Qualcomm Incorporated

Nemerix Sa

Joel Brenner

Angelo Genghi

Radiolocalization receiver having a plurality of correlation taps, and including a module of cross-correlation detection in which spurious correlation terms are detected by statistical analysis of the frequencies of the candidate peaks. The system can restrict further integration to those taps whose frequency is outside the cross-interference signal, or trigger new acquisition of different space vehicles, upon detection of a cross-interference situation.

GNSS receiver with cross-correlation rejection

Radiolocalization receiver with a massively parallel array of correlators, comprising a data compression module () to compress the incoherent integration values accumulated into the incoherent integration memories (). By compressing incoherent integration values, relevant memory saving can be obtained or, in alternative, loss of data by excessive prescaling can be avoided or attenuated. The invention proposes a simple compression scheme based on offset subtraction which allows save memory size.

Memory reduction in GNSS receiver

A Frequency discriminator based on a combination of Discrete Fourier Transform (DFT) operator and half-bin DFT operator, corresponding to a set of Twiddle factors with frequency double than the sampling frequency. The frequency estimators are so chosen as not to have any zero or discontinuity point. Therefore the discriminator of embodiments of invention is more stable and well-behaved in an extended operating range. The discriminator of the invention, when applied to a Global Positioning System (GPS) receiver, allows a safer lock to the carrier frequency, even in presence of a large initial error, and avoids the problem of false locks.

Wideband frequency discriminator and radiolocalization receiver

Frequency discriminator based on a variant of the DFT transform in which the usual twiddle factors are replaced with twiddle factors as for a DFT on a number of points which is the double as the actual number of sample points. The DFT so modified allows half-bin frequency discrimination, with few added computational burden. Two DFT shifted of half bin with respect to the zero frequency provide a linear response of the discrimination and good immunity to noise. The discriminator is particularly useful in FLL for tracking signals in a GPS receiver.

Half bin linear frequency discriminator

Acquisition method for a localization receiver, in particular for a Global Positioning System (GPS) receiver. It involves the calculation of an interpolated Fast Fourier Transform (FFT) spectrum (S') of correlated signals in which the frequency lines corresponding to half-integer values of the frequency resolution defined by the FFT are obtained by a combination of both amplitude and phase values of the FFT spectrum (S).

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Arzo, Switzerland

Joel Brenner