Avalanche Transceiver Inertial Step Navigation
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Solution Overview
Problem
Conventional avalanche transceivers face challenges in providing precise and reliable guidance to buried victims due to signal overlap, environmental interference, and inaccurate distance information, especially in rough terrain, leading to uncertainty and potential incorrect behavior during searches.
Innovation Solution
The integration of an inertial sensor unit with a step duration determination unit and a step length determination unit, which allows for independent navigation by determining step duration and length using acceleration data, even when radio signals fail, and correcting for rotary movements and falls, enabling more accurate and stable guidance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If multiple avalanche transceivers send out carrier signals simultaneously, then the search coverage area is improved, but signal overlap and interference occur making detection difficult
Solution Approach 1:
The patent implements periodic transmission of carrier signals with alternating phases (0度和180度反相信号) at standardized intervals (e.g., 457 kHz). This periodic action allows multiple transceivers to operate simultaneously while enabling the receiver to distinguish between different sources through phase discrimination, thus maintaining search coverage while reducing signal interference.
2Measurement precision
If magnetic field distance measurement is used for navigation, then target distance information is provided, but distance information becomes erratic at great distances or with rocky ground
Solution Approach 1:
The patent introduces an inertial sensor unit as an intermediary measurement system. This unit uses accelerometers and gyroscopes to track the searcher's movement and calculate distance through integration of acceleration data. This intermediary approach provides continuous distance information that is not affected by magnetic field distortions from rocky ground or signal attenuation at great distances.
3Productivity
If conventional pedometer step detection is used, then step frequency can be determined, but step detection fails in rough terrain or with heavy footwear
Solution Approach 1:
The patent implements dynamic step detection using inertial sensors that continuously monitor acceleration patterns. The system adapts to varying terrain conditions by analyzing the dynamic characteristics of each step, including amplitude, frequency, and pattern recognition. This dynamic approach allows reliable step detection whether the searcher is wearing heavy footwear, moving through rough terrain, or varying their walking pace.
4Measurement precision
If radio signals are used for navigation, then magnetic field distance and angle can be determined, but signal detection fails during time intervals due to drift or environmental influences
Solution Approach 1:
The patent implements prior cushioning by continuously running inertial navigation in parallel with radio signal detection. When radio signals are available, the inertial system is calibrated and runs alongside. When radio signals fail due to drift or environmental influences, the inertial system seamlessly takes over, providing continuous navigation without interruption. This prepares the system in advance for potential signal failures.
5Measurement precision
If magnetic field lines are followed for search navigation, then direction to buried subject is provided, but several buried subjects cause magnetic field overlap making search impossible
Solution Approach 1:
The patent segments the navigation function into independent inertial and magnetic field components. The inertial sensor unit independently tracks position and direction without being affected by magnetic field overlaps from multiple buried subjects. This segmentation allows the searcher to maintain navigation capability even when magnetic field information becomes unreliable due to multiple signal sources.
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
This solution provides more precise and faster target guidance to buried individuals, reducing uncertainty and stress for searchers by using inertial data to determine step length and direction, even in the absence of reliable radio signals, and accounting for terrain variations and user movements.
Implementation Method 1
an inertial sensor unit (7), which on the output side has a step duration determination unit (11) for determining a step duration tS and a step length determination unit (16) for determining a first step length lSB
Implementation Method 2
in a gyroscope (9) a control angle and an acceleration value aearth are determined in an acceleration sensor (10)
Implementation Method 3
The acceleration value aearth is supplied in parallel via a bandpass filter (12) to a first edge detector (13a)
Implementation Method 4
a first edge detector (13a) for rising edges and to a second edge detector (13b) for falling edges
Implementation Method 5
A time difference determination unit (14) for detecting a step start and an associated step end receives the output signals of the edge detectors (13a, 13b) in order to determine the step duration tS from the time difference
Implementation Method 6
a magnetic field distance unit (3) for determining a magnetic field distance DH from received radio signals
Implementation Method 7
a magnetic field angle unit (4) for determining a magnetic field angle from the field vector direction of received radio signals
Data Source
AI summary
In an avalanche transceiver comprising a transmit/receive unit (1), at least one transmit/receive antenna (2), a magnetic field distance unit (3) and a magnetic field angle unit (4), the magnetic field distance unit (3) and the magnetic field angle unit (4) are connected on the output side via a search navigation unit (5) to a display (6), wherein the avalanche transceiver further comprises an inertial sensor unit (7) which is connected on the output side via a step duration determination unit (11) and a step length determination unit (16) to the search navigation unit (5).