U-blox Ag

Andreas Thiel

Heinz Mathis

Eric De Mey

Daniel Kaegi

Michael Ammann

Etienne Favey

Peter Karlsson

Roland Mester

Sylvia Lu

Pascal Flammant

For suppression of continuous wave interferers at, e.g., up to four interferer frequencies (f, f, f, f) in a GNSS receiver base band circuit a raw digital signal is, in a band stop unit (), shifted, by a first mixer (), by the negative of the first interferer frequency (f) in the frequency domain whereupon the continuous wave interferer is suppressed by a band stop filter (), a linear phase FIR filter with a suppression band centered at zero, e.g., a filter subtracting a mean over previous subsequent signal values from the actual signal value. After further shifting of the shifted digital signal by the negative of the difference between the second interferer frequency (f) and the first interferer frequency (f) the shifted digital signal is again filtered by an identical band stop filter () and so on. After the last filtering step the shifted digital signal is shifted back to its original position in the frequency domain to provide a filtered digital signal which corresponds to the raw digital signal with narrow interferer bands centered at the interferer frequencies (f, f, f, f) suppressed.

Method of processing a digital signal derived from an analog input signal of a GNSS receiver, a GNSS receiver base band circuit for carrying out the method and a GNSS receiver

A satellite positioning receiver. The receiver comprises: an RF front end, for receiving satellite positioning signals; an analog to digital converter, for sampling the received signals to generate signal samples; a memory; and a processor, for processing the signal samples to derive code-phases and pseudo-ranges and to calculate a position fix. The processor has a first mode in which it is operable to process the samples as they are generated, to calculate the position fix. It also has a second mode in which it is operable to store the samples or the code-phases or pseudo-ranges in the memory for later processing.

Hybrid satellite positioning receiver

An acquisition unit of a GNSS receiver base band circuit comprises a correlator () with a correlator shift register () to which a correlation sequence derived from a basic sequence characteristic for a satellite is fed by a code generator (). Each of the N=32 or more memory cells of the correlator shift register () is connected to two correlator cells () for multiplying digital values of the correlator sequence from the memory cell with data values of a data sequence, adding up the products and storing the sum in a register as a correlation value pertaining to one of N relative phase positions of the correlation sequence relative to the data sequence during a correlation phase. During a subsequent read-out phase the registers of each row of correlator cells () are connected to form a daisy chain and the correlation values are fed through the same to appear sequentially at the output of the last register in the row while the correlator shift register () and the rows of registers are sequentially filled with initial values for the next correlation phase.

An analog die () and a digital die () are supported by a plate () consisting of an electrically conductive material. Pads () of the dies () are connected to each other, to plate () or to pins () surrounding the latter by bond wires (). The upper side of the plate () is covered by a plastic mold () encapsulating the dies (), the bond wires () and, in part, the pins (). For the suppression of external jamming signals as well as internal ones picked up by bond wires the digital die () comprises an adjustable notch filter which suppresses narrow frequency bands where jamming signals have been detected.

GNSS receiver package

A sychronization circuit comprising an analog feedback shift register for generating an internal sequence which is synchronized with an external sequence containing repetitions of a fundamental sequence has a feedback circuit which, for the formation of a new value of a fundamental sequence, combines at least two values (x,x) stored in the shift register according to a feedback function (f(x,x)), which is then scaled with a factor k, 0.9&#x3c;k&#x3c;0.99. The synchronization behaviour is improved, especially in the case of signals with strong background noise, by using a feedback function which is substantially linear in the sectors defined by the signs of the arguments and whose sign corresponds to that of the negative of the product of the negative arguments and whose magnitude is 1 if the magnitudes of the arguments are each 1. A function which meets these requirements and has proved useful is f(x, . . . , x)=&#x2212;sig((&#x2212;x)&#xb7; . . . &#xb7;(&#x2212;x))&#xb7;(|x|+ . . . +|x|)/m. For improving the signal/noise ratio, there is a buffer in front of the analog feedback shift register, where, for the generation of the external sequence, segments of an input sequence which contain several, e.g. twenty, successive instances of the fundamental sequence are added and then read out repeatedly.

Synchronization circuit

A method for generating an internal sequence of analog values having a specific period includes producing an intermediate value by a logical combination of an actual value of the external sequence with an actual value of a second generating sequence, producing an input value to an analog feedback shift register by superposition of the intermediate value with an analog feedback value derived according to a feedback function from analog values in the analog feedback shift register, and feeding the input value to an input of the analog feedback shift register. A position of an actual value of the second generating sequence corresponds to a position of a segment in the first generating sequence, the segment including a determinative set of n binary values derived from the analog values in the analog feedback shift register.

Method for producing a sequence synchronized with an external signal and synchronization circuit and receiver

For allowing positioning of a GPS receiver within a building, GPS primary positioning signals received by an outdoor receive antenna are up-converted to different carrier frequencies in the 2.4 GHz ISM band and the converted signals are transmitted each by a transmit antenna inside the building, the transmit antennas serving at the same time as access points of a WLAN which is used for transmitting additional positioning data like the positions of the transmit antennas and the signal delay times associated with them. By cycling through the secondary positioning signals received from the transmit antennas, i.e., down-converting each of them during an assigned time slot, and determining clock bias differences in the receiver, the position of the latter is determined using TDOA algorithms.

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Wilen b. Wollerau, Switzerland

Andreas Thiel