LIDAR system offers peerless precision in remote measurements

May 24, 2009

By combining the best of two different distance measurement approaches with a super-accurate technology called an optical frequency comb, researchers at the National Institute of Standards and Technology have built a laser ranging system that can pinpoint multiple objects with nanometer precision over distances up to 100 kilometers. The novel LIDAR ("light detection and ranging") system could have applications from precision manufacturing lines on Earth to maintaining networks of satellites in perfect formation, creating a giant space-based platform to search for new planets.

LIDAR transmits light through the air and analyzes the weak reflected signal to measure the distance, or range, to the target. NIST's new LIDAR, described in Nature Photonics, has a unique combination of capabilities, including precision, rapid updates from multiple reference points at the same time, and minimal "measurement ambiguity." The system can update measurements to multiple targets simultaneously every 200 microseconds.

Measurement ambiguity in a LIDAR system is due to the fact that, if the target is at long range from the instrument, the system can't distinguish between two different distances that are multiples of its "ambiguity range." The new NIST LIDAR has a comfortably large ambiguity range of at least 1.5 meters—large enough to check the coarse distance with widely available technologies such as GPS.

No other ranging system offers this combination of features, according to the new paper. NIST's LIDAR could enable multiple satellites to maintain tight spacing and pointing while flying in precision formations, acting as a single research instrument in space, the paper states. Formation flying has been proposed as a means to enhance searches for extraterrestrial planets, enable imaging of black holes with multiple X-ray telescopes on different satellites, and support tests of through measurements of satellite spacing in a . The new LIDAR could enable continuous comparisons and feedback of distances to multiple reference points on multiple satellites. There also may be applications in automated manufacturing, where many parts need to fit together with tight tolerances, according to Nate Newbury, the principal investigator.

NIST's LIDAR design derives its power from combining the best of two different approaches to absolute distance measurements: the time-of-flight method, which offers a large ambiguity range, and interferometry, which is ultraprecise. The LIDAR relies on a pair of optical frequency combs, tools for precisely measuring different colors (or frequencies) of light. The frequency combs used in the LIDAR are based on ultrafast-pulsed fiber lasers, which are potentially smaller and more portable than typical combs that generate laser light from crystals.

The two combs operate at slightly different numbers of pulses per second. Pulses from one comb are reflected from a moving target and a stationary reference plane. The second comb serves as precise timer to measure the delay between the reflections returning from the target and from the reference plane. A computer calculates the distance between the target and the reference plane by multiplying the time delay by the speed of light.

More information: I. Coddington, W. C. Swann, L. Nenadovic and N. R. Newbury. Rapid, precise absolute distance measurements at long range. . Published online May 24, 2009.

Source: National Institute of Standards and Technology (news : web)

Explore further: Optical nanoantennas set the stage for a NEMS lab-on-a-chip revolution

add to favorites email to friend print save as pdf

Related Stories

Enhanced LIDAR improves range, vibration measures

Feb 02, 2006

Scientists at the National Institute of Standards and Technology have demonstrated the use of an ultrafast laser "frequency comb" system for improved remote measurements of distance and vibration. The technology, ...

'Tunable' network features coordinated frequency combs

May 11, 2007

A super stable fiber-optic network that can be tuned across a range of visible and near-infrared frequencies while synchronizing the oscillations of light waves from different sources has been demonstrated at the National ...

Soldiers to get 3-D maps in near-real-time

Mar 31, 2008

In the near future, soldiers may be using maps that are more akin to long-range but highly accurate security cameras: the maps will enable troops to see both the exterior and interior of buildings, as well ...

Recommended for you

New filter could advance terahertz data transmission

11 hours ago

University of Utah engineers have discovered a new approach for designing filters capable of separating different frequencies in the terahertz spectrum, the next generation of communications bandwidth that ...

The super-resolution revolution

11 hours ago

Cambridge scientists are part of a resolution revolution. Building powerful instruments that shatter the physical limits of optical microscopy, they are beginning to watch molecular processes as they happen, ...

Precision gas sensor could fit on a chip

12 hours ago

Using their expertise in silicon optics, Cornell engineers have miniaturized a light source in the elusive mid-infrared (mid-IR) spectrum, effectively squeezing the capabilities of a large, tabletop laser onto a 1-millimeter ...

A new X-ray microscope for nanoscale imaging

14 hours ago

Delivering the capability to image nanostructures and chemical reactions down to nanometer resolution requires a new class of x-ray microscope that can perform precision microscopy experiments using ultra-bright ...

New research signals big future for quantum radar

Feb 26, 2015

A prototype quantum radar that has the potential to detect objects which are invisible to conventional systems has been developed by an international research team led by a quantum information scientist at the University ...

User comments : 1

Adjust slider to filter visible comments by rank

Display comments: newest first

rwinners
not rated yet May 25, 2009
Damm! 100km! Doesn't give us speeders much chance!

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.