Adjustable Sampling Ranging System for Lidar Resolution

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Solution Overview

Problem

Lidar systems face a trade-off between ranging resolution and dynamic range, where increasing sampling frequency improves resolution but reduces dynamic range, and vice versa, often leading to missed targets due to power constraints.

Innovation Solution

A ranging system that generates a wideband incident wave, uses low-pass filtering and adjustable sampling frequencies to calculate cross-correlation, allowing for simultaneous fine ranging resolution and wide dynamic range without excessive power consumption.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If sampling frequency is increased to improve ranging resolution, then ranging resolution is improved, but ranging dynamic range becomes narrower

Engineering Contradiction:

Improveranging resolutionVSAvoidranging dynamic range

Core Design Contradiction:

Measurement precisionVSAdaptability or versatility

Solution Approach 1:

The patent applies dynamics by making the sampling frequency adjustable rather than fixed. The system can dynamically change sampling frequency based on the required ranging dynamic range, allowing it to adapt between fine resolution mode (higher sampling frequency) and wide dynamic range mode (lower sampling frequency), thus resolving the contradiction between these two parameters.

Inventive Principle:

Principle #15Dynamics

Solution Approach 2:

The patent changes the sampling frequency parameter to resolve the contradiction. By adjusting this parameter, the system can optimize performance for different scenarios: higher sampling frequency for fine ranging resolution and lower sampling frequency for wider ranging dynamic range, eliminating the need to permanently trade off between the two.

Inventive Principle:

Principle #35Parameter changes

2Adaptability or versatility

If sampling frequency is lowered to achieve wider ranging dynamic range, then ranging dynamic range is widened, but ranging resolution deteriorates

Engineering Contradiction:

Improveranging dynamic rangeVSAvoidranging resolution

Core Design Contradiction:

Adaptability or versatilityVSMeasurement precision

Solution Approach 1:

The system dynamically adjusts sampling frequency based on operational requirements. When wide ranging dynamic range is needed, the sampling frequency is lowered; when fine ranging resolution is needed, it is increased. This dynamic adaptation resolves the contradiction by allowing the system to have both capabilities at different times.

Inventive Principle:

Principle #15Dynamics

Solution Approach 2:

The sampling frequency parameter is made variable to resolve the contradiction. The system can switch between different sampling frequency values to achieve either wide ranging dynamic range or fine ranging resolution depending on the specific application scenario, eliminating the permanent trade-off.

Inventive Principle:

Principle #35Parameter changes

3Measurement precision

If higher sampling frequency is used to achieve fine ranging resolution, then ranging resolution is improved, but power consumption increases

Engineering Contradiction:

Improveranging resolutionVSAvoidpower consumption

Core Design Contradiction:

Measurement precisionVSUse of energy by moving object

Solution Approach 1:

The system dynamically adjusts sampling frequency to match the actual ranging requirements. Instead of continuously operating at high sampling frequency, it only increases sampling frequency when fine ranging resolution is actually needed, thereby reducing overall power consumption while maintaining the capability for high-resolution ranging when required.

Inventive Principle:

Principle #15Dynamics

Solution Approach 2:

The sampling frequency parameter is adjusted based on power budget and resolution requirements. By changing this parameter, the system can operate at lower power consumption levels during normal operation and only increase power consumption temporarily when fine ranging resolution is required, thus resolving the contradiction between resolution and power usage.

Inventive Principle:

Principle #35Parameter changes

4Use of energy by moving object

If lower sampling frequency is used to reduce power consumption, then power consumption is reduced, but target detection reliability decreases

Engineering Contradiction:

Improvepower consumptionVSAvoidtarget detection reliability

Core Design Contradiction:

Use of energy by moving objectVSReliability

Solution Approach 1:

The system dynamically adjusts sampling frequency based on detection requirements and power availability. When power consumption needs to be reduced, it lowers sampling frequency, but when target detection reliability is critical, it increases sampling frequency to ensure adequate sampling of the reflected signal, thus resolving the contradiction adaptively.

Inventive Principle:

Principle #15Dynamics

Solution Approach 2:

The sampling frequency parameter is adjusted to balance power consumption and detection reliability. The system can operate at lower sampling frequencies to save power during normal conditions and switch to higher sampling frequencies when reliable target detection is required, eliminating the permanent trade-off between these parameters.

Inventive Principle:

Principle #35Parameter changes

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

Ensures target detection by widening the dynamic range while maintaining fine ranging resolution, within a predetermined power budget, by adjusting filtering bandwidth and sampling frequency.

Implementation Method 1

perform low-pass filtering on the detected signal at a preset filtering bandwidth that is adjustable

Methodology Applied

Scientific EffectLow-pass filtering: Filter (electronic)

Implementation Method 2

calculate cross-correlation of a feedback signal that originates from the filtered signal and a reference signal that corresponds to the incident wave

Methodology Applied

Scientific EffectCross-correlation:

Implementation Method 3

The source generates an incident wave that is wideband

Methodology Applied

Scientific EffectWideband signal generation:

Implementation Method 4

The feedback detector is to detect the reflected wave to generate a detected signal

Methodology Applied

Scientific EffectWave detection:

Implementation Method 5

measures a distance therefrom to a target by illuminating the target with laser light and measuring time of flight the laser light takes to return to the lidar system

Methodology Applied

Scientific EffectTime of flight measurement: Time of Flight

Data Source

PatentUS11740339B2Ranging system

Publication Date: 2023.08.29 NATIONAL TSING HUA UNIVERSITY

AI summary

A ranging system includes: a source generating a wideband incident wave that is transmitted toward a target and that is reflected by the target to form a reflected wave; a feedback detector to detect the reflected wave to generate a detected signal; an operator configured to perform low-pass filtering on the detected signal at an adjustable filtering bandwidth to generate a filtered signal, and calculate cross-correlation of a feedback signal that originates from the filtered signal and a reference signal that corresponds to the incident wave to generate a cross-correlation result; and a controller calculating a distance to the target based on an operation output that originates from the cross-correlation result.