The invention discloses a method and device for acquiring a satellite navigation signal, belonging to the technical field of communication. The method comprises the following steps of: acquiring an in-phase component and a quadrature component, wherein the in-phase component contains a C/A code; respectively carrying out correlation operation on the acquired in-phase component containing the C/A code, and the quadrature component with a local C/A code; carrying out FFT (Fast Fourier Transform) on obtained correction operation results; carrying out differential coherent accumulation on the FFT results; judging according to the results of the differential coherent accumulation, wherein if the results are larger than a threshold value, the satellite signal is successfully acquired, or else, the satellite signal is failed to acquire. The method solves the problem that navigation signals with high symbol hopping ratio cannot be integrated and accumulated for a long time; and the differential coherent accumulation method is adopted, thus the signal to noise ratio is increased and the satellite signals are successfully acquired.

Method and device for acquiring satellite navigation signal

The invention relates to a GPS weak signal capturing method based on a sequential probability ratio The method comprises the steps of: (1) performing parallel code domain planar search on a sampled and quantized intermediate frequency digital signal which is output by the front end of a receiver, (2) calculating a threshold value corresponding to different unrelated accumulation times under a preset condition of false-alarm probability, (3) calculating a probability density function contained in an assumed signal, (4) calculating a probability (5) that the assumed signal is more than the threshold value, ending the search stage, if a signal is captured, or repeating the step (3), (4), (5) if no signal is captured, and if the unrelated integral accumulation times M reaches to 100 but still no signal is fund, that means no signal exists, ending the capturing stage as well The method of the invention can efficiently shorten the capturing time of strong signals, reduce the whole capturing time and increase the capturing property

GPS weak signal capturing method based on sequential probability ratio

The invention provides an adaptive seamless switching method of indoor and outdoor positioning. Four state modes of an intelligent terminal according to the coverage and distribution of satellite signals and wireless local area network signals are defined, namely: an indoor working mode, an indoor non-working mode, an outdoor working mode and an aliasing mode. In the initial state mode judgment, the judgment is preferentially performed according to the number of scanned satellites and the satellite signal strength. After the device works normally, conditional state transition can be performedamong various working modes, and the transition condition depends on a combined factor of the number of satellites, the satellite signal strength, the wireless local area network signal strength and the like. By adoption of the method, indoor and outdoor integrated positioning can be effectively achieved, adaptive seamless switching in indoor and outdoor scenes is achieved, and meanwhile the powerconsumption of the intelligent terminal is reduced, so that the adaptive seamless switching method has a wide application scene.

Adaptive seamless switching method of indoor and outdoor positioning

The embodiment of the invention discloses a signal capture method and device. The method and the device are applied to a time division and code division orthogonal frequency division multiplexing TC-OFDM system. The method comprises the steps of carrying out incoherent loss compensation on an incoherent integral result Z (n), judging whether the incoherent integral result after the incoherent loss compensation satisfies a preset threshold judging condition or not; and capturing signals if the preset threshold judging condition is satisfied. According to the method and the device, through combination of coherent/incoherent integrals and loss compensation of the incoherent integral result, the signals are captured; a relative capture peak can be effectively improved; the capture missing probability of weak signals can be reduced; therefore, the capture capability of the location receiver of the TC-OFDM system to the weak signals can be improved; and the weak signals can be captured effectively.

Signal capture method and device

The application provides a position method and apparatus based on a mobile terminal The method comprises the following steps: the mobile terminal at least including a first positioning system and a second positioning system, based on whether the mobile terminal is at a region of a specified type, what the positioning system the mobile terminal works at, and/or whether the mobile terminal caters to the specific conditions, determining whether the mobile terminal works at the second positioning system or works at a state whereby the second positioning system and the first positioning system cooperates, wherein the second positioning system includes a bipolar positioning system and the first positioning system belongs to other positioning systems other than the second positioning system According to the solution of the application, by determining whether the mobile terminal is at a region of a specified type, what the positioning system the mobile terminal works at, and/or whether the mobile terminal caters to the specific conditions, the method can determine whether the mobile terminal works at the second positioning system or works at a state whereby the second positioning system and the first positioning system cooperates, and can acquire more accurate positioning information

