improved by adopting pure phase-locked loop phase discriminator and other modes, and the positioning speed and positioning performance are finally improved in the weak-signal and complicated-signal environments.

The invention discloses a rapid acquiring method suitable for a GPS (Global Positioning System) weak signal. The rapid acquiring method comprises the following steps of (1) taking a section of data of an Mms intermediate frequency signal, wherein M is larger than 1 and is less than or equal to 10; dividing the section of the data in a plurality of 1ms data, carrying out coherent integration by applying a frequency domain circular correlation method based on FFT (Fast Fourier Transform), carrying out incoherent accumulation for every result, and obtaining the primary frequency of the intermediate frequency signal and a pseudo code initial phase; (2) stripping pseudo code information in the intermediate frequency data by multiplying a section of intermediate frequency data which is additionally used with the pseudo code initial phase obtained in step (1); and (3) setting 21 to-be-acquired frequencies within a frequency shifting range [-500Hz, 500Hz] according to the primary frequency obtained in step (1), carrying out time domain sliding acquisition, and obtaining a carrier frequency with the accuracy being 50Hz. The rapid acquiring method disclosed by the invention has the advantages that the acquiring speed is rapid, the acquiring accuracy is high, the operating amount is less, the carried frequency error can be controlled within 25Hz, and the treating efficiency of a follow-up circuit is greatly increased.

The invention discloses a capturing method based on a signal light and a capturing system based on a signal light. A signal light capture technology is used, aiming is initialized according to the prediction position of the ephemeris, an optimal uncertain area is determined, a scanning path is set, each area in the uncertain area is scanned by using a fine tracking fast reflector, and image processing is performed by using a gray scale enhancement method, so that the signal-to-noise ratio is improved, the signal capture difficulty is reduced, and the capture time is shortened. According to theinvention, the communication beam, namely signal light, is used as an alignment beam; A beacon light transmitting system and a beacon light receiving system of an existing active communication terminal are omitted, a target or an indicator light of a reverse modulation terminal is omitted, the system structure is effectively simplified, the size, the weight and the power consumption of the systemare reduced, and the applicability of the free space laser communication system to a small platform and a movable platform is improved.

The invention provides a method for quickly acquiring GPS signals and a GPS signal quick acquiring system which comprises the method. The main hardware parts of the system mainly comprise a quick acquisition module; the quick acquisition module acquires the GPS signals in parallel in large scale, obtains the initial phase and frequency information of the GPS signals and sends the signals to a correlator; and the correlator completes the carrier removal correlation of corresponding phase and frequency, and then accumulates the data and saves the data in a register. A microprocessor schedules the assembly lines of the quick acquisition module and the multi-channel correlator, simultaneously distributes the satellite number of the next quick acquisition module, confirms the data given by the channels of the correlator by quick detection algorithm processing so as to quickly and accurately acquire the GPS signals.

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 P code catching method and a P code catching device. The method comprises the following steps that IF (intermediate frequency) signals and local carrier signals from a carrier generator are multiplied, and I-Q two-path base band signals with rest Doppler frequency are obtained; the base band signals are extracted to obtain base band data to be processed, and the base band data to be processed is stored according to the sub segment; the local P code is used as a tap coefficient, each sub segment is respectively subjected to partial PMF to obtain accumulation results, and the code phase searching is completed; the filtering results after the PMF processing is subjected to buffer memory, in addition, fast FFT is respectively carried out, the frequency spectrum analysis is realized, and the frequency searching is completed; the accumulation according to points is carried out after the parallel model delivery is respectively carried out on the output results of the FFT processing, M point incoherent accumulation results are obtained, and the caught results are found, wherein the caught results include but are not limited to the maximum correlation value, the second correlation value, the frequency, the phase, the paragraph and the like. The method and the device provided by the invention have the advantages that a PMF and FFT combination mode is adopted, the P code catching sensitivity is improved, and the catching speed is obviously accelerated, so the requirements of actual signals are met.

