Lidar Sensing Arrangements for Velocity Tracking
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Solution Overview
Problem
Current LIDAR systems face challenges in accurately capturing and tracking the velocity of objects within a field of view, particularly in applications requiring continuous and timely detection for safe operation of autonomous vehicles.
Innovation Solution
A LIDAR system that generates a beam with discrete frequencies, using a wavelength dispersive element to sweep the beam over a range of angles, and a processor to determine velocity by analyzing beat frequencies and phase shifts in object signals, allowing for precise distance and velocity calculations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a LIDAR system uses traditional time-of-flight measurement methods, then distance can be determined, but velocity measurement precision is insufficient for reliable continuous tracking
Solution Approach 1:
The patent applies parameter changes by using frequency modulation of the laser beam instead of traditional pulsed time-of-flight measurement. The laser frequency is swept across a range and the beat frequency of the reflected signal is measured, which directly provides velocity information through the Doppler effect while maintaining continuous operation for reliable tracking.
Solution Approach 2:
The patent replaces mechanical scanning systems with a wavelength dispersive element that spatially separates different frequencies of the laser beam. This substitution enables simultaneous measurement of multiple parameters (distance and velocity) without mechanical moving parts, improving reliability for continuous tracking.
2Reliability
If a LIDAR system increases measurement frequency for continuous tracking, then reliability improves, but velocity determination accuracy deteriorates
Solution Approach 1:
The patent uses frequency sweeping of the laser beam combined with beat frequency measurement to simultaneously achieve continuous tracking and high velocity precision. The beat frequency is directly proportional to the Doppler shift, providing accurate velocity measurements even at high measurement frequencies required for continuous autonomous vehicle operation.
3Area of stationary object
If a LIDAR system uses wavelength dispersive element to sweep beam over range of angles, then field of view coverage improves, but device complexity increases
Solution Approach 1:
The wavelength dispersive element serves multiple functions simultaneously: it sweeps the beam across the field of view, spatially separates different frequencies, and enables both distance and velocity measurements. This multi-functionality reduces the need for separate scanning mechanisms and spectral analysis components, thereby reducing overall device complexity despite the expanded field of view capability.
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
Enables reliable and timely detection of object velocities, reducing errors and enhancing monitoring capabilities, particularly in applications like autonomous vehicles where precision tracking is critical.
Implementation Method 1
a wavelength dispersive element positioned to receive at least a portion of the beam and configured to sweep the beam over a range of angles in a field of view (FOV), where each discrete frequency of the beam corresponds to a different angle in the FOV
Implementation Method 2
an interferometer, and a beam splitting device positioned between the light source and the wavelength dispersive element, the beam splitting device configured to receive the beam generated by the light source and split the beam into an object beam that is directed toward the wavelength dispersive element and a reference beam that is directed toward the interferometer, where the interferometer is configured to detect frequencies of the reference beam
Implementation Method 3
determine a velocity of the object based on the beam... calculate a first beat frequency for the first portion of the object signal and calculate a second beat frequency for the second portion of the object signal
Data Source
AI summary
System and methods for Light Detecting and Ranging (LIDAR) are disclosed. The LIDAR system includes a light source that is configured project a beam at various wavelengths toward a wavelength dispersive element. The wavelength dispersive element is configured to receive the beam and direct at least a portion of the beam into a field of view (FOV) at an angle dependent on frequency. The system also includes a detector that is positioned to receive portions of the beam reflected from an object within the FOV and a processor that is configured to control the light source and determine a velocity of the object.