Novatel Inc.

Ian Williamson

David Brown

Patrick C Fenton

David C Brown

Thomas John Ford

Janet Brown Neumann

A receiver includes a pre-correlation filter that forms an image of the average chip shape of a received signal over a specified period of time. The filter includes an array of complex accumulation registers that accumulate measurements that are associated with signal samples from specific ranges of locations, or code chip phase angles, along a spread-spectrum chip. Using the accumulated measurements, the receiver estimates the location of the chip transitions in a direct path signal component. The receiver may thereafter change the starting points, sizes and numbers of ranges, such that the accumulation registers accumulate more detail from the chip edges. The receiver in addition may use the accumulated measurements from selected registers and/or selected groups of registers, to produce the correlation values that are needed to perform one or more correlation techniques and/or one or more multipath mitigation techniques. As appropriate, the sizes and/or starting points of the bins, and/or the selections of the bins for the various groupings may be altered, to change the spacings, locations, and so forth to which correlation values correspond.

Apparatus for and method of making pulse-shape measurements

A receiver utilizes an array of complex accumulation registers to form an image of the average chip shape or, as appropriate, chip edge shape, of the received signal over a specified period of time as a time series of complex power measurements. The receiver divides the length of the chip into a plurality of ranges, or bins, and, as appropriate, extends the bins to cover additional chips or portions thereof. When a sample is taken, the receiver enables the respective registers that are associated with the corresponding bin or bins, and the respective registers then accumulates the associated power measurement. The receiver uses the accumulated measurements from selected registers and/or selected groups of registers, to produce the correlation values that are needed to perform one or more correlation techniques and/or one or more multipath mitigation techniques. As appropriate, the sizes and/or starting points of the bins, and/or the selections of the bins for the various groupings may be altered, to change the spacings, locations, and so forth to which correlation values correspond.

System and method for making correlation measurements utilizing pulse shape measurements

A receiver that uses a single processor to control a GPS sub-system and an inertial (&ldquo;INS&rdquo;) sub-system and, through software integration, shares GPS and INS position and covariance information between the sub-systems. The receiver time tags the INS measurement data using a counter that is slaved to GPS time, and the receiver then uses separate INS and GPS filters to produce GPS and INS position information that is synchronized in time. The GPS/INS receiver utilizes GPS position and associated covariance information in the updating of an INS Kalman filter, which provides updated system error information that is used in propagating inertial position, velocity and attitude. Whenever the receiver is stationary after initial movement, the INS sub-system performs &ldquo;zero-velocity updates,&rdquo; to more accurately compensate in the Kalman filter for component measurement biases and measurement noise. Further, if the receiver loses GPS satellite signals, the receiver utilizes the inertial position, velocity and covariance information provided by the Kalman filter in the GPS filters, to speed up GPS satellite signal re-acquisition and associated ambiguity resolution operations.

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Calgary, Canada

Ian Williamson