BoomSAR

Last updated

The boomSAR is a mobile ultra-wideband synthetic aperture radar (UWB SAR) system designed by the U.S. Army Research Laboratory (ARL) in the mid-1990s to detect buried landmines and IEDs. Mounted atop a 45-meter telescoping boom on a stable moving vehicle, the boomSAR transmits low frequency (50 to 1100 MHz) short-pulse UWB signals over the side of the vehicle to scope out a 300-meter range area starting 50 meters from the base of the boom. [1] [2] It travels at an approximate rate of 1 km/hour and requires a relatively flat road that is wide enough to accommodate its 18 ft-wide base. [3]

Contents

Characteristics

The boomSAR is a fully polarimetric system that transmits and receives low-frequency waveforms with over 1 gigahertz of usable bandwidth, covering a spectrum from approximately 40 MHz to 1 GHz. [4] [5] Its testbed radar subsystems consist of the antennae, the transmitter, the analog-to-digital (A/D) converter, the processor/data storage system, the timing and control assembly, the MOCOMP subsystem, and the operator interface computer. [5] Much of these components are modular in nature for easy modification and upgrades and were constructed with commercial-off-the-shelf (COTS) technology to reduce costs. [5] [6]

Boom platform

The boom lift platform for the boomSAR is a 150-ft-high telescoping lift device with a basket which can be moved axially and radially and is able to handle a load capacity of 500 to 1000 lbs depending on the position of the telescoping arms. Built by JLG Inc, it possesses the unique capability of base movement while the boom is extended, allowing the boomSAR to conduct data collection using simulated airborne geometry. [5] [6] The down-look angles to the target typically varies from 45 degrees to 10 degrees depending on the range to the target and the height of the boom. [4]

Antennas

The boomSAR utilizes two transmitting and two receiving antennas to provide the full polarization matrix (HH, HV, VH, VV) in a quasi-monostatic sense. [4] All four antennas are 200 W, open-sided, and resistively terminated TEM horn antennas that are about two meters long with a 0.3-meter aperture. [2] [4] Since the subsystems were designed specifically for low-frequency UWB SAR application, the TEM horn antennas have a wide beamwidth in excess of 90 degrees and are fitted with a high-power, wide-bandwidth balun that can handle the 2-MW peak pulse of the impulse transmitter. [2] [5] According to later data, this antenna/balun combination is capable of transmitting a short-pulse UWB signal with a bandwidth from 40 MHz to over 2000 MHz with a pulse repetition frequency up to 1 kHz through the four TEM horn antennas. [1] [2]

Motion Compensation (MOCOMP) system

The boomSAR MOCOMP system consists of a computer and a geodimeter, which accounts for the motion compensation and positioning of the radar in three-dimensional space. The geodimeter consists of a robotic laser-ranging theodolite set up on one end of the aperture, a retro-reflector mounted on the boom lift platform near the antennas, and a control unit mounted on the base of the boom lift. As the retro-reflector moves with the boom lift platform, the theodolite tracks the horizontal and vertical angular positions of the retro-reflector and measures its range. The position of the retro-reflector is then transmitted to the geodimeter control unit using an FM radio link updated at a rate of 2.5 Hz. The control unit then proceeds to transmit the position information to the MOCOMP computer. [5]

Processing System

The processing system relies on a VME card-cage with a Sun SPARC 5 host and eight Intel i860-based CSPI Supercard array processors to obtain the computational power needed to presume, filter, and back-project the range profiles to form the SAR image. Image processing for the boomSAR occurs in the field immediately after data collection. In order to accommodate the boomSAR's very wide bandwidth for data transfer and parallel processing opportunities, scientists at the U.S. Army Research Laboratory have investigated the use of Mercury parallel processors. [7]

Analog-to-Digital converter

The A/D subsystem consists of a pair of Tektronix/Analytek VX2005C, 2 Gsamples/sec A/D converters, and a stable reference clock. It acts as a wide-band receiver for the radar and is uniquely capable of providing the time difference between the sample clock and the trigger event with 10 ps resolution. [4]

UWB Radar Performance Characteristics in 1911 [5]
FeatureBoomSAR
Data collection time/aperture1.0 km/hour
Power2 MW peak
PRF750 Hz
System bandwidth40 MHz to 1.0 GHz
Processor2 x 6 i860 processors
Data storage capability3600 MB
A/D data transfer rate10 MB/s
Motion Compensation systemEmbedded data

