RAI
Well-known member
If I'm thinking of the same case, the TCAS could have averted a collision. It uses the squitter signals from the Mode-S transponders.
Passive radar reflector - anything better than Echomax?
- Thread starter JumbleDuck
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Refueler
Well-known member
I'd have to find the report and documentary - but the VERTICAL altitude radar was still in its boxes waiting to be installed ... the ATC was relying on verbal assessment and each party believed each to be at correct flight levels. As I recall - the Ukrainian flight deck reported verbally altitude wrongly and was advised to change to xx level ... misunderstanding by the Ukrainian flight deck occurred and BHAM.
If I recall - there was total loss of life - both aircraft. The ATC guy wrongly blamed himself.
anoccasionalyachtsman
Well-known member
It preceded mandatory TCAS, unfortunately for them.
Refueler
Well-known member
i have a feeling that you may be thinking of a later incident ? The Ukraine / Indian mid air was quite a few years ago ...
anoccasionalyachtsman
Well-known member
What I'm trying to establish is that the secondary radar you're talking about does or does not calculate altitude. I'm pretty sure that it asks the aircraft's transponder for it.
Refueler
Well-known member
No it was a narrow beam radar that gave altitude ... my Father was one who was pushing for installation of them for general use ... there are still odd ones around ... you will see the antenna doing a vertical oscillation.
Some airfields I have seen them at half runway length of to the side .... probably halfway so they can be turned to match the runway use direction.
And anyway - RADAR would never be an 'asking' unit ... and why the oscillating antenna ?
My original point was to question a statement that ATC had no altitude detection by radar ... which was not true for many airports .. I assume techno has evolved since those simple days of course.
RAI
Well-known member
Those nodding height finding radars were used only by the military, I believe. They even used them to talk a pilot down to a landing.
ICAO struggled to standardize the plethora of navigation aids after the war. Civil Aviation took the SSR route for surveillance.
anoccasionalyachtsman
Well-known member
On the interrogation - I think you might be surprised. I wanted to find out for sure, so had a read. @RAI answered the nodding bit - do the military there still use it? (I've been on a couple of RAF stations and not noticed it there).
Refueler
Well-known member
Sorry .. 'those nodding radars' were not only used by Military ... many were put to Civilian Airfields ...
RAI
Well-known member
SSR's were designed to act as data links between the radar and the transponders.
However, the airlines objected to the full functionality, as they already had a VHF data link capability, so Mode S transponders are about as far as it's got.
However the airlines did go for TCAS/ACAS using a so called Mode S long squitter to enable aircraft to locate each other and issue dive/climb alerts to the pilots.
The military also use Mode-S transponders but call it IFF. They may have taken on the data link capability.
However, the airlines objected to the full functionality, as they already had a VHF data link capability, so Mode S transponders are about as far as it's got.
However the airlines did go for TCAS/ACAS using a so called Mode S long squitter to enable aircraft to locate each other and issue dive/climb alerts to the pilots.
The military also use Mode-S transponders but call it IFF. They may have taken on the data link capability.
RAI
Well-known member
Perhaps to enable the civil runway for military landings in poor weather. I don't think they are used anymore.
AN/FPS-6 Heightfinder radar
I think the military have moved on to phased array radars for surveillance.
Refueler
Well-known member
1. I am talking about years before
2. My Father as a Chief Ops in CAA was in favour and supported their installation
3. The Mid-air accident I mentioned has reference to the non installation of the gear
As to transducers and so - of course world moved on. But I am old enough to have seen them and heard talk about them.
RAI
Well-known member
I can remember the height finders too, but they are long gone from civil aviation.
Satellite navigation is slowly penetrating the civil aviation field with ADS used for surveillance.
Slowboat35
Well-known member
Regardless of various assertions to the contrary no Western civil ATC radar I am aware of has any height -detection ability whatsoever and any Eastern bloc one will probably be a military derivative. No civil airfield (in the West) that I am aware of has a vertically scanning head. That is purely a military system for PAR approaches (Precision Approach Radar) which allows a controller to talk down an aircraft in bad vis - an extremely antiquated though on a small local scale quite effective system originating in the '50s if not earlier and now totally superceded many, many decades ago in civvy street by ILS and more recently GPS approaches.
