Global positioning system course acquisition code receiver

Claim 2

A receiver comprising in combination: means for generating a local oscillator signal; a first receiver channel including, means for receiving a transmitted signal, and down-converting means connected to said local-oscillator-generating means, said first receiver-channel down-converting means for mixing said local-oscillator signal with a signal derived from said first receiver-channel received signal to generate a first down-converted signal; a second receiver channel including, means for receiving said transmitted signal, and down-converting means connected to said local-oscillator-generating means, said second receiver-channel down-converting means for mixing said local-oscillator signal with a signal derived from said second receiver-channel received signal to generate a second down-converted signal; carrier-synthesizer means for generating a signal having a frequency established by carrier-synthesizer-means-driving signals; first counter means coupled to said first receiver channel and connected to said carrier-synthesizer means, said first counter means for developing signals representing a count which is incremented at each of a series of times marked by said carrier-synthesizer-means-generated signal when a signal developed from said first down-converted signal has a predetermined one of two states and decremented at each of said carrier-synthesizer-means-generated-signal marked times otherwise; second counter means coupled to said second receiver channel and connected to said carrier-synthesizer means, said second counter means for developing signals represented a count which is incremented at each of a series of times marked by said carrier-synthesizer-means-generated signal when a signal developed from said second down-converted signal has a predetermined one of two states and decremented at each of said carrier-synthesizer-means-generated-signal marked times otherwise; and controller means connected to said carrier-synthesizer means and connected to said first and said second counter means, said controller means being responsive to said first-counter-means-developed signals and operative to develop said carrier-synthesizer-means-driving signals so as to lock the frequency of said carrier-synthesizer-means-generated signal to the frequency of said first down-converted signal.

Claim 3

A GPS satellite receiver comprising in combination: means for generating a local oscillator signal; a first receiver channel including, means for receiving a satellite signal, and down-converting means conencted to said local-oscillator-generating means, said first receiver-channel down-converting means for mixing said local-oscillator signal with a signal derived from said first receiver-channel received-satellite signal to generate a first down-converted satellite signal; a second receiver channel including, means for receiving said satellite signal, and down-converting means connected to said local-oscillator-generating means, said second receiver-channel down-converting means for mixing said local-oscillator signal with a signal derived from said second receiver-channel received-satellite signal to generate a second down-converted satellite signal; carrier-synthesizer means for generating a first signal having a frequency established by carrier-synthesizer-means-driving signals; first Q-counter means coupled to said first receiver channel and connected to said carrier-synthesizer means, said first Q-counter means for developing signals representing a count which is incremented at each of a series of times marked by said carrier-synthesizer-means-generated first signal when a signal developed from said first down-converted satellite signal has a predetermined one of two states and decremented at each of said carrier-synthesizer-means-generated-first-signal marked times otherwise; second Q-counter means coupled to said second receiver channel and connected to said carrier-synthesizer means, said second Q-counter means for developing signals representing a count which is incremented at each of a series of times marked by said carrier-synthesizer-means-generated first signal when a signal developed from said second down-converted satellite signal has a predetermined one of two states and decremented at each of said carrier-synthesizer-means-generated-first-signal marked times otherwise; and controller means connected to said carrier-synthesizer means and connected to said first and said second Q-counter means, said controller means being responsive to said first Q-counter-means-developed signals and operative to develop said carrier-synthesizer-means-driving signals so as to lock the frequency of said carrier-synthesizer-means-generated first signal to the frequency of said first down-converted satellite signal.

Claim 4

A GPS satellite receiver comprising in combination: means for generating a local oscillator signal; a first receiver channel including, means for receiving a satellite signal, and down-converting means conencted to said local-oscillator-generating means, said first receiver-channel down-converting means for mixing said local-oscillator signal with a signal derived from said first receiver-channel received-satellite signal to generate a first down-converted satellite signal; a second receiver channel including, means for receiving said satellite signal, and down-converting means connected to said local-oscillator-generating means, said second receiver-channel down-converting means for mixing said local-oscillator signal with a signal derived from said second receiver-channel received-satellite signal to generate a second down-converted satellite signal; carrier-synthesizer means for generating a first signal having a frequency established by carrier-synthesizer-means-driving signals; first Q-counter means coupled to said first receiver channel and connected to said carrier-synthesizer means, said first Q-counter means for developing signals representing a count which is incremented at each of a series of times marked by said carrier-synthesizer-means-generated first signal when a signal developed from said first down-converted satellite signal has a predetermined one of two states and decremented at each of said carrier-synthesizer-means-generated-first-signal marked times otherwise; second Q-counter means coupled to said second receiver channel and connected to said carrier-synthesizer means, said second Q-counter means for developing signals representing a count which is incremented at each of a series of times marked by said carrier-synthesizer-means-generated first signal when a signal developed from said second down-converted satellite signal has a predetermined one of two states and decremented at each of said carrier-synthesizer-means-generated-first-signal marked times otherwise; and controller means connected to said carrier-synthesizer means and connected to said first and said second Q-counter means, said controller means being responsive to said first Q-counter-means-developed signals and operative to develop said carrier-synthesizer-means-driving signals so as to lock the frequency of said carrier-synthesizer-means-generated first signal to the frequency of said first down-converted satellite signal.

