Ground Transmitter Clock Model for Precise Positioning
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Solution Overview
Problem
Existing local positioning systems face challenges in achieving precise positioning without relying on base stations, GPS synchronization, or atomic clocks, particularly in environments with limited GPS access and high accuracy requirements.
Innovation Solution
A system utilizing ground transmitters that transmit ranging signals with code modulation, allowing a rover to determine its position by measuring code phases from satellites or other transmitters, and generating clock models based on transmitter clocks to achieve centimeter-level accuracy without a base station or GPS synchronization.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a base station is used for clock error corrections, then positioning accuracy is improved, but device complexity and operational difficulty increase due to precise location requirements and surveying needs
Solution Approach 1:
The patent extracts the clock error correction function from the base station and implements it directly in each ground transmitter through individual clock models. This eliminates the need for a separate base station while maintaining positioning accuracy, as each transmitter independently corrects its own clock errors using its received satellite signals.
Solution Approach 2:
Each ground transmitter serves itself by generating its own clock model based on satellite signal measurements. The transmitter independently determines its clock bias and drift without requiring external base station intervention, enabling autonomous operation and simplifying system deployment.
2Reliability
If GPS time synchronization is used, then clock errors are mitigated, but positioning accuracy deteriorates due to residual errors in carrier-phase and code-phase signals
Solution Approach 1:
The patent changes the clock synchronization approach from direct GPS time locking to generating individual clock models for each transmitter. By modeling clock bias and drift as separate parameters rather than forcing synchronization to GPS time, the system eliminates residual errors in carrier-phase and code-phase measurements while maintaining reliable time reference.
3Measurement precision
If atomic clocks are used in each ground transmitter, then clock drift is negligible for precise positioning, but cost and size increase making them impractical for commercial applications
Solution Approach 1:
The patent replaces expensive atomic clocks with inexpensive quartz oscillators in each ground transmitter. By implementing individual clock models that account for quartz clock drift characteristics, the system achieves precise positioning without requiring costly atomic timekeeping, making the solution practical for commercial deployment.
4Adaptability or versatility
If base station is moved to different locations, then system adaptability improves, but time consumption increases due to required resurveying for precise location determination
Solution Approach 1:
Each ground transmitter independently determines its own clock parameters through satellite signal measurements without requiring external base station surveys. This self-calibration capability allows transmitters to be deployed and moved freely without time-consuming resurveying, as each unit autonomously establishes its timing reference.
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
Enables precise positioning within a one-meter level of accuracy using ground transmitters, eliminating the need for base stations and GPS synchronization, and reducing costs by avoiding the use of atomic clocks.
Implementation Method 1
The ground transmitter transmits a ranging signal with code modulation
Implementation Method 2
The ground transmitter measures a code phase of the received satellite signal
Data Source
AI summary
A precise positioning method and system is disclosed wherein at least one ground transmitter is used for transmitting a ranging signal with code modulation. The at least one ground transmitter is configured to receive a signal from at least one satellite and a second ground transmitter. The at least one ground transmitter measures a code phase of the received signals. The measured code phase information is communicated to a rover that is associated with a user. The rover can determine the user's precise position based on the measured code and/or carrier phase information and a clock correction model.