Abstract: A four-arm helical antenna is provided, including: a metal top surface; four groups of helical antennas connected to the metal top surface to constitute a hollow cylinder, wherein any group of helical antennas comprises an antenna main arm and an antenna branch aria connected to each other, and the antenna main arm comprises a first bending portion arranged on a side surface of the hollow cylinder and a second bending portion arranged on a top surface of the hollow cylinder, and the antenna branch arm comprises a third bending portion arranged on the side surface of the hollow cylinder. The whole four-arm helical antenna is easy to adjust, and the antenna size can be adjusted flexibly according to installation requirements, and it's more suitable for miniaturization application requirements of the four-arm helical antenna.

Abstract: A phase-locked loop circuit is provided, including: a phase frequency comparing unit to compare phase of an external reference clock signal and phase of a comparing clock signal, and generate an error signal corresponding to the comparing result; an oscillation unit to generate an internal clock signal having oscillation frequency corresponding to the error signal; a frequency dividing unit to divide frequency of the internal clock signal according to a pre-set dividing ratio, to generate the comparing clock signal; a control unit to generate a control signal to respectively change connection of the oscillation unit and connection of the frequency dividing unit after phase comparing. The phase-locked loop circuit can detect and correct mistaken locking and harmonic locking. There is no need to reset the circuit when mistakenly locked, sudden output phase change and additional spike signal that affecting the integrity of the clock signal are prevented.

Abstract: The present application provides a method for navigation and positioning of a receiver, including: receiving basic broadcast messages and correction parameters of a plurality of satellites, and establishing a pseudorange observation equation and a carrier-phase observation equation corresponding to each of satellites respectively; correcting the pseudorange observation equation and the carrier-phase observation equation using the received correction parameters to obtain the corrected pseudorange observation equation and the corrected carrier-phase observation equation; constructing a first observation according to the corrected pseudorange observation equation and the corrected carrier-phase observation equation; constructing a second observation according to the corrected pseudorange observation equation and the corrected carrier-phase observation equation; and jointly solving the obtained first observations and second observations of the plurality of satellites to obtain anoperation result of user positioni

Abstract: The present invention relates to a method for acquiring satellite signals. The method utilizes the predictability of the first two words of each sub-frame of the navigation message, by controlling the acquisition time of the intermediate frequency data and the PN code, acquiring corresponding intermediate frequency data and PN code from the acquisition time, processing the intermediate frequency data and the PN code to determine whether the satellite signal is acquired, during the acquisition processing and determination process, the navigation message peeling operation is performed using the predictability of the first two words of each sub-frame of the satellite navigation message and PN code, in this way, extending the time of coherent integration is achieved, and thereby improves the acquisition sensitivity.

Abstract: Un-differential correction distributed processing system and method based on a receiver of a reference station, in which main calculation tasks of conventional centralized data processing are transferred to the receiver of the reference station. The receiver of the reference station executes tasks of the PPP calculation, the PPP un-differential ambiguity fixing and the un-differential correction product generating via data interaction with servers. The client generates a relevant virtual un-differential correction by visiting a reference station area code address server and achieves PPP-RTK calculation under area augmentation. Load of server is greatly reduced, and problem of overload on relevant servers is solved; meanwhile, there is no need for the client to arrange a machine room of servers that needs specially-assigned person on duty, thus reducing user's maintenance work on the servers and saving costs.

Abstract: The present invention provides an integrated navigation system and its positioning method, and it pertains to the technical field of satellite navigation.

Abstract: A GNSS board comprises a narrowband interference suppression module comprising an interference suppression pathway to receive an intermediate frequency (IF) signal, a bypass pathway to receive an intermediate frequency signal, an interference control switch, and a data strobe switch, wherein, the interference suppression pathway includes a signal conversion module, an interference detection module and an interference processing module, wherein the signal conversion module converts the intermediate frequency signal from a time domain signal to a frequency domain signal; the interference detection module determines whether there is interference with the frequency domain signal, and in the case of interference, obtains interference frequency information, makes the interference control switch close and the data strobe switch switch from the bypass pathway to the interference suppression pathway; and the interference processing module performs interference suppression processing on the frequency domain signal base

Abstract: The present invention relates to a radio frequency circuit structure for implementing a function of converting a satellite signal of a global navigation satellite system into a baseband signal. The radio frequency circuit structure comprises a channel dividing function module, a plurality of frequency converting function modules, a plurality of local oscillator signal modules, and a plurality of analog-to-digital convertor modules. The channel dividing function module is used for dividing a satellite signal of the global navigation satellite system received by an antenna into satellite signals in a plurality of channels. Each of the frequency converting function modules is used for performing frequency conversion on the satellite signals in the corresponding channels to form near zero-frequency signals. Each of the local oscillator signal module is used for generating a local oscillator signal and outputting the local oscillator signal to the frequency converting function module.

Abstract: A reference station transmitter based distributed processing system and method for zero-difference correction. The system and method transfer a main computation task in conventional centralized data processing to a reference station transmitter for completion; the reference station transmitter realizes tasks such as conventional PPP resolving, PPP zero-difference ambiguity fixation and zero-difference correction product generation via data interaction with a server; and a user end generates a relevant virtual zero-difference correction by accessing a reference station area code address server, so as to realize PPP-RTK resolving under regional enhancement.