equipment that looks like an SMR but on its side

The one rotating horizontally looks like a standard Surface Movement Radar (SMR). But the one next it, rotating vertically (like a windmill or wind turbine), what is that? Wouldn't that be scanning a vertical slice? It also doesn't look like a PAR, which has a vertically scanning component.

The example shown here is seen at Amsterdam Airport Schiphol (EHAM). I failed to find the right keywords to find anything about it.


1 Answer 1


That is a bird tracking radar antenna to detect and track birds in the vicinity of the airport. The vertical component is used to determine the bird's altitude.

ROBIN's 3D Flex

ROBIN's 3D Flex system consists of a horizontal S-band radar, combined with a flexible Frequency Modulated Continuous Wave (FMCW) radar. The horizontal S-band radar identifies the presence and number of birds in time – including their location, height, direction, speed and route – up to 10 kilometres away, all around, day and night.

The FMCW radar has three modes:

  • 'Scanning' mode, by which 3D information is retrieved for all desired directions.
  • 'Staring' mode, in which the radar points in one direction to identify targets up to 6 km away.
  • 'Automatic Acquisition' mode, where the vertical X-Band radar slews in azimuth to the cue of the horizontal S-Band radar, based on the objects with highest RCS. In this way much of the bird tracks (in all directions) will be assigned elevation data.

(Robin Radar Systems - 3D Flex Radar System - Bird Strike Prevention in 3D)

Apparently, Amsterdam Schiphol was the first airport to be equipped with such a radar system in 2013 due to a large number of geese in the vicinity:

Schiphol first deployed a single bird radar (Robin 3D Flex) at the ‘Polderbaan’, one of it’s six runways. After successful testing Schiphol acquired four more 3D Flex radars to cover the entire airport.

Robin Radar Systems’ 3D Flex radars detect and track birds in and a round the airport up to 6-8km away. They also provide the height information of the birds. Each bird controller receives the radar data on an iPad in their vehicles.

Robin 3D Flex at Schiphol

(Robin Radar Systems - Schiphol Case Study)

  • 15
    $\begingroup$ Now I'm just imagining ATC being somehow in contact with those birds - "Canadian Goose CG103, you are cleared for landing in the field to the east of runway 6..." $\endgroup$ Sep 23, 2021 at 19:27
  • 7
    $\begingroup$ CG103, you are deviating from your assigned vector. Please return to designated airways or you will be shot down. $\endgroup$ Sep 24, 2021 at 7:17
  • $\begingroup$ Is it possible the vertical antenna does scan a slice and is aimed along the runways? The first quotation is not really clear (not your fault!), as it also says the horizontal one scans heights. Great find btw. $\endgroup$
    – user14897
    Sep 24, 2021 at 22:58
  • 1
    $\begingroup$ @ymb1 "the vertical X-Band radar slews in azimuth to the cue of the horizontal S-Band radar, based on the objects with highest RCS" -> that sounds like it is only scanning a slice, but not necessarily along the runway since it can slew in azimuth. I agree though that the description is not very good (sounds like something the marketing department wrote). E.g. in the paragraph before they claim that the horizontal S-band radar can also measure height, which does not make sense. $\endgroup$
    – Bianfable
    Sep 25, 2021 at 10:08

You must log in to answer this question.