Java Tracking Basketballs from 22,000 nautical miles

by Tim O'Brien

For all the hot air that is thrown around by the self-appointed luminaries of dynamic languages and enterprisey platforms comparing everyone's favorite language and engaging in an endless back and forth. Nothing beats a press release like this. Listen people, Java is going to run a 143 foot tall, 1250 ton radar array that puts out 32 MW and is used to track objects in space. That's cool. Here's a quote from the Sun press release:

The Eglin Space Surveillance Radar (FPS-85), which schedules and tracks catalogued space objects, is currently undergoing a complex modernization process to replace legacy mission-critical components built from one-of-a-kind equipment and custom software. The Sun Java Real-Time System, a high-level development platform for creating applications that require unprecedented execution predictability, will enable ITT to run the new solution using Java technology on Solaris 10 OS and standard hardware.

Right, right..... ok, I hate to parrot the Sun Press Release, but it gave me an excuse to quote the Global Security page on the AN/FPS-85 Space Track Radar. This thing sounds like it is from the Deathstar. Here's a quote form that page, I added the emphasized text to provide some clarity.

The AN/FPS-85 can detect, track and identify up to 200 satellites simultaneously. The maximum beam deflection is 60 degrees on either side of the antenna center line which provides 120 degrees azimuth of azimuth coverage. The antenna is inclined +45 degrees for scan coverage of +3 to +105 degrees elevation.

Generating a combined output of 32 megawatts, the AN/FPS-85 is the only phased array radar capable of tracking satellites in deep space orbit. A study was conducted in 1976 by the Air Force Rome Air Development Center to determine the feasibility of extending the AN/FPS-85 radar performance to synchronous ranges. Several modifications involving mixed integration, coherent integration, and transmit power increases were examined considering the target effects of six typical objects and considering the Faraday rotation propagation effects. It was concluded that the AN/FPS-85 radar can achieve synchronous capability at a relatively modest cost and with varying levels of radar time penalty depending upon the modification and target of interest. The radar can track an object the size of a basketball at a distance of more than 22,000 nautical miles [in Java].


2008-04-14 14:27:07
I'm a little confused about the last line in your quote. As far as I can tell, 22,000nm is 2.2 × 10-5 meters. That distance seems a little odd for a radar. In this above context, what does 'nm' mean. Nanometers doesn't seem correct.


2008-04-15 07:20:00
Ok, at first it sounds impressing. But such a phased array radar sure is a complex beast with many components. Where does Java come into play, what are the real time requirements it has to fulfill?
I would not be surprised if most/all of the signal processing will still be done with C/C++ or even assembler.

Patrick Carroll
2008-04-15 10:26:27
Back in the day, when I was going through the 30XX school at Keesler AFB, MS, my class got to take a field trip to Eglin, to get an idea of the assorted comm-electronics maintenance issues we might face. Part of the trip was a visit to this radar.

It's truly spectacular. Imagine a football field on its side. That's the scale of this thing.

The next most impressive sight was the base telephone exchange. Hundreds of Strowger switches clicking away. With any luck, all that's been replaced by now.