Measurement and signature intelligence

As of 2004, China was reported not to be pursuing the more specialized MASINT technologies,[11] although it does produce its antisubmarine sensors.

Following the first successful launch on December 19, 2006, about a year after the intended launch date, further satellites were launched at roughly six-month intervals, and the entire system of this five-satellite SAR Lupe synthetic aperture radar constellation achieved full operational readiness on 22 July 2008.[12]

Italy and France are cooperating on the deployment of the dual-use Orfeo civilian and military satellite system.[13]

Orfeo is a dual-use (civilian and military) earth observation satellite network developed jointly between France and Italy. Italy is developing the Cosmo-Skymed X-band polarimetric synthetic aperture radar, to fly on two of the satellites.

Russia does have nonimaging infrared satellites to detect missile launches.[14] Russia produces, of course, a wide range of antisubmarine warfare sensors.

UK developed the first successful acoustic system, sound ranging to detect hostile artillery and anti-submarine acoustic detection in World War I. In the 1990s, an improved acoustic system for artillery location acoustic artillery location system was introduced, which complements Counter-battery radar.

Within the US Intelligence Community the Directorate of MASINT and Technical Collections office of the Defense Intelligence Agency is the central agency for MASINT. This was formerly called the Central MASINT Office. For education and research, there is the Center for MASINT Studies and Research of the Air Force Institute of Technology.

Clearly, the National Reconnaissance Office and National Security Agency work in collecting MASINT, especially with military components. Other intelligence community organizations also have a collection role and possibly an analytic role. In 1962, the Central Intelligence Agency, Deputy Directorate for Research (now the Deputy Directorate for Science and Technology), formally took on ELINT and COMINT responsibilities.[15]

The consolidation of the ELINT program was one of the major goals of the reorganization. ... it is responsible for:

• Research, development, testing, and production of ELINT and COMINT collection equipment for all Agency operations.
• Technical operation and maintenance of CIA deployed non-agent ELINT systems.
• Training and maintenance of agent ELINT equipment
• Technical support to the Third Party Agreements.
• Data reduction of Agency-collected ELINT signals.
• ELINT support peculiar to the penetration problems associated with the Agent's reconnaissance program under NRO.
• Maintain a quick reaction capability for ELINT and COMINT equipment.

CIA's Office of Research and Development was formed to stimulate research and innovation testing leading to the exploitation of non-agent intelligence collection methods. ... All non-agent technical collection systems will be considered by this office and those appropriate for field deployment will be so deployed. The Agency's missile detection system, Project [deleted] based on backscatter radar is an example. This office will also provide integrated systems analysis of all possible collection methods against the Soviet antiballistic missile program is an example.[15]

It is not clear where ELINT would end and MASINT would begin for some of these projects, but the role of both is potentially present. MASINT, in any event, was not formalized as a US-defined intelligence discipline until 1986.

CIA took on a more distinct MASINT responsibility in 1987.[16] The National Security Archive commented, "In 1987, Deputy Director for Science and Technology Evan Hineman established ... a new Office for Special Projects, concerned not with satellites, but with emplaced sensors—sensors that could be placed in a fixed location to collect signals intelligence or measurement and signature intelligence (MASINT) about a specific target. Such sensors had been used to monitor Chinese missile tests, Soviet laser activity, military movements, and foreign nuclear programs. The office was established to bring together scientists from the DS&T's Office of SIGINT Operations, who designed such systems, with operators from the Directorate of Operations, who were responsible for transporting the devices to their clandestine locations and installing them.

The National Geospatial-Intelligence Agency plays a role in geophysical MASINT.

All nuclear testing, of any level, was forbidden under the Comprehensive Test Ban Treaty (CTBT) (which has not entered into force), but there is controversy over whether the preparatory commission for the Comprehensive Nuclear-Test-Ban Treaty Organization (CTBTO) or the Treaty Organization itself will be able to detect sufficiently small events. It is possible to gain valuable data from a nuclear test that has an extremely low yield, useless as a weapon but sufficient to test weapons technology. CTBT does not recognize the threshold principle and assumes all tests are detectable.

The CTBTO runs an International Monitoring System (IMS) of MASINT sensors for verification, which include seismic, acoustic, and radionuclide techniques. See National technical means of verification for a discussion of the controversies surrounding the ability of the IMS to detect nuclear tests.

