44 results about "Squitter" patented technology

This invention relates to the field of satellite communication technology, and in particular to a method for transmitting positioning information using an anti-interference BeiDou positioning base station. The method involves acquiring signals transmitted by the user terminal through the anti-interference base station and transmitting them to the master control station. The master control station then transmits the signals to the BeiDou satellite for processing to obtain navigation messages. These navigation messages are then sent to the user terminal via the master control station and the anti-interference base station. The user terminal performs positioning calculations based on the satellite signals to achieve real-time location updates. During transmission, the master control station calculates the bit error rate (BER) in the BeiDou satellite's navigation message generation process. Based on the BER, it determines whether the transmission process conforms to standards. Furthermore, based on this determination, it further assesses the transmission process in conjunction with data integrity, or identifies the reasons for non-compliance based on the BER and generates corresponding instructions. These instructions are used to adjust relevant parameters, thereby reducing the BER, improving the accuracy of navigation message generation, and ultimately increasing information transmission efficiency. This provides positioning support for operational equipment, inspection personnel, and other similar applications.

The application discloses a satellite broadcast simulation method, device and equipment and a readable storage medium, and relates to the technical field of satellite communication. The satellite broadcast simulation method comprises the following steps: acquiring navigation message data and enhanced message data; framing the navigation message data and the enhanced message data respectively to obtain navigation signal frames and enhanced signal frames; and modulating the navigation signal frames and the enhanced signal frames simultaneously in response to a timing control signal, and transmitting the modulated navigation signal frames and enhanced signal frames. The application simulates the process of broadcasting navigation signals and enhanced signals by real low-orbit satellites, thereby improving the authenticity of the test environment for the receiving terminal of the low-orbit satellite communication system, and simultaneously modulating based on the timing control signal, thereby avoiding the delay error in the early receiving and framing process and reducing the probability of timing error.

The application discloses a B3I signal simulation method and device, terminal equipment and storage medium, through obtaining ephemeris data, generating pseudo code and extension code, and modulating the same, a real B3I signal can be quickly and accurately generated. In this way, the original signal simulation can be freed from the dependence on hardware equipment, and only ephemeris data provided by a user and satellite messages of a Beidou satellite are needed to generate a corresponding B3I signal. In addition, a Doppler frequency shift is calculated according to the distance between a satellite and the user, and is applied to carrier modulation, so that the B3I signals of various satellites can be more accurately simulated. By comprehensively considering ephemeris data, distance calculation, pseudo code generation, Doppler frequency shift and navigation messages and the like, a real B3I signal with a Doppler effect can be generated, which provides a beneficial tool and data for testing and verification of a B3I signal receiver, so that the research and development efficiency of a navigation satellite signal receiver is improved.

The invention discloses a broadcast ionosphere model adaptive selection method for a GNSS (Global Navigation Satellite System) terminal, which comprises the following steps: receiving navigation message information broadcasted by each GNSS system in real time, and obtaining various broadcast ionosphere model parameters; calculating the geographic latitude corresponding to the ionospheric puncture point according to the current position coordinate of the user, the satellite elevation angle and the azimuth angle; according to the geographic latitude and the time period of the current calculation time, selecting an optimal broadcast ionosphere model under the current space-time condition; and according to the optimal broadcast ionosphere model and the broadcast ionosphere model parameters, calculating to obtain a correction value of the ionosphere delay amount. According to the invention, by selecting the optimal broadcast ionosphere model in the current environment, the positioning precision is improved, the error of a certain model is prevented from being amplified, the advantages of each broadcast ionosphere model are exerted, and the stability and consistency of system positioning are improved; dynamic environment change is supported, and good space-time adaptive capacity is achieved; and model selection is realized only at a user side without modifying the broadcasting format of the existing satellite message.

The invention discloses a differential broadcast telegraph text integration method for a Roland time service system. The method comprises the following steps: extracting differential correction parameters of differential stations in a broadcast station coverage area within a preset time period; obtaining a plurality of differential correction values of each differential station in a preset time period; grouping all the differential stations according to the differential correction deviation of the differential stations; determining the newest statistical average value of each differential station in an updating period of a differential correction parameter; for each group, determining all statistical average values of each group based on the latest difference correction difference value of each difference station; obtaining a differential correction parameter of each group according to all statistical average values of each group; and loading the differential correction parameter of each group, the latest statistical average value of each differential station in the group and the data age of the differential correction parameter of the group into a broadcast message for broadcast. According to the invention, the space occupied by the differential telegraph text is saved, the time consumed for broadcasting the differential telegraph text is reduced, and the actual service life of the differential correction parameter is prolonged.