Claim 5

A GPS satellite receiver as recited in claim 2 wherein said carrier-synthesizer means further generates a second signal which is in phase quadrature with said carrier-synthesizer-means-generated first signal and wherein the receiver further comprises first I-counter means coupled to said first receiver channel, connected to said carrier-synthesizer means and connected to said controller means, said I-counter means for developing controller-means-driving signals representing a count which is incremented at each of a series of times marked by said carrier-synthesizer-means-generated second signal when said signal developed from said first down-converted satellite signal has a predetermined one of two states and decremented at each of said second carrier-synthesizer-means-generated-signal marked times otherwise.

Claim 6

A GPS satellite receiver as recited in claim 3 further comprising second I-counter means coupled to said second receiver channel, connected to said carrier-synthesizer means and connected to said controller means, said I-counter means for developing controller-means-driving signals representing a count which is incremented at each of a series of times marked by said carrier-synthesizer-means-generated second signal when said signal developed from said second down-converted satellite signal has a predetermined one of two states and decremented at each of said second carrier-synthesizer-means-generated-signal marked times otherwise.

Claim 7

A GPS satellite receiver as recited in claim 2 wherein said carrier-synthesizer means further generates a second signal which is in phase quadrature with said carrier-synthesizer-means-generated first signal and wherein the receiver further comprises I-counter means coupled to said second receiver channel, connected to said carrier-synthesizer means and connected to said controller means, said I-counter means for developing controller-means-driving signals representing a count which is incremented at each of a series of times marked by said carrier-synthesizer-means-generated second signal when said signal developed from said second down-converted satellite signal has a predetermined one of two states and decremented at each of said second carrier-synthesizer-means-generated-signal marked times otherwise.

Claim 8

A GPS satellite receiver comprising in combination: means for generating a local oscillator signal; a first receiver channel including, means for receiving a satellite signal which is biphase modulated by a PRN code, and down-converting means connected to said local-oscillator-generating means, said first receiver-channel down-converting means for mixing said local oscillator signal with a signal derived from said first receiver-channel received-satellite signal to generate a first down-converted satellite signal; a second receiver channel including, means for receiving said satellite signal, and down-converting means connected to said local-oscillator-generating means, said second receiver-channel down-converting means for mixing said local oscillator signal with a signal derived from said second receiver-channel received-satellite signal to generate a second down-converted satellite signal; carrier-synthesizer means for generating a first signal having a frequency established by carrier-synthesizer-means-driving signals; PRN-code-synthesizer means for generating an early, a punctual, and a late signal each representing said PRN code and each having a phase established by PRN-code-synthesizer-means-driving signals; first exclusive-OR-gate means connected to said PRN-code-synthesizer means and connected to said first receiver channel, said first exclusive-OR-gate means for comparing the state of a signal developed from said first down-converted satellite signal with the state of said PRN-code-synthesizer-means-generated punctual signal to develop a signal, second exclusive-OR-gate means connected to said PRN-code-synthesizer means and connected to said second receiver channel, said second exclusive-OR-gate means for comparing the state of a signal developed from said second converted satellite signal with the state of said PRN-code-synthesizer-means-generated punctual signal to develop a signal, first Q-counter means connected to said first receiver channel, connected to said carrier-synthesizer means, and connected to said first exclusive-OR-gate means, said first Q-counter means for developing signal representing a count which is incremented at each of a series of times marked by said carrier-synthesizer-means-generated first signal when said first exclusive-OR-gate-developed signal has a predetermined one of two states and decremented at each of said carrier-synthesizer-means-generated-first-signal marked times otherwise; second Q-counter means connected to said second receiver channel, connected to said carrier-synthesizer means, and connected to said second exclusive-OR-gate means, said second Q-counter means for developing signals representing a count which is incremented at each of a series of times marked by said carrier-synthesizer-means-generated first signal when said second exclusive-OR-gate-developed signal has a predetermined one of two states and decremented at each of said carrier-synthesizer-means-generated-first-signal marked times otherwise; and controller means connected to said carrier-synthesizer means and connected to said first and said second Q-counter means, said controller means being responsive to said first Q-counter-means-developed signals and operative to develop said carrier-synthesizer-means-driving signals so as to lock the frequency of said carrier-synthesizer-means-generated first signal to the frequency of said first down-converted satellite signal.

