LIDAR Controller Variable Spacer Periods Interference
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Solution Overview
Problem
Conventional LIDAR systems face challenges in discriminating between actual signals and interference from nearby LIDAR devices emitting light pulses at the same wavelength, leading to incorrect information about surroundings, especially in automotive applications where fast response times are crucial.
Innovation Solution
A LIDAR device with a controller that varies the length of spacer periods between scan cycles, time-shifting each cycle to decrease the probability of receiving parasitic signals, and optionally randomizing the read order of sensor lines to mitigate interference without requiring coordination between devices.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If LIDAR systems use fixed timing windows for signal detection, then the system structure remains simple and fast, but parasitic interference from other LIDAR devices cannot be effectively discriminated
Solution Approach 1:
The patent applies dynamics by making the spacer period variable rather than fixed. The controller dynamically adjusts the length of spacer periods between scan cycles, creating an irregular timing pattern that prevents systematic accumulation of parasitic signals while maintaining system simplicity. This resolves the contradiction by introducing temporal variability without requiring complex inter-device coordination.
Solution Approach 2:
The patent changes the timing parameter (spacer period length) to resolve the interference problem. By varying the spacer period within a range while keeping it greater than the sensor dead time, the system distributes parasitic signals across different time bins, converting them into background noise rather than distinct interference peaks, thereby improving signal discrimination without increasing device complexity.
2Measurement precision
If LIDAR systems coordinate timing windows of different devices to reduce parasitic signals, then interference discrimination improves, but frame rate decreases and response time increases
Solution Approach 1:
The patent extracts the timing variability function from the traditional coordinated timing approach. Instead of requiring multiple devices to synchronize their timing windows, each device independently varies its own spacer periods, removing the need for inter-device coordination while still achieving parasitic signal discrimination. This maintains fast frame rates by eliminating coordination overhead.
Solution Approach 2:
Each LIDAR device serves itself by independently varying its spacer periods according to a predetermined range. This self-service approach eliminates the need for external coordination mechanisms, maintaining system simplicity and fast response times while effectively discriminating parasitic signals through the irregular timing patterns generated by each device autonomously.
3Measurement precision
If LIDAR systems use longer measurement windows subdivided into multiple timing windows, then parasitic signal discrimination improves, but system complexity and cost increase significantly
Solution Approach 1:
The patent segments the measurement process into multiple scan cycles with variable spacer periods rather than using a single long measurement window. Each scan cycle uses a standard timing window, but the variable spacing between cycles creates temporal separation that distributes parasitic signals. This segmentation approach maintains architectural simplicity while achieving effective signal discrimination.
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 effectively reduces parasitic interference, maintaining fast response times and improving image resolution in automotive LIDAR systems by distributing parasitic signals as background noise, rather than high-intensity peaks, thereby enhancing detection accuracy.
Implementation Method 1
an emitter for emitting output signals
Implementation Method 2
sensors based upon Time-of-Flight (TOF) light detection and ranging (LIDAR)
Implementation Method 3
a sensor for detecting input signals... each SPAD device functions as a TOF sensor and is used to collect information about both the three-dimensional location and the intensity of the light incident on it
Data Source
AI summary
A light detection and ranging (LIDAR) device having a sensor for detecting input signals and an emitter for emitting output signals. A controller controls the emitter to emit output signals and reads the input signals from the sensor during a plurality of scan cycles. Each scan cycle is separated by a spacer period, and the controller is configured to vary the length of the spacer periods between the plurality of scan cycles. The LIDAR device may form part of a LIDAR system. Methods for reducing interference in a LIDAR system, and methods and software for controlling a LIDAR device are also disclosed.