Philip Moffa, Larry Yujiri, Hiroshi Agravante, Giovanni De Amici, David Dixon, Steven Fornaca, Charles Jackson, Talbot Jaeger, Karen Jordan, Randolph Quon, Kent Rasmussen, Thomas Samec, Merit Shoucri
TRW has developed a new passive millimeter wave camera for the Navy using its unique Millimeter Wave Monolithic Integrated Circuit (MMIC) technology. It operates as a pushbroom or scanning imager and can be utilized for missions that do not require as rapid a frame rate as in video-rate imagery. It is designed as a large-aperture, wide-field-of-view camera. Its focal plane consists of two rows of MMIC-based direct detection receivers and provides full sampling of the imaged scene.
Objects hidden under a lossy medium, like soil, can be detected when the boundary between the object and the medium acts as a reflector for incoming microwave radiation. Under typical soil conditions, the maximum depth at which the object can be detected is a few wavelengths. It is therefore advantageous to employ low-frequency receivers. Under a contract from the US Army CECOM-NVESD, TRW has designed and built the Microwave Radiometer Mine Detector; a hand-held man-portable unit, which employs a cold radiometric sky as the illuminating source. The breadboard unit works at 5 Ghz using a direct RF-gain, total-power radiometer. The unit was field-tested at the Army facility at Fort AP Hill during August of 1999. The test yielded a probability of detection of 45 percent and a false alarm rate of 0.11/m2.
TRW has developed a passive millimeter wave demonstration camera using its unique millimeter wave monolithic integrated circuit (MMIC) technology. It operates in a 10 GHz band around 89 GHz, has a field of view of 10 degree(s) by 15 degree(s), and can process and display data in real-time at video rates. Its focal plane consists of 1040 MMIC direct detection receivers.
The concept of using passive microwave radiometers for the detection of buried objects is well rooted in the theory of radiation propagation through lossy media. As the dielectric discontinuity at the boundary layer between the foreign object and the soil cause a reflection of the incoming radiation,the object present different radiometric properties than the surrounding background, and becomes detectable as a change in the antenna temperature. Under a contract from the US Army's Night Vision and Electronics Sensors, TRW has designed and built two hand-held man- portable units, which employ the cold radiometric sky as the illuminating source. The units work at 1.7 and 5 GHz using direct RF-gain, total-power radiometers. The units were field-tested at the Army facility at Fort AP Hill during October of 1998. The test yielded a very exciting detection rate of 100 percent and a false alarm rate of 0.28/m2.
TRW has recently developed InP low noise amplifiers operating at 140 GHz. Similar to the evolution of 94 GHz GaAs technology, this lays the foundation for the development of a 140 GHz MMIC receiver for use in a next generation passive millimeter-wave video camera capable of generating a real time display of the imaged scene. The advantages of going to 140 GHz, and the use of InP technology, will be discussed.
Millimeter wave (MMW) radiometers operating at 97 and 140 GHz were used to obtain passive MMW images and brightness temperatures of military vehicles at various altitudes and depression angles. The line-scanning radiometer system used for the measurements is described, and several passive MMW images are presented. The upper-bound MMW brightness temperatures of a number of different types of vehicles in an open area were determined and shown to have similar values at various depression angles.
A state-of-the-art W-Band passive millimeter wave focal plane array (FPA) consisting of 1040 highly integrated direct detection pixel has been designed, developed, assembled and tested. The FPA has been integrated into a passive millimeter wave video camera and has generated real time images. Each pixel is a highly integrated MMIC chip receiver. The MMIC chip is a wide band, high gain, low noise, 0.1 micrometer InGaAs HEMT amplifier with an integrated switch and Schottky barrier diode detector. The FPA uses a brick architecture. Each brick or module consists of 4 MMIC chips or pixels and lay side-by- side on the card. Many cards are stacked to create the array of pixels. In the next generation FPA, the 1 X 4 modules and cards have been dramatically simplified with 50% less assembly time. In addition, the module and card still require no tuning and minimal test time. Thus a significant cost reduction in the FPA is expected over the first generation FPA without sacrificing performance. To further reduce cost and improve performance, new MMIC chips are being designed.
Larry Yujiri, Hiroshi Agravante, Steven Fornaca, Bruce Hauss, Ronald Johnson, Roger Kuroda, Bill Quon, Arlen Rowe, Thomas Samec, Merit Shoucri, Karen Yokoyama
A passive millimeter-wave (PMMW) camera capable of generating a real time display of the imaged scene, similar to video cameras, has been developed at TRW and is undergoing field testing. The camera operates at 89 GHz, acquiring images at a frame rate of 17 Hz. This work reports on the video imaging generated by the camera. This research is carried out under the Passive Millimeter-Wave Camera Consortium, a cost-shared program between the Defense Advanced Research Programs Agency and an industrial consortium that includes Honeywell, McDonnell Douglas and TRW. It is managed for the Department of Defense by NASA-LaRC.
