Co-located Transmitter Diversity for Multipath Positioning
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Solution Overview
Problem
In urban and indoor environments, existing positioning systems face challenges in accurately estimating the position of receivers due to multipath effects, which cause errors in range measurements and impair the precision of trilateration processing, especially when line-of-sight signals are blocked by obstacles.
Innovation Solution
The use of co-located transmitters, which are installed at close proximity to each other, allows for the reception of ranging signals and the estimation of the receiver's position based on the relationship between information extracted from these signals and the locations of the transmitters, enabling the differentiation and weighting of line-of-sight and multipath signals to improve positioning accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If traditional trilateration is used with geographically-distributed transmitters, then position estimation can be performed, but accuracy deteriorates when line-of-sight signals are blocked by buildings and multipath effects occur
Solution Approach 1:
The patent segments the transmitter system into multiple co-located transmitters (at least two transmitters positioned at the same or nearly the same location) that transmit signals with different characteristics. This segmentation allows the receiver to process multiple independent signal paths and identify line-of-sight signals even when traditional single-transmitter approaches fail due to multipath interference.
Solution Approach 2:
The patent introduces a new dimension to the positioning problem by using multiple transmitters at the same location with different signal characteristics (such as different frequencies, codes, or modulation schemes) rather than relying solely on geographic distribution. This additional dimension provides redundancy and enables signal discrimination to combat multipath effects.
2Measurement precision
If co-located transmitters are used to differentiate line-of-sight and multipath signals, then position estimation accuracy is improved, but device complexity increases
Solution Approach 1:
The patent merges multiple transmitters at the same physical location to create a co-located transmitter array. This combining approach allows the system to transmit multiple signals with different characteristics from the same location, enabling the receiver to identify line-of-sight paths by comparing signals that have traveled different paths to reach the same receiver.
Solution Approach 2:
The patent uses multiple copies of transmitters at the same location, each transmitting similar but distinguishable signals. These copied transmitters provide redundant signal paths that allow the receiver to identify and select the line-of-sight signal by comparing arrival times and signal characteristics, thereby improving accuracy without requiring complex individual transmitter designs.
3Measurement precision
If multiple co-located transmitters transmit ranging signals, then line-of-sight signals can be identified amidst multipath interference, but processing time increases
Solution Approach 1:
The patent implements preliminary action by having co-located transmitters send multiple ranging signals with different characteristics before the final position calculation. The receiver uses these pre-sent signals to identify line-of-sight paths through comparison of arrival times and signal properties, enabling faster and more accurate position estimation by eliminating the need for complex post-processing of ambiguous signals.
Data Source
AI summary
Systems and methods for estimating a position of receiver using sets of two or more transmitters that share one or more common characteristics with each other. The systems and methods may estimate the position of the receiver using signals that were transmitted from a different transmitter in a set of co-located transmitters.