Common Coordinate-Quartz Loop for GNSS Shock Mitigation
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Solution Overview
Problem
Global navigation satellite systems (GNSS) measurements are adversely affected by shock and vibration, leading to decreased accuracy and reliability, particularly in applications like construction vehicles where antennas and receivers are subjected to significant mechanical disturbances.
Innovation Solution
A method and apparatus that utilize a navigation receiver and antenna subjected to vibration and shock, employing a local oscillator based on a quartz crystal oscillator frequency, generating intermediate signals, and using phase-lock loops with channel correlators, accumulators, and loop filters to track and correct phase and frequency errors, thereby mitigating the impact of shock and vibration on GNSS measurements.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If the antenna and receiver are mounted on construction vehicles for mobile operation, then the system gains mobility and operational flexibility, but the measurements are adversely affected by shock and vibration, leading to decreased accuracy
Solution Approach 1:
The patent implements feedback mechanisms through phase-lock loops that continuously monitor and correct for shock and vibration effects on the antenna and receiver. The system uses feedback signals from accelerometers and other sensors to compensate for mechanical disturbances in real-time, maintaining measurement accuracy despite mobile operation conditions.
Solution Approach 2:
The patent introduces intermediary components such as isolators, dampers, and stabilization mechanisms between the construction vehicle platform and the GNSS antenna/receiver system. These intermediaries reduce the transmission of shock and vibration from the vehicle to the measurement equipment, thereby maintaining accuracy during mobile operation.
2Device complexity
If traditional GNSS tracking systems are used in mobile applications, then the system structure remains simple, but shock and vibration cause loss of lock and measurement errors
Solution Approach 1:
The patent employs dynamic tracking algorithms and adaptive filtering techniques that adjust tracking parameters in real-time based on detected vibration and shock levels. The system dynamically modifies loop bandwidths, integration times, and other parameters to maintain reliable tracking under varying mobile operation conditions without requiring overly complex hardware.
Solution Approach 2:
The patent implements preliminary correction measures by pre-characterizing the vibration profiles of construction vehicles and pre-configuring compensation parameters. Acceleration data is collected and processed in advance to predict and compensate for upcoming shock events, maintaining tracking reliability before disturbances occur.
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 solution effectively reduces the impact of shock and vibration on GNSS measurements, enhancing the accuracy and reliability of location determination by stabilizing the local oscillator frequency and correcting phase errors, thus maintaining precise coordinate calculations even under dynamic conditions.
Implementation Method 1
A local oscillator generates a local oscillator signal having a local oscillator frequency; the local oscillator signal is based on the quartz crystal oscillator signal, and the local oscillator frequency is based on the quartz crystal oscillator frequency
Implementation Method 2
For each individual sequence of digital signals in the group of sequences of digital signals, a phase of the individual sequence of digital signals is tracked with an individual channel phase-lock loop
Implementation Method 3
An individual channel correlator, operating at a first clock frequency, generates a sequence of in-phase correlation signals and a sequence of quadrature-phase correlation signals
Data Source
AI summary
A navigation receiver operably coupled to an antenna can determine location by receiving and processing radiofrequency navigation signals from global navigation satellites.The navigation receiver includes a quartz crystal oscillator that serves as a reference frequency source for a local oscillator signal that is mixed with the radiofrequency navigation signals to generate intermediate signals at intermediate frequencies lower than the radiofrequencies.In particular applications, the quartz crystal oscillator and the antenna are subjected to vibration and shock.A shift in the frequency or phase of the intermediate signals can result, and performance of phase-lock loops can degrade.Performance is improved with a phase-lock loop that processes a combination of individual channel control signals and common control signals.The common control signals are generated by a common coordinate-quartz loop discriminator that processes signals generated from the entire group of navigation signals received by the navigation receiver.