Lasing for Range
NEWER LASER RANGEFINDERS IMPROVE WARFIGHTER EFFECTIVENESS.
Laser rangefinders were the first military application of the laser as a tool of war. First used on tanks in the 1960s, laser rangefinders are now a necessary part of most direct fire targeting systems used by the Department of Defense. Earlier generations of laser rangefinders used complicated optical components that made the devices, bulky, heavy and very expensive.
Not anymore.
A representative of the Army’s Program Executive Office Soldier (PEO Soldier), Fort Belvoir, Va. spelled out some of the key requirements laser rangefinders must meet before they can be considered for use by the warfighter:
• Be light enough for use in the handheld mode
• Be able to integrate with GPS receivers to provide accurate target location
• Be able to obtain target location information on all targets that could be recognized
• Have direct view optics
• Incorporate improved night vision capability
• Be safe and supportable
PEO Soldier sensors and lasers enhance the soldier’s ability to see in all battlefield and lighting conditions, to acquire targets of military significance prior to being detected and to target three objects accurately for engagement by the soldier, other soldiers or by precisionguided munitions. In short, sensors and lasers provide soldiers the ability to see always, acquire first and target once.
Simrad Optronics, ASA, developed the first portable laser rangefinder for artillery forward observers in 1973. Since then, Simrad Optronics has developed increasingly sophisticated systems for the military, law enforcement and federal agencies, in conjunction with their U.S. distributor SPA-Simrad, with headquarters in Fort Lauderdale, Fla. The Simrad LP10 Target Locator and FOI 2000 Forward Observer System are two of the latest products. The LP10 Target Locator has a built in laser rangefinder, digital magnetic compass, GPS and a powerful computer, according to Jason Bombaci, SPASimrad U.S. representative. The Simrad LP10TL provides fast and reliable target grid coordinates and correction data. Other features include a connector for external power and data communications, including external GPS, datum and coordinate systems and reticle illumination. “One of the key advantages of our system is that it has a GPS/CPU built into the range finder,” said Bombaci. The Simrad LP10TL can utilize either an internal or external GPS—“We can get targeting acquisition achieved to a 10- digit grid at a distance of 20,000 meters.”
The LP10TL provides fall-of-shot correction. “That means that you lase where the round falls and our system automatically sends fire corrections to ensure that the second round lands on the target,” explained Bombaci. Equipment weight is always a consideration for the warfighter and the LP10TL by itself weighs only six pounds.
The LP10TL is the key system component of the FOI 2000 Forward Observer System. It can be placed on a tripod along with Vectronix’s Gonio Light Electronic Goniometer and the optional Mk 11-7 north-finding gyro from Diehl Avionik Systems. Over 230 Forward Observer units were just sold to Sweden and Norway, according to Bombaci. “We’re just starting tests and evaluations with U.S. forces,” said Bombaci. Both systems have gone through all the military specific tests for sand, dust fog and moisture. “The 11th Air Cavalry Regiment has already purchased 22 of the LP10 target locators,” said Bombaci. Use of the full FOI 2000 Forward Observer System results in more accurate readings and should be used when precision is paramount.
Since accuracy, target discrimination and range to target are among the characteristics that are critical to laser target rangefinders and designators, the Army’s Redstone Technical Test Center, Redstone Arsenal, Ala., has a lab devoted to advanced testing. A representative of The Electro- Optics Sensor and Subsystems (lab testing) explained that the typical process of testing a rangefinder (electro optical) consists of both laboratory and field tests. “In the laboratory, we can characterize the laser beam without the influence of the atmosphere and system stabilization. Hence, the primary laser beam parameters are measured.” The beam parameters are:
• The average energy contained in a single laser pulse
• The beam divergence or rate of beam spread
• The boresight error between the beam centroid and the sighting reticle
• The rangefinder sensitivity to detect a target return pulse
He continued, “In the field, we characterize the rangefinder’s accuracy for displaying the true range to target, its ability to discriminate the distance between two neighboring targets (laser spot strikes both targets), and the probability of displaying the correct range to target.” Additional tests include subjecting the rangefinder to environmental stimulation such as vibration, drops, rough handling, salt fog and immersion in water “Rangefinder sensitivity is the most technically challenging parameter to accurately measure. The field evaluation requires considerable time to conduct due to constantly having to relocate targets to seek the performance threshold condition.”
Of course, weight is always of paramount importance when equipping the warfighter.
The FOI 2000 weighs in at 26 pounds, which might sound like a lot, but not when compared to legacy systems such as the AN/PAQ-3 Modular Universal Laser Equipment (MULE) system used by the U.S. Marine Corps. The full MULE system weighs 108 pounds.
