GPS Receiver Power Control for Date Acquisition
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Solution Overview
Problem
GPS receiver apparatuses consume significant power when acquiring date information from GPS signals, especially when using small batteries, due to the need for continuous radio wave reception until the first sub-frame is received, which reduces operational time.
Innovation Solution
A GPS receiver apparatus with a reception unit, synchronization controller, and power controller that synchronizes with GPS signals to acquire specific information from a specific sub-frame with lower power consumption by stopping and restarting power supply based on predetermined timing signals, allowing for efficient power management during data acquisition.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of information
If continuous radio wave reception is performed to acquire date information from the first sub-frame, then the date information can be acquired, but power consumption increases significantly
Solution Approach 1:
The patent applies preliminary action by first acquiring time information from the second sub-frame before attempting to acquire date information from the first sub-frame. The controller uses the time information to calculate when the first sub-frame will be transmitted and waits for that specific timing, rather than continuously receiving. This preliminary acquisition of time information enables subsequent targeted reception, reducing overall power consumption while ensuring date information is acquired when needed.
Solution Approach 2:
The patent implements periodic action by receiving radio waves only at specific intervals rather than continuously. The controller calculates the transmission timing of the first sub-frame based on time information from the second sub-frame, then receives radio waves only at that calculated timing. This periodic reception approach maintains the ability to acquire date information while significantly reducing power consumption compared to continuous reception.
2Loss of information
If continuous reception is maintained to ensure first sub-frame acquisition, then date information can be obtained, but operational time of the device is reduced
Solution Approach 1:
The patent uses preliminary action by first obtaining time information from the second sub-frame, then using that information to calculate the exact timing when the first sub-frame will be transmitted. This preliminary step allows the device to enter a low-power state and wake up only at the necessary moment to acquire date information, thereby extending operational time while ensuring date information is successfully acquired.
Solution Approach 2:
The patent applies periodic action by receiving radio waves only at specific calculated intervals based on the transmission timing of the first sub-frame, rather than maintaining continuous reception. This approach ensures date information is acquired when needed while significantly extending the operational time of battery-powered devices by minimizing the duration of high-power reception operations.
3Use of energy by moving object
If power supply is stopped immediately after time correction, then power consumption is reduced, but date information cannot be acquired
Solution Approach 1:
The patent applies preliminary action by first acquiring time information from the second sub-frame and using it to calculate the transmission timing of the first sub-frame. Only after this preliminary calculation is complete does the controller stop power supply to the tuner circuit and signal processing circuit. This ensures that date information acquisition is not compromised, as the controller knows exactly when to reactivate power supply to capture the first sub-frame.
Solution Approach 2:
The patent implements periodic action by stopping power supply after initial time correction, then reactiving it only at the calculated transmission timing of the first sub-frame. This periodic power supply approach reduces overall power consumption while ensuring that date information is acquired at the appropriate moment when the first sub-frame is transmitted.
Data Source
AI summary
The first reception operation is started in response to an acquisition request. Power supply to a RF unit and a demodulator is stopped after synchronization with the GPS signal is established. Based on information acquired from a sub-frame in the GPS signal, a time point to start the second reception operation is determined. Elapsed time is counted using a counter clock synchronized with transmission timing of the navigation message, while a reception frequency of the satellite, a PRN code unique to the satellite, and a frequency and a phase of the PRN code are retained. When the elapsed time arrives at the time point, the power supply to the RF unit and the demodulator is restarted.