Pulse Coding for LIDAR Return Differentiation
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Solution Overview
Problem
In crowded environments, differentiating returns from multiple LIDAR and radar systems is difficult due to interference, and conventional techniques are inadequate for high-speed vehicles that require faster data accumulation and higher transmission repetition rates, limiting the ability to discern multiple range returns.
Innovation Solution
Implementing a coding technique on transmitted pulses to identify their source and timing, allowing the receiver to differentiate between first, second, and third range returns, thereby increasing transmission repetition rates without confusion and enabling faster data accumulation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If conventional pulse transmission techniques are used in crowded environments, then the system can operate with simple transmission protocols, but the ability to differentiate returns from multiple LIDAR and radar systems deteriorates due to interference
Solution Approach 1:
The patent applies code modulation to pulses of electromagnetic energy, analogous to color changes, where each transmitter is assigned a unique code sequence that modulates the pulse characteristics. This allows receivers to differentiate between multiple transmitters in crowded environments by identifying the unique code patterns, resolving the contradiction between simple transmission protocols and accurate return differentiation.
2Productivity
If transmission repetition rate is increased for faster data accumulation, then productivity improves, but the ability to discern multiple range returns deteriorates due to pulse overlap and confusion
Solution Approach 1:
The patent implements periodic code sequences on transmitted pulses, where each pulse is modulated with a specific code from a repeating sequence. This periodic coding allows the receiver to distinguish between pulses from different transmission cycles and multiple range returns, enabling high transmission repetition rates without loss of range discrimination capability.
Solution Approach 2:
By modulating pulses with unique code sequences, the patent creates distinct 'signatures' for each pulse, allowing the receiver to identify the origin and timing of each return pulse even when multiple pulses are in flight simultaneously. This code-based differentiation maintains measurement precision while enabling increased productivity through higher transmission repetition rates.
3Measurement precision
If coding techniques are implemented on transmitted pulses to improve return differentiation, then measurement precision improves, but device complexity increases due to code imposition and decoding requirements
Solution Approach 1:
The patent uses periodic code sequences that can be implemented through simple modulation techniques on the transmitted pulses. The periodic nature of the codes allows for efficient correlation-based decoding at the receiver, which maintains measurement precision while managing device complexity through mathematically elegant and computationally efficient signal processing methods.
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 allows for faster and more accurate data generation in 3D point clouds, enhancing the ability to detect hazards and navigate vehicles by distinguishing between multiple range returns, thereby improving operational efficiency and reducing system complexity.
Implementation Method 1
LIDAR systems provide optical pulses to the environment and receive return pulses which are processed to locate objects and targets in the environment
Data Source
AI summary
A platform operates in an environment with other platforms using active sensing. The platform includes an active sensing system configured to provide a point cloud associated with the environment. The point cloud is used to navigate the platform. The active sensing system includes a transmitter configured to provide pulses of electromagnetic energy in a light band or a radar band or sonic energy and a receiver configured to receive returns associated with the pulses striking one or more targets in the environment. The transmitter is configured to impose a code onto the pulses, and the receiver is configured to detect the code to determine when the pulses of light where transmitted or to determine a source of the pulses.