Radiofrequency signal receiver with means for improving the reception dynamic of said signals

• US 7,092,433 B2
• Filed: 04/30/2002
• Issued: 08/15/2006
• Est. Priority Date: 05/04/2001
• Status: Expired due to Fees

• Current Assignee: Asulab SA (The Swatch Group AG)
• Original Assignee: Asulab SA (The Swatch Group AG)
• Inventors: Oesch, Yves, Farine, Pierre-André, Monthéard, Anne
• Primary Examiner(s): Bayard, Emmanuel
• Assistant Examiner(s): Williams, Lawrence B.
• Application Number:
  US10/137,027
• Publication Number:
  US 20020167995A1
• Time in Patent Office: 1,568 Days
• Field of Search: 375147-148, 375/150, 375249-250, 375/305, 375/336, 370/320, 701/213
• US Class Current: 375/148
• CPC Class Codes: G01S 19/246 involving long acquisition integration times, extended snapshots of signals or methods specifically directed towards weak signal acquisition
• CPC Class Codes: G01S 19/29 carrier including Doppler, related G01S19/246 takes precedence
• CPC Class Codes: H04B 1/708 Parallel implementation
• CPC Class Codes: H04B 1/709 Correlator structure

Abstract

The receiver includes: a correlation stage (7) formed of several correlation channels (7′) for receiving intermediate signals (IF) in order to correlate them, in operating channel control loops, with the carrier frequency and specific code replicas of visible emitting satellites to be searched and tracked, each channel having a correlator (8) in which at least one integrator counter (28, 29, 30, 31) provides, at the end of each determined integration period of the correlated signals, a binary output word whose value allows detection of the presence or absence of the visible satellite to be searched and tracked; and a microprocessor for processing the data drawn, after correlation, from the radio-frequency signals. The microprocessor configures at least one unused channel placed in parallel with one of the operating channels for searching and/or tracking the same visible satellite, the unused channel being configured so that the integration period of its integrator counter is different from that of the integrator counter of the operating channel.

Claims

1. A receiver for radio-frequency signals transmitted by transmitting sources, in particular of the GPS type, said receiver including:

receiving and shaping means with frequency conversion for the radio-frequency signals for generating intermediate signals,

a correlation stage formed of several correlation channels for receiving the intermediate signals in order to correlate them, in control loops of operating channels, with carrier frequency replicas and specific code replicas of visible transmitting sources to be searched and tracked, each channel being provided with a correlator in which at least one integrator counter is capable of providing, at the end of each determined integration period of the correlated signals, a binary output word whose value, compared to a determined detection threshold level, allows detection of the presence or absence of the transmitting source to be searched and tracked, and

microprocessor means connected to the correlation stage for processing data extracted, after correlation, from the radio-frequency signals, wherein the microprocessor means is arranged to configure at least one unused channel placed in parallel with one of the operating channels for searching and/or tracking a same visible transmitting source, the unused channel being configured so that the integration period of its integrator counter is different from the integration period of the integrator counter of the operating channel.

2. A receiver according to claim 1, for receiving radio-frequency signals transmitted by satellites, wherein the correlation stage includes a greater number of correlation channels than a number of visible satellites so that at least one unused channel can be connected in parallel with an operating channel for searching and/or tracking a same specific visible satellite.

3. A receiver according to claim 2, wherein the number of channels is greater than or equal to 12.

4. A receiver according to claim 1, wherein several unused channels are configured to be connected each in parallel with one of the operating channels, the integration period of the integrator counter of each unused channel being greater than the integration period of the integrator counter of the respective operating channel.

5. A receiver according to claim 1 for receiving radio-frequency signals transmitted by satellites, wherein the integration period of the integrator counter of a channel operating in visible satellite searching and/or tracking phase is equivalent to a repetition period a the specific code of a transmitting satellite, and wherein the integration period of the integrator counter of an unused channel configured to be connected in parallel to the operating channel is greater than the repetition period of the specific code and preferably equal to double said repetition period.

6. A receiver according to claim 1, wherein a set of data input and output registers is placed as an interface between the correlation stage and the microprocessor means in order to receive data transmitted by the microprocessor means to the correlation stage and data provided by the correlation stage for the microprocessor means.

7. A receiver according to claim 6, wherein a set of registers is provided for each channel of the correlation stage.

8. A receiver according to claim 1 for receiving radio-frequency signals transmitted by satellites, wherein, in each channel, a controller, including a digital signal processing algorithm, is associated with the correlator to allow all synchronisation tasks for searching and tracking a satellite to be performed autonomously independently of the microprocessor means, when the channel is set into operation.

9. A receiver according to claim 1 for receiving radio-frequency signals transmitted by satellites, wherein each channel receives complex intermediate signals formed of an in-phase signal component and a quadrature phase signal component, in that each correlator of the channels includes:

first mixers for correlating the in-phase signal component with a first carrier frequency replica and for correlating the quadrature-phase signal component with a second carrier frequency replica offset by 90°

with respect to the first carrier frequency replica; and

second mixers for correlating the output in-phase signal of the first mixers with a first early specific code replica and with a second late specific code replica and for correlating the quadrature-phase output signal of the first mixers with the first early replica and the second late replica, and in that four integrator counters per channel receive the correlated output signals from the second mixers in order to each provide a binary output word whose value, compared to the determined detection threshold level, allows detection of the presence or absence of a satellite to be searched and tracked.

10. A receiver according to claim 1, wherein after the integrator counters, each channel correlator includes a carrier discriminator in a carrier correction control loop and a code discriminator in a code correction control loop, each discriminator being configured by the microprocessor means to take account of output values of the integrator counters over a discriminator period N times greater than the integration period, N being an integer number, the discriminator period of an unused channel connected in parallel to an operating channel being greater than the discriminator period of the operating channel, preferably equal to double said discriminator period.