UWB Positioning via Phase and Time Angle of Arrival
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Solution Overview
Problem
Existing wireless positioning and tracking systems, including GPS and UWB, face limitations in accuracy, precision, and cost-effectiveness, especially in indoor environments and areas with obstacles, due to environmental interference and the limitations of time measurement accuracy in UWB time-of-flight based systems.
Innovation Solution
A system and method using phase and time angle of arrival of ultrawideband signals to determine the position of a tag antenna relative to multiple base antennas, incorporating differential phase and time of arrival measurements to improve accuracy and precision, and utilizing compact, low-power integrated UWB transceivers like the DW1000 for cost-effectiveness.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If UWB time of flight based systems are used for positioning, then positioning capability is provided, but positioning accuracy and precision are limited due to ultimate limitations in time measurement accuracy
Solution Approach 1:
The patent transitions from one-dimensional time-of-flight measurement to two-dimensional measurement by incorporating phase angle of arrival (AOA) measurements. This dimensional expansion allows the system to determine both the distance (range) and direction (angle) of the tag, thereby achieving more precise positioning without being limited by the inherent time measurement accuracy constraints of UWB pulse signals.
Solution Approach 2:
The patent introduces phase angle of arrival measurements as an intermediary parameter to complement time of flight measurements. By using the phase information of the UWB signal across multiple antennas, the system creates an additional measurement dimension that mediates between the limited time measurement precision and the required high positioning accuracy, enabling accurate position determination through combined range and angle data.
2Measurement precision
If existing wireless data communication signal systems such as WiFi, Bluetooth and Zigbee are used for positioning, then short range positioning is achieved, but positioning accuracy degrades due to environmental interference in crowded or obstacle filled areas
Solution Approach 1:
The patent changes the fundamental parameter used for positioning from communication signal strength (as in WiFi, Bluetooth, Zigbee) to UWB pulse signal phase and time angle measurements. This parameter change enables the system to achieve higher positioning accuracy while being less susceptible to environmental interference, as the UWB pulse signals with their wide bandwidth and precise timing capabilities can penetrate and resolve signals through obstacles more effectively than narrowband communication signals.
3Measurement precision
If GPS and satellite based systems are used for positioning, then long range tracking is provided, but positioning effectiveness and accuracy are reduced in sheltered or indoor environments
Solution Approach 1:
The patent replaces satellite-based mechanical/optical positioning systems with a wireless UWB-based positioning system that operates on electromagnetic pulse signals. This substitution enables positioning capability to be transferred from outdoor satellite environments to indoor environments, as the UWB pulse signals can be transmitted and received through walls and other obstacles, providing accurate positioning in sheltered areas where GPS signals cannot penetrate.
4Measurement precision
If UWB systems with multiple base antennas are used for phase and time angle measurement, then positioning precision is improved, but system complexity increases
Solution Approach 1:
The patent segments the positioning system into functional modules: a set of base antennas for signal reception, a processor for measuring phase and time angle of arrival, and a processor for calculating position. This segmentation allows the system to achieve high positioning precision through multiple antennas while managing complexity by distributing functions across separate processing units and using standardized UWB transceiver modules.
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
Enhances positioning accuracy and precision, reduces errors, and provides a cost-effective solution for UWB position location, enabling reliable tracking in challenging environments by disambiguating phase angles and combining with range measurements for 3D location determination.
Implementation Method 1
measuring a phase and time of arrival of an ultrawideband signal transmitted by the tag antenna at a first base antenna and a second base antenna
Data Source
AI summary
A system and method can determine the position of a tag antenna relative to a plurality of spaced apart fixed base antennae using ultrawideband signals by using an angle of arrival determined by time of arrival of an ultrawideband signal from the tag antenna to disambiguate a differential phase angle of arrival measured from the differential phase of the ultrawideband signal between the two base antennae. Accordingly, a non-ambiguous phase angle of arrival of the ultrawideband signal from the tag antenna may be used with a range of the tag antenna measured by one or more methods including by 2-way time of flight, to determine the position of the tag antenna relative to the base antennae. The system and method can also use a plurality of pairs of antennae to determine a 3D position of the tag antenna.