Positioning method and apparatus based on mobile terminal

The invention relates to an adaptive coherent accumulation joint acquisition method under GNSS weak signal, which belongs to the field of signal acquisition. The method preserves the performance of hiThe invention relates to an adaptive coherent accumulation joint acquisition method under GNSS weak signal, which belongs to the field of signal acquisition. The method preserves the performance of high acquisition probability of the prior coherent accumulation method and avoids the flip effect of navigation data in the piriorcoherent accumulation method. The method uses the coherent accumulationgh acquisition probability of the prior coherent accumulation method and avoids the flip effect of navigation data in the piriorcoherent accumulation method. The method uses the coherent accumulationand the differential accumulation, and can detect the flip position of the navigation data in the process of acquisition. Before the flip of the navigation data is detected, the coherent accumulationand the differential accumulation, and can detect the flip position of the navigation data in the process of acquisition. Before the flip of the navigation data is detected, the coherent accumulationmethod is used firstly. After the flip of the navigation data is detected, the differential accumulation method is used. Thus, the method has the advantages of high processing gains of the coherent acmethod is used firstly. After the flip of the navigation data is detected, the differential accumulation method is used. Thus, the method has the advantages of high processing gains of the coherent accumulation and no flip effect of the navigation data on the differential accumulation. In addition, different from the threshold value detected by fixed acquisition in the traditional method, the adapcumulation and no flip effect of the navigation data on the differential accumulation. In addition, different from the threshold value detected by fixed acquisition in the traditional method, the adaptive coherent accumulation joint acquisition method adjusts the threshold value adaptively according to the noise of a received signal. Compared with the traditional method, the adaptive coherent accutive coherent accumulation joint acquisition method adjusts the threshold value adaptively according to the noise of a received signal. Compared with the traditional method, the adaptive coherent accumulation joint acquisition method improves the detection probability, shortens the acquisition time and is suitable for accurate positioning in a weak signal environment.mulation joint acquisition method improves the detection probability, shortens the acquisition time and is suitable for accurate positioning in a weak signal environment.

Adaptive coherent accumulation joint acquisition method under GNSS weak signal

The invention discloses a positioning method for indoor and outdoor environment seamless switching realized by global navigation satellite system (GNSS)-based fingerprint positioning technique, relates to the technical field of satellite positioning and navigation, and solves the problem that for the positioning service under the indoor and outdoor environments, seamless positioning switching is difficult to realize under indoor and outdoor environments because a user needs receivers in indoor and outdoor systems at the same time By the positioning method, N GNSS fingerprint positioning nodes are introduced indoors; information frames of the GNSS fingerprint positioning nodes consist of positioning information frames and information frames for location based service (LBS); during positioning, when the positioning is realized by an outdoor positioning way, if the number of visible satellites which participate in the positioning is less than 4, the positioning is switched to an indoor fingerprint positioning way; and when the positioning is realized by the indoor fingerprint positioning way, if that the user leaves the indoor environment is judged, the positioning is carried out in the outdoor positioning way The positioning method is suitable to be used in the field of the satellite positioning and navigation

Positioning method for indoor and outdoor environment seamless switching realized by global navigation satellite system (GNSS)-based fingerprint positioning technique

The invention provides a navigation satellite signal capturing method based on peak value location comparison, relating to a navigation satellite signal capturing method and solving the problems that the conventional navigation satellite signal capturing method has lower detection probability of small correlating peak values in a weak signal condition and the system has high false-alarm rate. Themethod comprises the following steps of: carrying out correlation calculation on a signal for many times, searching for the maximum value after each correlation calculation, and recording the position of the maximum value; judging if the signal exists according to the position of the maximum value when the positions of the maximum values are enough recorded, and then determining if the navigationsatellite signal capture is successful. The method provided by the invention is suitable for capturing the navigation satellite signal.

Ruofei Ma

Papers

Adaptive coherent accumulation joint acquisition method under GNSS weak signal

Positioning method for indoor and outdoor environment seamless switching realized by global navigation satellite system (GNSS)-based fingerprint positioning technique

Navigation satellite signal capturing method based on peak value location comparison