Indoor Locator Nodes Using Radio Phase Shift Tracking
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Solution Overview
Problem
Existing location tracking systems for emergency responders, such as firefighters, are ineffective indoors due to reliance on GPS signals, which have limited effectiveness inside buildings, and require pre-deployment of beacons or sensors.
Innovation Solution
A system of locator nodes that use radio transceivers to measure distance by phase shift of radio waves, allowing accurate tracking of emergency responders' positions without the need for GPS or pre-deployment of equipment, using a combination of low and high-frequency signals to determine precise distances and positions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If GPS-based tracking is used, then outdoor location tracking is effective, but indoor tracking effectiveness deteriorates
Solution Approach 1:
The patent introduces radio frequency signals as an intermediary medium for location determination indoors, replacing GPS satellite signals. The system uses transmitted radio signals and their reflections to calculate positions through time-of-flight measurements, enabling reliable indoor tracking where GPS fails.
Solution Approach 2:
The system changes the fundamental parameter of signal source from external satellite-based GPS signals to local device-generated radio frequency signals. This parameter change allows the system to adapt from outdoor satellite dependency to indoor autonomous signal generation and processing.
2Reliability
If beacon and sensor deployment is performed, then indoor location tracking can be achieved, but system complexity and setup time increase
Solution Approach 1:
The patent enables location tracking devices to determine positions autonomously by having each device transmit radio signals and process the reflections itself. This self-service approach eliminates the need for external beacons or sensors, reducing system complexity while maintaining indoor tracking capability.
Solution Approach 2:
Instead of using fixed infrastructure (beacons/sensors) that emit signals for devices to detect, the system inverts the approach by having each mobile device emit signals and detect their own reflections. This inversion eliminates infrastructure requirements while achieving the same location determination goal.
3Measurement precision
If high frequency signals are used for distance measurement, then measurement precision improves, but signal wavelength becomes shorter than distance causing phase ambiguity
Solution Approach 1:
The patent segments the distance measurement into two components: integer wavelengths (N) determined by counting signal cycles, and fractional wavelength (φ) determined by phase shift measurement. This segmentation allows the system to use high-frequency signals for precise fractional measurement while using lower-frequency reference signals to resolve the integer wavelength component, eliminating phase ambiguity.
Solution Approach 2:
The system introduces a lower-frequency reference signal as an intermediary to resolve the phase ambiguity problem. This reference signal has a wavelength longer than the measurement distance, allowing unambiguous determination of the integer number of wavelengths, which then combines with the high-frequency signal's phase measurement for complete distance determination.
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
Enables real-time tracking and location mapping of emergency responders indoors without the need for beacon setup or prior knowledge of the building, maintaining accurate location information and allowing for effective incident management.
Implementation Method 1
measure distance by phase shift of radio waves
Implementation Method 2
receiving at the first node a return signal received from the remote node
Implementation Method 3
generating a second signal, the second signal having a frequency that is a multiple of a frequency of the first signal
Implementation Method 4
the second signal being synchronized with the first signal and being phase-locked to the received return signal
Data Source
AI summary
A system, method and device for tracking at least one of objects, vehicles and personnel at a scene by determining a distance between a first node and a remote node are disclosed. In some embodiments, a method is provided for tracking emergency responders at an emergency incident scene by determining a distance between nodes positioned on the emergency responders and enabling mapping of the relative positions of the emergency responders.