Lidar Beam Power Distribution for Solar Noise
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Solution Overview
Problem
Lidar systems face challenges in achieving non-uniform beam power distribution across a field of regard, which affects the accuracy and efficiency of distance measurement, particularly due to solar background noise and the need for eye-safe operation.
Innovation Solution
A lidar system with a light source and scanner that dynamically varies the power of output beams based on their orientation relative to the field of regard, using optical elements to split and direct light into multiple beams with different power levels and angular separations, allowing for increased power towards the center and reduced power towards the edges.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If uniform beam power is used across the field of regard, then the system structure is simple, but the signal-to-noise ratio is reduced due to solar background noise at certain angles
Solution Approach 1:
The patent applies local quality by assigning different power levels to different regions of the field of regard. Specifically, beams directed toward the solar zenith angle region are assigned reduced power to minimize solar background noise interference, while beams in other regions maintain higher power levels. This regional differentiation optimizes the signal-to-noise ratio without requiring complete system redesign.
Solution Approach 2:
The patent implements dynamic beam power distribution by continuously adjusting the power of individual beams based on their angular position relative to the solar zenith angle. The system dynamically identifies which beams are affected by solar background noise and adjusts their power levels in real-time, creating a adaptive power distribution strategy that responds to changing environmental conditions.
2Measurement precision
If higher beam power is used to improve signal-to-noise ratio, then measurement accuracy improves, but the risk of eye damage increases
Solution Approach 1:
The patent changes the power parameter of laser beams dynamically based on their angular position. By adjusting the power parameter rather than maintaining a fixed high power level, the system achieves sufficient signal-to-noise ratio for accurate measurements while staying below eye safety thresholds. This parameter modulation allows the system to operate at the optimal point between measurement accuracy and safety.
3Measurement precision
If beam power is increased to compensate for solar background noise, then signal-to-noise ratio improves, but energy consumption increases
Solution Approach 1:
The patent applies partial action by selectively increasing beam power only for those specific angular regions where solar background noise is problematic, rather than uniformly increasing power across the entire field of regard. This targeted approach achieves the necessary signal-to-noise ratio improvement in affected regions while minimizing unnecessary energy consumption in regions where solar interference is not an issue.
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 enhances the signal-to-noise ratio by optimizing beam power distribution, reducing the risk of eye damage and improving measurement accuracy while conserving energy.
Implementation Method 1
a diffractive optical element configured to split the light into multiple output beams with non-equal power, angularly separated along a vertical dimension
Implementation Method 2
The light source emits light toward a target which then scatters the light. Some of the scattered light is received back at the receiver.
Data Source
AI summary
A lidar system includes a light source configured to emit light, a scanner configured to scan a field of regard of the lidar system using (i) a first output beam that includes at least a portion of the emitted light and has a first amount of power and (ii) a second output beam that includes at least a portion of the emitted light and has a second amount of power different from the first amount of power, with an angular separation between the first output beam and the second output beam along a vertical dimension of the field of regard, and a receiver configured to detect light associated with the first output beam and light associated with the second output beam scattered by one or more remote targets.