107 results about "Software receiver" patented technology

A whole bit acquisition method for GPS weak signals relates to the acquisition treatment of a receiver in GNSS, and solves the problems that the prior software receiver can not forecast the information bit reversal, thereby easily causing the failure of the acquisition, and the better acquisition effect is difficult to achieve by adopting the differential coherent cumulative method. 20 sequences which are compressed into 4096 sampling points are acquired after satellite signals are subjected to the treatments related to frequency mixing, sampling, quantifying and time-domain averaging; the IFFT calculation is carried out after multiplying the 20 sequences with the sequences which are conjugated with the local stored pseudo-code FFT sequences through the FFT calculation; the maximum value which is obtained by the extraction after the mod squaring of the 20 two-dimensional pseudo-code auto-correlation value matrix is compared with a threshold value sigma 1, if the maximum value is larger than the sigma 1, the acquisition is successful; if the maximum value is smaller than the sigma 1, the whole bit algorithm is utilized to seek a peak value of the extracted related values by carrying out the coherent accumulation and the non-coherent accumulation of the 20 two-dimensional pseudo-code auto-correlation value matrix after the information bit reversal, the peak value is compared with the threshold value sigma 2, if the peak value is larger than the sigma 2, the acquisition is successful; and if the peak value is smaller than the sigma 2, the re-acquisition is carried out.

Disclosed is a GPS (global positioning system) software receiver tracking method based on an FPGA (field programmable gate array). Inputted digital intermediate-frequency signals are transmitted into a code correlator after multiplying two channels I and Q of a carrier generator to obtain six channels of relevant results; in a carrier tracking loop, IP and QP in six channels of relevant outputs are transmitted into a phase decision device, frequency discrimination computation is carried out by a carrier frequency discriminator when phase deviation meets the condition that delta theta is larger than theta H, phase discrimination computation is carried out by a carrier phase discriminator if the phase deviation meets the condition that delta theta is smaller than theta H, a result is transmitted into the carrier generator after being filtered by a carrier loop filter so that carrier frequency is adjusted; and in a code tracking loop, IE, IL, QE and QL are taken to be transmitted into a code loop discriminator to be in phase discrimination computation, and results are transmitted into a CA (coarse acquisition) code generator after being filtered by a code loop filter so that phase ofCA codes is adjusted. The two loops are cross-coupled, the carrier frequency and the phase of the codes are synchronously tracked, accordingly, locally reproduced carriers and codes are aligned with signals, and navigation data bits are obtained after integral judgment for the IP is carried out by a posterior integral accumulation decision device.

The invention discloses a realizing method of a multi-mode GNSS (Global Navigation Satellite System) software receiver based on a multi-core processor. One of N available cores is distributed to be used as a scheduling core for scheduling and controlling a multi-mode GNSS receiver, and the rest N-1 cores are used as processing cores for processing intermediate-frequency signals of the receiver. The realizing method comprises the steps of: firstly, distributing all the processing cores to form a related operation module by the scheduling core for completing satellite search of a GNSS, feeding the searched result back to the scheduling core; and then scheduling the processing cores by the scheduling core according to the searched result, reserving partial processing cores to maintain the work of the related operation module, forming a data channel consisting of a satellite tracking channel module and a positioning resolving module through the rest processing cores to complete the processing of the intermediate-frequency signal of the GNSS for realizing positioning navigation. By using strong processing capacity of the multi-core processor, the traditional GNSS hardware baseband chipis replaced with the multi-core processor for processing navigation signals of different types of satellites of multiple systems, and flexible configuration and scheduling can be realized.

The invention discloses a GPS positioning method and GPS software receiver which is based on dual-core processor, wherein, GPS positioning method includes the following steps: lower frequency process, signal capture, parallel arithmetic carrier wave, C/A code tracking process, pseudorange and ephemeris data resolving, satellite preferable choice, single point positioning resolving involved in GPS receiver and output; GPS software receiver which is based on dual-core processor, including GPS PF hardware part and PC, the PC machine at least includes two parallel equipped processors the first arithmetic processor and second arithmetic processor. The invention GPS positioning method uses multi-operation core processor as the operation platform, which designs and achieves parallel processing and algorithms for capturing and tracking GPS signal, which reduces resolving time significantly and enhances working efficiency of work.

The invention designs a GPS software receiver, which is suitable for various working environments with low signal to noise ratio, high dynamic, assistance of an inertial navigation system (INS) or independent working and the like, automatically regulates performance as required to adapt to different working environments and achieves the optimal information utilization to the fullest extent as possible. An implementation method for the GPS software receiver comprises the following steps of: independently regulating the tracking bandwidth of each tracking channel according to signal strength; combining the advantages of long-term noncorrelation integral and short-term correlation integral to design a tracking loop with high-sensitivity real-time output; realizing real-time estimation of a receiver crystal frequency error model by using a method for estimating fixed intervals; and finally, based on the deep combination, improving capture velocity and tracking dynamic performance of a weak signal. The implementation method for the GPS software receiver can fully use all detectable satellite signals, can improve the tracking dynamic performance of the weak signal by utilizing auxiliary information of INS information, and also accelerates new star search when INS information assistance exists.

