Principle of FMCW radar by Tobias Otto, TU Delft

Principle of FMCW radar from tobiasotto

Cassidian announces passive radar system

Cassidian, the German defense and security division of EADS, is in the news with development of a stealth radar system.

It said its "passive radar" system can not only locate difficult-to-detect stealth aircraft, the system itself is practically undetectable since it doesn't emit radiation. Instead, it analyses radiation reflections from other emitters, such as radio and television stations, to detect objects.

"The principle of passive radar has been known for a long time," says Elmar Compans, head of Sensors and Electronic Warfare at Cassidian. "However, we have now integrated the latest capabilities of digital receiver and signal processing technology to significantly enhance range and detection accuracy by monitoring various emitters at the same time."

Cassidian said its passive radar meets the requirements of civil and military airspace control, which couldn't be fully met with standard emitting radar: In civil application, passive radar makes cost-effective air traffic control possible without any additional emissions and without demands on transmission frequencies; in military applications, it provides large-area surveillance using networked receivers but cannot be located by hostile forces.

"The particular characteristics of the omnipresent radio signals used for operation enable detection of even objects that are difficult to detect, such as stealth aircraft or stealth ships," Cassidian said.

"A further advantage of the new technology is its increased detection capacity in areas of radar shadow such as mountainous terrain and its capability to locate extremely slow and low flying objects."

The system is also mobile. It can be deployed in a vehicle of the size of a commercial van.

Testing of the system, including at Stuttgart Airport, has proved successful and a production prototype system will be manufactured for evaluation program by Cassidian and its customers by the end of the year.

A demonstrator passive radar system has been delivered to the German Federal Office of Defense Technology and Procurement, the company said.

In other Cassidian developments, the reported its Barracuda unmanned aerial system has completed a series of test flights at a military airfield in Canada.

Five tests were conducted this month and last and involved the Barracuda demonstrator flying in combination with a modified Lear jet to simulate another unmanned aerial vehicle.

In the tests the two aircraft flew missions where they each had different role profiles that were autonomously coordinated and synchronized with each other.

Cassidian said that coordination between the two aircraft was mostly automated but missions could be adapted by uploading new mission data while the aircraft were in the mission zone through the use of a new network-centric data link.

Flight test engineers transmitted new individual waypoints to the aircraft as well as entire mission segments from the ground station to the UAS in flight.

"With these latest successful flights by our UAS technology demonstrator, we have made another great leap forward in our developments for the world's most promising future markets in our industry," said Cassidian Chief Executive Officer Stefan Zoller.

The Barracuda demonstrator was designed as a technology test bed. It has a modular structure, enabling a variety of systems and flight profiles to be tested and a wide range of mission requirements to be demonstrated.

Its avionics system was also developed as an open and modular structure, the company said.

Source

Lifting the Fog: A Brief History of Radar

One of the worst airplane disasters in history occurred as a consequence of a series of unfortunate events. The location of the disaster was the island of Tenerife, the largest and most populated island of the Canary Islands, on March 27th, 1977. Two Boeing 747 planes prepared for departure on a crowded runway where they were instructed to follow a procedure called “backtaxi” where a portion of the runway is used as a taxiway for aircraft to taxi in the opposite direction from which they will take off. Through a series of misinterpreted communications between air traffic controllers and the pilots, one of the planes began their take off before the other, backtaxiing plane had cleared the same runway. Dense fog shrouded the planes from sight and they did not realize that they were barreling towards disaster until they were 2,000 feet from each other. A detailed account of the events of this fateful day can be found here.

Computer rendering of the Tenerife disaster. Source: http://www.nycaviation.com

Of all the events that led up to the disaster, the straw that broke the camel’s back was a dense layer of fog that clouded the two planes from each others', and the air traffic controller’s, vision. Unfortunately, the small airport on Tenerife was not equipped with ground-based radar, a tool that would have allowed the controllers to see the location of the planes even with the heavy cover of fog. Although this disaster happened 35 years ago, ground-based radar technology was already available, in fact, this technology was developed long before 1977.

‘Spy’ Radar Arrays Arrive in Adelaide

AN/SPY-1D(V) phased array radar for Hobart Class Air Warfare Destroyers (all photos : Lockheed Martin)

Minister for Defence Materiel Jason Clare announced the arrival in Adelaide of the first two state of the art ‘SPY’ radar array faces that will be installed on the Air Warfare Destroyers (AWDs).

“The multi-function SPY radar is capable of search, automatic detection, tracking of air and surface targets and missile engagement support,” Mr Clare said.

“It works to distinguish signals from stationary or moving targets and to identify and reject ‘clutter’ such as clouds and flocks of birds.”