The LP10TL and FOI 2000 systems use software for establishing azimuth references via celestial bodies and has about 50 years of celestial information stored up, according to Bombaci. “So, you can confirm your location by looking at the moon, the sun or other celestial bodies,” said Bombaci. He added, “We believe we have made our system one of the most advanced, yet user-friendly in the world.”
Another device is the Mark VIIE, an enhanced version of the Mark VII eyesafe laser rangefinder. The Mark VII was proven in the mountains of Afghanistan and the deserts of Iraq where it provided accurate target locations necessary to employ precisionguided munitions. The Mark VII system is currently deployed with U.S. Army forward observers and scouts, U.S. Air Force tactical air control parties, U.S. Marine Corps forward observers and forward air controllers and members of special operations forces. The Mark VIIE has day/night capabilities and has an embedded Global Positioning System (GPS) to provide precision target location and improved target location error without the weight or size of a separate GPS device. It provides a more user-friendly and flexible graphical user interface than its predecessor and it operates using standard commercial batteries. The Mark VIIE provides both direct view day optics and an un-cooled thermal sight for nighttime operations. It can be used to conduct surveillance and target enemy positions for air or artillery engagement.
The Mark VIIE allows for determination of targeting information at longer distances, thus providing a greater chance remaining undetected. Then, there is Vectronix Inc., with U. S. headquarters in Leesburg, Va., which launched the first binocular-rangefinder. In 1992 Vectronix (then a technology division of Leica) launched Vector, with binocular optics, eye-safe laser rangefinder, digital compass and clinometer. The Vector family of laser rangefinders has become the standard for the U.S. Army, Marine Corps, Navy and special forces, according to Lewis Shadle, vice-president of business development for Vectronix.
“A Vectronix core competency is the ability to build highly specialized electro-optics and lasers, and we have an array of advanced laser rangefinders,” said Shadle. Over four years ago, “We received requests from special forces operators, particularly Navy SEALS, for a smaller-size device that met SEAL submersion requirements,” said Shadle. “It was a significant challenge for us to reduce size and weight while maintaining the expected performance and equally difficult to develop a device that maintained water integrity at depth.”
Yet, within six months, Vectronix had developed the Pocket Laser Rangefinder (PLRF), with four variants. “We had to incorporate things such as beam shaping of the laser and a different bonding and sealing technique had to be used for waterproofing,” said Shadle.
The PLRF is waterproof to a depth of 60 feet, so it can be used during an egress from a submerged platform. The normal military waterproofing standard is for a device to be submersed to 7 feet for up to one hour. “It’s a small package with high accuracy,” said Shadle. He continued, “It has a digital magnetic compass with built-in software that identifies specific coordinates for artillery fire or precision-guided munitions to be called in.”
Last September, the Naval Surface Warfare Center awarded Vectronix a $10 million contract for the PLRF15C.
As for future developments in laser technology, the Redstone Technical Test Center representative was quite specific as to what center specialists would like to see. “The most desirable advance in laser technology would be the decrease in hardware size without sacrificing performance. This includes the increase in laser efficiency to reduce the power demanded from the battery supply.”
The PEO Soldier representative listed several specific improvements that the Army would like to see:
• reduced weight
• Increased night target acquisition
• Improved target location accuracy
• Elimination of dependence on magnetic compasses to determine azimuth
• Integration with a lightweight designation module
For Vectronix, the future is now, as they’ve already developed a laser rangefinder that meets some of the improvements that have been specified by the military. Called the Long Range Thermal Video Imagery System (LRTV), the device maintains all functions of the Vector and PLRF with additional capabilities. “It’s a handheld, lightweight, multi-function, day-night laser rangefinder,” explained Shadle. “Because of its thermal imaging capability it can be used for day and night missions. It also provides an embedded GPS and a color video channel. It has a high-resolution video camera and can export the image to a command and control terminal or facility.”
Calls for fire are usually called in by radio. With the LRTV information formerly called in by radio can be sent up-channel. “This aids in target identification and confirmation,” said Shadle. The LRTV can also be used for post-attack bombdamage assessments.
The LRTV is under evaluation with numerous U.S. military organizations, according to Shadle. “In September, some of the units will be fielded in Iraq for assessments of usability and functionality,” said Shadle.
Over the last 50 years, continual advancements have been made in laser technology to serve the warfighter. As companies such as Simrad Optronics and Vectronix Inc. continue to develop and enhance their product lines, it’s expected that the advancements will continue. ♦