The invention discloses a GPS/CAPS double-mode software receiver based on a personal computer (PC) which is characterized by adopting the existing special GPS/CAPS double-mode antenna module and radio frequency module, and implementing the other modules on the common PC completely; acquiring the intermediate frequency GPS/CAPS data of the GPS/CAPS radio frequency module respectively by a double-channel synchronous data acquisition card, storing the data into the hard disk of the PC, and implementing baseband signal processing and position resolving of all the satellite navigation signals by virtue of abundant software resources of the PC. For the complicated pseudorange extraction problem in the receiver, the invention further discloses a software post-processing method which comprises the following steps: recovering delay inequality from satellite frame headers to antenna so as to establish a pseudorange extraction method by which the pseudorange can be calculated and realize double-mode position resolving. The GPS/CAPS double-mode software receiver and the software post-processing method shorten research and development period, lower cost and realize high-precision positioning by satellite constellations of two systems.

A spread spectrum signal receiver comprises a radio signal processing unit, at least partly implemented in software running on a processor. The processing unit determines a candidate collection of subsets of signal sources from a group of potential sources, by the criterion that an anticipated processing intensity required to derive position/time related data from that subset is equal to or less than a maximum specified processing intensity. Each subset contains at least a minimum number of signal sources necessary to produce position/time related data. The processing unit also selects a set of preferred signal sources from a candidate subset, based on a highest estimated quality of the position/time related data attainable during a subsequent operating period for the receiver without exceeding the maximum specified processing intensity. During the subsequent operating period, the receiver receives spread spectrum signals from the selected set of signal sources and produces position/time related data therefrom.

The invention relates to a navigation and position equipment in the electronic technical field and real-time processing thereof, in particular to a real-time software receiver of the global position system, which implements real-time location by using the received GPS signal from the global position satellite system and is used for the signal sampling and the computer software processing, as well as a real-time processing method of the invention. The apparatus consists of a complex programmable logic device and an interface module of serial-to-parallel conversion, etc. The method executes the processing of baseband signal for the computer software under the windows XP environment, the method mainly resolves the related technical problems of how to implement the interfaces of signal sampling and transmission modules and the processing of baseband signal, etc. The invention has the advantages that the apparatus implements the real-time execution in the windows XP system of Microsoft, and the software adopts the bit arithmetic way, which reduces the computation, accelerates the processing speed and achieves real-time location, and higher precision and sensitivity through the rapidity of signal processing.

The invention discloses a GPS software receiver baseband signal real-time tracking method based on code memory, wherein the method is based on prestored and fine-adjusted local C/A code to perform binary system storage and performs table lookup and invocation to solve the problem that real-time code which wastes time are generated in GPS software receiver tracking signal time. In GPS software receiver tracking loop, the process that local C/A code is generated through minute adjustment is longest in the three longest processes, namely generation of fine-adjusted local C/A code, generation of local carrier wave and related integration and the time for generating fine-adjusted local C/A code is nearly half of the entire signal tracking and processing time. The invention uses the binary data of prestored and fine-adjusted local C/A code and directly loads data to perform table lookup and call data so that the fine-adjusted early code and late code can not be generated in every tracking cycle, the time wasted by real-time code can be saved, the time for the generation of codes in tracking cycle is saved and the tracking speed doubles.

A spread spectrum signal receiver includes a radio signal processing unit, which is at least partly implemented in software running on a processor. The processing unit is adapted to estimate a respective processing demand required to produce position/time related data based on each subset of a number of candidate subsets of signal sources among a group of potential signal sources. Each candidate subset contains at least a minimum number of signal sources, which is necessary to produce the position/time related data of a desired quality. The processing unit is adapted to select a set of preferred signal sources from the group of potential signal sources based on a candidate subset, which is associated with a lowest estimated processing demand during a subsequent receiver operating period. Then, the receiver receives spread spectrum signals from the selected set of signal sources, and based on the received signals produces position/time related data.

The invention discloses a satellite/ inertial ultra-tight integration system and method based on a Beidou/GPS dual-mode software receiver. The system comprises an active satellite antenna module, a satellite radio frequency receiving module, a satellite baseband processing module, an inertial navigation module and an integrated navigation module. The method comprises the following steps: after theBeidou/GPS dual-mode software receiver finishes first positioning, carrying out initialization on an inertial navigation system; entering an ultra-tight integration mode, and estimating I,Q information IINS and QINS; serving the difference value between I,Q information obtained by the Beidou/GPS dual-mode software receiver and the IINS and QINS as observed quantity of an EKF; carrying out correction on the inertial navigation system; and estimating carrier Doppler frequency and pseudo code phase of a satellite signal, and feeding the carrier Doppler frequency and the pseudo code phase back toa carrier NCO and a code NCO to form a closed loop. The system and method can improve positioning accuracy of the satellite/ inertial integrated navigation system, improve system robustness, and improve tracking performance of the satellite receiver under high-dynamic weak-signal and strong-interference conditions.

