Wideband receiver for the measurement of distance by pseudo-random code signals
AssigneeSextant Avionique
InventorsPatrice Guillard, Alain Renard
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Abstract
This receiver comprises a signal processor using the correlation of the received composite signal with early/late, locally generated pseudo-random codes. The code generator sends its signals to a delay line whose evenly spaced out outputs (E2, E1, P, L1, L2) are combined according to the relationship: c=E2-2E1+2L1-L2 before being sent to one of the correlators (C2) while the other (C1) receives the punctual signal (P). This especially reduces the positional error due to the multiple-path delays.
Claims8
A wideband receiver for the measurement of distance by signals modulated by pseudo-random codes, said receiver demodulating and decoding a composite HF signal including several transmitted signals modulated by pseudo-random codes, said receiver comprising frequency-changing, filtering and sampling-encoding means and a plurality of channels, each designed to demodulate and decode one of the signals modulated by pseudo-random codes on the basis of the samples given by the sampling-encoding means, each channel comprising a pseudo-random code generator synchronized by a control signal and correlation means receiving said samples of the composite signal and the code given by the pseudo-random code generator with adjustable delays and giving correlation signals so as to make it possible to determine said control signal, wherein said correlation means comprise at least two correlators, means for the combination of early and late pseudo-random codes to give a quadruple correlation signal and switch-over means to configure said correlators in a first mode of acquisition as early and late correlators and in a second mode as punctual and combined quadruple correlators.
A wideband receiver for the measurement of distance by signals modulated by pseudo-random codes, said receiver demodulating and decoding a composite HF signal including several transmitted signals modulated by pseudo-random codes, said receiver comprising:
- sampling-encoding means;
- a plurality of channels, each channel designed to demodulate and decode one signal modulated by pseudo-random codes on the basis of samples given by said sampling-encoding means, each channel comprising:
- a pseudo-random code generator;
- a control signal synchronizing said pseudo-random code generator;
- correlation means receiving samples of the composite signal and pseudo-random codes supplied by said pseudo-random code generator, said correlation means giving correlation signals for determining the control signal, said correlation means comprising:
- at least first and second correlators;
- combination means for the combination of early and late pseudo-random codes into a quadruple correlation signal;
- and
- switch-over means for configuring said correlators in one of a first mode of acquisition and a second mode of tracking;
- wherein, during said second mode, said first correlator is configured to receive a punctual signal and said second correlator is configured to receive said quadruple correlation signal.
Dependencies are inferred from the claim text.