Current unmanned aircraft – including the MQ-1 Predator, MQ-9 Reaper and RQ-4 Global Hawk have excelled against terrorists, both for near-persistent intelligence, surveillance and reconnaissance and strike capability for Reapers and Predators. This was partly due to the permissive environments of southwest Asia counter terrorism missions against technologically inferior groups. In active operation with the USAF since 2001, Global Hawk is capable of flying at altitudes up to 60,000ft for more than 30 hours continuously. It is powered by a Rolls-Royce AE 3007 turbofan engine. The RQ-4 fleet carries out a range of missions including near real-time imagery, signals intelligence, airborne communications gateway and tactical networking.
The future conflicts shall involve operating them in anti-access/area-denial (A2/AD) environments established by more advanced nation-state adversaries. These platforms they are slow-moving and easy targets for advanced radar and anti-aircraft batteries of near-peer competitors. In June 2017, United States Air Force EQ-4 “Global Hawk” drone was shot down over the Mediterranean Sea off the coast of Syria, by a Russian S-300 surface-to-air missile fired from the Russian Base at Tartus, Syria.
Operation for A2AD environments requires either stand-off spectral imaging systems or penetrating spectral imaging systems. Stand-off systems require operations at high altitude (>50,000’) and long slant ranges (>60km), which necessitates advances in hardware and software.
The goal of the Standoff High Resolution Imaging (SHRI) effort is to perform exploratory and advanced development of technologies and systems to extend the effective range of high altitude reconnaissance imaging systems such as those employed on the U-2 and Global Hawk. Effective range is defined to be the range at which National Image Interpretability Rating Scales (NIIRS) 5 or better image quality can be achieved. Both broadband day and night imaging are within the scope of this effort.
A mix of capabilities to penetrate the highly contested environment as well as deliver effects from stand-off ranges offers a balanced approach to counter the A2/AD strategy,” stated the Air Force’s Air Superiority Flight Plan 2030, released in May 2016. The plan lists kinetic and non-kinetic concepts to achieve this, which include long-range strike capabilities, penetrating counter-air capabilities and electronic warfare, among others.
Penetrating spectral platforms must be compact and low cost, and they may operate on expendable platforms. AFRL has on-going activities to develop next generation hardware and software for spectral imaging in A2AD, which include novel longwave infrared spectrometer designs for increased sensitivity, advanced atmospheric compensation and target detection techniques, and research into compact and low cost spectral systems.
The EO-CHIL programme focuses on investigating, developing, and demonstrating concepts, components and systems technologies in order to enhance imaging performance for standoff high-resolution imaging (SHRI), hyperspectral sensing, infrared search and track (IRST), and sense and avoid (SAA) technology.
The primary aim of the programme is to defeat adversary anti-access and area denial (A2 / AD) threat environments through extended-range high-resolution imaging, hyperspectral sensing, and close-in imaging with expendable sensors.
Reaper and Global Hawk Modernization
Raytheon Company received a contract in Jan 2019 to maintain and modernise both hardware and software of the ground control systems and onboard sensors used by the US Air Force (USAF) fleet of RQ-4 Global Hawk remotely piloted aircraft. The scope of work includes the provision of software upgrades to defend against cyber threats.
Raytheon IIS Mission Support and Modernization vice-president Todd Probert told Air Force Technology: “Every connected system is a potential vector for a cyber-attack. Just as consumers get security updates for their phones and computers, Raytheon constantly provides cybersecurity upgrades to military systems like the Global Hawk ground control station to secure them against this constantly evolving threat.”
In August 2016, Raytheon obtained a $104m contract to modernise the Global Hawk ground segment. The contract involved moving payload and aircraft operators into mission control buildings. The new mission control stations at Beale and Grand Forks Air Force Bases replaced the existing, shelter-based, mission control and launch and recovery elements.
The U.S. Air Force says it will pursue a “distributed” combination of existing manned and unmanned aircraft with new sensors and other equipment to be able to extend the reach of those surveillance capabilities into heavily defended areas, especially during any potential large-scale high-end conflict, especially against a near-peer opponent such as Russia or China.
