Shared-LO GNSS Receiver Architecture for Multi-Band Interference Control
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Solution Overview
Problem
Existing GNSS receivers require separate receivers for each frequency band, leading to high power consumption due to the need for multiple frequency synthesizers, and face interference issues from harmonic blockers and unwanted frequency spurs.
Innovation Solution
A system with multiple receivers sharing a single local oscillator, switching between modes based on signal characteristics to conserve power and mitigate interference, using discrete-time superheterodyne mixers and sample reordering circuits to achieve superheterodyne operation without costly filters.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If separate receivers are used for each frequency band, then each band can be tracked independently, but power consumption increases due to multiple frequency synthesizers
Solution Approach 1:
The patent merges multiple frequency synthesizers into a single shared synthesizer that provides local oscillation signals to multiple receivers simultaneously. This combining approach eliminates redundant frequency generation hardware, reducing power consumption while maintaining the ability to track multiple frequency bands independently through separate receiver chains that share the common local oscillator resource.
Solution Approach 2:
The single frequency synthesizer is designed to serve multiple functions by generating local oscillation signals for different frequency bands on demand. The synthesizer can be controlled to provide appropriate frequency outputs to different receivers based on which bands need to be tracked, making one device perform the work of multiple dedicated synthesizers while consuming less power.
2Adaptability or versatility
If multiple local oscillators are used for different receivers, then each receiver operates independently, but interference from harmonic blockers and frequency spurs increases
Solution Approach 1:
By merging the local oscillation source into a single synthesizer, the patent eliminates the interference problems caused by multiple independent oscillators. The single synthesizer generates coherent signals that avoid harmonic blocker interference and frequency spur issues that arise when multiple oscillators operate in proximity, while receiver independence is maintained through separate signal processing chains.
3Use of energy by moving object
If a single local oscillator is shared among all receivers, then power consumption is reduced, but signal characteristics may not suit all frequency bands simultaneously
Solution Approach 1:
The system dynamically controls the single shared frequency synthesizer to adjust its output frequency based on which receivers need to operate at any given time. The synthesizer can be tuned to provide appropriate local oscillation frequencies to different receivers as needed, allowing power savings from sharing while maintaining adaptability to different signal requirements through dynamic frequency switching and selective activation of receiver chains.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
Reduces power consumption and suppresses interference, enhancing signal quality by sharing local oscillators and using discrete-time mixers to handle multiple frequency bands efficiently.
Implementation Method 1
a local oscillator configured to generate a local oscillation signal
Implementation Method 2
a primary mixer configured to mix an input signal with a reference signal at a reference frequency to generate a first output signal
Implementation Method 3
a divider configured to divide the reference signal into a second reference signal at a second frequency
Implementation Method 4
a secondary mixer coupled to the primary mixer and configured to mix the first output signal and the second reference signal at the second frequency
Data Source
AI summary
There is provide a system comprising a plurality of receivers, each receiver comprising a local oscillator configured to generate a local oscillation signal, a primary mixer configured to mix an input signal with a reference signal at a reference frequency to generate a first output signal, a divider configured to divide the reference signal into a second reference signal at a second frequency and a secondary mixer coupled to the primary mixer and configured to mix the first output signal and the second reference signal at the second frequency. In a first mode, the reference signal for a first of a plurality of the receivers is the local oscillation signal from the first receiver and, in a second mode, the reference signal is the local oscillation signal from another of the plurality of receivers.