The application provides an optimization method of a Beidou satellite navigation signal acquisition algorithm based on modulation code polarity compensation, aiming at greatly reducing the operation complexity and operation time of the polarity compensation algorithm in the multi-period acquisition algorithm under multiple modulation types without affecting the acquisition accuracy. The application widens the coherent accumulation time and introduces a fast polarity compensation technology for the text information, uses the modulation code to perform coherent accumulation operation on the matching filter operation result, finds the coherent accumulation operation result with the maximum peak value, and extends the fast polarity compensation method to other Beidou satellite signals, compares the peak-to-peak ratio of the coherent accumulation operation result of each carrier frequency with a threshold value, and if the peak-to-peak ratio is greater than the threshold value, the corresponding carrier frequency is confirmed as the real carrier frequency of the intermediate frequency navigation satellite signal. The application expands the application field of the algorithm and improves the accumulation efficiency of the multi-period coherent accumulation.

The application provides a carrier phase polarity determination method and device, a chip and electronic equipment. The method comprises the following steps: determining the polarity of a frequency point of a satellite signal; determining whether the frequency point is stably tracked in the case that the polarity of the frequency point is invalid; determining whether the frequency point has a cycle slip in the case that the frequency point is stably tracked; and modifying the polarity of the frequency point as valid in the case that the frequency point has no cycle slip. In the case that the polarity of the frequency point is determined as invalid for the first time, in order to avoid misjudgment, the stable tracking condition and the cycle slip condition of the frequency point are determined again, and the polarity of the frequency point is modified as valid in the case that the frequency point is stably tracked and has no cycle slip, so that the carrier observation value is continuous. The application can better maintain the polarity of the carrier phase, reduce the problem of invalid polarity caused by high navigation message error rate, and improve the continuity and availability of the carrier phase.

Provided in the embodiments of the present disclosure are a terminal position determination method, an apparatus, a device and a storage medium. The terminal position determination method is applied to a terminal, and comprises: receiving a navigation signal and a communication broadcast signal broadcast by an access device; on the basis of the received navigation signal or communication broadcast signal, determining a plurality of frequency offset estimated values; on the basis of the received communication broadcast signal, acquiring first position-related information of the access device; on the basis of the first position-related information and the plurality of frequency offset estimated values, determining initial position information of the terminal; on the basis of the received navigation signal, acquiring a navigation message; on the basis of the navigation message, acquiring second position-related information of the access device; and using the second position-related information to update the initial position information, so as to obtain position information of the terminal.

The present application belongs to the field of positioning and navigation technology, and provides a kind of ultra-wideband positioning signal transmission method with narrowband communication signal tight coupling, including a kind of narrowband signal coupling ultra-wideband signal design method and a kind of communication information assisted positioning service process.Based on the narrowband assisted ultra-wideband signal designed and transmitted based on the method, the characteristic is that the ultra-wideband positioning signal is time-domain tightly coupled with the narrowband communication signal, and the narrowband communication signal can be used to realize the functions of wake-up, access control and other functions of ultra-wideband radio terminal, and can also transmit channel impulse response, navigation text and other information.Compared with the traditional ultra-wideband positioning system, more flexible terminal access mechanism can be realized, and the user capacity of the positioning base station is improved, which can be used on the ultra-wideband positioning base station and terminal with ranging and angle measurement capability.

A method, apparatus, and storage medium for estimating the carrier-to-noise ratio (CNR) of a digital navigation signal are disclosed. The method includes: preprocessing a digital navigation signal to obtain a first in-phase component signal and a first quadrature component signal; removing modulation messages from the first in-phase component signal and the first quadrature component signal to obtain a second in-phase component signal and a second quadrature component signal; accumulating the second in-phase component signal and the second quadrature component signal to obtain the power of the second in-phase component signal and the power of the second quadrature component signal; performing a reliability estimation of the signal amplitude based on the power of the second in-phase component signal and the power of the second quadrature component signal, and the current phase-locked loop (PLL) state, to obtain an amplitude estimation result; and estimating the CNR of the digital navigation signal under the current PLL state based on the amplitude estimation result.