With its budget request for the 2019 fiscal year, which it released earlier in February 2018, it formally announced it would favor of mix of upgraded E-3 airborne early warning and control planes, high-flying RQ-4 Global Hawk unmanned aircraft, and medium-altitude MQ-9 Reaper drones. To support this new concept, seven E-3s will receive improved sensors, as well as updated communications gear and data links to be able to better share a variety of information with other aircraft and troops on the ground. The Block 40 Global Hawks will also get improved connectivity so they can distribute data from their own multi-purpose radars, which can operate in a ground moving target indicator (GMTI) mode, in near real time. Lastly, some Reapers will get a new GMTI-capable radar.
The War Zone’s own Tyler Rogoway has already explored this issue in depth, noting that the Air Force appeared to be moving toward developing a new, low-observable platform – or using a classified system it already has – to act as an important sensor node as part of a distributed “system or systems” to support the battlefield management and command and control mission, also referred to as BMC2. Such an aircraft could be manned, unmanned, or even a pilot-optional design and would use its systems to gather battlefield intelligence in high threat areas near or forward of the front lines, all the while relaying that information back to other aircraft or ground command centers with the ability to process it and pass it along to other units.
But a larger stealthy sensor platform able to carry a larger, more powerful lower intercept radar could offer capability of conducting long-endurance missions to collect radar imagery and other data, monitoring enemy movements across a wide area deep inside hostile territory with a low likelihood of detection. This in turn could give air and ground commanders a much better picture of the overall battlefield and an opponent’s activities, even in denied areas.
Standoff High Resolution Imaging (SHRI) effort
The AFRL EO Threat and Target Detection branch has an evolving portfolio of passive and active-illuminated electro-optical (EO) sensor research. Current passive hyperspectral systems typically operate at low to medium altitudes in non-contested environments. These systems may operate in the visible, near and short-wave infrared for a day-only capability, or operate in the long-wave infrared to provide day/night capability.
Additionally, hyperspectral imaging in the near-infrared and short-wave infrared is dependent on solar illumination, which varies in intensity and sun-target-sensor viewing angle. These factors complicate target and background spectrum retrieval. Advances in broad-band, high-radiant-intensity sources such as supercontinuum lasers (SCLs) may enable active spectral imagers. Innovative system designs might provide for sequential solar and laser operation to allow for invariance to illumination conditions.
AFRL has new efforts to model and measure active spectral imagers operating in the 1-2.5 micron band. The utility of SCLs may be hampered by atmospheric turbulence, near-field backscatter, or system calibration issues. The available laser power may stress the trade between area coverage and signal-to-noise (SNR).
AFRL has modeled future system concepts that indicate the potential ability to significantly increase the effective range of current operational platforms under realistic atmospheric conditions. For better daytime imaging, this future imaging system requires investments in: small-pitch, large-format detector technology; large lightweight optics; and algorithms to reduce the effects of turbulence, jitter/drift, and atmospheric extinction and scattering. The models suggest resources for nighttime imaging are best invested in midwave infrared (MWIR) detectors and improved optics.
At the heart of both daytime and nighttime concepts is the transition from scanning time-delay integration (TDI) or step-stare collection systems to collection based on a staring multi-frame restoration (MFR) approach. MFR can utilize multiple frames of data to accomplish various objectives, including: noise, jitter, and drift reduction; turbulence compensation; and resolution enhancement. As a result, MFR can provide higher image quality compared to conventional techniques. Additionally, an imaging system build around MFR also provides video/motion imagery. Consequently, a program including the development of MFR-enabling focal plane arrays and algorithms along with rigorous test and evaluation is seen as a core component of the research.
The objective of the EO-CHIL Program is to conduct Research and Development to advance and mature AFRL’s portfolio of electro-optical sensors and related technology for intelligence, surveillance, and reconnaissance (ISR), targeting and situation awareness for manned, remotely piloted, and autonomous aircraft.
This effort encompasses the development, measurement, modeling, and test or evaluation of single-band, multi-band, and hyperspectral sensors, associated processing algorithms, and their resulting imagery or data. These sensors may be employed for air-to-air or air-to-ground missions and work at ranges consistent with the proposed mission.
These missions span operational ranges from less than a kilometer to hundreds of kilometers to enable EO/IR ISR, targeting, and autonomy missions. All of these sensors share common elements, namely optical hardware (e.g. detectors, dewars, optics, scanners), software (e.g. image correction, enhancement, and material signature ID) and electronics (e.g. control, data storage, and data processing) that require development and testing.
