Radar that sees like a camera?

I've written before about advances in radar imaging technology, with specific reference to Northrop Grumman's MP-RTIP project, which can produce images like this (click it for a larger view):




and NASA's AIRSAR project, which produced this image:




Note that neither of the images above has any photographic or optical elements at all. They were both produced by radio returns alone. That's pretty amazing, when you think about it . . . but it's only a shadow of what's coming down the pike. The US Office of Naval Research has just solicited proposals from industry for new and improved surveillance technologies. They want:

"... an all-weather, day-night approach for use when electro-optic techniques are ineffective. The concept would utilize one or more distributed airborne platforms, and is capable of imaging an area of at least 5 by 5 miles, at least 1 foot resolution, with 0.5 Hz updates. Typical footprints are centered between 5 and 100 miles from the airborne platform. The desired output would be video-like radio frequency (RF) imagery of static and moving objects. Typical targets include urban structure, vehicles, and dismounts. Typical environments are urban and littoral areas with moderate to high density vehicle and dismount traffic, strong discrete scattering, blockage and shadowing. It is strongly desired to develop a solution that builds upon, and/or upgrades, an existing military RF sensor capability."

There's more at the link. Bold print is my emphasis.

Does "video-like radio frequence imagery of static and moving objects" sound familiar? It sure does to me . . . in fact, it sounds just like what we've already seen from MP-RTIP and AIRSAR, only more so!

The MP-RTIP radar has previously flown beneath the Proteus aircraft test-bed:




However, it's now been developed to the point where it's planned to install it on the next generation of Northrop Grumman's RQ-4 Global Hawk unmanned aerial vehicle, the Block 40 version, pictured below. The housing for the MP-RTIP radar beneath the fuselage is highlighted by a red oval.




A Northrop Grumman news release pointed out:

Use of the MP-RTIP sensor on the Block 40 Global Hawks marks the first time the active electronic scanned array (AESA) technology has been used on a high-altitude unmanned aircraft. AESA technology provides all-weather, day-night synthetic aperture radar mapping and ground moving target indicator capability.

. . .

Flying at altitudes of more than 60,000 feet for more than 32 hours per sortie at speeds approaching 340 knots, the MP-RTIP-equipped Block 40 Global Hawk can persistently see through most type of weather, day or night. As the world's first fully autonomous high-altitude, long-endurance unmanned aircraft system, Global Hawk is the platform of choice for a wide variety of sensors, foreign and domestic, meeting the global need for persistent ISR.

There's more at the link.

Of particular interest, given the Office of Naval Research's solicitation, is that a navalized version of the RQ-4 Global Hawk won the competition to provide the US Navy's Broad Area Maritime Surveillance aircraft last year. Note, too, that MP-RTIP is current technology. The ONR solicitation wants new technology, to improve on what MP-RTIP can already deliver.

This isn't the only area where radar imaging is venturing into uncharted territory. DARPA's Special Projects Office speaks of urban operations as the the new frontier for radar. (The link is to an Adobe Acrobat document in .PDF format.)

SPO believes radar can, in fact, use multipath to extend reconnaissance into two new frontiers: urban canyons and the interiors of buildings. In short, we believe we can transform "Can you hear me now?" into "We can see you now".

These applications may strike you as fanciful, but the whole history of radar suggests the path from the fantastic to the fundamental can be quite short. Until the mid-1930s, the radar effect was little more than an interesting anomaly. A few short years later, radar allowed England to survive the Battle of Britain and to turn the tables on the Axis by breaking the U-boat fleet.

In this age of asymmetric warfare, is it possible urban radar could bring about a stunning new advantage?

. . .

Imagine a commander being able to drive or fly down a city block and monitor buildings on both sides of the street, to find occupants inside, determine the layouts of the buildings, and locate weapon caches. We will be developing capabilities in advanced multistatic sensors and signal processing to create urban radar systems that will allow reconnaissance over whole city blocks.

Again, there's more at the link.

I think, to adapt the words of the song, "we ain't seen nothin' yet" in terms of radio frequency imaging of our world. I'm going to watch developments in this field with great interest.

Peter