Reconfigurable LNA Resonance Shifting for GPS Front-End Jammers
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current GPS receiver front-end designs face challenges in maintaining low phase noise and high linearity while minimizing power consumption, especially when strong Tx jammer power is present, which can interfere with GPS signal reception.
Innovation Solution
A reconfigurable Low Noise Amplifier (LNA) with an adjustable resonant frequency is implemented, allowing it to shift away from jamming frequencies, thereby enhancing jammer suppression without increasing power consumption.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If high linearity and low noise figure are provided to reject interfering signals and receive desired signals with high sensitivity, then GPS signal reception quality is improved, but power consumption increases
Solution Approach 1:
The LNA resonant frequency is made dynamically adjustable through a tuning circuit that can shift the resonant frequency based on detected jammer signals. This dynamic adaptation allows the system to maintain high GPS signal reception quality by suppressing jammers without requiring continuously high power consumption, as the system only activates enhanced suppression when jammers are detected.
Solution Approach 2:
The invention changes the resonant frequency parameter of the LNA to optimize performance. By adjusting the resonant frequency away from jammer frequencies and toward GPS signal frequencies, the system improves signal reception quality while avoiding the need for continuously high power operation, as tuning is performed adaptively based on environmental conditions.
2Measurement precision
If very low phase noise is maintained in the GPS LO to avoid mixing down to the IF Band through reciprocal mixing, then signal reception accuracy is improved, but power consumption increases excessively
Solution Approach 1:
The LNA is configured to preemptively suppress jammer signals before they can reach the LO and cause reciprocal mixing. By placing the LNA at the front end with adjustable resonant frequency, the system prevents harmful signals from entering the receiver chain, thereby relaxing the LO phase noise requirements and reducing the power consumption needed to maintain signal reception accuracy.
Solution Approach 2:
The LNA acts as an intermediary component between the antenna and the LO, filtering out jammer signals before they can interfere with the LO operation. This intermediary function protects the LO from reciprocal mixing effects, allowing the system to maintain measurement precision without requiring the LO to operate at excessively high power levels for very low phase noise.
3Power
If the LNA resonant frequency is fixed to amplify GPS signals, then signal amplification is optimized, but jammer suppression capability is reduced
Solution Approach 1:
The LNA resonant frequency is made dynamically adjustable rather than fixed. The tuning circuit detects jammer signals and shifts the resonant frequency accordingly, allowing the system to maintain optimized GPS signal amplification while gaining the capability to suppress jammers by tuning the resonant frequency away from jammer frequencies when needed.
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
The reconfigurable LNA effectively suppresses both self and external jammers by dynamically adjusting its resonant frequency, improving GPS signal reception while reducing the stringent requirements on local oscillator noise, thus conserving power.
Implementation Method 1
an LNA with a resonant frequency tuned to provide signal amplification in the GPS L1 band
Data Source
AI summary
A reconfigurable LNA for increased jammer rejection is disclosed. An exemplary embodiment includes an LNA having a tunable resonant frequency, and a detector configured to output a control signal to tune the resonant frequency of the LNA to increase jammer suppression. An exemplary method includes detecting if a jammer is present, tuning a resonant frequency of an LNA away from the jammer to increase jammer rejection if the jammer is present, and tuning the resonant frequency of the LNA to a selected operating frequency if the jammer is not present.