| Class / Patent application number | Description | Number of patent applications / Date published |
|---|
| 342357050 | Using Doppler frequency shift | 15 |
| 20080272960 | Method and system for GPS position measuring and frequency error detecting method - A receiver terminal receives a frequency from an external reference oscillator portion, which is more accurate than that of a frequency generated within the receiver in a local oscillator portion. The frequency from the local oscillator portion is measured using the external frequency as the reference, which determines the error in the local oscillator frequency relative to the external reference and permits the local oscillator frequency to be corrected to within the error of the external oscillator frequency. A plurality of candidate values for the remaining local frequency error are selected within a predetermined frequency range to include any remaining error of the local oscillator frequency. The received signal from a satellite is correlated with a matching pseudorandom code to detect the signal and measure the signal delay and Doppler shift of the signal relative to the corrected local oscillator frequency. The delay value is used to obtain a pseudorange measurement and the measured Doppler shift permits further correction to the local oscillator frequency, thus reducing the frequency search range for the remaining satellites. | 11-06-2008 |
| 20080284644 | SATELLITE POSITIONING METHOD AND SYSTEM - According to the present invention, each navigation satellite ( | 11-20-2008 |
| 20090002226 | POSITION AND TIME DETERMINATION UNDER WEAK SIGNAL CONDITIONS - Described herein are systems and methods that are capable of determining receiver position and system time under weak signal conditions. When the receiver is unable to accurately determine the satellite signal travel time, e.g., due to weak signal reception or some other condition, the receiver can still estimate the pseudo-range for the satellite based on an initial receiver position and system time. In this case, the system and methods described herein provide the necessary initial receiver position and system time with enough accuracy to estimate the pseudo-range, even under weak signal conditions. The receiver can then use the estimated pseudo-range to determine a more accurate receiver position. | 01-01-2009 |
| 20090066566 | Method and system for GPS position measuring and frequency error detecting method - A receiver terminal receives a frequency from an external reference oscillator portion, which is more accurate than that of a frequency generated within the receiver in a local oscillator portion. The frequency from the local oscillator portion is measured using the external frequency as the reference, which determines the error in the local oscillator frequency relative to the external reference and permits the local oscillator frequency to be corrected to within the error of the external oscillator frequency. A plurality of candidate values for the remaining local frequency error are selected within a predetermined frequency range to include any remaining error of the local oscillator frequency. The received signal from a satellite is correlated with a matching pseudorandom code to detect the signal and measure the signal delay and Doppler shift of the signal relative to the corrected local oscillator frequency. The delay value is used to obtain a pseudorange measurement and the measured Doppler shift permits further correction to the local oscillator frequency, thus reducing the frequency search range for the remaining satellites. | 03-12-2009 |
| 20090102709 | SATELLITE-BASED POSITIONING SYSTEM IMPROVEMENT - A method, device and system for determining a receiver location using weak signal satellite transmissions. The invention involves a sequence of exchanges between an aiding source and a receiver that serve to provide aiding information to the receiver so that the receiver's location may be determined in the presence of weak satellite transmissions. With the aiding information, the novel receiver detects, acquires and tracks weak satellite signals and computes position solutions from calculated pseudo ranges despite the inability to extract time synchronization date f, 'n the weak satellite signals. The invention includes as features, methods and apparatus for the calibration of a local oscillator, the cancellation of cross correlations, a Doppler location scheme, an ensemble averaging scheme, the calculation of almanac aiding from a table of orbit coefficients, absolute time determination, and a modified search engine. | 04-23-2009 |
| 20090102710 | MULTI-FUNCTION DEVICE WITH POSITIONING SYSTEM AND SHARED PROCESSOR - A multi-function device with a positioning function and a real time positioning engine is disclosed. The device contains also a shared processor used by the positioning function and other functions of the device, such as a mobile radio-communication function. The positioning engine performs in real time the most computational intensive calculations of the positioning function, such as downsampling, Doppler mixing and correlation calculations. Since the received signal need not be stored, the memory requirements of the positioning function are significantly reduced if aiding data is available. | 04-23-2009 |
| 20090109088 | SATELLITE-BASED POSITIONING SYSTEM IMPROVEMENT - A method, device and system for determining a receiver location using weak signal satellite transmissions. The invention involves a sequence of exchanges between an aiding source and a receiver that serve to provide aiding information to the receiver so that the receiver's location may be determined in the presence of weak satellite transmissions. With the aiding information, the novel receiver detects, acquires and tracks weak satellite signals and computes position solutions from calculated pseudo ranges despite the inability to extract time synchronization date f, 'n the weak satellite signals. The invention includes as features, methods and apparatus for the calibration of a local oscillator, the cancellation of cross correlations, a Doppler location scheme, an ensemble averaging scheme, the calculation of almanac aiding from a table of orbit coefficients, absolute time determination, and a modified search engine. | 04-30-2009 |
