Tracking of signals with at least one subcarrier
A system for tracking a received signal with a subcarrier, the received signal representing a carrier signal modulated with a code signal and with a subcarrier signal. The system comprises independent and cooperatively operating loops: a phase lock loop tracking the carrier signal, a subcarrier lock loop tracking the subcarrier signal, and a delay lock loop tracking the code signal. The subcarrier lock loop comprises a first controllable oscillator and a first early-minus-late discriminator generating a control signal for the first controllable oscillator. The delay lock loop comprising a second controllable oscillator and a second arctan discriminator generating a control signal for the second controllable oscillator.
1. A system for tracking of a received signal with at least one subcarrier, wherein the received signal represents a carrier signal modulated with a code signal and modulated with a subcarrier signal, wherein the system comprises the following independent and cooperatively operating loops:
a phase lock loop for tracking the carrier signal;
a subcarrier lock loop for tracking the subcarrier signal, which comprises a first controllable oscillator and one of an early-minus-late discriminator or a first arctan discriminator, for generating a control signal for the first controllable oscillator,
wherein one of
the early-minus-late discriminator generates the control signal based on a difference between correlation results with a replica of an advanced subcarrier signal and a replica of a delayed subcarrier signal, or
the first arctan discriminator generates the control signal based on correlation results with a cosine subcarrier replica and a sine subcarrier replica; and
a delay lock loop for tracking the code signal, which comprises a second controllable oscillator and a second arctan discriminator for generating a control signal for the second controllable oscillator,
wherein one of
the second arctan discriminator generates the control signal based on correlation results with a replica of a prompt subcarrier signal multiplied with a prompt code signal and the replica of the prompt subcarrier signal multiplied with the difference of an advanced code signal and a delayed code signal, or
the second arctan discriminator generates the control signal based on correlation results with the cosine subcarrier replica multiplied with the prompt code signal and the cosine subcarrier replica multiplied with the difference of the advanced code signal and the delayed code signal.
2. The system of claim 1 , wherein the early-minus-late discriminator is implemented as one of a dot-product-power discriminator, an early-minus-late-power discriminator, an early-minus-late-envelope discriminator, or a double-delta discriminator.
3. The system of claim 1 , wherein the early-minus-late discriminator is implemented as one of a coherent discriminator or a non-coherent discriminator.
4. The system of claim 1 , wherein at least one of the arctan discriminators is implemented as one of a Costas discriminator, an IQ-product discriminator, a decision-directed Q discriminator, a Q-over-I discriminator, a two-quadrant arctangent discriminator, or a frequency lock loop discriminator.
5. The system of claim 1 , wherein the controllable oscillators are implemented by numerical controlled oscillators.
6. The system of claim 1 being configured for tracking one of a Binary Offset Carrier signal, a Multiplexed Binary Offset Carrier signal, a Composite Binary Offset Carrier signal, or a Composite Binary Offset Carrier signal using a cosine subcarrier.
7. A system for tracking of a received signal with at least one subcarrier, wherein the received signal represents a carrier signal modulated with a code signal and modulated with a subcarrier signal, wherein the system comprises the following independent and cooperatively operating loops:
a phase lock loop for tracking the carrier signal;
a subcarrier lock loop for tracking the subcarrier signal, which comprises a controllable oscillator and one of an early-minus-late discriminator or a first arctan discriminator, for generating a control signal for the controllable oscillator,
wherein one of
the early-minus-late discriminator generates the control signal based on a difference between correlation results with a replica composed of an early subcarrier signal and a prompt code signal and a replica composed of a late subcarrier signal and the prompt code signal, or
the first arctan discriminator generates the control signal based on correlation results with a replica composed of a sine subcarrier signal and a prompt code signal and a replica composed of a cosine subcarrier signal and the prompt code signal; and
a detection path for detecting a delay estimate of the code signal, which comprises a second arctan discriminator and a delay estimate detector, wherein the second arctan discriminator generates an input signal for the delay estimate detector based on correlation results with a replica composed of a prompt subcarrier signal and the difference of an early code signal and a late code signal and a replica composed of the prompt subcarrier signal and the prompt code signal or based on correlation results with a replica composed of a cosine subcarrier signal and the difference of the early code signal and the late code signal and a replica composed of a sine prompt subcarrier signal and the prompt code signal.
8. The system of claim 7 , wherein the early-minus-late discriminator is implemented as one of a dot-product-power discriminator, an early-minus-late-power discriminator, an early-minus-late-envelope discriminator, or a double-delta discriminator.
9. The system of claim 7 , wherein the early-minus-late discriminator is implemented as one of a coherent discriminator or a non-coherent discriminator.
10. The system of claim 7 , wherein at least one of the arctan discriminators is implemented as one of a Costas discriminator, an IQ-product discriminator, a decision-directed Q discriminator, a Q-over-I discriminator, a two-quadrant arctangent discriminator, or a frequency lock loop discriminator.
11. The system of claim 7 , wherein the controllable oscillator is implemented by a numerical controlled oscillator.
12. The system of claim 7 being configured for tracking one of a Binary Offset Carrier signal, a Multiplexed Binary Offset Carrier signal, a Composite Binary Offset Carrier signal, or a Composite Binary Offset Carrier signal using a cosine subcarrier.
