Position Detection System Asynchronous Phase Difference Measurement
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Solution Overview
Problem
Existing position detection systems face challenges in achieving high accuracy and simplicity due to the need for precise synchronization of fixed stations and limited range of position identification, particularly when using pulse signals and rectangular service areas.
Innovation Solution
A position detection system comprising a mobile station and at least three fixed stations with asynchronously operating reference clock circuits, where the mobile station transmits trigger and first radio signals, and the reference station transmits second radio signals, allowing for phase difference calculations to determine the mobile station's position without requiring synchronization between stations, thereby improving distance resolution and reducing system complexity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If pulse signals are used for position detection, then measurement resolution can be improved by decreasing pulse width, but occupied bandwidth increases
Solution Approach 1:
The patent changes the fundamental parameter from pulse width (time domain) to phase difference (frequency domain). By measuring phase differences of continuous wave signals instead of pulse widths, the system achieves high measurement resolution without increasing bandwidth occupation. The phase difference measurement allows for precise distance calculation using the relationship between phase shift and propagation distance.
2Measurement precision
If pulse signals are used for position detection, then measurement resolution can be improved by decreasing pulse width, but complicated synchronization processing is required
Solution Approach 1:
The patent transitions from time-domain pulse synchronization to frequency-domain phase difference measurement. Each fixed station independently measures the phase difference between its local reference clock and the received signal phase, eliminating the need for complex inter-station synchronization. The mobile station transmits signals based on its own reference clock, and each fixed station autonomously performs phase comparison without requiring synchronized operation with other fixed stations.
3Measurement precision
If phase difference measurement is performed using reference clocks, then distance resolution is improved, but synchronization between fixed stations becomes necessary
Solution Approach 1:
The patent segments the measurement process so that each fixed station independently performs phase difference measurement using its own reference clock. Instead of requiring centralized synchronization, each station autonomously measures the phase difference between the received signal and its local reference, dividing the complex synchronization task into independent parallel operations that can be performed without inter-station coordination.
4Measurement precision
If rectangular service area is used for position identification, then position can be identified within the area, but location and usage conditions are limited
Solution Approach 1:
The patent creates a universal position detection system that can identify positions anywhere within the coverage area of the fixed stations, not limited to rectangular geometries. The phase difference measurement method works with any spatial arrangement of fixed stations and can determine positions in two-dimensional space, making the system adaptable to various service area shapes and usage scenarios including outdoor mobile communication and indoor positioning.
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
The system achieves high-accuracy position detection with improved distance resolution using narrowband radio signals, simplifies system building by eliminating synchronization needs, and reduces costs by allowing fixed stations to operate with the same reference clock frequency and potentially function as both fixed and reference stations.
Implementation Method 1
a radio signal transmission circuit (2C, 3C) and a transmission antenna (2D, 3F). Each fixed station (4-6) includes a radio signal reception circuit (4C-6C) and a reception antenna (4D-6D)
Implementation Method 2
Each fixed station receives the first radio signal and extracts a first phase difference between a carrier included in the first radio signal and a reference clock of each fixed station
Data Source
AI summary
A position detection system includes a mobile station, a reference station, fixed stations to, and a server. The mobile station transmits a first radio signal S1 and the reference station transmits a second radio signal S2 multiple times. Each of the fixed stations extracts a first phase difference based on the first radio signal S1 and extracts second phase differences based on the second radio signals S2. The server calculates time variations of the second phase differences based on the multiple second phase differences to calculate a third phase difference. The server cancels phase offset by the respective fixed stations using phase difference information between the mobile station and the respective fixed stations and phase difference information between the reference station and the respective fixed stations and acquires distance information between the respective fixed stations and the mobile station to calculate the position of the mobile station.