Optical Distance Measurement Using FPGA Timing Instead of High-Speed ADCs
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Solution Overview
Problem
Existing LIDAR systems used in unmanned vehicles lack sufficient measurement precision for complex environments, requiring improved techniques for distance measurement with higher resolution and reduced cost and power consumption.
Innovation Solution
The use of a Field-Programmable Gate Array (FPGA) to process analog pulse signals from light detection, enabling high-resolution time measurements and digitization of light pulses with picosecond-level precision, reducing reliance on high-speed analog-to-digital converters.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If existing LIDAR systems are used for distance measurement, then basic obstacle detection is achieved, but measurement precision is insufficient for complex environments
Solution Approach 1:
The patent replaces traditional high-speed analog-to-digital converters and complex timing circuits with an FPGA-based direct digital synthesis system. The FPGA generates precise timing signals and processes return light pulses directly in the digital domain, eliminating the need for high-speed ADCs and reducing overall system complexity while achieving picosecond-level time resolution for distance measurement.
Solution Approach 2:
The patent changes the operating parameters by using FPGA's programmable logic to generate timing signals at precise intervals and process digital pulses with high-resolution counters. This allows the system to achieve superior measurement precision through software-configurable parameters rather than fixed hardware characteristics, enabling adaptation to complex environments.
2Measurement precision
If high-speed analog-to-digital converters are used to improve measurement resolution, then time measurement precision is improved, but cost and power consumption increase
Solution Approach 1:
The patent substitutes high-speed analog-to-digital converters with an FPGA-based direct digital timing system. The FPGA directly processes the return light pulse signal in the digital domain, generating time measurements through internal counters and logic without requiring high-speed ADC conversion. This substitution dramatically reduces power consumption while maintaining or improving time measurement resolution.
Solution Approach 2:
The patent employs standard FPGA devices and conventional digital circuits instead of expensive high-speed ADC components. The FPGA's programmable nature allows it to perform high-precision timing functions using lower-cost, lower-power digital logic elements, achieving the same or better performance with more economical components.
3Measurement precision
If high-speed analog-to-digital converters are used to achieve high-resolution measurements, then measurement precision is improved, but device complexity and cost increase
Solution Approach 1:
The patent eliminates high-speed analog-to-digital converters entirely by implementing a direct digital timing approach within the FPGA. The system uses the FPGA's internal digital logic to generate timing signals, count return pulse periods, and calculate distance measurements, replacing complex analog conversion hardware with simpler programmable digital logic.
Solution Approach 2:
The FPGA serves multiple functions simultaneously: it generates outbound light pulse timing signals, processes return light pulse detections, performs time-to-distance conversions, and provides digital signal processing. This multi-functional approach consolidates what would otherwise require separate high-speed ADC, timing circuit, and processing components into a single programmable device, reducing overall system complexity.
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 provides centimeter-level precision in distance measurements with lower costs and power consumption, suitable for complex and dynamic environments, such as obstacle detection and environmental mapping by unmanned vehicles.
Implementation Method 1
a returning light pulse reflected from the object
Implementation Method 2
a light sensor configured to receive a returning light pulse reflected from the object and output an analog pulse signal representing the returning light pulse
Implementation Method 3
calculate the distance to the object based on the plurality of digital signal values and the plurality of time measurements
Data Source
AI summary
Systems and methods for performing optical distance measurement are provided. In one aspect, a system for measuring a distance to an object comprises a light emitter configured to emit an outbound light pulse, and a light sensor configured to receive a returning light pulse reflected from the object and output an analog pulse signal representing the returning light pulse. The system also comprises a field-programmable gate array (FPGA) coupled to the light sensor. The FPGA is configured to convert the analog pulse signal to a plurality of digital signal values, and generate a plurality of time measurements corresponding to the plurality of digital signal values. The system also comprises a controller configured to calculate the distance to the object based on the plurality of digital signal values and the plurality of time measurements.