| 20090303115 | METHODS AND SYSTEMS FOR STATIONARY USER DETECTION IN A HYBRID POSITIONING SYSTEM - This disclosure describes methods and systems for stationary user detection in a hybrid location system. In some embodiments, the method for determining whether a satellite enabled device is stationary by measuring the Doppler frequency of received satellite signals can include acquiring satellite measurements from at least two satellites, wherein the satellite measurements include Doppler frequency measurements, acquiring a rough estimate of location of the satellite enabled device and calculating an internal frequency offset of satellite enabled device. | 12-10-2009 |
| 20090309787 | METHOD AND COMMUNICATION SYSTEM FOR LIMITING THE FUNCTIONALITY OF AN ELECTRONIC DEVICE - Embodiments of the present invention recite a method and system for limiting the functionality of a mobile electronic device. In one embodiment, a Global Navigation Satellite System (GNSS) receiver configured to determine a GNSS Doppler frequency shift measurement corresponding to a GNSS signal. A control component is configured to control an operation of the mobile electronic device in response to a control signal which is generated when the GNSS Doppler frequency shift measurement is used to determine that the speed of the mobile electronic device exceeds a speed threshold. | 12-17-2009 |
| 20090315764 | PRECISE ABSOLUTE TIME TRANSFER FROM A SATELLITE SYSTEM - Systems and methods according to one or more embodiments are provided for obtaining a precise absolute time using a satellite system. The precise absolute time may be used, for example, as an aid for positioning systems including navigation in attenuated or jammed environments. A method of obtaining precise absolute time transfer from a satellite according to an embodiment comprises: receiving a precision time signal from a satellite, wherein the precision time signal comprises a periodic repeating code; determining a timing phase of the code; receiving additional aiding information; and using the timing phase and the additional aiding information to determine a precise absolute time. | 12-24-2009 |
| 20090322599 | SATELLITE NAVIGATIO RECEIVER HAVING CONFIGURABLE ACQUISITION AND TRACKING ENGINES - A satellite navigation receiver having a flexible acquisition and tracking engine architecture. The flexible acquisition engine has a reconfigurable delay line that can be used either as a single entity or divided into different sections. Consequently, it can be configured to search different satellite vehicles, a single Doppler frequency, and full CA code in parallel. When configuring the delay line into different sections, each section is used to search a partial CA code. In this configuration, multiple Doppler mode, multiple satellite vehicles, multiple Doppler frequencies, and partial CA code can be searched in parallel. Furthermore, the different sections of the CA code can be time-multiplexed into a correlator, which can then be over clocked to achieve full CA code correlation. The flexible tracking engine includes a number of parallel tracking channels, whereby each individual channel has a number of taps or fingers, which can be used to lock onto different delays. During tracking, one of the taps can be used to lock on to the center of the peak. This leaves the other taps free to be used to perform other functions, such as determining the shape of the peak, detecting earlier arrivals for line of sight component, and obtaining an estimate of the noise floor. The flexible tracking engine is configurable to help acquisition functions, such as fine acquisition, false trigger detection, and/or fast reacquisition. | 12-31-2009 |
| 20100066605 | METHOD AND SYSTEM FOR DOPPLER ESTIMATION - Aspects of a method and system for Doppler estimation may include generating, in a GNSS receiver operating in a duty-cycle mode, a plurality of lag-m products that may be based on a plurality of correlation coefficients corresponding to one or more received signals, wherein the plurality of correlation coefficients may be generated during an active period of the duty-cycle mode of operation. A Doppler frequency may be estimated based on the plurality of lag-m products. The GNSS receiver may be compliant with one or more standards comprising GALILEO, GLONASS, IRNSS, and BEIDOU. The active period of the duty-cycle mode may be chosen arbitrarily from a range of 1% to 99%. | 03-18-2010 |
| 20100073227 | Detecting Lack of Movement to Aid GNSS Receivers - Embodiments of the invention provide a method of detecting movement to aid GNSS receivers. By detecting when the user is stationary, the Doppler frequency estimation can be corrected or the SNR can be boosted more both of which lead to improved performance. The embodiments allow a GNSS receiver to process signals in when the signal level would otherwise be too low—for example indoors. The embodiments can improve performance when one or more satellites are temporarily blocked but one or more satellites are still being tracked. | 03-25-2010 |
| 20100176988 | INITIAL POSITION DETERMINATION METHOD, POSITIONING METHOD, AND POSITIONING APPARATUS - A method of determining an initial position in executing a positioning calculation based on satellite signals from positioning satellites, includes: (a) executing position converging calculation based on the satellite signals using each of a plurality of first candidate positions as a provisional initial position; (b) selecting at least one second candidate position from the first candidate positions based on a calculation result of the position converging calculation; and (c) selecting the initial position from one of the second candidate positions using the satellite signals. | 07-15-2010 |
| 20100194633 | POSITION CALCULATING METHOD AND POSITION CALCULATING DEVICE - A position calculating method includes: calculating the satellite position of a positioning satellite on the basis of satellite orbit information in an orthogonal coordinate system having the Earth center as the origin; detecting a Doppler frequency by receiving a positioning signal from the positioning satellite; and calculating the position of a position calculating device using the satellite positions of the plurality of positioning satellites and the Doppler frequency in a spherical coordinate system in which the Earth center is the origin and a distance from the Earth center to the Earth's surface is a radius vector. | 08-05-2010 |