The invention relates to a satellite navigation system baseband signal processing system, which belongs to the field of satellite navigation. The system comprises a multi-channel pre-processing module, a multi-channel data buffer module, a code generation/external interface module, a capturing channel, a tracking channel and a control module. The multi-channel pre-processing module is used for pre-processing an input signal. The multi-channel data buffer module forms one or more data buffer areas. The code generation/external interface module provides a pseudo-random code for the capturing channel and the tracking channel. The capturing channel captures data from a multi-channel data buffer area. The tracking channel tracks a signal in the multi-channel data buffer area. The control module carries out scene mode judgment according to signals in the capturing channel and the tracking channel, and determines configuration parameters for each module based on a judgment result. According to the invention, the configuration parameters of each module can be adjusted according to an environment state; hardware resources are flexibly and rationally allocated; and an optimum performance result is realized through the minimum hardware resource.

The invention relates to the field of capturing and processing of a receiver in a global navigation satellite system (GNSS), in particular to a BOC modulating signal capturing method based on overlapped difference circulation coherent integration. The BOC modulating signal capturing method based on overlapped difference circulation coherent integration comprises the steps that an intermediate-frequency signal is received by the receiver to serve as a receiving signal for data processing; a signal obtained after carrier waves are removed is taken as an input signal of four branches; self overlapping is conducted on a data block; the PRN codes of a satellite to be captured and a BOC signal obtained after BOC modulation are generated locally, and fast Fourier transformation is conducted; Fourier inversion is conducted, and a model is solved; multiplication is conducted on the local PRN codes, and Fourier inversion is conducted; subtraction is conducted, and an obtained value and a conjugate value are reserved; the conjugate value obtained through the current branch is multiplied by the same-level value of the next branch. By the adoption of the BOC modulating signal capturing method based on overlapped difference circulation coherent integration, weak signals can be well captured, and the adaptability of the receiver to the weak signals is improved.

The invention discloses a DS/FH frequency-hopping spectrum-spreading data transmission signal capturing method based on long code phase assistance, capable of solving the technical problems of relatively high cost and low efficiency of an existing method for keeping system synchronization for a DS/FH frequency-hopping spectrum-spreading hybrid system. Based on a local oscillator, the following steps are implemented: S100, carrying out carrier stripping on a signal at a set frequency hopping frequency point; S200, calculating code phase shift and Doppler shift of the signal at the current frequency hopping frequency point based on the step S100; S300, realizing synchronization of frequency hopping patterns based on the step S200; and S400, calculating Doppler shift of the signal at all frequency hopping points. According to the DS/FH frequency-hopping spectrum-spreading data transmission signal capturing method, the problem that receivers cannot be synchronized due to inconsistent Doppler shift of different frequency hopping points is solved; the DS/FH frequency-hopping spectrum-spreading data transmission signals based on long code phase assistance are captured, and the complexityis low, and implementation is flexible. The DS/FH frequency-hopping spectrum-spreading data transmission signal capturing method can effectively reduce the calculation amount and average capture time,improves the capture speed, can be used for capturing spectrum-spreading signals, and is higher in anti-interference capability.

The invention discloses a signal acquisition method of a GPS receiver, and the method comprises the following steps: Step 1: searching order of Doppler frequency shift is set; Step 2: the GPS receiver receives an intermediate frequency digital signal, and rough acquisition is carried out on the signal, thus obtaining rough Doppler frequency shift and a C/A code phase; and Step 3: fine acquisition is carried out on the signal after the rough acquisition, thus obtaining fine Doppler frequency shift; in the method, through the rough acquisition of the intermediate frequency digital signal and according to motion characteristics of a carrier, frequencies which are more likely to occur in the Doppler frequency shift are firstly searched, and the order-jump search of the Doppler frequency shift reduces the Doppler frequency shift search times, reduces the search calculation and enhances the acquisition speed; and the fine acquisition of the intermediate frequency digital signal shortens the Doppler frequency shift search step size, and the fine Doppler frequency shift obtained by adopting conic fitting has the advantages of high speed, high precision, accurate acquisition results, easy operation and insensitivity to jump of navigation data bits.

