Northrop Grumman eyes multifunction radar and digital signal processing work for time-sensitive targeting

Summary points:

• The U.S. Air Force Research Laboratory has awarded a contract to Northrop Grumman to develop cutting-edge multi-spectral sensing technologies for future air, space, and command-and-control systems.
• Northrop Grumman's project focuses on advancing digital AESA radar systems, which integrate radar, electronic warfare, and communications capabilities into a multifunctional platform for surveillance and targeting.
• The MUSTER program aims to explore a range of technologies, including passive RF sensing, hyperspectral imaging, laser radar, and infrared search-and-track systems, enhancing situational awareness in contested environments.

WRIGHT-PATTERSON AFB, Ohio – U.S. Air Force researchers needed enabling technologies in passive radio-frequency (RF) sensors and digital signal processing for next-generation global persistent awareness. They found a solution from Northrop Grumman Corp.

Officials of the Air Force Research Laboratory at Wright-Patterson Air Force Base, Ohio, announced a $4.6 million contract in September to the Northrop Grumman Mission Systems segment in Linthicum, Md., for the Multi-Spectral Sensing Technologies Research and Development (MUSTER) project.

MUSTER seeks to develop and test electro-optical and RF sensors for future air, space, and command-and-control systems for surveillance and reconnaissance; time-sensitive targeting; and battlespace access.

This contract to Northrop Grumman involves the MUSTER project's Arrays at Commercial Timescales Integration and Validation (ACT IV), which involves advanced research in multispectral sensing and digital active electronically scanned array (AESA) radar systems.

Digital multifunction radar

ACT-IV describes an AESA digital multifunction radar system capable of performing radar, electronic warfare (EW), and communications simultaneously through controlling many independent digital transmit-and-receive channels.

The core technology is based on advanced semiconductors originally developed under supervision of the U.S. Defense Advanced Research Projects Agency (DARPA) in Arlington, Va., to shorten phased-array design cycles and simplify upgrades. ACT-IV also is developing new algorithms and software for next-generation digital radars and multifunction systems.

This contract to Northrop Grumman is based on an updated solicitation for the MUSTER program, which began in 2021. The updated program, issued last May, has 13 research topics: multiband multifunction array development; fully adaptive radar; advanced digital multifunction arrays; laser radar imaging, systems, components, and applications; passive radio frequency sensing; sensor information processing and integration; passive electro-optic and infrared sensor technology; novel infrared hardware and algorithms; hyperspectral imaging technology; standoff high resolution imaging (SHRI); infrared search and track technology; and passive infrared space-based sensing.

Multiband multifunction array development seeks to develop advanced antenna and electromagnetic technology for air, ground, and space-based sensing applications like radar, communications, satellite operations, and intelligence, surveillance, and reconnaissance systems (ISR) from HF to W-Band frequencies.

Tell me more about multifunction active electronically scanned array (AESA) radar ... 

• Multifunction active electronically scanned array (AESA) radar uses a fixed array of small individual radar elements that can steer the radar beam electronically without physical movement. The system can perform several tasks simultaneously, like detecting and tracking targets, guiding missiles, and conducting surveillance. The radar can perform a variety of roles beyond just detection, such as targeting, tracking, imaging, electronic warfare (EW), and even communications. It allows for simultaneous multi-mode operation, enabling the radar to detect air, surface, and ground targets, as well as providing capabilities like weather monitoring or electronic countermeasures (ECM).

It involves detection; tracking; data fusion; modeling, and simulation of difficult targets in rapidly changing environments; antenna and scattering theory; situational awareness; architectures and algorithms for intelligence, surveillance, navigation, and communications.

The focus is on multiband and multifunction low cost lightweight planar and conformal phased array antennas operating at different power densities; small antennas with the gain performance of conventional antennas; radiating, wave guiding, wave transforming, and electromagnetically responsive structures and materials for aircraft; computational electromagnetic methods; space-based RF sensing; and RF technology for disaggregated systems.

Fully adaptive radar seeks to exploit all available degrees-of-freedom on transmit and receive for target detection; and tracking and classification in computationally demanding data-starved scenarios.

Advanced digital multifunction arrays involves digital RF sensors able to perform many tasks simultaneously, such as radar, electronic warfare (EW), and communications.

Digital beamforming

This will develop sensors with digital beamforming and an intelligent sensor resource manager (ISRM) for passive radar illumination, multi-mode resource allocation ,and scheduling coalescence.

Laser radar imaging involves laser radar (ladar)-based approaches for surveillance, precision attack, and air-to-air engagements. This may include the ability to detect, track, and identify difficult air and ground targets in challenging environments.

Included in the project are new ideas for active focal plane arrays with integrated read-out integrated circuits (ROICs) and flight laser systems and components. Direct-detection and coherent ladar are of interest.

Passive RF sensing involves situational awareness, tracking, and targeting applications. It should be able to exploit any available RF sources to provide situational awareness.

Tell me more about the integrated circuit technology necessary for multifunction AESA radar ...

• AESA radar uses an array of small, solid-state transmit and receive modules that are controlled individually for rapid beam steering and multi-target tracking without physically moving parts. It often involves power amplifier ICs built from gallium nitride (GaN) that boost the radar signals to high levels for long-range detection. Low-noise amplifiers (LNAs) boost weak radar returns without introducing too much noise, as the signals from distant objects are often very weak. Phase shifters control the phase of the individual radar elements to steer the radar beam electronically without moving parts. Microwave ICs manipulate the phase of the signals at microwave frequencies, while digital signal processing (DSP) ICs process large amounts of data in real-time for signal conditioning, target detection and tracking algorithms, and adaptive beamforming. Modern AESA systems use sophisticated DSPs that are optimized for high-speed computations and low power consumption.

Waveform phenomenology, design, and applications seeks to identify signal phenomenology for new and difficult-to-detect RF waveforms. This involves noise-like waveforms, interference-tolerant waveforms, and low-probability-of-intercept waveforms.

Sensor information processing and integration seeks to understand of massive amounts of data coming from distributed sensors and develop actionable intelligence using autonomous or semi-autonomous situational awareness.

Passive electro-optic and infrared sensor technology involves target detection, recognition, and tracking using any infrared waveband. Novel infrared hardware and algorithms involves developing computers and software algorithms that can detect low-signal targets in noisy and heavily cluttered environments using infrared sensors.

Hyperspectral imaging technology involves day and nighttime hyperspectral technologies for enhanced material detection and identification in contested environments.

High-resolution imaging

Standoff high-resolution imaging (SHRI) seeks to advance long-range multi-band imaging in contested environments using large-format high-temperature imaging and video arrays with reduced detector size, and high-speed sampling.

Infrared search and track (IRST) technology seeks to develop an advanced long-range wide-field-of-view staring IRST system that can operate at video rates.

Passive infrared space-based sensing seeks to develop passive infrared sensing with reduced cost, size, and weight. This involves optics and data processing.

For more information contact Northrop Grumman Mission Systems online at www.northropgrumman.com/who-we-are/business-sectors/mission-systems, the Air Force Research Laboratory at www.afrl.af.mil, or DARPA at www.darpa.mil/news/2021/phased-array-system.