LIDAR Amplitude-Frequency Modulation for Single-Measurement Resolution
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Solution Overview
Problem
Current LIDAR systems require multiple measurements and longer times to achieve high-resolution three-dimensional images, especially in automotive applications, due to limitations in frequency modulation, which restricts their ability to capture high-resolution images efficiently.
Innovation Solution
Integrating amplitude modulation into LIDAR systems alongside frequency modulation, allowing for simultaneous frequency and amplitude modulation of laser beams, enabling distance and speed determination from a single measurement through complex Fourier transformation, thereby reducing measurement time and improving resolution.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If multiple measurements are taken with frequency modulation to achieve high resolution, then measurement precision is improved, but measurement time increases significantly
Solution Approach 1:
The patent combines frequency modulation and amplitude modulation into a single measurement process. The laser beam is simultaneously modulated in frequency and amplitude, allowing both distance and speed information to be extracted from one reflected signal through heterodyne detection and Fourier transformation, thereby achieving high-resolution measurements without requiring multiple sequential measurements
Solution Approach 2:
The patent adds amplitude modulation as an additional dimension to the traditional frequency modulation approach. By modulating both frequency and amplitude simultaneously, the system extracts information from multiple signal dimensions (phase from frequency modulation, amplitude modulation depth from amplitude modulation), enabling high-resolution distance and speed measurement in a single measurement cycle
2Measurement precision
If several measurements are performed to determine distance and speed, then measurement precision is improved, but productivity decreases
Solution Approach 1:
The patent merges distance measurement and speed measurement into a single simultaneous operation. Both parameters are determined from one reflected signal by analyzing different aspects of the heterodyne mixed signal through Fourier transformation, eliminating the need for separate measurement sequences and thereby increasing image generation rate while maintaining precision
Solution Approach 2:
The patent enables continuous extraction of both distance and speed information from an ongoing single measurement process. The heterodyne detection continuously produces a mixed signal containing both types of information, allowing real-time determination of multiple parameters without interrupting the measurement flow, thus improving productivity
3Measurement precision
If multiple LIDAR systems are combined to achieve higher resolution, then measurement precision is improved, but device complexity increases significantly
Solution Approach 1:
The patent makes a single LIDAR system multi-functional by enabling it to simultaneously perform both distance measurement and speed measurement with high precision. The single system extracts multiple types of information (distance, speed) from one measurement through dual modulation, eliminating the need for multiple separate LIDAR systems and reducing overall device 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 significantly reduces measurement time, enhances resolution, and is cost-effective with minimal additional hardware requirements, allowing for reliable and fast distance measurement, even at close ranges, while self-checking for errors due to the combined use of both modulation methods.
Implementation Method 1
a laser device (10) which generates a frequency-modulated single-mode laser beam
Implementation Method 2
a controllable optical modulator (30) for amplitude modulation of the frequency-modulated single-mode laser beam
Implementation Method 3
The detector device is designed to superimpose the received signals and thus effect a frequency conversion to a lower intermediate frequency. In this respect, the detector device acts as a frequency mixer
Implementation Method 4
By detecting a portion of the emitted laser light reflected by an object during such a chirp, the distance and also the relative speed can be detected using the optical Doppler effect
Data Source
AI summary
An optical measuring device, in particular for a motor vehicle, includes a laser device designed to generate a single-mode laser beam whose frequency can be modulated and a controllable optical modulator designed for adjustable amplitude modulation of the frequency-modulated single-mode laser beam generated by the laser device. The measuring device also contains a detector device designed to receive part of the frequency-modulated single-mode laser beam generated by the laser device for superimposition with an amplitude- and frequency-modulated single-mode laser beam reflected by an object. An evaluation circuit is designed to transmit the signal superimposed by the detector device into the frequency domain and to determine the distance and speed of an object reflecting the single-mode laser beam.