Patent application number | Description | Published |
20090096668 | SIGNAL ACQUISITION/TRACKING METHOD AND CORRELATOR FOR THE SAME - A Doppler frequency searching method and correlator are disclosed. In the present invention, before Doppler frequency removal, a received signal is converted into digital form and the spreading code is removed. Then the signal is down-sampled to have a low sampling rate, which can be determined according to the maximum Doppler frequency to be searched. The Doppler frequency searching is done by stages. Each stage is in charge of a portion of the Doppler frequency to be removed. The sampling rate can be further reduced in each stage. Each stage can have a plurality of Doppler frequency removal units sharing the portion of Doppler frequency that the stage is to remove. Power consumption is reduced since Doppler frequency removal is executed with low sampling rate. | 04-16-2009 |
20090103656 | CORRELATION DEVICE AND METHOD FOR DIFFERENT MODULATED SIGNALS - A correlation device and method for different modulated signals such as BPSK signal and BOC signal. According to the present invention, the correlation device has one or more sections. Each section comprises a correlation unit for executing correlation; a first signal path for passing a received signal directly to the correlation unit; a second signal path for transferring a BOC signal into a BPSK-like signal and passing the signal to the correlation unit. The correlation unit has a multiplexer for selecting to allow an output of one of the first and second signal paths to be subject to signal correlation. The correlation results of the respective sections can be combined. | 04-23-2009 |
20090135063 | SATELLITE SEARCH METHOD AND RECEIVER USING THE SAME - A satellite time dynamic search method and a receiver implementing such a method are disclosed. In the present invention, a predetermined period of time is sampled into multiple time samples. The time samples are sieved according to a search result of a satellite selected from candidate satellites each time. By repeatedly doing so, the finally remaining time sample will approach a true satellite system time, and accordingly the candidate satellites converge to the most possible ones as to facilitate satellite search. | 05-28-2009 |
20090309791 | SYNC DETECTION DEVICE AND METHOD FOR GNSS - A sync detection device and method for a GNSS receiver. In modernized GNSS, each satellite transmits a data signal and a pilot signal. Correlations are performed between a data symbol stream converted from the data signal with possible hypotheses to find a leading edge of a frame of the data signal (i.e. frame sync detection) and between a pilot symbol stream converted from the pilot signal with possible hypotheses to find a leading edge of a code sequence of the pilot signal (i.e. pilot sync detection). The possible hypotheses for the frame sync detection are selected according to a result of pilot sync detection when pilot sync is done. Frame sync can be efficiently achieved since a range of the selected possible hypotheses is quite limited. | 12-17-2009 |
20100007556 | COLD START SATELLITE SEARCH METHOD - A method for searching satellites in a cold start state. The method of the present invention, a first satellite, which is predetermined or randomly selected, is searched. Then, a second satellite to be searched is selected according to the searching result (hit or missed) for the first satellite and respective interrelationships between the first satellite and the other satellites. In practice, an initial weight factor table is provided. Depending on the searching result, the initial weight factor table is updated according to the interrelationships between the satellites during searching. By using the method of the present invention, the time-to-first-fix (TTFF) can be reduced to a shorter period of time so as to provide a rapid cold start satellite positioning. | 01-14-2010 |
20100045527 | METHOD AND APPARATUS FOR COLLECTING SUBFRAMES OF SATELLITE NAVIGATION DATA - A method and apparatus for collecting subframes of navigation data of satellites are disclosed. In the method of the present invention, the subframe is divided into several sub-units, each sub-units includes one or more words. When a receiver receives a subframe with a subframe ID, the respective required sub-units of the subframe are checked. A dummy sub-unit is not necessary to be considered. Valid ones of the required sub-units are collected. If not all the required sub-units of the subframe have been collected, the absent sub-units are to be collected when the next subframe with the same subframe ID is received. Some protection schemes can be applied to raise the reliability of such sub-unit collection. Especially when the signal is weak or unstable, the present invention may significantly improve the TTFF (Time To First Fix) performance of the receiver. | 02-25-2010 |
20100195746 | BOC SIGNAL ACQUISITION AND TRACKING METHOD AND APPARATUS - A BOC signal acquisition and tracking apparatus and method. In the present invention, at least a BOC signal, a BOC-cos signal and a PRN coded signal are generated for a received signal. Depending on application condition (e.g. acquisition mode or tracking mode), autocorrelation of the BOC signal is combined with cross-correlation of the BOC signal and one of the BOC-cos signal and the PRN coded signal to generate a proper combined correlation result. | 08-05-2010 |
20100254492 | DATA SIGNAL PHASE REVERSAL CORRECTION METHOD AND SYSTEM IMPLEMENTING THE SAME - A data signal phase reversal correction method and system implementing the same are disclosed. In the present invention, a pilot signal of a satellite is checked to see if there is a phase reversal according to an accumulation of correction results of symbols of the received pilot signal with corresponding symbols of a known pilot sequence. It is determined whether a phase correction of a data signal of the satellite is to be executed or not by referencing the phase reversal determination result of the pilot signal. | 10-07-2010 |
20100309960 | SIGNAL ACQUISITION/TRACKING METHOD AND CORRELATOR FOR THE SAME - A Doppler frequency searching method and correlator are disclosed. In the present invention, before Doppler frequency removal, a received signal is converted into digital form having a first sampling rate. Then the signal is down-sampled to have a low sampling rate. The Doppler frequency searching is done by stages. Each stage is in charge of a portion of the Doppler frequency to be removed. The sampling rate can be further reduced in each stage. Each stage can have at least one Doppler frequency removal unit sharing the portion of Doppler frequency that the stage is to remove. Power consumption is reduced since Doppler frequency removal is executed with low sampling rate. | 12-09-2010 |
20110096872 | CORRELATION DEVICE AND METHOD - A correlation device and method is provided. According to the present invention, the correlation device comprises a first signal path for receiving a received signal; at least one second signal path for receiving the received signal and eliminating effect of a subcarrier component of the received signal; and a correlation unit couple to the first signal path and each second signal path, for selecting an output of one of the first and second signal paths to execute signal correlation. | 04-28-2011 |