By John McHale
LAUREL, Md. — Experts at Computer I/O Corp. in Laurel, Md., are using commercial-off-the-shelf (COTS) VMEbus data acquisition and digital signal processing (DSP) hardware in a radar data collection and analysis system for the Naval Research Laboratory (NRL) in Washington.
Scientists in the NRL's Radar Division are developing the system for quick hook-up to ship radar.
"The performance and integration effort expended by Pentek and Computer I/O met NRL's requirements," says Kim Scheff, scientist, NRL Radar Division. "We are looking forward to many hours of data collection and online analysis of Navy radars, as well as more detailed signal processing and analysis work back at NRL."
NRL officials required the system to be comprised entirely of COTS equipment, be VMEbus-based, portable enough that it could easily travel aboard air carriers and move easily from ship to ship, flexible enough to work with analog and digital radar and accommodate online and post processing and signal analysis, and finally, the system had to be modular for future upgrades, Pentek officials say.
The radar data collection system captures, stores, archives, and analyzes wideband radar data, Pentek officials say. It uses three separate hardware subsystems in 6U VME format.
Subsystems 1 and 3 are field data acquisition and analysis units, which are enough to check through commercial airliners as standard luggage, Pentek officials explain. Subsystem 2 is rack-mounted and is used only in the laboratory.
Subsystem 1 is a configurable data acquisition system that digitizes incoming RF radar signals with either a Pentek 6465 2-channel 12-bit 65 MHz A-D converter, or a Pentek 6420 2-channel 14-bit 20 MHz A-D converter, company officials say.
The digitized outputs apply to two Pentek 6099A 512-megabyte buffers, which together collect 1,024 megabytes of data at 260 megabytes per second, Pentek officials say. They also provide a transition from the ECL interface of the A-D converters to the front panel data port (FPDP) interface required by the VMEbus AMD K6 board.
A COTS synchro-to-digital VMEbus converter provides data to compensate for ship roll, pitch, and yaw, when the data collection system operates aboard a ship, Pentek officials say.
The three subsystems use a Fibrechannel PMC card as slot-one controllers, while SPARC IIi 300 MHz single-board computers using Solaris 2.7 provide all system control and setup functions.
Subsystem 2 supplies a Fibre Channel interface to a RAID-3 disk array and enables data to be retrieved and stored on a local SCSI disk or SCSI digital linear tape. Subsystem 2 also serves as a file server for local clients to retrieve data via the 100 Base-T local area network, Pentek officials say.
Subsystem 3 retrieves data from a RAID-3 disk array and moves it to client users over the Ethernet connection. Data moves across the PMC and then across the PCI interface to local storage, or directly to the DSP system for analysis.
A Pentek 4291 Quad TMS320C6701 floating-point processor is used for the signal analysis tasks, company officials explain. The system is currently undergoing acceptance testing at Computer I/O and should be at NRL before the end of the year, Pentek officials say.
For more information on Pentek and Computer I/O go to their sites on the World Wide Web at http://www.pentek.com and http://www.pentek.com.
