Fly Under the Radar

Fly Under the Radar

Below Radar

I recently had a conversation with one of our members about the Battlefield 3 perk “Below Radar” for attack jets. It was such an interesting conversation I felt it was worth a short piece. Although my knowledge of radar systems is limited, I thought it might be cool to share what I do know, demonstrate a real world example of how this perk actually works and look at what I believe are a few misconceptions about military aircraft radars and how they are portrayed in BF3.

The “Below Radar” perk for BF3 is an one of the cooler bonuses I have seen in any game lately. Its based on fact and allows for evasion of active missile threats for an expert pilot in an intuitively obvious way. The perk lets pilots evade air to air missiles by flying low to the ground. Although this perk dumbs down the concept of how it actually works in reality its still not far off especially for a video game. I for one was impressed at this level of detail.


Energy is sent from the radar and bounces back off of obstacles revealing their position, direction of travel, and speed.

Now briefly, radar works by a transmitter sending out a pulse of energy into the air, this is known as an active state. Once the energy pulse is sent, the radar switches into a passive state and listens for any returning energy. Any objects that the pulse hits will cause some of that energy to bounce back to the transmitter where the radar detects it returning. The amount of time it takes to return lets the radar know how far away that object is whether it is a plane, dust, or a thunderstorm. Additionally with some math you can use the difference in frequency between the energy waves the radar sent and the waves that bounced back to determine the direction and speed of that object but that isn’t important for this article, if your really interested in knowing more, you can ask me or google “red shift”.


As for aircraft, by flying low, your hoping to hide your aircraft from enemy radar by using the shadows of objects that always there, in this case the terrain. You can see an example of how this works in this short animation I got from the Salt Lake City Doppler weather radar on Weather Underground. Now in this animation you can see the white plus is the radar’s actual location just north of the Great Salt Lake in Utah. The red arrow I have added in is pointing out two places that are in “shadow”. The radar’s beam is being blocked in two places by mountain peaks to the north resulting in the two gray cuts in the radar image. This is the same way that jets can shake missiles by diving behind a mountain or into a valley and hiding in this area of silence.


You can see one of the two mountain peaks creating the shadows on the weather radar. The green arrow is the location of the radar.

Tricky thing is that with aircraft enemy planes are constantly repositioning their radars as they fly. Also another interesting feature on this radar image that I noticed, you can actually see several aircraft coming into Camp Williams just to the west of Provo. They are the three little dots that approach from the west and then spiral down and disappear. Pretty cool, huh?


So Battlefield did a pretty nice job with this aspect of realism. However they didn’t quite get it perfect. This perk also works on heat seekers, something that shouldn’t ordinarily work since heat seekers don’t use radar but rather track the heat from the enemy aircraft’s engine. The same thing holds true for flares, while these seem to work against air to air missiles, they realistically should only work against heat seekers. They got so much right with this game that its hard to criticize such small oversights. The attention to detail on this is something I never expected to see in Battlefield 3. I for one am certainly impressed.

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Posted in Best of Elite, Elite Tech, Gaming Wright, News | 2 Comments

2 Comments on “Fly Under the Radar”
Comment #418


You know, Autonomous Cruise Control (found in higher end vehicles) uses radar to detect cars in front of your vehicle, and the distance of those cars so that it can automatically slow down when needed without any input from the driver.

December 15th, 2011, 5:05 pm
Comment #1199


Wow i had no idea that cars could actually do that nice one Crazedjoker.

December 28th, 2013, 3:24 am

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