Modem-Based Movement Detection for Low-Power IoT Positioning
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Solution Overview
Problem
Existing wireless communication devices face challenges in accurately detecting movement while minimizing power consumption, particularly in low-cost IoT devices, as relying on frequent GNSS wake-ups leads to high power consumption and less reliable positioning information.
Innovation Solution
A method where the modem estimates relative movement and sends a notification to the operating system if the movement exceeds a threshold, allowing the OS to decide on additional actions, such as activating GNSS, using a hierarchical approach that includes IMU, modem, and potentially GNSS for precise positioning.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If GNSS systems are activated at regular intervals to provide accurate location updates, then positioning accuracy is improved, but power consumption increases significantly
Solution Approach 1:
The positioning system is segmented into multiple levels: low-power sensors (accelerometer, motion sensors) for continuous monitoring and high-power GNSS for accurate positioning. The system segments the operation into movement detection phase (low power) and positioning phase (high power), activating GNSS only when movement is detected or location is actually needed.
Solution Approach 2:
The system performs preliminary movement detection using low-power sensors before activating the high-power GNSS system. By detecting movement in advance through accelerometer and motion sensors, the system prepares to activate GNSS only when necessary, avoiding unnecessary high-power consumption during stationary periods.
2Use of energy by moving object
If low-power add-on sensors like motion and accelerator sensors are used for positioning, then power consumption is reduced, but positioning reliability decreases
Solution Approach 1:
The system merges data from multiple sensor types (accelerometer, motion sensors, and GNSS) to create a hybrid positioning solution. Low-power sensors provide continuous movement data while GNSS provides accurate position fixes, and their combined information creates a reliable positioning system that maintains accuracy while reducing overall power consumption through intelligent sensor fusion.
Solution Approach 2:
The low-power motion and accelerometer sensors act as intermediaries between the device state and the high-power GNSS system. These intermediary sensors detect movement and trigger GNSS activation only when necessary, mediating between continuous monitoring requirements and power consumption constraints while maintaining positioning reliability.
3Reliability
If the operating system wakes up at regular intervals to check for movement, then movement detection capability is maintained, but power consumption increases
Solution Approach 1:
The modem performs self-service movement detection by autonomously monitoring its own movement state using low-power sensors and independently deciding when to activate the operating system. The modem serves itself by detecting movement and triggering OS wakeup only when necessary, eliminating the need for frequent regular OS wakeups and significantly reducing power consumption while maintaining movement detection capability.
Data Source
AI summary
A wireless communication device (100) and method therein for movement detection are disclosed. The wireless communication device comprises at least a modem (110) and an operating system (120). The wireless communication device (100) estimates by the modem (110) a relative movement of the wireless communication device. If the estimated relative movement is larger than a threshold, the modem (110) sends a movement notification to the operating system (120). The operating system (120) decides which action to be taken for the wireless communication device.