Lidar Reference Waveform Synthesis for High-Resolution Ranging
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Solution Overview
Problem
LIDAR systems face challenges in achieving high resolution distance measurements without increasing cost or power consumption by using high-sample rate ADCs, as they typically rely on these components for accurate time-of-flight calculations.
Innovation Solution
Synthesizing a high sample-rate reference waveform using a low-sample rate ADC in conjunction with a matched filter to improve temporal resolution, allowing for enhanced distance measurements by adjusting the sample times for each LIDAR pulse.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a high-sample rate ADC is used to achieve high resolution distance measurements, then measurement precision is improved, but device complexity and cost increase
Solution Approach 1:
The patent segments the sampling process into multiple passes, where each pass collects samples at a lower ADC sample rate. By dividing the waveform capture into segments and processing them separately, the system achieves high effective resolution without requiring a high-sample rate ADC for each individual sampling operation.
Solution Approach 2:
The patent transitions from a single-dimension approach (high sample rate in time domain) to a multi-dimensional approach by combining multiple low-sample-rate measurements taken at different time offsets. This dimensional expansion allows reconstruction of high-resolution waveforms through computational methods rather than relying solely on hardware sampling rate.
2Measurement precision
If a high-sample rate ADC is used to achieve high resolution distance measurements, then measurement precision is improved, but cost increases
Solution Approach 1:
The patent employs multiple inexpensive, low-sample-rate ADCs instead of a single expensive high-sample-rate ADC. Each low-sample-rate ADC performs its function and can be replaced or reset, providing a cost-effective alternative to investing in expensive high-speed conversion hardware.
Solution Approach 2:
The patent changes the sampling parameters dynamically by adjusting the time offset for each sampling pass. Instead of maintaining a constantly high sample rate, the system varies the sampling timing and combines results, achieving high resolution through parameter modulation rather than hardware speed.
3Measurement precision
If multiple sets of digital samples are obtained at different time delays to generate high resolution reference waveform, then measurement precision is improved, but device complexity increases
Solution Approach 1:
The patent performs preliminary sampling operations at multiple predetermined time offsets before the final measurement is needed. By pre-collecting sample sets at different delays and storing them, the system prepares high-resolution reference data in advance, reducing the complexity of real-time processing during actual measurement.
Solution Approach 2:
The patent creates multiple copies of the sampling process at different time offsets, generating redundant sample sets that can be combined. These copies allow the system to reconstruct high-resolution waveforms through computational combination rather than requiring complex real-time signal processing hardware.
Data Source
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AI summary
A method for determining, in an optical detection system, a distance to a target region includes obtaining first and second light pulses from a signal generator within the optical detection system and obtaining samples of the respective first and second light pulses, where the samples having a first temporal resolution. The method also includes generating a reference waveform having a second temporal resolution by combining the samples of the respective first and second light pulses, where the second temporal resolution being higher than the first temporal resolution. The method further includes obtaining a reflection of a third light pulse from the target region and determining an arrival time of the reflection of the third light pulse using the reference waveform.