The invention relates to an ultra-wideband navigation signal generation method and device based on linear frequency modulation spreading codes, and belongs to the technical field of satellite navigation. The method comprises the following steps: generating a linear frequency modulation spreading code of a data / pilot branch by using a phase quantization model meeting collaborative optimization constraints of generation complexity and sidelobe suppression performance; generating a pseudo-random spreading code of the data / pilot branch; generating a data code containing a navigation message; according to the pseudo-random spreading code and the linear frequency modulation spreading code of the pilot frequency branch, generating a digital baseband signal of the pilot frequency branch and performing digital-to-analog conversion; according to the data code and the pseudo-random spreading code and the linear frequency modulation spreading code of the data branch, generating a digital baseband signal of the data branch, and performing digital-to-analog conversion; and generating a complete ultra-wideband navigation signal according to the analog baseband signal of the data / pilot frequency and the radio frequency carrier. According to the method, the generation complexity of the ultra-wideband navigation signal can be greatly reduced, and a key technical support is provided for the application of the ultra-wideband navigation signal.

The application provides a navigation satellite message autonomous integrity monitoring method, which comprises the following steps: calculating first state information at a predetermined time through extrapolation based on historical navigation message parameters of an on-board message, and calculating second state information according to navigation message parameters of a new on-board message on the predetermined time, calculating a first difference between the two; obtaining regional system signals and global system signals on the same time, and calculating corresponding state information and a second difference between the state information; judging whether the first difference and the second difference exceed corresponding alarm thresholds, and if both exceed, generating an alarm information of the message integrity. Thus, the application can realize on-board message autonomous integrity monitoring, can monitor and alarm abnormalities of the message caused by uplink injection, malicious tampering and the like, and prevent error positioning results caused by the error message broadcast to the ground users.

The application relates to a GNSS high-sensitivity acquisition method and equipment applied to a deep space spacecraft. The core process of the method is as follows: the time and corresponding position of receiving GNSS signals by the spacecraft are acquired, the satellite position at the receiving time is calculated by combining the pre-stored target satellite orbit information, and the signal transmission time is obtained through iterative correction; the starting time of digital intermediate frequency data storage is determined according to the subframe period of the navigation message, so that the key specified bits of the message are completely contained, and the navigation message is stripped by using the fixed and predictable bits; the Doppler center frequency offset is obtained by calculating the relative speed of the line-of-sight direction between the star and the earth, the search range is determined by combining the speed uncertainty, the signal acquisition is completed in the limited range, and the code phase and the carrier frequency offset are solved. The application is suitable for the scene that the deep space signal is weak, the propagation time delay is long, and the Doppler characteristic is complex, the position mismatch error is avoided through iterative correction, a high-precision time reference is acquired, and the GNSS signal acquisition performance is significantly improved.

The invention belongs to the technical field of global navigation satellite system integrity monitoring, and discloses a Beidou CNAV telegraph text space signal integrity evaluation method and system. The method comprises the following steps: firstly, respectively screening obtained Beidou CNAV messages and post precise ephemeris to obtain available ephemeris; taking a precision satellite orbit and a precision satellite clock after the event as a reference, resolving a CNAV satellite clock error and a CNAV satellite orbit error in an observation period, and further calculating to obtain a worst user distance measurement error of a Beidou CNAV telegraph text space signal; and estimating the fault rate and the average fault duration of the Beidou CNAV telegraph text space signal by using the worst user ranging error large sample data set of the CNAV telegraph text space signal and adopting a confidence test iteration method. The method can provide key technical support for integrity evaluation of the Beidou system.

The application discloses a satellite-based time service method and device, electronic equipment and storage medium, comprising: receiving a short message signal of a geosynchronous satellite, the short message signal comprising an uplink time delay of a standard time sent by a ground control center to the geosynchronous satellite; receiving a navigation message of the geosynchronous satellite and obtaining a correction parameter of coordinated universal time from the navigation message; calculating a downlink time delay of the geosynchronous satellite to a time service device based on the uplink time delay; calculating a local time of the time service device by using the standard time, the uplink time delay, the correction parameter and the downlink time delay; and performing time service by using the local time, without positioning the time service device to calculate the downlink time delay, and without occupying the calculation resources of the ground control center, compared with the prior art, the time service time is shortened, the influence of the calculated position on the time service precision is reduced, and the time service speed and precision are improved.

