Questions tagged [radar]

Radar is a surveillance technology that uses radio waves to determine the range (and azimuth) of an aircraft. It works by measuring the time difference between a radio transmission and the echo or reply to that transmission. Radars are the most common surveillance equipment used by ATC.

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1answer
90 views

How do Luneberg lenses hide a stealth aircraft's real signature?

I thought aircraft was supposed to be stealth and not show up on radar under the right conditions. This article says Removable Luneburg lens type radar reflectors are sometimes attached to military ...
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Tail Warning Radar on the P-51

One of the "features" of the P-51 was a tail warning radar that was supposed to let pilots know if an enemy fighter was on your tail. However, a P-51 pilot told me that they generally ...
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Why does a radar altimeter show negative values on the ground?

This applies to the Airbus 320 or Boeing 737, among others: Although it is useless on ground, the radar altimeter will repeatedly display a value (including negative) for a specific runway and airport ...
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Why bits are mixed up (interleaved) during ATC transponder mode A and mode C reply format?

In the image above from radartutorial.eu, we can see that the sequence of bits are c1 a1 c2 a2 c4 a4 during the reply of ATC transponder mode A. Why are the bits not transmitted like c1 c2 c4 then a1 ...
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Is it possible to use multiple primary radars to determine an object's location in three-dimensional space?

My question is this: if, for example, I have multiple radars across an area, tracking a particular airborne object, can I use the returns from the radars to determine the geographical location of an ...
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103 views

Weapon vs normal aircraft track

I've read that some radars can detect stealth aircraft or aircraft with low radar cross section but are not powerful enough to allow a "weapons" track or allow a missile or another aircraft ...
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Is there any current and/or upcoming technology that alerts Air Traffic Controllers in case of loss of aircraft separation?

Currently doing an assignment and it to analyse an accident where older atc systems could have been at fault. In 1995 there was an incident where two aircraft came closer than the then current ...
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How is the terrain displayed on the ND in a A320?

When you turn on "TERR ON ND" in a A320, you see terrain info on you navigation display (ND), but where does its source come from ? if data comes from FMGS stored inside its memory, then how come it ...
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441 views

Could an AN/APG-79 AESA radar “lock-on” a single bird?

Could a fighter pilot in 2015 using an AN/APG-79 AESA radar "lock-on" a single bird? I know that modern radars like the AN/APG-79 in modern combat aircraft like the F/A-18F filter out false alarms ...
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Maximum Altitude/Minimum Range limits of ATC PSR

I am trying to get an understanding of the ability of an air traffic control primary radar such as an ATCR-33 to track high flying targets (above 40,000 feet) at relatively close ranges (less than 15 ...
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ASTERIX category 240 fields placement in a UDP packet

I searched the placement of ASTERIX Category 240 radar video data fields in a UDP packet. But I cannot find any useful info. Is there a standard for this work?
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Where is the airspace not covered by primary Radar?

Most ATC in the world rely primarily on secondary radar to know where planes are. This requires that the transponder on the plane works correctly. This means that maintenance and deployment of ...
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How does the F-22 Raptor radar reflector work?

The F-22 Raptor (and other stealth aircraft) can be made more visible to radar by using radar reflectors, or in other words, radar cross section (RCS) enhancers. In the comments section of this answer ...
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Do jetliners carry radar that can detect other aircraft?

If not, why not? For example, if a civilian jetliner is flying at night over the Ocean, or a remote area with no airports/ground radar stations, and another airplane is also heading towards it on a ...
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How are both squawk and altitude transmited when operating a Transponder in Mode C?

I know that in Mode $3$ (which includes Mode A and Mode C) the aircraft transmits $12$ information pulses. That corresponds to $2^{12}=4096$ squawk combinations in Mode A which are sent to ATC to ...
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What is this part on the Me 262?

I have seen this part on a me 262 model kit but I don't know what it is... I've make some research on it but I find nothing! Maybe it can be radar, or a weapon? Do you know what is this? And also its ...
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How big is the radar cross section of a modern glider?

I heard somewhere that modern glider made of plastic and composite materials are less detectable than other aircraft by primary radar. I wonder how much. What is the radar cross section of a typical ...
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How will the update from DO-260A to DO-260B improve safety and efficiency in air traffic management significantly?

From what I know, the version update from DO-260A and DO-260B offers new features such as on-ground vs airborne source selection logic, ADS-B failure annunciation, the split of the quality indicators ...
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Where is flight following available?

What local facilities are required for me to get flight following services? It seems that if I'm 100 miles from any control tower then I won't be able to get flight following. How close does a ...
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What is the broadcast rate of an ADS-B message?

From what I know, ADS-B (DF=17) message structure is 112 bits long. In terms of type of messages it transmits, there are aircraft identification, surface position, airborne position with baro altitude ...
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Can someone actually “fly under the radar”?

It is quite a common phrase, usually without having anything to do with radar or aviation. But. Is there such a thing as 'flying under the radar'? If so, why is this (and how low is that)?
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In Antonov An-225, why there are radioactive / nuclear signs?

Looking at some An-225 images, i see some radioactive signs near the nose radome. Why they are there? I'm sure it doesn't have a nuclear reactor on board or any nuclear medical equipment. The only ...
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What can cause a watchdog failure in an INDRA MSSR?

I am responsible for Mono-pulse Secondary Surveillance Radar (MSSR) system that resets itself after a watchdog failure. So far I have found the following: An unwanted number of replies are received ...
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How does an AMRAAM communicate securely with the aircraft that launched it?

From Wikipedia: It also incorporates a datalink to guide the missile to a point where its active radar turns on and makes terminal intercept of the target. An inertial reference unit and micro-...
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What prevents the use of auxiliary radar installations to allow radar control and MSAW protection in areas that would otherwise be masked by terrain?

