High-energy Laser Weapon System Research Articles

Inertial Stable Platforms for Precision Pointing of Optical Systems in Aerospace Applications

Both airborne and space-based high-energy laser weapon systems present interesting challenges for precision line-of-sight control. Sub-microradian to microradian pointing accuracies are required against dynamic targets. In addition, “absolute” pointing and accurate inertial angular rate measurement are required to support mission requirements. This paper addresses these unique directed-energy weapon (DEW) precision-pointing requirements and their associated implementation alternatives in the context of strapdown and stable platform inertial reference technologies. The contributions of this paper consider the broader issues of DEW requirement drivers, integration of the stabilization system with the rest of the optical system, and design tradeoffs between stable platform and strapdown stabilization mechanizations. Both types of mechanisms are mounted to the gimbal of an imaging system using gryo sensors (gyros) and accelerometers to maintain a desired orientation in inertial space independent of the craft motion. Although both can include an optical reference that propagates through the optical path for optical alignment and jitter control, only in the stable platform is the optical reference stabilized. When combined on the same platform with a stabilized inertial measurement system and closed-loop stabilization with the optical reference, the mechanism becomes a stabilized inertial reference unit, which provides a stabilized optical reference to the electro-optical/laser pointing and jitter control systems.

Is this the time for a high-energy laser weapon program?

The U.S. Department of Defense (DoD) has made large investments weaponizing laser technology for air defense. Despite billions of dollars spent, there has not been a successful transition of a high-energy laser (HEL) weapon from the lab to the field. Is the dream of a low-cost-per-shot, deep-magazine, speed-of-light HEL weapon an impossible dream or a set of technologies that are ready to emerge on the modern battlefield? Because of the rapid revolution taking place in modern warfare that is making conventional defensive weapons very expensive relative to the offensive weapons systems, the pull for less expensive air defense may necessitate a HEL weapon system. Also, due to the recent technological developments in solid-state lasers (SSL), especially fiber lasers, used throughout manufacturing for cutting and welding, a HEL weapon finally may be able to meet all the requirements of ease of use, sustainability, and reliability. Due to changes in warfare and SSL technology advances, the era of HEL weapons isn't over; it may be just starting if DoD takes an evolutionary approach to fielding a HEL weapon. The U.S. Navy, with its large ships and their available electric power, should lead the way.

Climate Change: Anticipated Effects on High-Energy Laser Weapon Systems in Maritime Environments

Abstract This study quantifies the potential impacts on ship-defense high-energy-laser (HEL) performance due to atmospheric effects in the marine boundary layer driven by recent observations and analysis of worldwide sea surface temperatures (SSTs). The atmospheric effects are defined using the worldwide probabilistic climatic database available in the High Energy Laser End-to-End Operational Simulation (HELEEOS) model, which includes an SST database for the period 1854–1997. A more recent worldwide sea surface temperature database was provided by the Naval Postgraduate School for the period 1990–2008. Mean differences and trends between the two SST databases are used to deduce possible climate change impacts on simulated maritime HEL engagements. The anticipated effects on HEL propagation performance are assessed at an operating wavelength of 1.0642 μm across the world’s oceans and mapped onto a 1° × 1° grid. The scenario evaluated is near surface and nearly horizontal over a range of 5000 m in which anticipated clear-air maritime aerosols occur. Summer and winter scenarios are considered. In addition to realistic vertical profiles of molecular and aerosol absorption and scattering, correlated optical turbulence profiles in probabilistic (percentile) format are used.

Navy High Energy Laser Weapon System

ABSTRACTThis paper will historically review and describe the Navy High Energy Laser Weapon System (HELWS).Advances in anti‐ship cruise missiles (ASMs), which present the greatest challenge in surface ship self defense, are necessitating the development of significantly more sophisticated and expensive surface‐to‐air missiles in order to counter the threat. The next generation of ASMs, as represented by the French ANS, will be capable of skimming only meters above the sea surface at multi‐mach speeds, while performing evasive maneuvers during terminal run‐in. This type of threat has essentially eliminated naval gun systems from the role of ship self‐defense, and has significantly reduced the effectiveness of current missile systems.Under development for the past twenty years, the High Energy Chemical Laser appears to be a feasible solution to the ship self‐defense problem. Capable of operating effectively in all weather conditions except dense fog, a HELWS requires no conventional fire control solution, since it operates at the speed of light. Any target that can be tracked can be engaged. Furthermore, once the beam director is locked onto a target, the system is insensitive to target maneuvers. By tailoring the lase period to the threat, the effective Pk of an HELWS is essentially 1. Using chemical energy as a primary power source removes the requirement for additional costly and heavy power generation equipment aboard ship. In the context of the foregoing arguments, cost per kill becomes a fraction of the cost of a two‐round missile salvo.The technology required to field a shipboard HELWS has been demonstrated by the Navy Mid‐InfraRed Advanced Chemical Laser (MIRACL) and the Sea Lite Beam Director (SLBD). Its success in bringing down a Mach 2.2 Vandal missile in 1989 was dramatic proof of the effectiveness of such a system. Recent studies have shown that the MIRACL/SLBD can be repackaged as a HELWS to fit into the equivalent volume occupied by a 5“/54 Mk 45 gun mount and its associated magazine. Replacing the gun system with this HELWS package would result in a 15 percent reduction in weight and translate to a 5 percent improvement in ship stability because of the weight redistribution.The one remaining issue is an operational demonstration of the High Energy Laser Weapon System in a shipboard environment. The Navy is currently studying the possibility of conducting an advanced technology demonstration of a shipboard HELWS to begin in FY 95. Such a demonstration will be designed to resolve the remaining issues associated with using high energy lasers for self‐defense at sea.