The invention provides a pseudocode-Doppler combined capturing method of a direct sequence spread spectrum MSK signal. The method comprises the following steps of converting the direct sequence spread spectrum MSK signal to an appropriate direct sequence spread spectrum BPSK signal through intermediate-frequency matching processing; performing Doppler compensation on sampling data of the appropriate direct sequence spread spectrum BPSK signal; capturing the code phase error, the Doppler channel and Doppler displacement value of the BPSK signal after Doppler compensation through a pseudocode parallel capturing method, and acquiring a Doppler frequency offset according to the Doppler channel and the pseudocode displacement value. The pseudocode-Doppler combined capturing method can realize capturing of the direct sequence spread spectrum MSK signal in a high dynamic condition and furthermore finishes combined estimation for the pseudocode phase and the Doppler frequency offset. On the condition of relatively low signal-to-noise ratio, not only is relatively low Doppler frequency offset estimation error realized, but also high pseudocode phase capturing performance is obtained, thereby ensuring relatively good coarse synchronization of a received signal before entering a signal tracking processing module.

The invention discloses a method for capturing a satellite signal in the technical field of satellite navigation and particularly relates to a method for fast capturing a COMPASS signal. According to the method, a path of serial search of a carrier frequency is converted into four paths of parallel search. The method comprises the processes of: obtaining a signal C(k) from a local pseudo-random code by FFT (fast fourier transform) and complex conjugate transformation, locally generating four paths of carrier waves to multiply by the COMPASS signal, obtaining four paths of signals Xj(k) (j=1,2,3,4) via FFT, respectively multiplying C(k) by Xj(k) (j=1,2,3,4), and delivering and obtaining a signal absolute value of rj(n) (j=1,2,3,4) via IFFT (inverse fast fourier transform), wherein the maximal value of each path of obtained signal is compared with the preset threshold to determine whether the satellite signal is really captured. The capturing speed of the COMPASS signal is improved under the condition without affecting the capturing precision.

The invention relates to a highly-dynamical weak signal GPS capturing method assisted by an inertial navigation system. The method comprises five steps that 1) capturing performances of coherent, non-coherent and differential coherent accumulation are compared, accumulation manners are selected and combined, and signal energy accumulation is reinforced; 2) coherent accumulation is carried out on input intermediate-frequency signals, the inertial navigation system and satellite ephemeris are used to estimate the Doppler parameter and code phase of received signals, and the frequency and the phase searching space are compressed; 3) Kalman filtering and smoothing are carried out on the estimation values of the Doppler parameters and the code phase, and a smoothing result is used to calculate the dynamic frequency/phase offset between local signals and the reception signals; 4) the dynamic offset amount of an output matrix of coherent accumulation is compensated by a cycled translation algorithm; and 5) non-coherent accumulation is carried out on the compensated output matrix, and an output result is compared with a threshold to deciding capture. The dynamic tolerance of GPS signal capturing is improved, and high-sensitivity GPS signal capturing can be realized in the highly dynamic environment.

The invention aims at providing a weak signal capturing method based on 1/5 bit differential circulation coherent integration. The method comprises the following steps of obtaining a section of intermediate-frequency signal data; performing carrier stripping treatment on the received signal data, performing data segmentation on the data without carrier; performing self-superposition and FFT (fast Fourier transform) on every data block; performing FFT and conjugation on locally-generated C/A codes, and multiplying the conjugate value with every result obtained in the step above and performing IFFT (inverse fast Fourier transform); performing complex conjugate multiplying on every data block processed in the step above and the data of the neighboring data blocks with data overlaying, and then performing grouped correlation summation; judging the volumes of obtained five results, obtaining the peak values of the results without data jump, comparing the peak values with a set threshold value gamma to determine whether signals are captured successfully. The weak signal capturing method based on the 1/5 bit differential circulation coherent integration can effectively help capture weak signals and improve the adaptability of a receiver to the weak signals.