Development

The boomSAR originated as an extension of the railSAR, a rail-guided UWB SAR system built on the rooftop of an ARL building. Once the railSAR displayed promising results from early foliage and ground penetration field trials, plans were made to transition the railSAR technology onto a mobile platform. [2] The initial goal behind the development of the boomSAR was to emulate the functions of an airborne radar system in order to better understand its full potential. Unlike an airborne system, the boomSAR provided a cost-effective method of determining the upper bound of performance for this approach to radar through precisely controlled and repeatable experiments. [3] [8]

In 1999, ARL collaborated with researchers in academia and industry to develop modeling and processing algorithms for the boomSAR. These include models for method of moments (MoM) and fast multipole method (FMM), which contributed to the development of automatic target recognition algorithms for penetration systems. [9] [10]

The boomSAR technology was later repurposed by the U.S. Army Research Laboratory to develop the UWB Synchronous Impulse Reconstruction (SIRE) radar, which mounted the SAR system on an all-terrain vehicle without the boom lift. [7] [11]

Testing

Aberdeen Proving Ground Test

In 1995, an initial data collection trial for the boomSAR was conducted at Aberdeen Proving Ground (APG) in Maryland to test its foliage and ground penetration capabilities. The testing site was characterized by a deciduous forest of varying density as well as straight and curved roads through the foliage that could accommodate the width of the boom lift. During the test, canonical targets and tactical targets were hidden in the forest or buried in the soil for the boomSAR to detect. The canonical targets included dipoles, trihedrals, and dihedrals arranged to test both radar calibration and performance, while tactical targets consisted of commercial utility cargo vehicles and HMMWVs placed around the site. [6]

The data collected from the APG test was later used to study methods for distinguishing vehicles from background clutter. Analysts determined that trees and vehicles have different frequency characteristics and that the difference in characteristics could aid automatic target discrimination processing. [12]

Yuma Proving Ground Test

In the late 1990s, two separate data collection efforts were conducted at Yuma Proving Ground in Arizona and Eglin Air Force Base in Florida as part of a research initiative sponsored by the Strategic Environmental Research and Development Program (SERDP) to enhance the detection of unexploded landmines. [1] [3] [8]

At Yuma Proving Ground, the trials were held at the Steel Crater Test Site, which partly overlapped with the neighboring Phillips Drop Zone and divided the area into two sections. The section overlapping the Phillips Drop Zone featured an almost homogeneous soil layer and was virtually free of vegetation due to the soil having been turned over to a depth of about 2 feet. In contrast to the plowed section, the natural section was relatively untouched. [5] During the test, the plowed section had more than 600 inert targets buried in the ground such as artillery shells, rockets, mortar shells, submunitions, bombs, and mines (M-20 anti-tank mines and Valmara 69 mines) as well as false targets like magnetic rocks, animal burrows, and soda cans. These inert targets were buried at different depths (surface to 2 meters deep) and entry angles (0 to 90 degrees) in order to provide a comprehensive performance evaluation for the boomSAR. On the other hand, the natural section predominantly featured tactical targets like vehicles, although it also had some mines, wires, and pipes hidden as well. The boomSAR was tasked with detecting the targets while driving down the nearby Corral Road. [3] [5]

According to the results of the trial, the M-20 mines were visible in both frequency bands when they were placed close to the surface, those that were deeply buried could not be detected in the high frequency band. On the other hand, the Valmara 69 mines could not be detected in the low frequency band but were somewhat visible in the high band. For this data, the researchers concluded that the boomSAR was better suited for using lower frequencies to find the deeply buried M-20 mines and higher frequencies for detecting the much smaller Valmara mines. [5]

See also

Related Research Articles

<span class="mw-page-title-main">Radar</span> Object detection system using radio waves

Radar is a radiolocation system that uses radio waves to determine the distance (ranging), angle (azimuth), and radial velocity of objects relative to the site. It is used to detect and track aircraft, ships, spacecraft, guided missiles, motor vehicles, map weather formations, and terrain. A radar system consists of a transmitter producing electromagnetic waves in the radio or microwaves domain, a transmitting antenna, a receiving antenna and a receiver and processor to determine properties of the objects. Radio waves from the transmitter reflect off the objects and return to the receiver, giving information about the objects' locations and speeds.

