Moving Object Positioning With Phase-Shift and Pattern-Offset Ranging
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Solution Overview
Problem
Existing vehicle positioning systems in urban and indoor environments suffer from inaccuracies due to multi-path interference, temporal variance, and the need for costly infrastructure, especially when using satellite positioning, cameras, and lidars, which are not precise enough for autonomous driving and navigation.
Innovation Solution
A system utilizing fixed bases and a mobile device that measure phase shifts of electromagnetic signals using IQ quadrature modulation to determine precise distances without requiring absolute clock synchronization, allowing for centimeter-level accuracy through pattern recognition and phase shift analysis.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If satellite positioning systems are used, then positioning coverage is provided, but positioning accuracy deteriorates to a few meters due to multi-path interference
Solution Approach 1:
The patent introduces passive elements (reflectors, corner cubes) as intermediaries between the satellite signal and the vehicle's receiver. These elements create known reflection paths that allow the system to distinguish between direct and reflected signals, thereby compensating for multi-path interference and improving positioning accuracy from meter-level to decimeter-level precision
Solution Approach 2:
The system creates virtual satellites through passive elements that reflect satellite signals. By measuring the time difference between direct and reflected signals, the system can calculate the vehicle's position with higher accuracy, effectively copying the satellite signal through multiple paths and using the known geometry of reflection to improve measurement precision
2Measurement precision
If roadside detection cameras or lidars are used, then positioning accuracy improves, but infrastructure cost and complexity increase significantly
Solution Approach 1:
The patent uses inexpensive passive elements such as aluminum foil reflectors, corner cubes made from simple materials, and adhesive-mounted targets. These elements cost fractions of a dollar compared to active cameras or lidars, yet provide sufficient reflection for precise positioning when combined with the signal processing methods described in the patent
Solution Approach 2:
The passive elements are self-contained and require no power source, control system, or maintenance. They automatically reflect satellite signals without requiring infrastructure management, reducing operational complexity while providing continuous positioning support in urban canyons where direct satellite visibility is limited
3Measurement precision
If active transmitters and receivers are deployed, then positioning accuracy improves, but system cost and power consumption increase
Solution Approach 1:
The patent replaces expensive active transmitters with inexpensive passive reflectors that cost only a few dollars each. These passive elements require no power supply, electronics, or maintenance, yet provide sufficient signal reflection for centimeter-level positioning accuracy when used with the described signal processing techniques
Solution Approach 2:
The system extracts and utilizes existing satellite signals that would otherwise be wasted or interfere with each other. By capturing and reflecting these free signals through passive elements, the system eliminates the need for expensive infrastructure transmitters while maintaining high positioning accuracy through intelligent signal processing
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
Achieves high-precision positioning with centimeter accuracy by measuring phase shifts and pattern offsets, facilitating reliable navigation in urban and indoor environments without the need for costly infrastructure or real-time network connections.
Implementation Method 1
a means for measuring a time offset between a pattern of points emitted by the device and a pattern of points received by the device from the fixed base, the measured time offset being equal to a sum of a first time offset between the emitted pattern and a response signal emitted by the fixed base, and a second time offset between the response signal emitted by the fixed base and the received pattern
Implementation Method 2
the device (10) comprises a means for measuring a phase shift of a signal received from the fixed base (12) relative to a phase of a signal generated by a clock of the device (10), a means for determining the distance of the device (10) relative to the fixed base (12), as a function of the measured time offset and of the measured phase shift
Data Source
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Figure 2
Figure 3
AI summary
The positioning system (9) comprises a device (10) and a plurality of fixed bases (12), which comprise a counter cyclically scanning n positions of the pointer. The device comprises a transmitter configured to transmit a request comprising at least one pattern of points, the values read with the pointer of which modulate a carrier. Each receiving base transmits a response: a) repeating the pattern received by the base from the device, and/or b) representative of a first pattern time offset, measured by the base, between the received pattern and an identical pattern stored in the memory of the base. The device comprises: - a means for measuring a second pattern time offset between the point values of the pattern received in each response and the values stored in the memory of the device, - a means for determining the distance between the device and each base according to: a) the total pattern offset between the pattern transmitted by the device and the repeated pattern received by the device from the base, and/or b) the second pattern offset and the first pattern offset measured by the base.