Passive Millimeter Wave (PMMW) imaging technology offers significant safety benefits to world aviation. Made possible by recent technological breakthroughs, PMMW imaging sensors provide visual-like images of objects under low visibility conditions (e.g., fog, clouds, snow, sandstorms, and smoke) which blind visual and infrared sensors. TRW has developed an advanced, demonstrator version of a PMMW imaging camera that, when front-mounted on an aircraft, gives images of the forward scene at a rate and quality sufficient to enhance aircrew vision and situational awareness under low visibility conditions. Potential aviation uses for a PMMW camera are numerous and include: (1) Enhanced vision for autonomous take- off, landing, and surface operations in Category III weather on Category I and non-precision runways; (2) Enhanced situational awareness during initial and final approach, including Controlled Flight Into Terrain (CFIT) mitigation; (3) Ground traffic control in low visibility; (4) Enhanced airport security. TRW leads a consortium which began flight tests with the demonstration PMMW camera in September 1997. Flight testing will continue in 1998. We discuss the characteristics of PMMW images, the current state of the technology, the integration of the camera with other flight avionics to form an enhanced vision system, and other aviation applications.
Extending earlier successful radiometric detection of both metal and plastic mines, both buried and unburied at 44 and 12 GHz, a lower frequency radiometer was tested to determine its effectiveness under soil conditions of higher water content. In addition, the ability to generate 2D images was evaluated using a novel image processing technique, and the results were compared to model predictions.
A passive millimeter wave (PMMW) camera capable of generating real time displays of the imaged scene, similar to video cameras, has been developed at TRW over the past two years. The camera operates at 89 GHz, has a 15 degree(s) X 10 degree(s) field-of-view, an aperture of 18' diameter, and displays the acquired image at a frame rate of 17 Hz. A major enabling technology is the focal plane array of direct detection MMIC receivers which enables this camera to be reliable and low cost, in addition to providing it with unique operational features. A state-of-the-art W-band passive millimeter wave FPA consisting of 1040 highly integrated direct detection MMIC pixels capable of generating real time images has been developed. We will discuss the assembly and test of high performing, high frequency GaAs MMIC chips in high volume and at low cost. This work reports on progress achieved to date in the development and manufacturing of this new sensor technology.
Larry Yujiri, Hiroshi Agravante, Mike Biedenbender, G. Samuel Dow, Martin Flannery, Steven Fornaca, Bruce Hauss, Ronald Johnson, Roger Kuroda, Karen Jordan, Paul Lee, Dennis Lo, Bill Quon, Arlen Rowe, Thomas Samec, Merit Shoucri, Karen Yokoyama, John Yun
A passive millimeter-wave camera capable of generating real time displays of the imaged scene, similar to video cameras, has been under development at TRW over the past two years. The camera operates at 89 GHz, has a 15 degree(s) X 10 degree(s) field-of-view, an aperture of 18' diameter, and displays the acquired image at a frame rate of 17 Hz. A major enabling technology is the focal plane array of direct detection MMIC receivers which guarantees reliable and low cost manufacturing of this camera, in addition to providing it with unique operational features. This work reports on progress achieved to date in the development and manufacturing of this new sensor technology.
In a continuing effort to develop new sensor technologies for the detection of land mines and other UXO, a variety of plastic and metal mines were acquired for detection tests utilizing a passive millimeter wave sensor at 44 GHz and at 12 GHz. These inert mines were surface- laid, covered with dry leaves, or buried in sand or soil, and the resulting target scene was scanned from an overhead position using the single channel sensor, generating a 2D image of the minefield.
Passive millimeter wave (PMMW) sensors have been proposed as forward vision sensors for enhanced vision systems used in low visibility aircraft landing. This work reports on progress achieved to date in the development and manufacturing of a demonstration PMMW camera. The unit is designed to be ground and flight tested starting 1996. The camera displays on a head-up or head-down display unit a real time true image of the forward scene. With appropriate head-up symbology and accurate navigation guidance provided by global positioning satellite receivers on-board the aircraft, pilots can autonomously (without ground assist) execute category 3 low visibility take-offs and landings on non-equipped runways. We shall discuss utility of fielding these systems to airlines and other users.
Passive millimeter wave (PMMW) imaging sensor technology has made significant advances in recent years to permit the development of manufacturable cameras which can be economically produced. In addition to its operation in adverse weather, the PMMW camera is non-emitting which makes it suitable for both military and civilian applications. For example, aircraft executing autonomous landing using GPS, need an all weather, real time, true image of the forward scene during the touch-down, roll-out, turn-off and taxi maneuvers. The PMMW camera not only provides such an image, but is easily implementable as a sensor for the pilot, and as a system which operates in an airport environment. We shall address these issues and discuss other applications of this new sensor technology.
The detection of land mines and other ordnance on the battlefield has grown in importance with their increased use, not only for military personnel, but for civilians after hostilities have ceased. The need for new approaches and sensors to increase the speed and efficiency of methods to clear mines is an issue that must be addressed. A method to detect metal mines, on top of or buried under dry sand, is demonstrated using the passive detection of naturally occurring millimeter wave radiation (at 44 GHz) emanating from the scene. Measurements will be shown that indicate the feasibility of detection of metal under at least 3 inches of dry sand.
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