53results about How to "Reduce time to first fix" patented technology

The invention relates to an auxiliary satellite navigation system and a global positioning system (GPS) receiver, in particular to a high-sensitivity navigation receiver mainly used indoors as well as an indoor positioning GPS receiver and an auxiliary satellite navigation positioning system adopting high-sensitivity satellite navigation positioning technology. The system at least comprises a terminal receiver, a reference receiver, a positioning server and a communication network; all devices are combined into an integral indoor positioning system; the entire system is divided into a high-sensitivity satellite navigation receiver and a network auxiliary system. Through adopting the positioning mode in which point positioning under weak signal condition is combined with continuous positioning under strong signal condition, the method mainly solves related technical problems such as the organic combination of integral hardware implementation. The invention has the advantages that: the system and the method improve the sensitivity index of a terminal user and reduce first positioning time; moreover, the designed navigation receiver can process indoor weak satellite signal, etc.

A navigation system includes a cellular phone, a base station and a network server. Each of them is paired with a GPS receiver. Cell phone GPS receivers are aided by information received from base stations and web servers, reducing the uncertainty of satellite searches. Time difference and/or frequency difference measurements are used with the collected data, and the cell phone and its GPS receiver assume they are precise time and frequency. The correction information is used to post-process the velocity solution computed by the cell phone to obtain a more accurate solution for the system.

The embodiment of the invention provides a method and a device for achieving bit synchronization and frame synchronization of a text of a receiver. Aiming at a 500 bps text in a navigation digital receiver, the method mainly comprises the following steps: adding two adjacent 1 ms accumulated values in the text with a set time length in turn, and acquiring a text after the bit synchronization according to the accumulated value after the addition; and searching a trellis code frame header in the text after the bit synchronization according to the scheduled format information, and finishing the synchronization of the text for the bit synchronization to be determined according to the searched trellis code frame header. The method and the device can improve the speed of the bit synchronizationand the frame synchronization of navigation texts of 500 bps and 50 bps in the navigation digital receiver, save system resources, and improve the system reliability. Besides, the method and the device achieves the bit synchronization and the frame synchronization in an FPGA (Field Programmable Gate Array), and can generate the satellite launch time more quickly and shorten the first-time positioning time of the navigation digital receiver.

The invention relates to a GPS/GALILEO navigation base band processing chip and a navigation receiver, belonging to the technical field of receiver of global satellite locating system. The navigation base band processing chip comprises a capturing engine, a tracking passage, a built-in processor and an interface control logic; and the built-in processor consists of a control logic, a built-in processor core, a digital operation module and a double-mouth RAM. The navigation base band processing chip works together with an external master control microprocessor, and calculates the user location according to the satellite trail parameter provided for the master control microprocessor and the information such as pseudo-range measurement; the master control microprocessor interacts with the navigation base band processing chip through a double-mouth RAM (Random Access Memory); a control logic circuit can cut off the clock or voltage of the idle circuit in the navigation base band processing chip so that the power consumption of the navigation base band are greatly reduced; simultaneously, the interface of the navigation base band processing chip and the master control microprocessor has the advantages of flexibility, convenience, strong expandability, and the like.

The invention relates to a capturing method of a satellite navigation signal in an adjustable carrier wave doppler frequency searching range. The method comprises the following steps that: an initial carrier wave doppler covering range and a corresponded carrier frequency is generated; code phase searching is completed under the carrier wave frequency to obtain a corresponded capturing result; because the covering of the initial carrier wave doppler is complete, search frequency point information of the carrier wave doppler that is frequency hopping information is written into a frequency hopping information memory to complete storage of the frequency hopping information that can be used for subsequent continuous capturing; and other unresearched satellites are switched for continuous execution. According to the invention, searching of an undetermined range of a carrier wave frequency can be completed at the expense of few hardware costs and a fast speed; satellites can be searched ina short time as much as possible; and first positioning time of a receiver is improved.

The invention provides a GNSS text demodulation method suitable for the navigation field. The method comprises that a main tracking channel and N auxiliary tracking channels are started after that a satellite is captured successfully; bit synchronization of the main tracking channel is controlled, one auxiliary tracking channel starts text demodulation, and the other N-1 auxiliary tracking channels start text demodulation successively by being delayed at preset time intervals; frame synchronization is carried out on navigation bit data streams obtained by the N auxiliary tracking channels; after successful bit synchronization of the main tracking channel, text demodulation of the main tracking channel is controlled; whether frame synchronization of the navigation bit data stream of a random auxiliary tracking channel succeeds is determined, if YES, a navigation bit data stream obtained by the main tracking channel continues collecting ephemeris, and the N auxiliary tracking channels are released; and otherwise, the navigation bit data stream obtained by the main tracking channel is used to carry out frame synchronization and collect ephemeris, and the N auxiliary tracking channelsare released. According to the invention, time of first positioning can be shortened effectively needless of adding too many hardware resources.

