Mote Network Spatial Mapping Without GPS
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Solution Overview
Problem
Existing wireless sensor networks, such as those used for environmental monitoring, face challenges in mapping unknown environments where GPS signals are unavailable, as they rely on external references for mote positioning.
Innovation Solution
A system of motes that can detect and map their spatial configuration without external references by using signal pulses with unique modulation frequencies, allowing motes to determine their relative positions and store time-stamps and frequencies to create a geometrical map of the environment.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If GPS systems are used to provide position information for each mote in the network, then the position of individual motes can be known, but GPS signal does not reach individual motes in remote environments such as oil wells or sewer systems
Solution Approach 1:
The patent uses signal pulses transmitted between motes as an intermediary mechanism to determine positions. Instead of relying on external GPS satellites, motes exchange signal pulses with each other, and the transmission times of these pulses are used to calculate distances and establish spatial relationships, thereby mediating the position determination problem in GPS-denied environments
Solution Approach 2:
The patent replaces the GPS satellite-based electromagnetic positioning system with a local acoustic or electromagnetic signal pulse exchange system. By substituting the external GPS infrastructure with a distributed mote-to-mote signal transmission mechanism, the system achieves position determination without relying on satellite signals that cannot reach remote environments
2Loss of information
If every mote sends out collected data to every other mote in the network, then substantially every mote knows what is happening in the network, but the device complexity and energy consumption increase
Solution Approach 1:
The patent segments the network communication into different functional groups: some motes are designated as cluster heads that collect and aggregate data from their respective clusters, while other motes only communicate with their cluster head. This segmentation reduces the number of direct communication links from O(n²) to approximately O(n), thereby reducing network complexity while maintaining information distribution
Solution Approach 2:
The patent merges the communication functions of multiple motes through cluster heads. Instead of each mote independently communicating with every other mote, motes within the same cluster merge their communication paths by routing data through their shared cluster head, reducing redundant transmissions and simplifying the network structure
Data Source
AI summary
Some embodiments provide a first mote and a system of motes for detecting a spatially configuration without the need for an external reference. A first mote is configured for wirelessly receiving a plurality of signal pulses transmitted by a plurality of second motes, each second mote transmitting the signal pulse at one particular modulation frequency from a plurality of frequencies of a frequency band. The first mote includes a receiver for determining from a received signal at least one of the plurality of signal pulses and for identifying the particular modulation frequency of the at least one signal pulse. The first mote further includes a clock for generating a time-stamp at which the signal pulse is received and a storage unit for storing the time-stamp and the corresponding identified particular modulation frequency. The system includes a plurality of first motes and second motes.