Spatially Distributed Antennas for TDOA Location Estimation
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Solution Overview
Problem
Existing wireless locationing systems face challenges in accurately estimating the position of a target object due to obstacles blocking radio frequency signals, leading to incomplete ranging processes and reduced location estimation accuracy in both indoor and outdoor environments.
Innovation Solution
The method involves a target object equipped with spatially distributed antennas or transceivers, which receive and process ranging packets from anchor pairs to calculate distance differences based on packet reception times, enabling multiple line-of-sight signal paths and reducing the impact of obstacles through time difference of arrival (TDOA) location estimation techniques.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a single antenna is used on the target object for receiving RF signals from anchors, then the device complexity is reduced, but the location estimation accuracy deteriorates due to signal blockage by obstacles
Solution Approach 1:
The target object is equipped with multiple spatially distributed antennas instead of a single antenna. Each antenna is positioned at different locations on the target object, allowing them to receive RF signals from different spatial paths. This segmentation of the receiving function across multiple spatially separated antennas enables the system to overcome signal blockage by obstacles, as at least one antenna may have a clear line-of-sight path to the anchors, thereby improving location estimation accuracy without significantly increasing device complexity
Solution Approach 2:
The patent introduces a spatial dimension by distributing antennas across different locations on the target object. Instead of relying on a single receiving point, the system utilizes multiple spatial positions to receive RF signals. This dimensional expansion in space allows the target object to capture signals from multiple geometric perspectives, increasing the probability of receiving unblocked signals and improving the robustness of location estimation in obstructed environments
2Measurement precision
If multiple spatially distributed antennas are used on the target object, then the location estimation accuracy is improved by providing additional time difference values, but the device complexity increases
Solution Approach 1:
The target object is equipped with multiple spatially distributed antennas instead of a single antenna. Each antenna is positioned at different locations on the target object, allowing them to receive RF signals from different spatial paths. This segmentation of the receiving function across multiple spatially separated antennas enables the system to overcome signal blockage by obstacles, as at least one antenna may have a clear line-of-sight path to the anchors, thereby improving location estimation accuracy without significantly increasing device complexity
Solution Approach 2:
The multiple antennas on the target object serve themselves by independently receiving RF signals from the anchors. Each antenna autonomously captures signals along its own spatial path, and the target object processes these signals to calculate multiple time difference of arrival (TDOA) values. This self-service capability allows the system to generate multiple location estimation data points without requiring external assistance, improving accuracy while keeping the added complexity manageable
3Reliability
If RF signals are transmitted in obstructed environments, then the basic locationing function is maintained, but the location estimation accuracy is reduced due to signal interference from obstacles
Solution Approach 1:
The patent introduces a spatial dimension by distributing antennas across different locations on the target object. Instead of relying on a single receiving point, the system utilizes multiple spatial positions to receive RF signals. This dimensional expansion in space allows the target object to capture signals from multiple geometric perspectives, increasing the probability of receiving unblocked signals and improving the robustness of location estimation in obstructed environments
Solution Approach 2:
The patent converts the harmful effect of obstacles into a beneficial outcome by using multiple spatially distributed antennas. While obstacles block signals from certain directions, they inadvertently guide the system to utilize antennas positioned in unblocked directions. The system benefits from this spatial diversity, as obstacles that block one antenna's path may not affect others, thereby transforming the harmful blockage into an opportunity to select the best available signal paths for accurate location estimation
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
This approach enhances location estimation accuracy by providing additional time difference values, even in obstructed environments, and increases the probability of obtaining valid calculations, making it more robust than existing methods.
Implementation Method 1
calculate distance differences based on packet reception times, enabling multiple line-of-sight signal paths and reducing the impact of obstacles through time difference of arrival (TDOA) location estimation techniques
Data Source
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AI summary
Systems and methods for locating a position of a target object (110, 210, 410) are provided. The target object can be equipped with a plurality of spatially distributed antennas (220a, 220b, 420a, 420b), and can be located within a network of a plurality of anchors (105, 305, 505) at fixed locations. A plurality of anchor pairs (105a, 105b, 305a, 305b, 505a, 505b) can be assigned. Each anchor pair can include at least two anchors. The anchor pairs can transmit and receive range request, REQ, and range response, RSP, packets (1210,1215.1220). The REQ and RSP packets can be received by the antennas on the target object (1225,1230). Distance differences between the target object to the first anchor and from the target object to the second anchor of each anchor pair can be estimated (1235), based on times at which the REQ packet and the RSP packet are received at the target object. The position of the target object can be estimated based on the distance differences (1240).