Pseudo-Random Signal Correlation for Boundary Detection
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Solution Overview
Problem
Existing systems for detecting whether a mobile working device is inside or outside a defined area, such as those using boundary conductors, face challenges in accurately determining the device's position, especially when switched on or in noisy conditions, and require complex signal processing and higher currents.
Innovation Solution
A method using a pseudo-random signal transmitted through a perimeter conductor, where a detection signal is received and correlated with a reference signal to determine the device's position, allowing for accurate identification of being inside or outside the area with minimal computing effort and lower current usage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If alternating current of two or more frequencies is used in the boundary conductor, then position detection accuracy is improved, but device complexity and computing effort increase
Solution Approach 1:
The patent changes the signal parameter from multi-frequency alternating current to pseudo-random binary signal. This allows position detection to be achieved through correlation processing rather than complex multi-frequency signal analysis, reducing computational complexity while maintaining detection accuracy
Solution Approach 2:
The mobile working device generates a local copy of the pseudo-random signal and compares it with the received signal through correlation. This copying approach enables accurate position detection without requiring complex multi-frequency signal processing
2Reliability
If higher current is used in the boundary conductor, then magnetic field strength increases and detection reliability improves, but energy consumption increases
Solution Approach 1:
The patent changes from continuous high-current alternating signal to lower-current pseudo-random binary signal. The correlation-based detection method maintains reliability even with lower signal strength, reducing energy consumption in the boundary conductor
Solution Approach 2:
The correlation process provides feedback on signal quality and position detection confidence. This allows the system to maintain reliable detection with optimized current levels rather than continuously high current
3Measurement precision
If complex signal processing is used to determine position, then measurement precision improves, but computing effort and processing time increase
Solution Approach 1:
The device creates a local copy of the known pseudo-random signal and performs correlation with the received signal. This copying method enables efficient position determination through straightforward correlation calculation rather than complex signal processing algorithms
Solution Approach 2:
The pseudo-random signal is periodic and repeats known patterns. This periodicity allows the correlation process to efficiently determine position by matching signal segments without requiring continuous complex processing of entire signal sequences
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 enables reliable detection of the device's position with high accuracy and low computational demands, even in noisy conditions, without the need for prior programming or synchronization, and can function with lower magnetic field strengths.
Implementation Method 1
An electric current flows through the boundary wire, which marks the outer boundary of the work area. The resulting electrical or magnetic field can be detected by a suitable sensor in the mobile working device
Implementation Method 2
The mobile working device is equipped with detection coils in which an alternating voltage is induced by the alternating magnetic field generated around the boundary wire
Data Source
Figure 1~2
Figure 3a~4
Figure 5
AI summary
The invention relates to a method for detecting a position with respect to a defined area (4), in particular in a mobile working machine, comprising the following steps: providing (S1) a current signal in a boundary conductor (3), which surrounds the defined area (4), in accordance with a boundary signal that is provided, the boundary signal (BS) corresponding to a pseudo-accident signal; receiving (S3) a detection signal of a magnetic field generated in the boundary conductor (3) by the current signal; generating a reconstructed boundary signal from the detection signal; providing (S4) a reference signal (RS) which has a bit pattern corresponding to the boundary signal (BS) provided; carrying out (S5) a correlation method in order to determine a time-based correlation offset between the reference signal and the reconstructed boundary signal and a correlation value (KKF) between the reference signal (RS) and the reconstructed boundary signal (BS), which are displaced in relation to each other by the correlation offset determined; and determining (S7) a position inside or outside the defined area (4) as a function of the correlation value (KKF) determined.