SSR provides the height data by interrogatng the aircraft's on-board system which returns a signal to the interrogating radar with additional coded date, ie altitude.
If Heathrow's radar is said to be able to reach 350Km it most certainly can't do that in primary mode with any hope of reliability, and at that range would probably see nothing below 20,000ft. It might manage to recieve SSR returns at that range, but even then such comparisons are pretty much meaningless nowadays when "Heathrow Radar" isn't a radar set located anywhere near Heathrow but part of a European integrated radar network that sends its data to recipients all over the place over fibre-optic cables...In any case Heathrow traffic is controlled from Swanwick near Southampton and has been for decades...As to where the radar heads themselves are is quite another matter.
However all this is all completely different to marine ship's radar!
SSR provides the height data by interrogatng the aircraft's on-board system which returns a signal to the interrogating radar with additional coded date, ie altitude.
If Heathrow's radar is said to be able to reach 350Km it most certainly can't do that in primary mode with any hope of reliability, and at that range would probably see nothing below 20,000ft. It might manage to recieve SSR returns at that range, but even then such comparisons are pretty much meaningless nowadays when "Heathrow Radar" isn't a radar set located anywhere near Heathrow but part of a European integrated radar network that sends its data to recipients all over the place over fibre-optic cables...In any case Heathrow traffic is controlled from Swanwick near Southampton and has been for decades...As to where the radar heads themselves are is quite another matter.
However all this is all completely different to marine ship's radar!
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Refueler
Well-known member
Interested in where you get info that :
1. "there are so few on a bridge these days." ?
2. "GMDSS was designed to reduce the cost of bridge crew" ?
And finally not all vessels have AIS integrated into the ECDIS ...
The standard Bridge crew consists of OOW + AB / OS at night ,
OOW alone in day ... with AB / OS working on deck with walkie-talkie to be called if needed.
Once vessel enters coastal waters or high traffic area - then an extra AB / OS or maybe Officer is assigned .. approaching Port Master is there ready to take the Con for finals and Pilotage ... with OOW and AB / OS
Been that way since year dot and still same today ... it was only Passenger ships and such that had extra on bridge.
The reduction of costs has been implemented by change of nationalities - not equipment. Why do you think myself and thousands of others left and took up Shipping related jobs ashore ? We were being asked to 'train' our replacements - who were paid a fraction of our salaries.
Its actually a very sore subject for many seafarers ...
PilotWolf
Well-known member
Pretty sure I was taught about PAR here when I did my PPL late 90’s
W.
W.
RAI
Well-known member
Things change.
End of an era for iconic Heathrow landmark - NATS Blog
SRE-M – Wikipedia
The SREM family claims 450km range.
The Heathrow beast used the same antenna. However, IIRC it was rotated at twice the normal rate and that shortened its range.
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LittleSister
Well-known member
Perhaps I can make my first million by designing a mast-top radar reflector mounting, which I fancy will harnesses the kinetic energy of the mast thrashing back and forth to maintain the mounting itself (and hence the radar reflector) perfectly horizontal or vertical.
You think a simple gimbal will keep anything perfectly level at all times? You could have saved the world the trouble of inventing gyroscopes!
Refueler
Well-known member
You are comparing apples with oranges ...
The simple gimbal unless damped or powered suffers from "overshoot" - get a box compas and tilt the bowl - then let go .. that is the gimbal will pass neutral point and swing back ... it will keep doing this like a pendulum till the momentum dissipates.
Early Steady Cams and other units had unpowered gimbals but suffered from 'overshoot' of neutral. That is why powered gimbals were then used - as in my Video Drones.
Gyros have a powered function that forces them to stay in neutral position - if deflected will return to neutral with virtually no overshoot.
About on-board gimbals ... pal of mine has his radar scanner mounted in a physical gimbal with damping.
RobbieW
Well-known member
I suspect that accelerometers are doing the driving so what you have is much the same chip as is in your phone. More or less a development from the inertial platform navigation systems used in long distance aircraft from the 60s on