A rough position is needed to assist a conventional rough time positioning method. For the condition of an unknown rough position, the space transmission finiteness of navigation signals is utilized, a fuzzy search GPS receiver rough time positioning method based on inter-satellite distance compression is provided to expand the application range of a conventional rough time positioning method, and inter-satellite distance compression is utilized to search for space. The method comprises the steps of: firstly, according to an inter-satellite distance, calculating a maximum pseudo range difference range between satellites; secondly, selecting three satellites in combination with elevation to carry out rough positioning on all fuzzy combined conditions, and according to pseudo range remains of all satellites after the positioning, selecting most reasonable fuzzy combination and positioning results; then according to the rough positioning result, restoring pseudo range fuzzy of all the satellite; and finally, using a five-state time-free positioning technology to estimate the position of a user. According to the invention, the rough time positioning is realized under the condition that the rough position is unknown, and the application range of rough time positioning is expanded.

The invention discloses a method of acquiring GPS standard time at terminals of a synchronous communication system and a system, comprising: acquiring absolute GPS standard time of a synchronous system clock by an SDPL positioning platform when determining system frame number; executing SUPL flow to perform positioning operation between the SUPL positioning platform and the mobile terminal, when at the starting moment of exchanging the positioning data, the SUPL positioning platform transmits the GPS standard time to the mobile terminal; computing the current GPS standard time according to the current system frame number and the absolute standard time by the mobile terminal. Due to synchronous characteristics between the base station of the synchronous communication system, the invention acquires correct GPS standard time.

The invention discloses a method for obtaining and conveying a GPS standard time in a TD-SCDMA radio communication system, which comprises the following steps: firstly, respectively receiving GPS satellite signals by each of TD-SCDMA base stations, obtaining the absolute GPS standard time when a TD-SCDMA system clock determines a system frame number, then respectively reporting the measured absolute GPS standard time to a radio network controller, memorizing the absolute GPS standard time which is reported by each base station and informing the absolute GPS standard time when the system clockof a community where the mobile terminal which needs to be positioned is positioned in determines the system frame number by the radio network controller, and then calculating the current standard GPS time according to the current frame number by the mobile terminal. The method utilizes the characteristics of the base stations of the TD-SCDMA radio communication system that the base stations are synchronized, the positions of the base stations are accurate, and each of the base stations has a GPS receiver with high accuracy, and the method can obtain more accurate GPS standard time.

An electronic device includes: a satellite signal receiving section that receives a satellite signal with which positioning information is overlapped from a positioning satellite; a reception control section that controls driving of the satellite signal receiving section; and a detecting section that detects a state change of the electronic device, in which the reception control section allows the satellite signal receiving section to enter a driving state when the detecting section detects the state change to receive the satellite signal. According to this electronic device, it is possible to reduce a TTFF at the positioning start, and to reduce power consumption in the satellite signal reception.

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.

The invention provides a satellite ephemeris forwarding method. The satellite ephemeris forwarding method comprises the following steps of: setting parameter information, comprising framing information and an ephemeris forwarding mode, of a satellite ephemeris forwarding system; carrying out self-positioning and acquiring local time and position information of the satellite ephemeris forwarding system; selecting an ephemeris forwarding working mode and capturing and tracking a satellite signal emitted by an outdoor visible satellite or a satellite signal simulator; analyzing the satellite signal to obtain corresponding satellite ephemeris information; judging the validity of the satellite ephemeris information, retaining the valid satellite ephemeris information, and eliminating the invalid satellite ephemeris information; framing the valid satellite ephemeris information according to the framing information; and selecting an ephemeris forwarding mode, forwarding the framed valid satellite ephemeris information to an external receiver, and displaying the system state of the satellite ephemeris forwarding system. According to the invention, the designed satellite ephemeris forwarding system is used for acquiring a satellite real-time signal and forwarding the analyzed valid ephemeris information to the external receiver, so that the first positioning time is shortened, and rapid positioning is realized.