Phase-Based Positioning Without Reference Nodes or Tight Sync
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Solution Overview
Problem
Existing one-way localization systems require a cost-effective and simplified manner to remove the phase offsets of devices in a one-way localization scheme, and the use of additional reference node or device is cost intensive and resource intensive, and the phase offsets of devices are not effectively addressed in existing one-way localization systems.
Innovation Solution
A system and method for phase-based positioning that utilizes a pair of anchors, such as a transceiver and receiver or transmitter and transceiver, to perform phase difference of arrival measurements without requiring precise synchronization or an additional reference device, by establishing a known phase relationship between signal fragments to cancel out unknown phase offsets.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a reference device is used to remove phase offsets in one-way localization, then measurement precision is improved, but device complexity and cost increase
Solution Approach 1:
The patent extracts and eliminates the need for a separate reference device by using the receiver device itself to perform phase measurements on both the first signal fragment from the target device and the second signal fragment from the transceiver device. The phase offset removal is achieved through phase differencing at the receiver, removing the complex reference device component while maintaining measurement precision.
Solution Approach 2:
The receiver device is given multiple functions: it serves as both the positioning target reference and the measurement device. By measuring phases of both signal fragments and calculating the phase difference, the receiver device universally performs the role that would traditionally require separate reference and measurement devices, simplifying the overall system.
2Measurement precision
If precise synchronization is implemented between transceiver and receiver, then measurement precision is improved, but device complexity and resource requirements increase
Solution Approach 1:
The patent converts the harmful effect of unknown phase offsets and lack of synchronization into a beneficial solution by using phase differencing. The phase offset φ_receiver appears in both phase measurements and cancels out when the difference is calculated: (φ_target - φ_receiver) - (φ_transceiver - φ_receiver) = φ_target - φ_transceiver. This eliminates the need for precise synchronization while maintaining measurement accuracy.
Solution Approach 2:
The patent changes the measurement parameter from absolute phase measurements (which require precise synchronization) to relative phase difference measurements. By measuring the phase difference between two signal fragments at the receiver, the system achieves positioning accuracy without requiring the transceiver and receiver to be precisely synchronized, as the common phase offset cancels out in the differencing operation.
3Measurement precision
If additional reference nodes are deployed for positioning, then measurement precision is improved, but loss of energy and resource consumption increase
Solution Approach 1:
The patent merges the functions of the reference node and the measurement receiver into a single device. The receiver device uses the known position information of both the transceiver device and itself to estimate the target device position, eliminating the need for an additional reference node. This consolidation reduces wireless capacity consumption and energy usage while maintaining positioning accuracy through the phase differencing method.
Data Source
AI summary
A system for phase-based positioning is provided including at least one target device to transmit a first signal fragment, and at least one transceiver device to receive the first signal fragment from the target device, to measure a phase of the first signal fragment, and to transmit a second signal fragment with a phase having a known phase relationship with the measured phase of the first signal fragment. The system includes at least one receiver device to receive the first signal fragment from the target device, to measure the phase of the first signal fragment, to receive the second signal fragment from the transceiver device, and to measure the phase of the second signal fragment. The system includes at least one processing unit to calculate a phase difference between the phase of the first and second signal fragments to estimate position information of the target device.