MASINT could be of tactical use in "Non-Cooperative Target Recognition" (NCTR) so that, even with the failure of identification friend or foe (IFF) systems, friendly fire incidents could be prevented.

Another strong need where MASINT may help is with unattended ground sensors (UGS).[17] During the Vietnam War, UGS did not provide the functionality desired in the McNamara Line and Operation Igloo White. They have improved considerably, but are still an additional capability for humans on the ground, not usually replacing people altogether.

In the U.S., much of the Igloo White technology came from Sandia National Laboratories, which subsequently designed the Mini Intrusion Detection System (MIDS) family, and the U.S. Marine Corps's AN/GSQ-261 Tactical Remote Sensor System (TRSS). Another major U.S. Army initiative was the Remotely Monitored Battlefield Sensor System (REMBASS), which it upgraded to Improved REMBASS (IREMBASS), and now is considering REMBASS II. The REMBASS generations, for example, increasingly intertwine interconnections of infrared MASINT, Magnetic MASINT, seismic MASINT, and acoustic MASINT.

The UK and Australia also are interested in UGS. Thales Defence Communications, a division of the French Thales Group and formerly Racal, builds the Covert Local Area Sensor System for Intruder Classification (CLASSIC) for use in 35 countries, including 12 NATO members. Australia adopted the CLASSIC 2000 version, which, in turn, becomes part of the Australian Ninox system, which also includes Textron Systems’ Terrain Commander surveillance system. CLASSIC has two kinds of sensors: Optical Acoustic Satcom Integrated Sensor (OASIS) and Air Deliverable Acoustic Sensor (ADAS), as well as television cameras, thermal imagers, and low-light cameras.

ADAS sensors were in a U.S. program, Army Rapid Force Projection Initiative advanced concept technology demonstration (ACTD), using OASIS acoustic sensors and central processing, but not the electro-optical component. ADAS sensors are emplaced in clusters of three or four, for increased detection capability and for triangulation. Textron says that the ADAS acoustic sensors can track fixed-wing aircraft, helicopters, and UAVs as well as traditional ground threats.

ACTD added Remote Miniature Weather Station (RMWS), from System Innovations. These RMWS measure temperature, humidity, wind direction and speed, visibility and barometric pressure, which can then be sent over commercial or military satellite links.

Employing UGS is especially challenging in urban areas, where there is a great deal more background energy and a need to separate important measurements from them. Acoustic sensors will need to distinguish vehicles and aircraft from footsteps (unless personnel detection is a goal), and things such as construction blasting. They will need to discriminate among simultaneous targets. Infrared imaging, for the urban environment, will need smaller pixels. If either the targets or the sensor is moving, micro-electromechanical accelerometers will be needed.

Still more of an UGS research program, under DARPA, is Smart Dust, which is a program for developing massively parallel networks of hundreds or thousands of "motes," in the order of 1 mm³.

Another DARPA program is WolfPack, a ground-based electronic warfare system. WolfPack is made up of a "pack" of "wolves." Wolves are distributed electronic detection nodes with location and classification capability, which may use radiofrequency MASINT techniques along with ELINT methods. The wolves could be hand, artillery, or airdrop delivered. WolfPack may fit into an Air Force program for a new subdiscipline of counter-ESM, as well as Distributed Suppression of Enemy Air Defenses (DSEAD), an enhancement on SEAD. If the Wolves are colocated with jammers or other ECM, and they are very close to the target, they will not need much power to mask the signatures of friendly ground forces, in frequencies used for communications or local detection. DSEAD works in a similar way, but at radar frequencies. It may be interesting to compare this counter-ELINT discipline with ECCM.

Sensing systems have five major subcomponents:

• Signal collectors, which concentrate the energy, as with a telescope lens, or a radar antenna that focuses the energy at a detector
• Signal detectors, such as charge-coupled devices for light or a radar receiver
• Signal processing, which may remove artifacts from single images, or compute a synthetic image from multiple views
• Recording mechanism
• Recording return mechanisms, such as digital telemetry from satellites or aircraft, ejection systems for recorded media, or physical return of a sensor carrier with the recordings aboard.

MASINT sensors may be framing or scanning or synthetic. A framing sensor, such as a conventional camera, records the received radiation as a single object. Scanning systems use a detector that moves across the field of radiation to create a raster or more complex object. Synthetic systems combine multiple objects into a single one.