Both primary1 and secondary2 radar, while extremely useful (nay, indispensable) for modern aviation and air traffic control, are limited to seeing only aircraft in their direct line of sight; if there ...
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Why does the radar dome on the E-3 have a white stripe down the middle?

Every picture I can find of the E-3 has a blue/black radar dome on top with a fairly thick white stripe down the middle but I can't figure out why. Is it related to the position of the radar unit ...
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Are old illegal air transfer methods still feasible today? [closed]

A retired soldier told me he used to know people who smuggled jewelries, hard drugs, guns and even people from middle eastern countries to Europe, specifically, Germany! Via planes! In fact, he said ...
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Why can’t a single-fan-beam radar determine the elevation angles of its primary targets?

A while back, I asked about the reason for one of the well-known limitations of most ATC primary radars (their inability to determine target altitudes).1 The answers boiled down to “single-beam fan-...
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How do people smuggle stuff with private airplanes? [closed]

I get it, the question seems as if I'm reaching out for answers from experienced smugglers! But no. As a matter of fact, I'm trying to get answers on air surveillance & security. Love it or hate ...
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Converting lat long & altitude into a line of sight target? [closed]

I want to design a long-range ADS-B receiver with a directional antenna (like a Yagi), but in order to maximize its range, I'll need to orient the antenna towards a target (plane) based on existing ...
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Did the Stuka Ju-87 really have a radio altimeter? If so, when?

This is what Wikipedia says near the end of its radio altimeter article: The radio altimeter first showed up in the German Junkers Ju-87 "Stuka" dive bomber which was equipped with one for ...
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Can a CIWS engage aerial targets?

Can a Phalanx-type Close-In Weapons System (CIWS) engage small aerial targets like drones, UAVs, rotorcraft? Is there any case that Phalanx was used against aerial targets?
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How does maneuvering affect radar detection of stealth aircraft?

Stealth aircraft like the F-22 and F-35 have very low radar cross sections. These planes have angles of their fuselage set-up in a way to deflect radar signals. As far as I understand another stealth ...
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593 views

What is garbling in the context of radar?

Garbling is a problem known to affect secondary surveillance radar (SSR). What is it and why is it a problem?
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What is in 'stealth paint' to reflect radar, and how does it work?

What is in the 'stealth paint' that coats stealth bombers e.g B-2 spirit, and stealth aircraft, e.g SR-71, and how does it absorb/deflect radar?
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What is the tolerance of SSR against signal frequency shifts?

I know that the Secondary surveillance radar (SSR) interrogates at 1030MHz, and the reply is at 1090MHz. What happens if the radio signal sent to the plane is less than/more than 1030MHz? Also what ...
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How is a missile lock detected?

How can a fighter aircraft involved in a face-off detect a missile lock from a trailing aircraft so that it can make evasive maneuvers?
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Detection of solar balloons by ATC primary surveillance radar [duplicate]

I am curious whether a 30 cubic meter solar balloon made of black nylon and filled with ambient air would be detectable by the primary radar used by ATC in Continental Europe. Due to its size and ...
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How did a Soviet SA-3 missile manage to shoot down the F-117 Nighthawk?

This question is about the F-117A that was shot down in 1999. How did an obsolete missile like the SA-3 shoot down such an advanced aircraft for its time? This question has nothing to do with how ...
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Is Doppler navigation still in use for civilian aircraft?

Is it possible to find an airliner nowadays with Doppler radar used for navigation purposes?
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Why do (or did, until very recently) aircraft transponders wait to be interrogated before broadcasting beacon signals?

An aircraft’s transponder transmits signals that announce (at the very least) the aircraft’s identity, altitude, and direction of motion (plus, for most newer aircraft, a whole slew of other useful ...
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NEXRAD—why is it 2D?

If you paid attention to NEXRAD training, you know that the colors of pixels show the maximum activity at any altitude in that air column. (It’s a “composite” view.) NEXRAD itself samples in three ...
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How did pilots avoid thunderstorms and related weather before “reliable” airborne weather radar was introduced on airliners?

How did airline and or mail pilots avoid hazardous weather especially at night before airborne weather radar systems were in use?
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On ATC's radar, does an aircraft that loses its transponder simply disappear?

If you look at shows like Air Crash Investigation, which surely take some creative license in how events are portrayed, they often portray the disappearance of an aircraft, or specifically loss of its ...
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Can radars detect small drones?

I've just started working with weather radars and such. With weather radars, it is possible to detect bird migrations with a specific algorithm and a lot of information about birds, but it would be a ...
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729 views

Are there any safety hazards when testing the F-16's fire control radar on the ground?

What are the procedures for ground testing an aircraft's fire control radar - for the F-16 or any other aircraft - and are there safety hazards associated with exposures to humans? Most importantly, ...
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202 views

How are military aircraft directed to targets?

How would a controller, say, AWACS or ground radar, direct via voice an aircraft to the location of an airborne target? I've seen it in movies, but don't know if they where right, nor did I ...
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Could an aircraft 'hide' in the aircraft shadow of another aircraft without being detected or noticed?

I just finished reading an interesting post where the author suggests that the missing Malaysian Airlines flight 370 could have 'hidden' under the cover of Singapore Airlines flight 68 to fly to a ...
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Can a helicopter mask itself from radar?

I have read somewhere that if a helicopter is traveling under 100 km/h and below 5 meters AGL then most radars will ignore it. From what I understand of this process, the radars can pick up things ...
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What is meant by a fused radar track?

Can anyone explain what a fused track is from the perspective of radar?