Capacitive Batch Pulse Counting for One-Way Time-of-Flight
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Solution Overview
Problem
Existing mobile ad hoc networks face challenges in accurately determining node positions and synchronization due to the reliance on expensive and precise clock sources for two-way time-of-flight techniques, which are prone to errors from reflection issues and 1/r4 losses, especially when nodes are uncooperative or in indoor environments.
Innovation Solution
Implementing capacitive batch counters to count pulses in electromagnetic signals, allowing for effective counting of pulses at ultra-high frequencies without the need for precise clock synchronization, using integrating circuits to reset and count batches of pulses, reducing the number of pulses counted and enabling accurate distance calculations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If two-way time-of-flight techniques are used for position determination, then distance measurement capability is improved, but measurement precision deteriorates due to reflection issues and 1/r4 losses
Solution Approach 1:
The patent inverts the conventional two-way time-of-flight approach by implementing one-way time-of-flight measurement. Instead of having the target node transmit a response signal that returns to the source node (which suffers from reflection and path loss), the source node transmits a signal and measures the time until the target node's antenna capacitively charges and triggers a response. This inversion eliminates the harmful reflection issues and 1/r4 losses associated with traditional two-way methods.
Solution Approach 2:
The patent introduces an intermediary mechanism - the capacitive charging of the target node's antenna - as a mediator between signal transmission and response generation. The transmitted signal capacitively charges the target antenna, and when the voltage reaches a threshold, it triggers the response transmission. This intermediary capacitive coupling mechanism enables accurate time-of-flight measurement without requiring the target to actively receive and process the signal, thereby avoiding reflection and path loss problems.
2Measurement precision
If precise clock sources are used for time-of-flight measurement, then measurement precision is improved, but device cost increases
Solution Approach 1:
The patent implements a self-service mechanism where the target node's own antenna capacitance serves as the timing reference. The transmitted signal capacitively charges the target antenna, and the voltage buildup rate (determined by the antenna's inherent capacitance and the transmitted power) automatically determines when the response is triggered. This self-charging mechanism eliminates the need for precise clock sources at both nodes, as the timing is inherently determined by the physical capacitance of the antenna itself, which is a stable and reproducible parameter.
Solution Approach 2:
The patent changes the fundamental parameter used for timing from clock frequency to capacitive voltage buildup. Instead of using high-precision clock sources and counting cycles, the system measures the time required for the antenna capacitance to charge to a threshold voltage level. This parameter change from temporal (clock cycles) to electrical (voltage threshold) enables the use of much lower-cost components while maintaining measurement precision.
3Productivity
If batch counting is implemented for pulse counting, then counting speed is improved, but measurement precision may worsen due to batching
Solution Approach 1:
The patent segments the pulse counting process into batches, where each batch corresponds to a fixed number of pulses that charge the integrating capacitor to the threshold voltage. The counter increments by the batch size (e.g., 16 or 32) rather than by one for each individual pulse. This segmentation enables the counter to operate at much lower speeds while still accurately tracking the total number of pulses, as each batch represents a known quantity of pulses that occurred during the integration period.
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 accurate position measurement with centimeter or millimeter precision at longer distances, reducing costs by using less precise clock sources and avoiding reliance on signal reflections and multi-path problems, suitable for forming coherent arrays and supporting operations like beamforming and synchronization.
Implementation Method 1
accumulating the electrical signal to generate a voltage using an integrating circuit
Implementation Method 2
converting the pulses contained in the electromagnetic signals into an electrical signal that identifies at least some of leading or trailing edges of the pulses
Data Source
AI summary
A method includes receiving electromagnetic signals containing pulses. The method also includes converting the pulses contained in the electromagnetic signals into an electrical signal that identifies at least some of leading or trailing edges of the pulses. The method further includes repeatedly (i) accumulating the electrical signal to generate a voltage using an integrating circuit and (ii) resetting the integrating circuit in response to the voltage of the integrating circuit meeting or exceeding a threshold voltage. In addition, the method includes providing a count value identifying a number of times that the voltage of the integrating circuit meets or exceeds the threshold voltage. Each time the voltage of the integrating circuit meets or exceeds the threshold voltage is representative of a specific number of pulses received in the electromagnetic signals.