This application relates to an adaptive rapid positioning method and system based on GNSS synchronization status, belonging to the field of navigation and positioning technology. The method includes: entering the normal positioning process when all tracked satellite signals have completed message time synchronization; otherwise, entering the adaptive time-free positioning process, which includes first dynamically determining the minimum reliable time unit and time search interval based on the synchronization status level of the tracked satellite signals; then determining a relatively accurate local reference time as the local baseline time based on the synchronization status level and time search interval; and after correcting the signal transmission time of the tracked satellites based on the local baseline time and the minimum reliable time unit, performing rapid AGPS iterative calculation. This method enables rapid receiver positioning under a wide range of time errors.

The invention provides a service message abnormity monitoring method and system based on a satellite-based augmentation system, and belongs to the field of satellite navigation and satellite-based augmentation. The method comprises the following steps: firstly, acquiring an enhanced message generated by a master control station based on observation station observation data calculation, and performing static inspection on the enhanced message; if the static check is passed, uploading an enhanced message; receiving the broadcasted enhanced telegraph text, sequentially comparing the satellite-ground consistency in real time, performing observation quality evaluation based on the O-C residual error to verify the enhancement effectiveness of the enhanced telegraph text, and performing PPP integrity test based on the monitoring station; if the test is passed, the service message is normal; and if the static check is not passed and static abnormity exists, or satellite-ground consistency comparison abnormity exists, or O-C residual verification is not passed, or positioning check is not passed and monitoring station PPP positioning abnormity is determined, fault association and positioning are carried out according to a determination result by constructing a rule base or an algorithm model. According to the invention, the abnormal monitoring capability of the telegraph text is enhanced.

This application discloses a ground station baseband system for timing and data broadcasting. The system receives downlink intermediate frequency (IF) signals and local location information via a baseband signal processing module. It analyzes the downlink IF signals to obtain a first timing message, a first broadcast data message, and measurement data, generating a timing signal. Based on the received second timing message and second broadcast data message, it generates an uplink IF signal. A time interval measurement module compares the timing signal with a preset timing reference signal to obtain a timing deviation monitoring value. A monitoring and data processing module analyzes the received first broadcast data message and first timing message to obtain the bit error rate, frame error rate, and frame loss rate, outputting these values. It also acquires the second timing message and second broadcast data message. This application enables simultaneous timing, timing performance monitoring, and data broadcasting services within a single ground station baseband system.

The application discloses a low-orbit satellite navigation message consistency comparison method, device, medium and product, and relates to the field of navigation message monitoring; the method comprises the following steps: acquiring message data; the message data comprises: an uploaded message and a returned message; the uploaded message is an uplink message broadcast by a ground control center through a low-orbit satellite; the returned message is a downlink message received and returned by a low-orbit satellite monitoring station; based on a set search window length, payload information is determined according to the message data; the payload information comprises: uploaded message payload information and returned message payload information; for any low-orbit satellite, a comparison result is determined according to the payload information; the comparison result is: complete consistency or inconsistency; based on all comparison results, information statistics are carried out to obtain statistical results; the statistical results are test pass or test fail. The application can accurately and reliably realize consistency monitoring.

The embodiment of the invention provides a positioning method, device and system, and relates to the technical field of satellite positioning. The positioning method comprises the following steps: receiving a pseudo satellite signal sent by a pseudo satellite base station; analyzing the pseudo satellite signal to obtain a navigation message containing pseudo satellite positioning information and positioning auxiliary information; determining the position of the receiver according to the pseudo satellite positioning information and the positioning auxiliary information; wherein the positioning auxiliary information comprises equipment delay information of the pseudo-satellite base station transmitting the pseudo-satellite signal. Therefore, the pseudo-satellite signal generated based on the satellite modulation technology can realize long-distance reliable transmission, and the positioning precision of the receiver can be improved by carrying the positioning auxiliary information in the pseudo-satellite signal.