<span class="mw-page-title-main">Doppler radar</span> Type of radar equipment

A Doppler radar is a specialized radar that uses the Doppler effect to produce velocity data about objects at a distance. It does this by bouncing a microwave signal off a desired target and analyzing how the object's motion has altered the frequency of the returned signal. This variation gives direct and highly accurate measurements of the radial component of a target's velocity relative to the radar. The term applies to radar systems in many domains like aviation, police radar detectors, navigation, meteorology, etc.

Ultra-wideband is a radio technology that can use a very low energy level for short-range, high-bandwidth communications over a large portion of the radio spectrum. UWB has traditional applications in non-cooperative radar imaging. Most recent applications target sensor data collection, precise locating, and tracking. UWB support started to appear in high-end smartphones in 2019.

The X band is the designation for a band of frequencies in the microwave radio region of the electromagnetic spectrum. In some cases, such as in communication engineering, the frequency range of the X band is rather indefinitely set at approximately 7.0–11.2 GHz. In radar engineering, the frequency range is specified by the Institute of Electrical and Electronics Engineers (IEEE) as 8.0–12.0 GHz. The X band is used for radar, satellite communication, and wireless computer networks.

<span class="mw-page-title-main">Synthetic-aperture radar</span> Form of radar used to create images of landscapes

Synthetic-aperture radar (SAR) is a form of radar that is used to create two-dimensional images or three-dimensional reconstructions of objects, such as landscapes. SAR uses the motion of the radar antenna over a target region to provide finer spatial resolution than conventional stationary beam-scanning radars. SAR is typically mounted on a moving platform, such as an aircraft or spacecraft, and has its origins in an advanced form of side looking airborne radar (SLAR). The distance the SAR device travels over a target during the period when the target scene is illuminated creates the large synthetic antenna aperture. Typically, the larger the aperture, the higher the image resolution will be, regardless of whether the aperture is physical or synthetic – this allows SAR to create high-resolution images with comparatively small physical antennas. For a fixed antenna size and orientation, objects which are further away remain illuminated longer – therefore SAR has the property of creating larger synthetic apertures for more distant objects, which results in a consistent spatial resolution over a range of viewing distances.

<span class="mw-page-title-main">Imaging radar</span> Application of radar which is used to create two-dimensional images

Imaging radar is an application of radar which is used to create two-dimensional images, typically of landscapes. Imaging radar provides its light to illuminate an area on the ground and take a picture at radio wavelengths. It uses an antenna and digital computer storage to record its images. In a radar image, one can see only the energy that was reflected back towards the radar antenna. The radar moves along a flight path and the area illuminated by the radar, or footprint, is moved along the surface in a swath, building the image as it does so.

Beamforming or spatial filtering is a signal processing technique used in sensor arrays for directional signal transmission or reception. This is achieved by combining elements in an antenna array in such a way that signals at particular angles experience constructive interference while others experience destructive interference. Beamforming can be used at both the transmitting and receiving ends in order to achieve spatial selectivity. The improvement compared with omnidirectional reception/transmission is known as the directivity of the array.

<span class="mw-page-title-main">Pulse-Doppler radar</span> Type of radar system

A pulse-Doppler radar is a radar system that determines the range to a target using pulse-timing techniques, and uses the Doppler effect of the returned signal to determine the target object's velocity. It combines the features of pulse radars and continuous-wave radars, which were formerly separate due to the complexity of the electronics.

A low-probability-of-intercept radar (LPIR) is a radar employing measures to avoid detection by passive radar detection equipment while it is searching for a target or engaged in target tracking. This characteristic is desirable in a radar because it allows finding and tracking an opponent without alerting them to the radar's presence. This also protects the radar installation from anti-radiation missiles (ARMs).

<span class="mw-page-title-main">SAR-Lupe</span> German military reconnaissance satellite system

SAR-Lupe is Germany's first reconnaissance satellite system and is used for military purposes. SAR is an abbreviation for synthetic-aperture radar, and "Lupe" is German for magnifying glass. The SAR-Lupe program consists of five identical (770 kg) satellites, developed by the German aeronautics company OHB-System, which are controlled by a ground station responsible for controlling the system and analysing the retrieved data. A large data archive of images will be kept in a former Cold War bunker belonging to the Kommando Strategische Aufklärung of the Bundeswehr. The total price of the satellites was over 250 million Euro.