Testing may occur in a laboratory, on a tower/mountaintop, or in an airborne environment and may involve evaluation and exploitation of imagery optimized for human or machine vision. Hardware to support and develop metrology, engineering targets, and ground truth equipment may be needed to facilitate testing. Supporting measurements such as prevailing weather, atmospheric transmission, atmospheric turbulence, and target and background signatures may also be required to document test conditions or model sensor performance.
AFRL has awarded a prime contract to engineering company Leidos
The US Air Force Research Laboratory (AFRL) has awarded a prime contract to engineering company Leidos for sensing technology. With a total contract ceiling of $47m, the single-award indefinite delivery / indefinite quantity (IDIQ) contract has a performance period of 87 months. The delivery will be carried out under the electro-optical combined hyperspectral imaging, infrared search and track, and long-range imaging (EO-CHIL) programme.
Leidos group president Mike Chagnon said: “The EO-CHIL award continues our collaborative role with the AFRL on leading-edge research and development programmes in key military and intelligence sensing technologies.
The scope of the programme covers advanced research in focal plane arrays, optics, spectrometers and optical systems, test targets, field and flight collections algorithm development, as well as simulation of operational imagery. It also includes novel sensor concepts and low cost, size, weight and power technology. Leidos has also been awarded an initial task order under the EO-CHIL programme.
TECHNICAL OBJECTIVES EO-CHIL programme.
Sensor Development and Characterization
AFRL/RY seeks unique and innovative approaches to advance knowledge, understanding, technology, and the state of the art in the areas of both active and passive HSI sensors and components. AFRL/RY has a particular desire for concepts that combine component-level enabling technology, such as research level super continuum lasers (SCLs), HSI systems, and research level detector technology including time-gated avalanche photodiode (APD) arrays for building 3D spectral images.
Atmospheric Characterization and Mitigation
AFRL/RY seeks unique and innovative approaches to advance knowledge, understanding, technology, and the state of the art in the area of atmospheric characterization and mitigation techniques. AFRL/RY has a requirement for an improved understanding of atmospheric properties for both short- and long-range HSI sensor testing as well as validated atmospheric models based on those properties.
AFRL/RY seeks unique and innovative approaches to advance knowledge, understanding, technology, and the state of the art in the area of phenomenology studies. AFRL/RY has a requirement to collect diurnal and seasonally-dependent atmospheric and BRDF measurements of targets envisioned for in-house sensors located in B622/B620 at Wright-Patterson AFB (WPAFB). Additionally, AFRL/RY desires phenomenological studies of IR sky radiances using an ABB Fourier-transform Infrared (FTIR) point spectrometer sky scanner, a Designs and Prototypes (D&P) FITR point spectrometer, and an Analytic Spectral Devices (ASD) field spectrometer.
Performance Modeling and Simulation
AFRL/RY seeks unique and innovative approaches to advance knowledge, understanding, technology, and the state of the art in the area of simulation of physics-based and/or empirical models to predict the performance of the various EO/IR sensors developed, measured or characterized under this effort. It is anticipated that the effort may involve the validation of such models over the conditions of interest.
AFRL/RY seeks unique and innovative approaches to advance knowledge, understanding, technology, and the state of the art in the area of algorithm development to optimize sensor capability, target detection, material ID, and false alarm mitigation. AFRL/RY desires that the algorithms support human visual interpretation, automated or aided processing, or fusion with other platform/off-board sensors. Additionally, AFRL/RL has a requirement these algorithms include atmospheric compensation and associated methods for retrieving material reflectance/emissivity.
Additionally, AFRL/RY desires that the design and implementation of any of the aforementioned algorithms be designed for a real-time (or near-real-time) capability via general-purpose graphical processing units (GPGPUs), programmable gate arrays (FPGAs), printable circuit board (PCB) processors or other similar technology.
Develop Test Targets
AFRL/RY seeks unique and innovative approaches in the development of test targets used during data collections. It is anticipated that this work may include the design, fabrication, and operation of spectral and spatial EO test targets to be used during outdoor data collections.
Targets shall be used to advance knowledge, understanding, technology, and the state of the art in evaluating metrics such as spatial resolution, spectral resolution, NIIRS, and other similar metrics associated with HSI system performance. Additional performance parameters might include path transmission, path radiance, downwelling radiance, and other parameters related to the imaging path.
References and resources also include: