Satellite Navigation Signal Constant Envelope Multiplexing
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Solution Overview
Problem
Existing satellite navigation systems face challenges in multiplexing multiple signals on the same frequency band, leading to increased complexity and power efficiency issues, as well as distortion due to non-linear amplification, which affects signal quality and performance.
Innovation Solution
A method for generating and receiving satellite navigation signals using constant envelope multiplexing of four signal components on two frequencies, allowing for flexible power allocation and distortion-free transmission by modulating in-phase and quadrature-phase baseband signals with orthogonal carrier phases.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If multiple signals are multiplexed on the same frequency band, then the frequency band utilization is improved, but the satellite payload complexity increases
Solution Approach 1:
The patent combines multiple DSSS signals into a single constant envelope signal through constant envelope multiplexing. Multiple signal components are processed and merged into one composite signal that maintains constant envelope properties, allowing them to share a common high-power amplifier without requiring separate amplifiers for each signal, thus improving frequency band utilization while controlling payload complexity.
Solution Approach 2:
The invention creates a universal multiplexing framework that can handle multiple different DSSS signals with different power allocations using a common processing architecture. The constant envelope multiplexing technique provides a multi-functional solution that works for various signal types and power requirements, making the satellite payload more versatile rather than requiring dedicated hardware for each signal type.
2Use of energy by moving object
If the HPA works in the non-linear saturated region to improve power efficiency, then the power efficiency is improved, but the signal distortion increases
Solution Approach 1:
The patent changes the envelope parameter of the multiplexed signal to maintain constant envelope. By ensuring the combined signal has constant amplitude (constant envelope), the signal can pass through the non-linear saturated HPA without suffering from amplitude distortion, phase distortion, or spectral regrowth. This parameter change allows the HPA to operate at maximum efficiency while preserving signal integrity.
3Reliability
If separate transmitting antenna and amplifier are used for different service signals, then the signal quality is maintained, but the total power, cost, volume and quality of the satellite payload increase
Solution Approach 1:
The patent merges multiple service signals into a single constant envelope multiplexed signal that can be transmitted through a common high-power amplifier. This combining approach allows multiple signals to share one amplifier instead of requiring separate amplifiers for each signal, significantly reducing the total power consumption, cost, volume, and complexity of the satellite payload while maintaining signal quality through the constant envelope property.
4Reliability
If AltBOC modulation technique is used for CEM, then the constant envelope is achieved, but the application flexibility is reduced due to equal power requirement
Solution Approach 1:
The patent introduces dynamic power allocation capability into the constant envelope multiplexing system. Unlike fixed equal-power schemes, this invention allows the power distribution among multiple DSSS signals to be dynamically adjusted according to different service requirements. The system can allocate different power levels to different signals while still maintaining the constant envelope property of the combined signal, thereby achieving both reliability and adaptability.
Data Source
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AI summary
The application relates to the satellite navigation signal, generating method, generating device, receiving method and receiving device. The navigation satellite signal generating device includes a baseband signal generator, a multiplexed signal generator and a modulator. The baseband signal generator is provided to generate a first baseband signal S1, a second baseband signal S2, a third baseband signal S3, and a forth baseband signal S4. The multiplexed signal generator is provided to set an amplitude and a phase of an in-phase baseband component and an amplitude and a phase of a quadrature-phase baseband component of a signal into which the first baseband signal S1, the second baseband signal S2, the third baseband signal S3 and the forth baseband signal S4 are multiplexed, so as to generate a multiplexed signal with constant envelope. The modulator is provided to modulate the multiplexed signal with constant envelope to a radio frequency, so as to generate the navigation satellite signal. The first baseband signal S1 and the second baseband signal S2 are modulated to a first carrier frequency f1 with carrier phases orthogonal to each other, and the third baseband signal S3 and the forth baseband signal S4 are modulated to a second carrier frequency f2 with carrier phases orthogonal to each other.