Radar Cross-Section (RCS)
Range Design & Evaluation

In the early 1980’s The Howland Company became heavily involved in the design and evaluation of radar cross section measurement facilities. Stealth technology had advanced to the point where the signals being returned from targets were at very low levels and could not be effectively measured using the existing technology. The Howland Company pioneered different chamber and anechoic material configurations to reduce the background level of reflected signals.

Outdoor RCS Ranges

Compact Ranges for RCS Measuremets

Imaging RCS Facilities

 

Bistatic RCS compact range, Pt Mugu
 --US Navy Photo

Outdoor RCS Ranges

The Howland Company's senior engineering staff has many years of experience both designing and managing day-to-day operations of outdoor RCS ranges, including some of the most important static and dynamic range facilities in the US.

Outdoor RCS ranges are described as static, with the target supported on a low-RCS pylon or column, or dynamic, with the target moving (e.g., flying) through the field of view of the range instrumentation.

The attraction of outdoor ranges for RCS measurements is that they can be designed to measure large targets over wide frequency ranges. The drawback of an outdoor range is that it can be difficult to conduct measurements in a secure environment.

 

Additional Information:

External Link  "US Restricted and Classified Test Sites" at Sean O'Connor's IMINT & Analysis blog contains descriptions of several outdoor RCS Ranges in the western United States.

 

Bluefire--"RCS Ranges of the Mojave Desert" by Tom Mahood

"Radar Ranges of the Mohave Desert," a series of web pages by Tom Mahood, describes in considerable detail several outdoor RCS ranges in remote corners of California.

 

RAMS RCS Range, Holloman AFB; antenna array is at the far end of the range, with the test pylon and target preparation area in the foreground.
NRTF/RATSCAT images courtesy USAF

NRTF RAMS target support and storage facilities   NRTF RAMS antenna array
     
Northrop Grumman UCAR stealth helicopter UAV model tested at RATSCAT Mainsite.

NRTF logo
National Radar Cross Section (RCS)
Test Facility (NRTF), White Sands Missile Range/Holloman AFB,
New Mexico

Low-Observable "stealth" helicopter Unmanned Combat Armed Rotorcraft (UCAR) prototype models being measured at the RATSCAT Mainsite: Northrop Grumman's design is shown at left, with Boeing's on the right. The Howland Company was a member of the design team for the RATSCAT Advanced Measurement Site (RAMS), above as well as the Mainsite's Integrated Radar Measurement System (IRMS), below.

Lockheed prototype Unmanned Combat Armed Rotorcraft (UCAR) stealth helicopter UAV model at RATSCAT Mainsite.
 
RATSCAT IRMS antenna array, electromagnetic design by The Howland Company.
 
RCS range complex, Sandia National Lab
 --Image from Google Earth
 

This aerial photo shows two RCS ranges at Sandia National Laboratories in New Mexico with a Howland Company connection. The long track-like structure is the 1200-foot Inverted Vee outdoor RCS range; and Building 9972, at the northeast end of the Vee range, houses a 110 ft x 42 ft x 26 ft (34m x 13m x 8m) RCS compact range. Both ranges were completed in the 1980s and, with upgrades made in 2008, continue to support Sandia's R&D mission.

 

Compact Range RCS Measurement Facilities

In the 1980's there was tremendous interest in adapting the compact range for radar cross-section measurements. Originally conceived as a method for testing X and Ku band fire control radars, there had to be significant changes in the compact range in order to make it usable for making RCS measurements of large targets.

Very large compact range reflectors were built, thus increasing the quiet zone size and extending the lowest frequency of operation. At the same time the edges of the reflector were redesigned to reduce the diffraction effects from the edge.

At this point it was found that the anechoic material in the chamber was the limiting factor in making low level RCS measurements. The Howland Company was tasked to provide the overall electromagnetic design and improved designs for the layout of the anechoic material.


MGM-8 target missile in the Bistatic Anechoic Chamber RCS facility
--US Navy Photo

Bistatic Anechoic Chamber (BAC) RCS
Measurement Compact Range, Radar Reflectivity
Lab, NAWC Pt. Mugu, California

     
     
Hughes Aircraft Chamber 1, Compund Reflector RCS Comapct Range
 --Hughes Aircraft Photo
RCS Measurement Complex, Hughes
Aircraft, El Segundo, California
  Large Anechoic Chamber (LAC) for RCS measurements, NAWC Pt. Mugu
 --US Navy Photo

Large Anechoic Chamber (LAC) RCS
Measurement Compact Range, Radar
Reflectivity Lab, NAWC Pt. Mugu
     

RCS Imaging Facilities

One intriguing problem has been how to test a stealth vehicle after manufacturing in order to insure that it is indeed "stealthy".

An imaging system can operate in an echoic chamber (one without anechoic material) and provide data on the low observable characteristics of the vehicle.

The Howland Company has provided design and engineering services for three different imaging systems, two for Lockheed-Martin and one for Boeing.

RCS Functional Test Facility, Lockheed Martin, Marietta, Georgia

Near Field Test Facility (NFTF), Boeing Phantom Works, St Louis

RF Field Probe, F-35 RCS Acceptance Test Facility, Fort Worth, Texas

 
F-22 Production RCS Imaging Facilty
 --Lockheed Martin Photo
Engineers from Lockheed and The Howland Company
celebrate the first full-up test of the
F-22 Aircraft RCS Functional Test Facility.