Distance measurement by means of an active optical sensor system
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing lidar systems are susceptible to interference from other light sources, leading to issues such as ghost targets and increased risk of eye damage due to high power emissions, and require high stability and cost-effective frequency modulation.
Innovation Solution
A method using an active optical sensor system that splits a frequency comb into two spectrally coded emission channels, employing two heterodyne measurements to coherently detect reflected portions, reducing interference susceptibility by encoding the channels and using separate heterodyne detectors with different reference pulse sequences.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If high power emissions are used in existing lidar systems, then distance measurement capability is improved, but eye damage risk increases
Solution Approach 1:
The frequency comb is segmented into two separate spectrally coded emission channels, each processed by independent heterodyne detection paths. This segmentation allows the system to achieve accurate distance measurement through coherent detection while using lower overall power, thereby reducing eye damage risk while maintaining measurement capability.
2Device complexity
If conventional lidar systems operate without spectral coding, then device complexity is reduced, but susceptibility to interference from other light sources increases
Solution Approach 1:
The system changes the spectral parameter of the emitted light by using spectrally coded emission channels with distinct frequency ranges. Each channel is assigned a specific frequency spectrum, enabling the system to distinguish between different light sources and reject interference, thereby improving reliability while maintaining manageable complexity through systematic spectral assignment.
3Reliability
If frequency comb splitting into multiple channels is implemented, then interference susceptibility is reduced, but device complexity increases
Solution Approach 1:
The system implements multi-functionality by using a single frequency comb source that serves multiple emission channels simultaneously. Each channel performs distance measurement independently with its own heterodyne detection path, allowing the system to achieve interference rejection through spectral diversity while reusing the common frequency comb generation mechanism, thus balancing reliability improvement with controlled complexity.
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 accurate and precise distance measurement with reduced interference, allowing for safer operation and cost-effective implementation in vehicles by using less expensive electronics.
Implementation Method 1
an initial pulse sequence with an initial frequency spectrum corresponding to a frequency comb is generated by means of a laser source
Implementation Method 2
A first distance of the object from the sensor system is determined by means of at least one first heterodyne measurement based on the first reference pulse sequence and based on portions of the first pulse sequence reflected by the object
Data Source
AI summary
A method for distance measurement by means of an active optical sensor system is disclosed, comprising: an initial pulse sequence with an initial frequency spectrum, which corresponds to a frequency comb, is generated using a laser source. Based thereon, a first pulse sequence and a first reference pulse sequence with a first frequency spectrum, which corresponds to a first part of the frequency comb, as well as a second pulse sequence and a second reference pulse sequence with a second frequency spectrum, which corresponds to a second part of the frequency comb, are generated. A first distance of the object is determined using a first heterodyne measurement based on the first reference pulse sequence and reflected portions of the first pulse sequence and a second distance is determined using a second heterodyne measurement based on the second reference pulse sequence and reflected portions of the second pulse sequence.