Matched-Filter LiDAR Orientation for Tilted Frame Alignment
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Solution Overview
Problem
Lidar systems face challenges in operating with low latency and rapid adaptation to environmental changes, particularly in automotive applications where high-speed movement requires rapid decision-making, and the laser source's energy management is critical to prevent overheating and ensure consistent energy delivery during variable firing rates.
Innovation Solution
A laser energy model and mirror motion model are used to predict and manage energy levels and targeting precision, allowing for granular scheduling of laser pulses and mirror motion, enabling high-rate, low-latency operation with precise targeting and adaptive detection intervals.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If the laser source firing rate is increased to rapidly respond to detected objects, then the response speed and detection capability are improved, but the laser source overheats and exceeds maximum energy limits
Solution Approach 1:
The system dynamically adjusts the laser source firing rate based on real-time energy model predictions and detection needs. The control circuit varies the firing rate between high-density periods (when objects are detected) and low-density periods (when no objects are present), allowing rapid response when needed while preventing overheating during normal operation
Solution Approach 2:
The system changes the temporal parameter of laser firing by implementing variable firing rates. During high-priority detection periods, the firing rate increases to provide dense sampling, while during low-priority periods, the firing rate decreases to allow energy dissipation and prevent overheating
2Measurement precision
If the laser source firing rate is increased to achieve high-density pulse firing, then the detection resolution is improved, but the energy management becomes difficult and overheating occurs
Solution Approach 1:
The system performs preliminary energy modeling to predict available laser source energy before initiating high-density firing sequences. The control circuit uses the energy model to determine safe firing rates and durations in advance, ensuring that high-resolution detection can be performed without exceeding energy limits or causing overheating
Solution Approach 2:
The system employs periodic high-density firing bursts interspersed with lower-density intervals. During detected object events, high-density pulses provide detailed resolution, followed by lower-density periods that allow energy recovery and dissipation, creating a rhythmic pattern that balances precision needs with thermal management
3Temperature
If the laser source firing rate is decreased to allow energy dissipation, then overheating is prevented, but the response latency increases
Solution Approach 1:
The system dynamically switches between low-density and high-density firing modes based on real-time conditions. When no objects are detected, the firing rate remains low to prevent overheating. When objects are detected, the system rapidly transitions to high-density firing to provide immediate detailed response, minimizing latency while managing thermal constraints
4Use of energy by moving object
If granular scheduling of laser pulses is implemented to manage energy, then energy efficiency is improved, but the system complexity increases
Solution Approach 1:
The control circuit automatically manages granular pulse scheduling based on predictions from the energy model and current system state. The system self-regulates firing rates, adjusts detection intervals, and coordinates mirror motion without requiring external intervention, achieving energy efficiency through automated decision-making that offsets the complexity burden
Data Source
AI summary
A lidar system comprises (1) an array of pixels for sensing incident light and (2) a circuit for processing a signal representative of the sensed incident light to detect a reflection of a laser pulse from a target within a field of view. The circuit can comprise a plurality of matched filters that are tuned to different reflected pulse shapes for detecting pulse reflections within the incident light, and wherein the circuit (1) applies the signal to the matched filters to determine an obliquity for the target based how the matched filters respond to the applied signal and (2) determines a correction angle based on the determined target obliquity, the correction angle for orienting the field of view to a frame of reference in response to a tilting of the lidar system. In an example embodiment, the circuit can comprise a signal processing circuit that performs the signal application and correction angle determination operations. In another example embodiment, the circuit can comprise (1) a signal processing circuit that performs the signal application operation and (2) a receiver controller circuit that performs the correction angle determination operation.