Terrain

[QJB]

Hi guys, I'm in Australia, just wondering.

Do controllers get any overlay of terrain on there screens? I'm pretty sure you guys get a terrain height indication, but can you see lakes, towns, major roads or detailed topography etc?

Cheers

J

[supraspinatus]

I'm not from, or working in Australia, but I guess it's the same here.

The radar is a MSSR. It is dependent on the transponder in aircraft. The radar calculates the position of the aircraft using the reply from the transponder. The transponder transmits a code (the squawk code) + altitude.
Without the transponder, the aircrafts are invisible on the radar.
A radar could also be a PSR (primary radar). With the primary radar we are able to see all moving objects of a certain size. If you've ever seen a radar on a movie with a green line moving/sweeping across the screen - that's a primary radar.


Terrain is just a map on the radar display. There is also minimum safe sector altitudes which is well above the terrain.
Everything else is also maps. We can order maps for anything. Lakes, highways, airways, fixes, sector borders, grandma's house, etc.

Approach controllers often use geographical maps, while area controllers mostly doesn't.

[conflict alert]

its not like google earth if thats what your asking. Radar terrain map is available which is a bundle of lines like contour lines with the lowest safe altitude within any contour 'bubble'. Other maps - as in charts - are available on the overhead displays (not on the radar screen). This is in NZ not OZ. We have VRP, AD, and Geographic Sectors, SUA depicted on radar, but its not like looking at a map with shading etc when it comes to terrain. Outlines of coastline and significant lakes are also displayed but no height info unless you 'flick' to the radar terrain map.

[orgASMic]

In Royal Air Force towers we use radar vector charts (RVCs) for terrain clearance. Each tower has its own specifically designed for it. RVCs are overlays which can be toggled on or off the radar display and are polar diagrams which divide the display up into areas. These areas will each have minimum vectoring height shown in them, based on the highest piece of terrain in that area. In lowland terrain this minimum vectoring height will be terrain plus 1000ft. In mountainous terrain (3000ft or higher) it will be terrain plus 2000ft. Both are then rounded up to the nearest 100ft. From these figures, controllers can then calculate minimum vectoring altitudes and FLs using the airfield QNH.

[Blockla]

but can you see lakes, towns, major roads or detailed topography etc?
the short answer is no, not in Australia.

Some lakes will be on the map (usually only within the TMA) but not all, roads almost never, towns maybe, if they have a known vfr tracking point near them, or other IFR point nearby...

Basically APP/TWR controllers will be aware of the tracking points and other items which are significant; they will have pretty good knowledge of what is where compared to the radar display; but certainly not everything will be known etc. As CA says they will have reference to maps, road atlases etc.; but these will not be on the radar screen; but a skilled controller can transpose the information from one to the other pretty accurately.

The radar terrain maps in Oz are just "boxes" with an altitude in that box describing the minimum height of safe flight over terrain, but only for that specific box...

[orgASMic]

Blockla

with an altitude in that box describing the minimum height of safe flight

Please tell me you can see the problem with this quote.

[Blockla]

Nope, no problem at all...???

[orgASMic]

Surely 'height' is with reference to the surface ie above ground level, and 'altitude' is with reference to mean sea level? This is a big problem in mountainous areas.