The invention discloses a GNSS-R delay mapping software receiver. The GNSS-R delay mapping software receiver comprises a direct mapping channel, a code generating module, a carrier generating module, a BAP processing module and relevant modules. Direct mapping digital intermediate frequency signals are captured and tracked through the direct mapping channel, and local codes are generated through the code generating module. Local carriers are generated by the carrier generating module to carry out carrier stripping on reflected signals. The reflected signals after carrier stripping are divided into L blocks with the length of one ms through the BAP processing module, the L blocks are overlaid and averaged, white noise suppression and non-specular reflection point signal component suppression are achieved, coherent processing is carried out on the signals processed by a BAP and the local codes through the relevant modules, and one-dimensional correlation power is output. The GNSS-R delay mapping software receiver has the advantages of having the functions of white noise suppression and non-specular reflection point signal component suppression, being small in computation complexity and the like.

The invention relates to the direct sequence spectrum spreading communication technical filed, in particular relates to a pseudocode sequence capturing method. The invention divides all the different-code phase sequence of a local replication code evenly into n subgroups, each subgroup includes m different-code phase sequences; adding up the m different-code phase sequences of each subgroup can get a composite code sequence of the subgroup. First, the invention searches the composite code sequences which include a satellite pseudocode sequence by correspondingly integrating a composite code sequence respectively with the received satellite pseudocode sequences; then, the invention searches the satellite pseudocode sequences in the m code phase sequences in the corresponding subgroups of the composite code sequence. The method can be widely used in software receivers for receiving GPS signals, Galileo signals, and other communication signals, and can flexibly capture direct sequence spectrum spreading codes with different length.

The invention discloses an avoiding and stripping method for Neumann-Hoffman codes in navigation messages of a Beidou navigation satellite system D1. The method comprises the steps that according to the encoding characteristics of the Neumann-Hoffman (NH) codes in a navigation message signal system of the Beidou navigation system D1, a unique sequence NH code avoiding method based on probability statistics is proposed at the satellite capturing stage, and the influence of jumping of the NH codes on capturing is successfully avoided; through parallel code phase search with the step length decreasing step by step, accurate capturing of the phase position and carrier frequency of spreading codes of a Beidou satellite is successfully achieved; meanwhile, an NH code stripping method for combined codes based on the NH codes and frame synchronization codes (Pre) is proposed in the frame synchronization step, and stripping of the NH codes and output of the navigation messages can be effectively achieved while subframes are synchronized. The avoiding and stripping method for the NH codes in the navigation messages of the Beidou navigation satellite system D1 is applicable to a Beidou satellite navigation receiver and a software receiver, and the same idea is applicable to other navigation satellite systems for which fixed sequence secondary encoding is adopted.

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 provides a software receiver-based distributed deep integrated navigation method and system. According to the software receiver-based distributed deep integrated navigation method and system, a GNSS software receiver adopts Doppler frequency shift calculated by Doppler frequency shift estimation; an auxiliary receiver tracking loop performs carrier tracking and code tracking, and filters outputted GNSS pseudo-range and pseudo-range rate information and provides the filtered information to an integrated navigation module; a carrier tracking loop adjusts a carrier NCO according to the Doppler frequency shift and carrier frequency errors outputted by a carrier loop filter; a code tracking loop adjust a code NCO according to frequency provided by the carrier tracking loop and code frequency errors outputted by a code loop filter; and therefore, two-way assistance of a GNSS and an SINS can be realized. With the software receiver-based distributed deep integrated navigation method and system of the invention adopted, the influence of the dynamic condition of a carrier on the carrier tracking loop can be decreased, and the tracking errors of the GNSS receiver can be decreased under a high dynamic environment, and the dynamic tracking performance of the GNSS receiver under the high dynamic environment can be improved, and therefore, the navigation and positioning accuracy of the integrated navigation system can be further improved.

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 navigation signal pseudo-range deviation correction method. The method comprises the following steps: S1, calibrating pseudo-range deviation characteristic parameters: measuring a satellite-ground distance between a satellite and an antenna; accurately measuring the transmission time delay of a receiving terminal of the large-aperture antenna; analyzing error characteristics of pseudo-range measurement of a receiver; S2, calibrating inter-satellite difference: calibrating the time delay of a receiving channel of the receiver; measuring the inter-station distance; measuring a satellite-ground distance; carrying out synchronous measurement testing of the antenna and an omnidirectional receiving antenna; synchronously calibrating inter-satellite differences of satellite navigation signals in a visual range; synchronously calibrating the inter-satellite difference of GNSS satellites; S3, testing and verifying: analyzing the positioning error of the receiver, andverifying the correction precision of the pseudo-range measurement correction parameter; and adjusting the pseudo-range measurement correlator interval of a software receiver and the filter bandwidthkey parameters, and researching the quantitative relation between the parameters of the software receiver and the signal ranging deviation. The method has the advantages that the influence of pseudo-range deviation on distance measurement of the software receiver is weakened, and the system positioning precision is improved.