Sensors may be passive or coupled to an active source (i.e., "active sensor"). Passive sensors receive radiation from the target, either from the energy the target emits, or from other sources not synchronized with the sensor.

Most MASINT sensors will create digital recordings or transmissions, but specific cases might use film recording, analog recording or transmissions, or even more specialized means of capturing information.

Figure "Remote Sensing Geometry" illustrates several key aspects of a scanning sensor.

Remote sensing geometry—relationships between scanning sensor and target

The instantaneous field of view (IFOV) is the area from which radiation currently impinges on the detector. The swath width is the distance, centered on the sensor path, from which signal will be captured in a single scan. Swath width is a function of the angular field of view (AFOV) of the scanning system. Most scanning sensors have an array of detectors such that the IFOV is the angle subtended by each detector and the AFOV is the total angle subtended by the array.

Push broom sensors either have a sufficiently large IFOV, or the scan moves fast enough with respect to the forward speed of the sensor platform, that an entire swath width is recorded without movement artifacts. These sensors are also known as survey or wide field devices, comparable to wide angle lenses on conventional cameras.

Whisk broom or spotlight sensors have the effect of stopping the scan, and focusing the detector on one part of the swath, typically capturing greater detail in that area. This is also called a close look scanner, comparable to a telephoto lens on a camera.

Passive sensors can capture information for which there is no way to generate man-made radiation, such as gravity. Geodetic passive sensors can provide detailed information on the geology or hydrology of the earth.

Active sensors are conceptually of two types, imaging and non-imaging. Especially when combining classes of sensor, such as MASINT and IMINT, it can be hard to define if a given MASINT sensor is imaging or not. In general, however, MASINT measurements are mapped to pixels of a clearly imaging system, or to geospatial coordinates known precisely to the MASINT sensor-carrying platform.

In MASINT, the active signal source can be anywhere in the electromagnetic spectrum, from radio waves to X-rays, limited only by the propagation of the signal from the source. X-ray sources, for example, must be in very close proximity to the target, while lasers can illuminate a target from a high satellite orbit. While this discussion has emphasized the electromagnetic spectrum, there are also both active (e.g., sonar) and passive (e.g., hydrophone and microbarograph) acoustic sensors.

Several factors make up the quality of a given sensor's information acquisition, but assessing quality can become quite complex when the end product combines the data from multiple sensors. Several factors, however, are commonly used to characterize the basic quality of a single sensing system.

• Spatial resolution defines the correspondence between each recorded pixel and the square real-world area that the pixel covers.
• Spectral resolution is the number of discrete frequency (or equivalent) bands recorded in an individual pixel. (Relatively coarse spectral resolution from one sensor, such as the spectroscopic analyzer that reveals a "bush" is painted plaster, may greatly enhance the ultimate value of a different sensor with finer spectral resolution.)
• Radiometric resolution is the number of levels of energy recorded, per pixel, in each spectral band.
• Temporal resolution describes the intervals at which the target is sensed. This is meaningful only in synthetic imaging, comparison over a longer time base, or in producing full-motion imagery.

Cross-cueing is the passing of detection, geolocation and targeting information to another sensor without human intervention.[22] In a system of sensors, each sensor must understand which other sensors complement it. Typically, some sensors are sensitive (i.e., with a low incidence of false negatives) while others have a low incidence of false positives. A fast sensitive sensor that covers a large area, such as SIGINT or acoustic, can pass coordinates of a target of interest to a sensitive narrowband RF spectrum analyzer for ELINT or a hyperspectral electro-optical sensor. Putting sensitive and selective, or otherwise complementary sensors, into the same reconnaissance or surveillance system enhances the capabilities of the entire system, as in the Rocket Launch Spotter.

When combining sensors, however, even a quite coarse sensor of one type can cause a huge increase in the value of another, more fine-grained sensor. For example, a highly precise visible-light camera can create an accurate representation of a tree and its foliage. A coarse spectral analyzer in the visible light spectrum, however, can reveal that the green leaves are painted plastic, and the "tree" is camouflaging something else. Once the fact of camouflage is determined, a next step might be to use imaging radar or some other sensing system that will not be confused by the paint.

Cueing, however, is a step before automatic target recognition, which requires both extensive signature libraries and reliable matching to it.