Optical Distance Measurement Using Time-Division Multiplexing
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Solution Overview
Problem
Existing optical distance measurement methods for driverless vehicle navigation, such as those using LIDAR sensors, face challenges in rapid pulse transmission and focusing measurements on specific areas, leading to inefficiencies and increased time requirements due to aliasing effects and the need to constantly measure the entire area rather than just the area of interest.
Innovation Solution
The method employs time-division multiplexing to assign specific measurement windows and time segments to receiving elements, allowing for simultaneous evaluation of multiple receiving elements by a single evaluation unit, enabling faster data transmission and focusing on a specific distance range by optimizing the use of transmission and reception elements.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If measurement pulses are emitted quickly in succession, then productivity increases, but aliasing effects occur causing measurement errors
Solution Approach 1:
The patent divides the receiving elements into multiple groups, where each group is assigned to a specific evaluation unit. This segmentation allows parallel processing of reflected pulses from different spatial regions, enabling higher pulse emission rates without aliasing effects because each evaluation unit independently processes its assigned group's signals.
Solution Approach 2:
The patent introduces a spatial dimension to the processing architecture by assigning different receiving element groups to different evaluation units. This dimensional expansion allows simultaneous independent processing of multiple pulse groups, resolving the aliasing problem while maintaining high productivity.
2Area of stationary object
If the entire area is constantly measured, then measurement coverage is complete, but time consumption increases
Solution Approach 1:
The patent segments the total measurement area into multiple sub-areas, each corresponding to a group of receiving elements assigned to a specific evaluation unit. This allows the system to process different spatial regions in parallel, maintaining complete coverage while reducing total measurement time through simultaneous independent evaluation of multiple areas.
Solution Approach 2:
The patent enables continuous measurement of the entire area by having multiple evaluation units process different receiving element groups simultaneously and continuously. Each evaluation unit continuously evaluates its assigned group without waiting for others, maintaining uninterrupted measurement coverage across all areas.
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 reduces the time required for distance measurement, allows for focused measurement on a specific area of interest, and achieves higher resolution by efficiently utilizing the evaluation unit, thereby improving the speed and accuracy of optical distance measurement in driverless navigation.
Implementation Method 1
They are based on the time-of-flight principle, whereby a scanning sensor, in particular a LIDAR (short for 'light detection and ranging') sensor, is used for the measurement. This sensor periodically emits measurement pulses that are reflected by objects, and the reflected measurement pulses are detected. By determining the travel time of the measurement pulses from the sensor to the objects and back, the distance to these objects can be deduced using the speed of light.
Implementation Method 2
the reflected measurement pulses are detected
Implementation Method 3
a scanning sensor, in particular a LIDAR (short for 'light detection and ranging') sensor, is used for the measurement
Data Source
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AI summary
A method (100) for optical distance measurement is proposed, wherein the method comprises the emission of measurement pulses by means of transmitting elements and the reception of reflected measurement pulses by means of receiving elements. Each receiving element is associated with a transmitting element. The method comprises the definition (101) of at least a first group of receiving elements comprising N receiving elements, wherein the transmitting elements associated with the first group of receiving elements each emit at least one measurement pulse for distance measurement (102), wherein emitted measurement pulses are reflected by at least one object in a measurement area (19) (104), and wherein the receiving elements of the first group receive the reflected measurement pulses (105).For the evaluation (106) of the reflected measurement pulses received by the receiving elements of the first group, a single evaluation unit is used by means of time-division multiplexing (107) (108), wherein each receiving element of the first group is assigned a measurement window (14) with a measurement window duration (14a) for receiving the measurement pulse by means of the assigned transmitting element (109) and a time interval (15a, 15b, 15c, 16a, 16b, 17a, 17b, 17c) is assigned for the transmission (111) of data to the evaluation unit (110), wherein the time interval (15a, 15b, 15c, 16a, 16b, 17a, 17b, 17c) is shorter than the measurement window duration (14a). The evaluation unit is only actively connected to the receiving elements of the first group during the respective assigned time periods (15a, 15b, 15c, 16a, 16b, 17a, 17b, 17c).