Radar engineering details are technical details pertaining to the components of a radar and their ability to detect the return energy from moving scatterers — determining an object's position or obstruction in the environment. This includes field of view in terms of solid angle and maximum unambiguous range and velocity, as well as angular, range and velocity resolution. Radar sensors are classified by application, architecture, radar mode, platform, and propagation window.

Radar MASINT is a subdiscipline of measurement and signature intelligence (MASINT) and refers to intelligence gathering activities that bring together disparate elements that do not fit within the definitions of signals intelligence (SIGINT), imagery intelligence (IMINT), or human intelligence (HUMINT).

Pulse-Doppler signal processing is a radar and CEUS performance enhancement strategy that allows small high-speed objects to be detected in close proximity to large slow moving objects. Detection improvements on the order of 1,000,000:1 are common. Small fast moving objects can be identified close to terrain, near the sea surface, and inside storms.

<span class="mw-page-title-main">Counter-IED equipment</span>

Counter-IED equipment are created primarily for military and law enforcement. They are used for standoff detection of explosives and explosive precursor components and defeating the Improvised Explosive Devices (IEDs) devices themselves as part of a broader counter-terrorism, counter-insurgency, or law enforcement effort.

<span class="mw-page-title-main">NISAR (satellite)</span> Joint NASA-ISRO synthetic radar aperture spacecraft

The NASA-ISRO Synthetic Aperture Radar (NISAR) mission is a joint project between NASA and ISRO to co-develop and launch a dual-frequency synthetic aperture radar on an Earth observation satellite. The satellite will be the first radar imaging satellite to use dual frequencies. It will be used for remote sensing, to observe and understand natural processes on Earth. For example, its left-facing instruments will study the Antarctic cryosphere. With a total cost estimated at US$1.5 billion, NISAR is likely to be the world's most expensive Earth-imaging satellite.

<span class="mw-page-title-main">High Resolution Wide Swath SAR imaging</span>

High Resolution Wide Swath (HRWS) imaging is an important branch in synthetic aperture radar (SAR) imaging, a remote sensing technique capable of providing high resolution images independent of weather conditions and sunlight illumination. This makes SAR very attractive for the systematic observation of dynamic processes on the Earth's surface, which is useful for environmental monitoring, earth resource mapping and military systems.

The Synchronous Impulse Reconstruction (SIRE) radar is a multiple-input, multiple-output (MIMO) radar system designed to detect landmines and improvised explosive devices (IEDs). It consists of a low frequency, impulse-based ultra-wideband (UWB) radar that uses 16 receivers with 2 transmitters at the ends of the 2 meter-wide receive array that send alternating, orthogonal waveforms into the ground and return signals reflected from targets in a given area. The SIRE radar system comes mounted on top of a vehicle and receives signals that form images that uncover up to 33 meters in the direction that the transmitters are facing. It is able to collect and process data as part of an affordable and lightweight package due to slow (40 MHz) yet inexpensive analog-to-digital (A/D) converters that sample the wide bandwidth of radar signals. It uses a GPS and Augmented Reality (AR) technology in conjunction with camera to create a live video stream with a more comprehensive visual display of the targets.

The railSAR, also known as the ultra-wideband Foliage Penetration Synthetic Aperture Radar, is a rail-guided, low-frequency impulse radar system that can detect and discern target objects hidden behind foliage. It was designed and developed by the U.S. Army Research Laboratory (ARL) in the early 1990s in order to demonstrate the capabilities of an airborne SAR for foliage and ground penetration. However, since conducting accurate, repeatable measurements on an airborne platform was both challenging and expensive, the railSAR was built on the rooftop of a four-story building within the Army Research Laboratory compound along a 104-meter laser-leveled track.

The Spectrally Agile Frequency-Incrementing Reconfigurable (SAFIRE) radar is a vehicle-mounted, forward-looking ground-penetrating radar (FLGPR) system designed to detect buried or hidden explosive hazards. It was developed by the U.S. Army Research Laboratory (ARL) in 2016 as part of a long generation of ultra-wideband (UWB) and synthetic aperture radar (SAR) systems created to combat buried landmines and IEDs. Past iterations include the railSAR, the boomSAR, and the SIRE radar.

