Sensor Node Positioning via Reference Node Transmit Power Control
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
RF-based sensor network location services face accuracy issues due to sensitivity to external environmental conditions, limiting their effectiveness in providing precise location data, especially in shadow areas.
Innovation Solution
A method and system where reference nodes in a sensor network vary their transmission power to send location information signals to sensor nodes, allowing the sensor nodes to calculate their position and associated error using a grid formed by the absolute coordinates of multiple reference nodes, reducing network traffic and improving accuracy compared to traditional triangulation methods.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If RF-based location services are used, then location data can be obtained in diverse environments, but accuracy in determined position is poor due to sensitivity to external environmental conditions
Solution Approach 1:
The patent introduces reference nodes as intermediary elements that provide known location information to sensor nodes. These reference nodes act as mediators between the environmental conditions and the location determination process, enabling accurate positioning by comparing received signal strength against known reference points rather than relying solely on direct RF propagation characteristics that are sensitive to environmental variations
Solution Approach 2:
The patent changes the parameter being measured from direct signal strength interpretation to relative signal strength comparison across multiple reference nodes. By transforming the location determination from an absolute measurement (prone to environmental interference) to a relative comparison (more robust), the system maintains accuracy despite environmental variations affecting absolute signal levels
2Measurement precision
If traditional triangulation methods are used, then location can be determined using signal strength, but network traffic increases and accuracy is limited
Solution Approach 1:
The patent applies partial action by having reference nodes transmit location information signals only when requested by sensor nodes, rather than continuously broadcasting. This on-demand transmission approach reduces overall network traffic while still providing necessary location data for accurate positioning
Solution Approach 2:
The patent implements preliminary action by having reference nodes pre-calculate and store location information that can be quickly transmitted when needed. The grid formation and location data preparation are done in advance, enabling rapid response to sensor node requests without requiring complex real-time calculations across the network
Data Source
AI summary
A method and apparatus for a sensor network having a plurality of reference nodes and a sensor node that enables the sensor node to compute a relative position through transmission range control and position mapping. In transmission range control, each reference node sends location information signals to the sensor node while varying transmission power. In position mapping, the sensor node forms a grid of vertical and horizontal lines corresponding to a square area defined by the neighboring reference nodes, extracts coordinates of intersections in the grid belonging to a shared region between areas covered by location information signals of various transmit power levels from the neighboring reference nodes, and sets the position of the sensor node to the middle points of the extracted coordinates. Each reference node sends a location information signal when a random backoff time expires after reception of a location information request signal.