The invention provides a BDSBAS hybrid authentication method fusing a domestic cryptographic algorithm and a TESLA protocol. According to the method, strong authentication of terrestrial broadcast node identities and generation of message digests are realized by introducing an SM3 hash algorithm, and efficient broadcast authentication of enhanced messages is realized by combining a time window delay release mechanism based on a symmetric key chain construction mode of a TESLA protocol. In the aspect of key management, the system generates a root key through a key management center, constructs a TESLA authentication chain through a Hash function, supports regular rotation, and ensures the security and traceability of the key. In the aspect of protocol design, compatible expansion and low-overhead receiving verification of a telegraph text structure are realized. The mechanism has the advantages of low calculation complexity, good broadcast adaptability and high security, is suitable for a large-range broadcast scene of the BDSBAS in civil aviation navigation enhancement, and effectively defends attacks such as data forgery and the like.

This invention discloses an enhanced assisted navigation message authentication method applicable to BeiDou B1C signals. Addressing the authentication performance bottleneck caused by the low effective data rate of BeiDou B1C signals, this invention proposes a dual-mode authentication architecture, including a self-authentication (SA) mode and an enhanced self-authentication (ESA) mode. In self-authentication mode, the system broadcasts the self-authentication page (SAP) and digital signature message and key (DSK) using subframe 3 of the B1C signal, and employs a time-interleaved broadcast strategy for multi-satellite coordinated broadcasting and receiver local reassembly. In enhanced self-authentication mode, the system utilizes the high bandwidth characteristics of PPP-B2b signals to transmit the enhanced authentication page (EAP), assisting the receiver in completing cross-channel authentication. This invention effectively solves the authentication problem at low data rates, achieving low-latency and high-reliability authentication of BeiDou B1C signals.

The invention relates to a hybrid frequency discrimination mode carrier frequency tracking method, which comprises the following steps of: S1, based on bit synchronization information of a received telegraph text, receiving an IQ coherent integral value synchronously corresponding to front and back half bits of each telegraph text bit; s2, calculating a conjugate product value of front and back adjacent IQ coherent integral values, and generating an IQ differential value sequence; s3, according to the IQ differential sequence, performing coherent frequency discrimination on the IQ differential values in bits, performing incoherent frequency discrimination on the IQ differential values between adjacent bits, and generating a coherent frequency discrimination and incoherent frequency discrimination alternating frequency tracking error sequence; and S4, filtering the frequency tracking error sequence to form a carrier frequency tracking loop. According to the method, the coherent frequency discrimination method and the incoherent frequency discrimination method are combined, the signal carrier frequency tracking sensitivity can be improved, and the signal carrier frequency tracking threshold can be reduced.

The application discloses a multi-satellite multi-frequency precise point positioning precise message broadcasting method, and the broadcasting method comprises the following steps: S1, using ephemeris parameters to characterize satellite ephemeris; S2, arranging basic ephemeris and navigation auxiliary information; S3, setting different information types and corresponding navigation information according to the requirement of information update frequency; S4, setting the message broadcasted by each satellite and the corresponding order according to the frequency of the satellite and the number of cooperative satellites; and S5, broadcasting the message. By adopting the method, the technical problem that the number of satellites is large, the amount of message data is large, and the communication efficiency of the message is low in the prior art can be solved, the broadcasting content of the precise message is simplified, the efficiency of the message broadcasting is improved, the amount of data broadcasted by a single satellite is reduced, and the effect that the ground user terminal collects the required message for positioning in a short time is ensured.

The invention discloses an analysis method, device and equipment for a low-orbit satellite navigation message, and relates to the technical field of navigation data businesses, in the method, a navigation service signal is received according to a spreading code period, and an offset range is determined based on the size of the spreading code period; the method comprises the following steps: determining the number of spreading code periods bearing a data initial position in a navigation service signal, respectively obtaining an association fusion value of the navigation service signal and a local reference signal in each spreading code period, and obtaining a corresponding accumulated value by adopting each obtained association fusion value accumulated by each offset, and determining a data initial position in the navigation service signal according to each accumulated value to obtain a message bit stream of the navigation service signal, determining a local bit stream of which the data coherence meets a preset coherence condition, and analyzing each navigation message frame contained in the local bit stream to obtain a navigation message of the low-orbit satellite. In this way, the efficiency and precision of navigation message analysis can be improved, and misjudgment of the initial position of the data and interference of incoherent data are avoided.

