Related Experiment Video
Updated: May 8, 2026
07:14
Tracking Infiltration Front Depth Using Time-lapse Multi-offset Gathers Collected with Array Antenna Ground Penetrating Radar
Published on: May 1, 2018
Comb-calibrated frequency-modulated continuous-wave ladar for absolute distance measurements
Esther Baumann1, Fabrizio R Giorgetta, Ian Coddington
1NIST, Boulder, Colorado 80305, USA. baumann@nist.gov
Optics Letters
|August 14, 2013
Summary
This study presents a comb-calibrated frequency-modulated continuous-wave (FMCW) laser detection and ranging (ladar) system for precise absolute distance measurements. The novel FMCW ladar achieves high accuracy and resolution using a frequency comb for calibration.
Area of Science:
- Optics and Photonics
- Metrology
- Laser Technology
Background:
- Accurate distance measurement is crucial in various scientific and industrial applications.
- Traditional laser ranging systems face limitations in absolute accuracy and resolution.
- Frequency-modulated continuous-wave (FMCW) ladar offers potential for high-precision measurements.
Purpose of the Study:
- To develop and demonstrate a comb-calibrated FMCW ladar system for absolute distance measurements.
- To achieve high accuracy and precision in ranging using a frequency comb as a reference.
- To enable rapid distance updates with high resolution.
Main Methods:
- Utilized a compact external cavity laser swept quasi-sinusoidally over 1 THz at a 1 kHz rate.
- Simultaneously recorded the heterodyne FMCW ladar signal and instantaneous laser frequency against a femtosecond fiber laser frequency comb.
- Employed demodulation of the ladar signal against the instantaneous laser frequency for range extraction.
Main Results:
- Achieved bandwidth-limited 130 μm resolution.
- Demonstrated ~100 nm accuracy directly linked to the frequency comb's repetition rate.
- Obtained distance precision of <100 nm at 1 ms update rates, improving to ~6 nm with 100 ms averaging.
- System operates with 1 ms update rates.
Conclusions:
- The comb-calibrated FMCW ladar system provides a robust method for absolute distance measurements.
- The system offers unprecedented accuracy and precision, leveraging frequency comb metrology.
- This technology has significant implications for precision engineering, scientific instrumentation, and advanced manufacturing.
Related Concept Videos
01:30Electronic Distance Measuring Instruments
Electronic Distance Measuring Instruments (EDMs) are essential tools in modern surveying, offering precise distance measurements by emitting electromagnetic signals and calculating the time required for these signals to travel to a target and return. Two primary types of signals are used in EDMs — light waves and microwaves — each suited to specific environmental and distance requirements. Light-wave-based EDMs utilize either infrared or laser light, providing high accuracy over short distances...
01:15Distance Corrections
To achieve precise distance measurements, especially in surveying and construction, certain corrections must be applied to account for potential sources of error like the standardization errors, temperature variations, and slope adjustments.Standardization error emerges when measurement equipment undergoes changes, such as wear, repairs, or weather impacts. To address this, surveyors compare the equipment’s readings to a standard. This process identifies any deviation that might lead to...
01:10Design Example: Measuring Distance Between Two Points with Obstructions
When measuring distances in areas with physical obstructions, such as a lake in a field, surveyors must employ techniques to calculate accurate lengths without direct line measurements. One effective method is the offset technique, which allows for precise distance estimation over inaccessible stretches.In this scenario, a surveyor must measure a side of an area that crosses a lake. Since the measuring tape cannot span the lake, the surveyor begins by establishing a baseline that aligns with...