公开(公告)号：EP1565762A2

公开(公告)日：2005-08-24

申请号：EP02773144.7

申请日：2002-02-11

申请人： Sirf Technology, Inc.

发明人： VAN ROY, Benjamin ,  TSITSIKLIS, John ,  CHOU, Andrew

IPC分类号： G01S1/00

CPC分类号： G01S19/09 ,  G01S19/42 ,  G01S2205/008

摘要： Some embodiments of the invention provide a location-determination system that includes a number of transmitters and at least one receiver. Based on a reference signal received by the receiver, this location-determination system identifies an estimated location of the receiver within a region. In some embodiments, the system selects one or more locations within the region. For each particular selected location, the system calculates a metric value that quantifies the similarity between the received signal and the signal that the receiver could expect to receive at the particular location, in the absence or presence of interference. Based on the calculated metric value or values, the system identifies the estimated location of the receiver.

公开(公告)号：EP1497669A2

公开(公告)日：2005-01-19

申请号：EP03747036.6

申请日：2003-04-18

申请人： SiRF Technology, Inc.

发明人： BLOEBAUM, L., Scott ,  BHARTI, Piyush ,  CHUNG, Sherk ,  VAN ROY, Benjamin ,  MANN, Wallace

IPC分类号： G01S1/04 ,  H04B1/38

CPC分类号： G01S19/29 ,  G01S19/235 ,  G01S19/37 ,  H03J1/0008 ,  H03J7/04 ,  H04B1/3805

摘要： In a mobile communication device, a method for compensating for a frequency adjustment in an oscillator shared between a communication circuit and a positioning signal receiver is provided. In one embodiment, the method begins to receive and store a positioning signal at a first time point. When, at a second time point, the operating frequency of the shared oscillator is adjusted, the frequency adjustment is recorded. After the positioning signal is completely received and stored, the processing of the positioning signal takes into consideration the frequency adjustment. In that embodiment, the processing hypothesizes a frequency shift in the received positioning signal. According to another aspect of the present invention, a method for determining the operating frequency of an oscillator detects a beginning time point of a reference signal received by the mobile communication device and enables a counter to count in step with a clock signal derived from the oscillator. When an ending time point of the reference signal is received by the mobile communication device, the count is stopped, and the frequency of the oscillator is determined based on the count in the counter and an expected time that elapsed between the beginning time point and the ending time point.

公开(公告)号：EP1449005B1

公开(公告)日：2009-03-25

申请号：EP02752163.2

申请日：2002-06-21

申请人： SiRF Technology, Inc.

发明人： SAHAI, Anant ,  TSITSIKLIS, John ,  VAN ROY, Benjamin ,  CHOU, Andrew ,  MANN, Wallace ,  STONE, Jesse, R. ,  FONG, WungKum

IPC分类号： G01S1/04

CPC分类号： G01S19/30

摘要： According to one aspect of the invention, sampled data that is received from a receiver is divided into segments of data of increasing length. A current value range for a delay value and a current value range for a modulation frequency value are calculated relative to each signal source from a set of signal sources that are overhead the signal receiver. An estimate for the delay value and an estimate for the modulation frequency value are calculated by iteratively updating the current value range for the delay value and for the modulation frequency value. The iterative update of the current value range for the delay value and for the modulation frequency value is performed overthe set of signal sources and over the segments of data of increasing length. According to another aspect of the technique, for each signal source, I and Q correlation integrals and their magnitude value are calculated corresponding to the estimate of the modulation frequency value and the estimate of the delay value. In addition, for each signal source, I and Q correlation integrals and thier magnitude values are calculated corresponding to a set of delay values that surround the estimate of the delay value. A shape of a magnitude-curve is interpolated using the magnitude values corresponding to the estimate of the delay value and corresponding to the set of delay values that surround the estimate of the delay value. The location of the receiver is calculated using the shape of the magnitude-curve to represent the I and Q correlation integrals for each signal source.

公开(公告)号：EP1604298A2

公开(公告)日：2005-12-14

申请号：EP02746615.0

申请日：2002-06-21

申请人： Sirf Technology, Inc.

发明人： SAHAI, Anant ,  TSITSIKLIS, John ,  VAN ROY, Benjamin

IPC分类号： G06F17/16 ,  G01S1/00 ,  H04B1/707

CPC分类号： G06F17/15 ,  G01S19/29

摘要： Techniques are provided for synthesizing a long coherent I and Q correlation integral at a particular frequency by synthetically combining a sequence of shorter correlation integrals at the same or different frequency. Techniques are also provided for acquiring a carrier-modulated signal with an unknown shift of the carrier frequency, and possibly some additional unknown signal parameters. These techniques involve synthesizing coherent correlation sums at a fine frequency resolution, using coherent correlation sums that are calculated at a coarse frequency resolution. This approach allows for coherent processing of the received signal over an arbitrarily long time interval, while avoiding the excessive computational requirements of traditional methods.

公开(公告)号：EP1449005A2

公开(公告)日：2004-08-25

申请号：EP02752163.2

申请日：2002-06-21

申请人： SiRF Technology, Inc.

发明人： SAHAI, Anant ,  TSITSIKLIS, John ,  VAN ROY, Benjamin ,  CHOU, Andrew ,  MANN, Wallace ,  STONE, Jesse, R. ,  FONG, WungKum

IPC分类号： G01S1/04

CPC分类号： G01S19/30

摘要： According to one aspect of the invention, sampled data that is received from a receiver is divided into segments of data of increasing length. A current value range for a delay value and a current value range for a modulation frequency value are calculated relative to each signal source from a set of signal sources that are overhead the signal receiver. An estimate for the delay value and an estimate for the modulation frequency value are calculated by iteratively updating the current value range for the delay value and for the modulation frequency value. The iterative update of the current value range for the delay value and for the modulation frequency value is performed overthe set of signal sources and over the segments of data of increasing length. According to another aspect of the technique, for each signal source, I and Q correlation integrals and their magnitude value are calculated corresponding to the estimate of the modulation frequency value and the estimate of the delay value. In addition, for each signal source, I and Q correlation integrals and thier magnitude values are calculated corresponding to a set of delay values that surround the estimate of the delay value. A shape of a magnitude-curve is interpolated using the magnitude values corresponding to the estimate of the delay value and corresponding to the set of delay values that surround the estimate of the delay value. The location of the receiver is calculated using the shape of the magnitude-curve to represent the I and Q correlation integrals for each signal source.