The application discloses a regional unmanned aerial vehicle dynamic time synchronization method and system, relates to unmanned aerial vehicles and time synchronization, and comprises the following steps: generating a clock reference signal as a frequency time reference benchmark of other components; generating a first time synchronization electric text frame corresponding to the clock reference signal and modulating the first time synchronization electric text frame to generate a transmission enhanced radio frequency signal; receiving an enhanced radio frequency signal transmitted by a ground center, demodulating the first time synchronization electric text frame, and measuring an observation quantity after frame synchronization; forming a second time synchronization electric text frame according to a measured time delay and unmanned aerial vehicle self-measured time information; calculating an initial clock difference by analyzing the measured time delay and the unmanned aerial vehicle self-measured time information in the second time synchronization electric text frame; correcting the initial clock difference data according to unmanned aerial vehicle motion errors to generate corrected clock difference results; and adjusting an unmanned aerial vehicle local clock reference signal according to the clock difference results. The method can improve the time synchronization precision between loads of an air-based regional navigation enhancement system.

The application discloses a performance monitoring method and system of a radio time service system, and relates to the radio time service field.The method comprises the following steps: judging the working state of a monitoring receiver according to the working state information of the monitoring receiver and the state information of an external reference time frequency signal; when the working state of the monitoring receiver is normal, the monitoring receiver demodulates time service message parameters according to the received radio time service signal of the radio time service system, and measures signal quality parameters; the monitoring receiver takes a standard frequency signal as a reference input; the monitoring receiver receives the radio time service signal and outputs at least one 1PPS timing signal; a time difference measuring device measures the deviation between the 1PPS timing signal output by the receiver and a standard time 1PPS signal, and obtains a time service deviation; and the performance of the radio time service system is determined according to the time service deviation, the time service message parameters and the signal quality parameters.The application can realize unified and comprehensive monitoring of the radio time service system.

The present application relates to the field of satellite positioning technology, and particularly relates to a robust filtering method based on satellite quality evaluation, comprising the following steps: step 1: a receiver collects navigation messages in real time; step 2: single point positioning is used to obtain the receiver position and signal quality evaluation parameters; step 3: satellite signal quality evaluation is performed to determine whether the observation matrix is full rank; step 4: a robustness factor is calculated, and a Kalman gain is calculated; step 5: multi-epoch joint observation is performed to establish full-rank complete geometric constraints to solve new predicted values; and step 6: the current epoch parameters are retained, and the next epoch is solved. The scheme of the present application has the advantages that it can be used to reduce the influence of weak satellite signal strength, multipath effect and the like on positioning accuracy, and improve the continuous positioning calculation capability.

The invention discloses a power system time synchronization protection method, device and equipment, and a storage medium, and relates to the technical field of power. The method comprises the following steps: acquiring navigation data of an observable satellite of a single Beidou system under at least two frequency bands; the pseudo-range of the receiving antenna relative to the observable satellite, the navigation message of the observable satellite, the coordinates of the receiving antenna and the clock skew of the single Beidou system are obtained; consistency detection is carried out on the following items: ephemeris parameters, a pseudo range of a receiving antenna relative to an observable satellite, coordinates of the receiving antenna, clock skew and clock stability; validity detection is carried out on ephemeris parameters meeting consistency detection, the pseudo-range of a receiving antenna relative to an observable satellite, the coordinates of the receiving antenna, clock skew and clock stability; and taming the local clock. According to the invention, the problems of increased purchase and operation and maintenance cost and time reliability caused by incapability of determining the authenticity of satellite signals in the protection technology of the current time synchronization device are solved.

The application relates to the technical field of satellite navigation, and discloses a navigation enhancement signal transmitting method, device, equipment and storage medium. The method processes initial navigation signals to obtain a navigation enhancement signal baseband waveform. The device, the equipment and the storage medium correspond to the method. Through multi-link cooperative optimization, the application significantly improves the reliability and accuracy of navigation enhancement signal transmission, realizes low-cost and anti-radiation satellite-borne navigation enhancement signal transmission, and is suitable for the strict requirements of high-precision navigation scenes on signal quality.