Terrestrial nonimaging infrared MASINT
Terrestrial nonimaging infrared MASINT is a subset of electro-optical MASINT, a subset of measurement and signature intelligence, which senses energy, energy differences, or energy spectra in the infrared wavelengths, using ground-based sensors. While infrared IMINT and MASINT operate in the same wavelengths, MASINT does not “take pictures” in the conventional sense, but it can validate IMINT pictures. Where an IR IMINT sensor would take a picture that fills a frame, the IR MASINT sensor gives a list, by coordinate, of IR wavelengths and energy. A classic example of validation would be analyzing the detailed optical spectrum of a green area in a photograph: is the green from natural plant life, or is it camouflage paint?
Infrared MASINT sensors are almost always coupled with other intelligence collection technologies, including IMINT (both in the visual and infrared wavelengths), geophysical MASINT, and other techniques that complement one another in reducing false detection.
Unattended sensing on land
The United States Army's AN/GSQ-187 Improved Remote Battlefield Sensor System (I-REMBASS) contains a Passive Infrared Sensor, DT-565/GSQ, that detects vehicles and personnel, giving a count of targets passing through its view, and their direction of movement. The passive IR sensor is coupled with a magnetic MASINT sensor.
I-REMBASS detection capabilities
|Target type||Detection range|
|Personnel on foot||3-50 meters|
|Wheeled vehicles||15-250 meter|
|Tracked vehicles||25-350 meters|
It is, however, considered an obsolescent system, due to large size, short battery life, and aging technology not readily updated. As an alternative, the New Zealand Defense Technology Agency (DTA) supported the development of a feasibility demonstration of unattended sensors, using, to the greatest extent, commercial off-the-shelf (COTS) technologies. The project, done at the Department of Electrical and Computer Engineering of the University of Auckland, used commercial wireless transmission (IEEE 802.15) and the Freescale Zigbee as the microcontroller and radio transceiver. 
In the prototype, passive infrared (PIR) sensors were paired with seismic sensor The selected PIR sensor does not image targets, but detects people from body temperature and vehicles from engine heat, with low power consumption and a wide-angle detection space. The major limitation is that they do not detect motion, which is necessary to categorize targets. Seismic sensing, however, does give motion information.
Shallow-water operations  require generalizing IR imaging to include a non-developmental Thermal Imaging Sensor System (TISS) to surface ships with a day/night, high-resolution, infrared (IR) and visual imaging, and laser range-finder capability to augment existing optical and radar sensors, especially against small boats and floating mines. Similar systems are now available in Army helicopters and armored fighting vehicles.
Defeating passive IR triggered improvised explosive devices
Some of the more sophisticated improvised explosive devices (IED) being encountered in Iraq use passive IR sensors as their trigger. The U.S. military has a number of initiatives that could be considered counter-MASINT in this area. For example, the United States Marine Corps has a funding request to "Initiate an Explosive Hazard Defeat for IED Neutralization effort focused on applying passive infrared phenomenology understanding to a capability enabling defeat of PIR devices from significant stand-off distances."
- Pike, John E. (2005), AN/GSQ-187 Improved Remote Battlefield Sensor System
- Hahn, George F. (2005), Investigation of an Unattended Wireless Ground Sensor
- National Academy of Sciences Commission on Geosciences, Environment and Resources (April 29-May 2, 1991), Symposium on Naval Warfare and Coastal Oceanography. Retrieved on 2007-10-17
- Department of the Navy (February 2008), MARINE CORPS LANDING FORCE TECHNOLOGY, Fiscal Year 2009 RESEARCH, DEVELOPMENT, TEST & EVALUATION, NAVY BUDGET ACTIVITIES 1-3, Exhibit R-2a