Digital correlator for a receptor of signals from satellite radio-navigation systems

A digital correlator of a receiver for reception of signals of satellite radio navigation systems comprising:

• an input signal switch whose inputs form signal inputs of the digital correlator;
• a digital carrier generator;
• a processor;
• first and second digital mixers of inphase and quadrature correlation processing channels, respectively;
• first, second, third and fourth demodulators;
• first, second, third and fourth storage units;
• a reference C/A code generator of GPS/GLONASS satellite radio navigation systems;
• a control register;
• a programmable delay line;
• a digital C/A code generator of GPS/GLONASS satellite radio navigation systems;
• a data exchange unit connected through respective buses to the processor, to outputs of the first, the second, the third and the fourth storage units, to control inputs of the digital carrier generator, to the control register, and to the digital C/A code generator of the GPS/GLONASS satellite radio navigation systems;
• and
• first and second decision making units;
• wherein clock inputs of the first, second, third and fourth storage units, clock inputs of the digital C/A code generator, clock inputs of the digital carrier generator and clock inputs of the programmable delay line form a clock input of the digital correlator;
• a control input of the input signal switch is connected to a first output of the control register;
• an output of the input signal switch is connected to first inputs of the first and second digital mixers,
• second inputs of the first and second digital mixers are connected, respectively, to cosine and sine outputs of the digital carrier generator, and the outputs of the first and second digital mixers are connected, respectively, to a junction between first inputs of the first and second demodulators and to a junction between first inputs of the third and fourth demodulators,
• outputs of the first, second, third and fourth demodulators are connected, respectively, to the signal inputs of the first, second, third and fourth storage units,
• second inputs of the first and fourth demodulators are connected to an output of a punctual copy of a reference C/A code of the programmable delay line,
• second inputs of the second and third demodulators are connected to at least one of an output of a difference copy, the difference copy being equal to a difference between an early and a late copy of the reference C/A code of the programmable delay line, and an output of the early copy of the reference C/A code of the programmable delay line,
• a signal input of the programmable delay line is connected to an output of the reference C/A code generator of the GPS/GLONASS satellite radio navigation systems,
• a signal input of the reference C/A code generator of the GPS/GLONASS satellite radio navigation systems is connected to an output of the digital C/A code generator,
• a control input of the reference C/A code generator of the GPS/GLONASS satellite radio navigation systems and a control input of the programmable delay line are connected, respectively, to first and second outputs of the control register,
• control inputs and outputs of the first and the second decision making units are connected through corresponding buses to the data exchange unit,
• first and second signal inputs of the first decision making unit are connected, respectively, to outputs of the second and third storage units,
• first and second signal inputs of the second decision making unit are connected, respectively, to outputs of the first and fourth storage units,
• each of the first and second decision making units comprises:
• a first modulus determining device and a second modulus determining device, inputs of the first modulus determining device and the second modulus determining device form, respectively, the first signal input and the second signal input of the decision making unit,
• an adder whose inputs are connected to outputs of the modulus determining devices,
• a register of thresholds whose input forms the control input of the decision making unit,
• first, second and third threshold devices whose signal inputs are connected, respectively, to an adder output and to outputs of the first and second modulus determining device, a reference input of the first threshold device being connected to a first output of the register of thresholds, reference inputs of the second and third threshold devices are connected to a second output of the register of thresholds, the outputs of the first, the second and the third threshold devices are connected through an OR circuit to an input of a detection signal shaper whose output is an output of the decision making unit.