Optoelectronic Sensor Dual Sampling Memory Unambiguity Range
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Solution Overview
Problem
Conventional pulse-based distance measurement methods in optoelectronic sensors are limited by the unambiguity range, which restricts the measurement range and pulse repetition frequency, leading to difficulties in accurately detecting distances beyond this range and potential interference from late echoes from far objects.
Innovation Solution
The implementation of two sampling memories with partially overlapping recording regions and phase coding to synchronize and differentiate between early and late echoes, allowing for extended measurement range without compromising response time or repetition rate, and enabling detection beyond the unambiguity range.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If the pulse repetition frequency is increased to improve response time, then the measurement range is limited by the unambiguity range
Solution Approach 1:
The recording of reception signals is segmented across multiple sampling memories. The first sampling memory records signals for a first time interval, and the second sampling memory records signals for a second time interval that extends beyond the unambiguity range. This segmentation allows the system to capture both near and far echoes without ambiguity, resolving the contradiction between fast response and extended range.
2Length of stationary object
If the unambiguity range is extended to increase measurement range, then the pulse repetition frequency must be reduced
Solution Approach 1:
The patent introduces an additional dimension in the form of multiple sampling memories operating with different time intervals. Instead of extending a single recording interval (one-dimensional approach), the system uses parallel recording channels with overlapping intervals, effectively adding a temporal dimension to the measurement process. This allows simultaneous capture of multiple distance ranges without reducing pulse repetition frequency.
3Length of stationary object
If multiple sampling memories with overlapping recording regions are used to extend measurement range, then device complexity increases
Solution Approach 1:
The patent merges the recording functions of multiple sampling memories into a unified evaluation process. The first and second sampling memories record signals in overlapping time intervals, and the control unit combines these recordings to produce a comprehensive distance measurement. This merging approach allows the system to achieve extended measurement range while managing complexity through integrated signal processing rather than fully independent subsystems.
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 significantly increases the measurement range while maintaining response time and repetition rate, allowing for accurate detection of both near and far objects by effectively distinguishing and recording echoes from both regions, thus overcoming the limitations of conventional methods.
Implementation Method 1
a light transmitter for transmitting a transmission light pulse into the monitoring area, a light receiver for generating a reception signal from the light pulse remitted or reflected by objects in the monitoring area
Implementation Method 2
determine a reception point in time from the reception signal and, from that, the distance of the object by means of a light time of flight method
Data Source
AI summary
A distance-measuring optoelectronic sensor (10) uses two sampling memories for detection of objects in a monitoring zone (20). The sensor (10) has a light transmitter (12) for transmitting a transmission light pulse (16) into the monitoring area (20), a light receiver (26) for generating a reception signal from the light pulse (22) remitted by objects in the monitoring area (20), a control and evaluation unit (32) configured to determine a reception point in time from the reception signal and the distance of the object by means of a light time of flight method, and a first and second sampling memory (34a, 34b) having a plurality of memory cells each for storing a section of the reception signal. Partially overlapping recording regions are used, with each alternately recording a reception signal for a longer duration than a time interval between two successive transmission light pulses (16).