References

  1. 1 2 3 Mokole, Eric; Hansen, Pete (2010). "Survey of Ultra-wideband Radar". In Sabath, Frank; Mokole, Eric; Schenk, Uwe; Nitsch, Daniel (eds.). Ultra-Wideband, Short-Pulse Electromagnetics 7. Berlin, Germany: Springer Science & Business Media. pp. 571–585. doi:10.1007/978-0-387-37731-5. ISBN   978-0387-37728-5.
  2. 1 2 3 4 5 Ressler, Marc (May 31, 1996). "The Army Research Laboratory ultra wideband BoomSAR". IGARSS '96. 1996 International Geoscience and Remote Sensing Symposium. Vol. 3. pp. 1886–1888. doi:10.1109/IGARSS.1996.516828. ISBN   0-7803-3068-4. S2CID   62582116.
  3. 1 2 3 4 DeLuca, Clyde; Marinelli, Vincent; Ressler, Marc; Ton, Tuan (September 4, 1998). Dubey, Abinash C; Harvey, James F; Broach, J. Thomas (eds.). "Unexploded ordnance detection experiments using ultrawideband synthetic aperture radar". Detection and Remediation Technologies for Mines and Minelike Targets III. 3392: 668–677. Bibcode:1998SPIE.3392..668D. doi:10.1117/12.324239. S2CID   17386967.
  4. 1 2 3 4 5 Carin, L.; Geng, N.; McClure, M.; Sichina, J.; Lam Nguyen (1999). "Ultra-wide-band synthetic-aperture radar for mine-field detection". IEEE Antennas and Propagation Magazine. 41: 18–33. doi:10.1109/74.755021.
  5. 1 2 3 4 5 6 7 8 9 10 Happ, Lynn; Le, Francis; Ressler, Marc; Kappra, Karl (June 17, 1996). Ustach, Gerald S. (ed.). "Low-frequency ultrawideband synthetic aperture radar: frequency subbanding for targets obscured by the ground". Radar Sensor Technology. 2747: 194–201. Bibcode:1996SPIE.2747..194H. doi:10.1117/12.243078. S2CID   122629520.
  6. 1 2 3 Happ, Lynn; Kappra, Karl; Ressler, Marc; Sichina, Jeffrey; Sturgess, Keith; Le, Francis (May 13, 1996). "Low-frequency ultra-wideband synthetic aperture radar 1995 BoomSAR tests". Proceedings of the 1996 IEEE National Radar Conference. pp. 54–59. doi:10.1109/NRC.1996.510656. ISBN   0-7803-3145-1. S2CID   110533918.
  7. 1 2 Zhang, Tianyi; Ren, Jiaying; Li, Jian; Greene, David; Johnston, Jeremy; Nguyen, Lam (2019). "RFI Mitigation Based on Compressive Sensing Methods for UWB Radar Imaging". In Maio, Antonio; Eldar, Yonina; Haimovich, Alexander (eds.). Compressed Sensing in Radar Signal Processing. Cambridge, UK: Cambridge University Press. pp. 72–103. ISBN   9781108552653.
  8. 1 2 Ressler, Marc. "Low-Frequency Ultra-Wideband Synethetic Aperture Radar (SAR) for Remote Detection of UXO". SERDP. Retrieved November 1, 2019.
  9. ↑ Carin, Lawrence (December 23, 1999). "UWB SAR for Subsurface-Target identification" (PDF). Defense Technical Information Center. Archived (PDF) from the original on November 1, 2019. Retrieved November 1, 2019.
  10. ↑ "Synthetic Aperture Radar for Foliage & Ground Penetration". Duke Electrical and Computer Engineering. Retrieved November 1, 2019.
  11. ↑ Nguyen, Lam (April 29, 2009). Ranney, Kenneth I; Doerry, Armin W (eds.). "SAR imaging technique for reduction of sidelobes and noise". Radar Sensor Technology XIII. 7308: 73080U. Bibcode:2009SPIE.7308E..0UN. doi:10.1117/12.820480. S2CID   121909055.
  12. ↑ Taylor, James (2000). Ultra-Wideband Radar Technology. Boca Raton, FL: CRC Press. pp. 350–365. ISBN   9780849342677.
This page is based on this Wikipedia article
Text is available under the CC BY-SA 4.0 license; additional terms may apply.
Images, videos and audio are available under their respective licenses.