Claim 9

A GPS satellite receiver comprising in combination: means for generating a local oscillator signal; a first receiver channel including, means for receiving a satellite signal which is biphase modulated by a PRN code, and down-converting means connected to said local-oscillator-generating means, said first receiver-channel down-converting means for mixing said local oscillator signal with a signal derived from said first receiver-channel received-satellite signal to generate a first down-converted satellite signal; a second receiver channel including, means for receiving said satellite signal, and down-converting means connected to said local-oscillator-generating means, said second receiver-channel down-converting means for mixing said local oscillator signal with a signal derived from said second receiver-channel received-satellite signal to generate a second down-converted satellite signal; carrier-synthesizer means for generating a first signal having a frequency established by carrier-synthesizer-means-driving signals; PRN-code-synthesizer means for generating an early, a punctual, and a late signal each representing said PRN code and each having a phase established by PRN-code-synthesizer-means-driving signals; first exclusive-OR-gate means connected to said PRN-code-synthesizer means and connected to said first receiver channel, said first exclusive-OR-gate means for comparing the state of a signal developed from said first down-converted satellite signal with the state of said PRN-code-synthesizer-means-generated punctual signal to develop a signal, second exclusive-OR-gate means connected to said PRN-code-synthesizer means and connected to said second receiver channel, said second exclusive-OR-gate means for comparing the state of a signal developed from said second converted satellite signal with the state of said PRN-code-synthesizer-means-generated punctual signal to develop a signal, first Q-counter means connected to said first receiver channel, connected to said carrier-synthesizer means, and connected to said first exclusive-OR-gate means, said first Q-counter means for developing signal representing a count which is incremented at each of a series of times marked by said carrier-synthesizer-means-generated first signal when said first exclusive-OR-gate-developed signal has a predetermined one of two states and decremented at each of said carrier-synthesizer-means-generated-first-signal marked times otherwise; second Q-counter means connected to said second receiver channel, connected to said carrier-synthesizer means, and connected to said second exclusive-OR-gate means, said second Q-counter means for developing signals representing a count which is incremented at each of a series of times marked by said carrier-synthesizer-means-generated first signal when said second exclusive-OR-gate-developed signal has a predetermined one of two states and decremented at each of said carrier-synthesizer-means-generated-first-signal marked times otherwise; and controller means connected to said carrier-synthesizer means and connected to said first and said second Q-counter means, said controller means being responsive to said first Q-counter-means-developed signals and operative to develop said carrier-synthesizer-means-driving signals so as to lock the frequency of said carrier-synthesizer-means-generated first signal to the frequency of said first down-converted satellite signal.

Claim 10

A GPS satellite receiver as recited in claim 6 further comprising early/late means connected to said PRN-code synthesizer, connected to said first receiver channel, and connected to said controller means, said early/late means for comparing the state of said signal developed from said first down-converted satellite signal with the state of said early and said late PRN-code-synthesizer-means-developed signals to develop controller-means-driving signals representing the difference between an early and a late count, and wherein said controller means is further responsive to said early/late-means-developed signals and operative to develop said PRN-code-synthesizer-means-driving signals so as to lock the phase of said PRN-code-synthesizer-developed signals to said satellite-signal PRN-code phase.

Claim 11

A GPS satellite receiver as recited in claim 7 wherein said carrier-synthesizer means further generates a second signal which is in phase quadrature with said carrier-synthesizer-means-generated first signal and wherein the receiver further comprises first I-counter means connected to said first exclusive-OR-gate means, connected to said carrier-synthesizer means and connected to said controller means, said I-counter means for developing controller-means-driving signals representing a count which is incremented at each of a series of times marked by said carrier-synthesizer-means-generated second signal when said first exclusive-OR-gate-developed signal has a predetermined one of two states and decremented at each of said second carrier-synthesizer-means-generated-signal marked times otherwise.

Claim 12

A GPS satellite receiver as recited in claim 8 further comprising second I-counter means connected to said second exclusive-OR-gate means, connected to said carrier-synthesizer means and connected to said controller means, said I-counter means for developing controller-means-driving signals representing a count which is incremented at each of a series of times marked by said carrier-synthesizer-means-generated second signal when said second exclusive-OR-gate-developed signal has a predetermined one of two states and decremented at each of said second carrier-synthesizer-means-generated-signal marked times otherwise.

Claim 13

A GPS satellite receiver as recited in claim 7 wherein said carrier-synthesizer means further generates a second signal which is in phase quadrature with said carrier-synthesizer-means-generated first signal and wherein the receiver further comprises I-counter means connected to said second exclusive-OR-gate means, connected to said carrier-synthesizer means and connected to said controller means, said I-counter means for developing controller-means-driving signals representing a count which is incremented at each of a series of times marked by said carrier-synthesizer-means-generated second signal when said second exclusive-OR-gate-developed signal has a predetermined one of two states and decremented at each of said second carrier-synthesizer-means-generated-signal marked times otherwise.