Aviation News

NATS, has handled its 1,000,000th flight of 2006.
Jun 16, 2006
Author: press release

This milestone reflects the continued growth in UKflights in the first five months of the year. In May, NATS handled 213,288 flights, an increase of 3.9 per cent over the same month last year.

SITA expands into the Greek market with Athens International Airport
Jun 16, 2006
Author: Press Release

SITA, the market leader in the provision of IT solutions to the world’s leading airports, today announced details of a partnership with Athens International Airport (AIA) as SITA continues to develop the $2 billion mass airport market by creating a global network of resellers.

BA World Cargo launches New premium products
Jun 16, 2006
Author: press release

BA World Cargo has today announced the launch of two new premium products, set to form a key offering of the newly named £15m 'Premia' premium facility at London Heathrow.

Swissport Aviation Security (Checkport),
Jun 15, 2006
Author: Press Release

Swissport Aviation Security (Checkport), a product line of Swissport International, the world’s Number 1 ground handler starts to provide full security services including passenger profiling for US carriers outside the States.

American Science and Engineering, Inc (AS&E)
Jun 15, 2006
Author: Press Release

Visitors to this year´s Airport Build & Supply Exhibition will see the new SmartCheck Personnel Screening System in action.

Easat Antennas

SURFACE MOVEMENT RADAR (SMR) – UNDERSTANDING THE PITFALLS IN RADAR SENSOR CHOICE.

Surface movement radar is an important airport safety system used for detecting and tracking aircraft and utility vehicles on the airport taxi ways and apron areas. The system must be capable of operating in all weather conditions, even more so in rain or fog when the visibility is reduced and the radar is the operator’s only means of monitoring the airport surface.

Easat offers two solutions for SMR applications, namely the EA7401M Linear Array antenna and the EA3462 High Gain Reflector Antenna as the preferred ‘front end’ of the radar sensor. Both antennas offer different levels of performance and both offer a superior level of detection to that offered by even the most advanced Slotted Waveguide Antennas.

System Performance

A common misconception is that antenna gain is the most critical aspect of the antenna performance, however whilst important, it is only one of several factors that determine the overall detection performance of this critical safety system.

Other key antenna parameters affecting detection performance are:

  • Frequency choice: X Band is preferred solution offering superior weather penetration when compared to the considerably more expensive Ku Band sensors.
  • Narrow azimuth beam width: A necessary feature essential to offering resolution characteristics previously offered by Ku band sensors and essential to help minimize clutter in this high clutter environment.
  • Circular Polarisation: A preferred feature again offering superior weather penetration than Horizontally or Vertically polarized antennas.
  • Inverse Cosec2 beam shaping: a preferred feature reducing clutter by minimizing the illumination of airborne moisture much above the antenna elevation as experienced with fan beam Slotted Waveguide antennas. This feature also improves the detection of ground targets close in to the Antenna site.

By providing antennas which offer the best combination of these features, Easat’s EA7401M or EA3462 antennas provide the highest quality returns for the radar to process.

Understanding the methods of evaluation

Providing a quality radar sensor is quite clearly critical to the detection performance but it is not only the hardware that is of importance. Equally important is the customers understanding of and the methodology by which different sensors are assessed for suitability operating in the hostile clutter environment that exists at an airport.

Detection Performance Degradation with ‘Wet’ Runways

It is important to understand that unlike air surveillance radar which considers detection with only airborne clutter, detection of a target on the ground, if to be realistic, must take into account the adverse effects of ground reflections. This occurs when a radar signal reflects off a wet runway (bounce) into a rain cloud then back to the antenna. Two types of bounce occur and the effects on detection performance calculations can be dramatic.

Evaluating a typical radar sensor package and ignoring this adverse ‘bounce’ effect will indicate a detection range almost 80% greater than that achievable in reality. It is therefore quite possible that the selection of radar sensor equipment based on overly optimistic assumptions will result in selection of a sensor that works well in fine weather but has severe limitations in poor weather, just at the time when the Controller needs good detection performance most.

In order to minimise these effects and best compliment the Transceivers currently available, Easat’s Linear Array and Reflector antennas, unlike Slotted Waveguide's, offer zero squint with frequency change and comfortable operation, without distortion, at low pulse widths. Zero squint enables the Easat antennas to be used with Frequency Diverse, Frequency Agile and Solid State Digital X Band transceivers and low pulse widths improve range resolution whilst minimizing clutter.

Easat remains the only antenna manufacturer to regularly depict the performance of its radar sensor packages with the effects of ‘bounce’ on wet runways thereby ensuring realistic achievable detection of ground based targets.

Contact Details
T: + 44 (0) 1782 208028
F: + 44 (0) 1782 208060
E: antenna@easat.co.uk
W: www.easat.co.uk