13. A method for tracking a received signal with at least one subcarrier, wherein the received signal represents a carrier signal modulated with a code signal and modulated with a subcarrier signal, wherein the method comprises the following independently and cooperatively performed acts of:
tracking the carrier signal with a phase lock loop;
tracking the subcarrier signal with a subcarrier lock loop, which comprises a first controllable oscillator and one of an early-minus-late discriminator or a first arctan discriminator, for generating a control signal for the first controllable oscillator,
wherein one of
the early-minus-late discriminator generates the control signal based on a difference between correlation results with a replica of an advanced subcarrier signal and a replica of a delayed subcarrier signal, or
the first arctan discriminator generates the control signal based on correlation results with a cosine subcarrier replica and a sine subcarrier replica; and
tracking the code signal with a delay lock loop, which comprises a second controllable oscillator and a second arctan discriminator for generating a control signal for the second controllable oscillator,
wherein one of
the second arctan discriminator generates the control signal based on correlation results with a replica of a prompt subcarrier signal multiplied with a prompt code signal and the replica of the prompt subcarrier signal multiplied with the difference of an advanced code signal and a delayed code signal, or
the second arctan discriminator generates the control signal based on correlation results with the cosine subcarrier replica multiplied with the prompt code signal and the cosine subcarrier replica multiplied with the difference of the advanced code signal and the delayed code signal.
14. A method for tracking a received signal with at least one subcarrier, wherein the received signal represents a carrier signal modulated with a code signal and modulated with a subcarrier signal, wherein the method comprises the following independently and cooperatively performed acts of:
tracking the carrier signal with a phase lock loop;
tracking the subcarrier signal with a subcarrier lock loop, which comprises a controllable oscillator and one of an early-minus-late discriminator or a first arctan discriminator for, generating a control signal for the controllable oscillator,
wherein one of
the early-minus-late discriminator generates the control signal based on a difference between correlation results with a replica composed of an early subcarrier signal and a prompt code signal and a replica composed of a late subcarrier signal and theft prompt code signal, or
the first arctan discriminator generates the control signal based on correlation results with a replica composed of a sine subcarrier signal and a prompt code signal and a replica composed of a cosine subcarrier signal and the prompt code signal; and
detecting a delay estimate of the code signal with a detection path, which comprises a second arctan discriminator and a delay estimate detector, wherein the second arctan discriminator generates an input signal for the delay estimate detector based on correlation results with a replica composed of a prompt subcarrier signal and the difference of an early code signal and a late code signal and a replica composed of the prompt subcarrier signal and the prompt code signal or based on correlation results with a replica composed of a cosine subcarrier signal and the difference of the early code signal and the late code signal and a replica composed of a sine prompt subcarrier signal and the prompt code signal.
15. A non-transitory computer readable medium storing instructions executable by a computer processor for tracking a received signal with at least one subcarrier, wherein the received signal represents a carrier signal modulated with a code signal and modulated with a subcarrier signal, comprising the following independently and cooperatively performed instructions to:
track, via the processor, the carrier signal with a phase lock loop;
track, via the processor, the subcarrier signal with a subcarrier lock loop, which comprises a first controllable oscillator and one of an early-minus-late discriminator or a first arctan discriminator, for generating a control signal for the first controllable oscillator,
wherein one of
the early-minus-late discriminator generates the control signal based on a difference between correlation results with a replica of an advanced subcarrier signal and a replica of a delayed subcarrier signal, or
the first arctan discriminator generates the control signal based on correlation results with a cosine subcarrier replica and a sine subcarrier replica; and
track, via the processor, the code signal with a delay lock loop, which comprises a second controllable oscillator and a second arctan discriminator for generating a control signal for the second controllable oscillator,
wherein one of
the second arctan discriminator generates the control signal based on correlation results with a replica of a prompt subcarrier signal multiplied with a prompt code signal and the replica of the prompt subcarrier signal multiplied with the difference of an advanced code signal and a delayed code signal, or
the second arctan discriminator generates the control signal based on correlation results with the cosine subcarrier replica multiplied with the prompt code signal and the cosine subcarrier replica multiplied with the difference of the advanced code signal and the delayed code signal.
16. A non-transitory computer readable medium storing instructions executable by a computer processor for tracking a received signal with at least one subcarrier, wherein the received signal represents a carrier signal modulated with a code signal and modulated with a subcarrier signal, comprising the following independently and cooperatively performed instructions to:
track, via the processor, the carrier signal with a phase lock loop;
track, via the processor, the subcarrier signal with a subcarrier lock loop, which comprises a controllable oscillator and one of an early-minus-late discriminator or a first arctan discriminator, for generating a control signal for the controllable oscillator,
wherein one of
the early-minus-late discriminator generates the control signal based on a difference between correlation results with a replica composed of an early subcarrier signal and a prompt code signal and a replica composed of a late subcarrier signal and the prompt code signal, or
the first arctan discriminator generates the control signal based on correlation results with a replica composed of a sine subcarrier signal and a prompt code signal and a replica composed of a cosine subcarrier signal and the prompt code signal; and
detect, via the processor, a delay estimate of the code signal with a detection path, which comprises a second arctan discriminator and a delay estimate detector, wherein the second arctan discriminator generates an input signal for the delay estimate detector based on correlation results with a replica composed of a prompt subcarrier signal and the difference of an early code signal and a late code signal and a replica composed of the prompt subcarrier signal and the prompt code signal or based on correlation results with a replica composed of a cosine subcarrier signal and the difference of the early code signal and the late code signal and a replica composed of a sine prompt subcarrier signal and the prompt code signal.