The embodiment of the invention provides a method and device used for capturing and processing satellite data through a GPU. The method mainly includes the steps that a CPU and the GPU are arranged inside a software receiver of satellite signals, and the CPU inside the software receiver reads the satellite data and transmits the satellite data and capturing and processing instructions to the GPU; after the GPU receives the satellite data and the capturing and processing instructions, multiple channels inside the GPU capture and process the satellite data in parallel; the GPU accumulates capturing and processing results obtained through the channels, and an accumulating result is transmitted to the CPU. Due to the facts that the CPU and the GPU are arranged inside the software receiver of the satellite signals, the operation parts of capturing and processing the satellite data are performed on a GPU platform, the satellite capturing speed is greatly increased, the requirement for capturing satellite pilot signals in quantity in real time is met, and then satellites are rapidly recaptured in real time after lock losing.

The invention relates to a user channel satellite capture method based on a WCDMA (Wideband Code Diversion Multiple Access) system, comprising the following steps of: firstly screening access users out according to signing information of a PRACH (Physical Random Access Channel) access preamble on a wave beam access slot; then determining that a wave beam that each access user locates is a principle wave beam or a spanning wave beam; if the wave beam is the principle wave beam, determining the search starting time and a search interval of DPCH (Dedicated Physical Channel) channels corresponding to the access users by utilizing signing phases, searching the single-path retardation of the DPCH channels corresponding to the access users in the principle wave beam in the search interval, and then carrying out scrambling code tracking on the DPCH channels; and if the access users are the spanning wave beam access users, distributing the DPCH channels in the principle wave beam, determining the search starting time and a search interval of the DPCH channels corresponding to the spanning wave beam access users in the principle wave beam by taking the reference time of the principle wave beam as a reference, searching the single-path retardation of the DPCH channel corresponding to the spanning wave beam access users in the principle wave beam in the search interval, and then carrying out scrambling code tracking on the DPCH channels.

The invention provides a GPS weak signal capturing method based on difference circulation coherent integration. The method includes the steps that step1, a section of 20 ms+12 ms intermediate frequency is selected for receiving a signal, carrier wave stripping treatment and frequency mixing treatment are performed, and a Doppler frequency shift range, a search frequency stepping and a detection threshold value are set; step2, data partitioning treatment is performed on the signal after carrier wave stripping at the length of 4 ms, data blocks are respectively superposed, and then FFT treatment is performed on the data blocks; step3, FFT is performed on a C/A code generated locally, a conjugate is extracted, then the conjugate and all final results obtained in the step2 are multiplied, and IFFT treatment is performed; step4, the adjacent four data blocks multiply in a complex number conjugate mode after the treatment in the step3, then related grouping summation is performed, and obtained results are judged to determine whether capturing is successful or not. The GPS weak signal capturing method is used for capturing the weak signal through a GPS single-frequency civil software receiver.

The invention relates to a GNSS satellite acquisition method, a GNSS satellite acquisition device, a storage medium and a terminal. The method includes the following steps that: CA code sequences transmitted by a satellite in a current preset period are received; frequency conversion is performed on a first sequence based on a preset frequency sample set, and the converted sequence is folded, so that at least one folded sequence can be obtained, wherein the first sequence is a sequence in the CA code sequences which is corresponding to a frequency offset of kilohertz of a non-integer; a secondsequence is cyclically shifted by a preset number of times, so that at least one cyclically shifted sequence can be obtained; after time-frequency transformation is performed on the at least one folded sequence, correlation processing is performed on the at least one time-frequency transformed sequence and the at least one cyclically shifted sequence, and time-frequency inverse transformation isperformed on a correlation result, and the modulus square of the transformed correlation result is obtained, and is stored in a two-dimensional space defined by code phases and frequencies; and non-coherent accumulation is performed on the processed correlation result of the current preset period and the correlation result of a previous preset period, so that a GNSS satellite can be captured basedon a two-dimensional space. With the GNSS satellite acquisition method, the GNSS satellite acquisition device, the storage medium and the terminal provided by the technical schemes of the by presentinvention adopted, the GNSS satellite can be quickly captured with lower system complexity and power consumption.