GNSS Receiver Interference Management via Adaptive Signal Switching
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Solution Overview
Problem
Global navigation satellite system (GNSS) receivers experience performance degradation due to interference from external communication devices, such as modems, which generate harmonic elements that interfere with the GNSS frequency band, leading to inaccurate position calculations and reduced accuracy.
Innovation Solution
A GNSS receiver system that includes an internal signal processor, a switching circuit, and a control circuit to manage interference by blocking decoding operations when interference is detected and adjusting transmission power levels based on the frequency of the interference signal, ensuring accurate satellite signal processing even in the presence of interference.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If the modem circuit transmits communication signals, then communication function is provided, but harmonic elements interfere with the GNSS receiver frequency band
Solution Approach 1:
A blanking signal is introduced as an intermediary control mechanism between the modem circuit and GNSS receiver. The control circuit receives the blanking signal and uses it to determine whether to block satellite signal processing, thereby mediating the conflict between communication transmission and GNSS reception by adding a decision layer that considers both functions
2Measurement precision
If the GNSS receiver processes satellite signals, then position information is obtained, but performance degrades due to interference from communication devices
Solution Approach 1:
The system dynamically adjusts the processing of satellite signals based on real-time conditions. The control circuit continuously monitors the blanking signal frequency and dynamically determines whether to block or process satellite signals, making the GNSS receiver adaptive to changing interference conditions rather than using a fixed blocking approach
Solution Approach 2:
The control circuit changes the operational parameter of signal processing by comparing the blanking signal frequency against a reference value. When the frequency exceeds the reference value, the system changes from blocking mode to processing mode, using parameter comparison to dynamically adjust system behavior and maintain position accuracy under varying interference conditions
3Adaptability or versatility
If the decoding operation is blocked to avoid interference, then communication function is maintained, but satellite signal processing is interrupted
Solution Approach 1:
The system implements feedback by continuously monitoring the frequency of blanking signals and using this information to make informed decisions about satellite signal processing. The control circuit feeds back the comparison result between blanking signal frequency and reference value to determine whether to block or process signals, creating a closed-loop control system that optimizes both communication and positioning functions based on real-time conditions
Data Source
AI summary
A global navigation satellite system (GNSS) receiver includes an internal signal processor configured to perform an internal signal processing operation on a satellite signal to generate satellite information, a switching circuit configured to transmit the satellite signal to the internal signal processor, and a control circuit configured to receive a blanking signal from an external communication device instructing that the internal signal processing operation is to be blocked, and configured to output control information for reducing transmission power of the external communication device and to control the switching circuit to transmit the satellite signal to the internal signal processor regardless of the blanking signal when a frequency at which the blanking signal is received exceeds a reference value.