Programmable Pseudo-Random Sequence Generator for Low-Memory LiDAR
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing lidar systems require large memory storage for generating pseudo-random noise patterns, leading to increased costs and processing requirements, which hinders the ability to tune resolution and sensitivity effectively without significant memory usage.
Innovation Solution
A programmable pseudo-random sequence generator using a linear feedback shift register architecture with high-speed switches and binary adders, allowing for the generation of pseudo-random patterns without the need for large memory, enabling efficient switching between scan patterns and adjusting range and sensitivity in lidar systems.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If large memory storage is used to generate pseudo-random noise patterns, then the periodicity and sensitivity of the lidar waveform are improved, but the cost and processing requirements increase significantly
Solution Approach 1:
The patent replaces the traditional memory-based pseudo-random pattern generation system with an all-optical linear feedback shift register system. Instead of storing pseudo-random patterns in electronic memory and reading them out, the invention uses optical feedback through a circulator and optical modulator to generate the patterns directly in the optical domain, eliminating the need for large memory storage while maintaining the required periodicity and sensitivity.
Solution Approach 2:
The patent introduces a circulator as an intermediary component to enable optical feedback from the output back to the input of the shift register. This circulator allows the optical signal to traverse through the shift register stages multiple times, creating the pseudo-random pattern generation without requiring electronic memory storage, thus resolving the contradiction between sensitivity enhancement and memory usage.
2Measurement precision
If high-speed memory is used to implement pseudo-random patterns with long periodicity, then the resolution and sensitivity are improved, but the device complexity and cost increase
Solution Approach 1:
The patent replaces complex high-speed electronic memory systems with a simpler all-optical linear feedback shift register architecture. The optical implementation uses passive optical components (circulator, optical modulator, photodetector) to achieve the same function of generating long-periodicity pseudo-random patterns without requiring complex high-speed memory hardware, thereby reducing device complexity while maintaining resolution and sensitivity.
Solution Approach 2:
The patent utilizes periodic optical feedback through the circulator to generate pseudo-random patterns with extended periodicity. The optical signal circulates through the shift register stages repeatedly, with each circulation adding to the pattern length, achieving long periodicity (up to 2^17-1) without requiring proportionally large memory storage, thus simplifying the device while improving measurement precision.
3Measurement precision
If specialized lidar systems are designed for specific applications, then the measurement precision is optimized, but the adaptability to different applications decreases
Solution Approach 1:
The patent implements a dynamic and reconfigurable lidar system using an all-optical programmable linear feedback shift register. The system can be reprogrammed to generate different pseudo-random patterns and adjust its parameters (such as pattern length, bit period, and modulation depth) to suit different applications, whether for high-resolution short-range measurements or high-sensitivity long-range detection, thus achieving both precision and adaptability.
Solution Approach 2:
The patent creates a universal lidar architecture that can serve multiple applications through the all-optical programmable pseudo-random pattern generator. By replacing application-specific fixed designs with a reconfigurable optical system, the invention enables a single lidar platform to be adapted for various applications including atmospheric sensing, remote sensing, and target characterization, maintaining optimized measurement precision across different use cases.
Data Source
AI summary
A pseudo-random sequence generator for use within a universal lidar system and its corresponding method of operation. The pseudo-random sequence generator uses synchronized shift registers that are in series Binary adders are provided. The signal output of each of the shift registers is tapped and directed to the binary adders. High-speed switches are provided between the shift registers and the binary adders. The switches are programmed to connect only two of the shift registers to the binary adders for each of the pseudo-random patterns being generated. The binary adders generate an output signal that is received by the first shift register. The signal propagates through all the shift registers to the last shift register. The last shift register outputs a pseudo-random sequence.