Positioning Device Mode Switching Using Digital Map Data
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing positioning devices face inaccuracies in determining position due to multi-path distortion and limited satellite signal reception, particularly in environments like tunnels or underground parking, where the switch from absolute to relative positioning modes can result in inaccurate starting positions, affecting subsequent calculations.
Innovation Solution
The positioning device employs a digital map database with threshold distances to switch between absolute and relative positioning modes proactively, using three-dimensional information to predict and mitigate multi-path distortion and signal loss, ensuring accurate positioning by timing mode changes based on geographical object proximity and satellite visibility.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the positioning device switches from absolute to relative positioning mode when satellite signals are lost, then positioning can continue in challenging environments, but the starting position for relative positioning may be inaccurate due to multi-path distortion, affecting subsequent position calculations
Solution Approach 1:
The system performs preliminary assessment of satellite signal quality and multi-path distortion risk before switching modes. By evaluating signal characteristics and environmental factors in advance, the device determines the optimal switching moment, ensuring the last absolute position before transition remains accurate and serves as a reliable starting point for relative positioning
Solution Approach 2:
The system continuously monitors satellite signal quality, number of visible satellites, and environmental conditions to provide feedback on positioning reliability. This feedback mechanism enables dynamic mode selection, switching from absolute to relative positioning only when signal conditions deteriorate below acceptable thresholds, thereby maintaining overall positioning accuracy while ensuring availability
2Measurement precision
If the positioning device uses more satellites to improve position accuracy, then the determined position becomes more accurate, but the device becomes more complex and requires more computational resources
Solution Approach 1:
The system uses more than the minimum four satellites when available to improve accuracy, but dynamically adjusts the number of satellites used based on signal quality and environmental conditions. This partial action approach applies enhanced processing only when beneficial, avoiding unnecessary computational complexity when standard conditions suffice
Solution Approach 2:
The system changes processing parameters dynamically based on environmental conditions, adjusting the number of satellites used, weighting factors for different satellites, and computational algorithms according to signal quality, satellite geometry, and detected multi-path distortion levels, thereby optimizing accuracy while managing complexity
3Measurement precision
If the positioning device switches modes based on signal quality, then positioning accuracy is maintained, but the switching decision becomes more complex requiring additional judgment logic
Solution Approach 1:
The system implements self-service through automated environmental assessment and mode selection. The positioning device independently evaluates satellite signal characteristics, counts visible satellites, detects multi-path distortion indicators, and autonomously determines optimal positioning mode without requiring external intervention or complex manual decision logic
Solution Approach 2:
Continuous feedback on signal quality metrics enables automated switching decisions. The system monitors parameters such as number of visible satellites, signal-to-noise ratio, and geometric dilution of precision, using this feedback to trigger mode transitions when predefined thresholds are crossed, simplifying control logic through rule-based automation
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 positional accuracy by switching modes before significant errors occur, utilizing digital map data to predict satellite signal quality and geographical interference, thereby maintaining accurate navigation even in challenging environments.
Implementation Method 1
The positioning device is arranged to receive these signals and compute the travel time of such a radio signal based on the timing information comprised by the radio signal and a measured time of arrival of the radio signal using a clock comprised by the positioning device. The travel time is usually 65 - 85 milliseconds. Based on the travel time, the distance of the positioning device to the satellite can be computed
Data Source
Figure 1~2
Figure 3~4
Figure 5
AI summary
The invention relates to a positioning device (PD) arranged to determine a position using an absolute positioning system and a relative positioning system. The positioning device is arranged to work in a first mode, in which the position is determined using the absolute positioning system and possibly the relative positioning system, and in a second mode, in which the position is determined using the relative posit ioning system and possibly the absolute positioning system. In the first mode the absolute positioning system being weighted more heavily than in the second mode and the positioning device is arranged to switch from the first to the second mode. The positioning device (PD) has access to a digital map database (DMD, 3DMD) and the switch from the first to the second mode is decided based on at least the determined posit ion in combination with information stored in the digital map database (DMD, 3DMD).