56th Training Squadron
Fighter Academics
Part 1
Air Combat Prep
Lesson 1
Radar & HUD
This lesson is a basic guide to the F-16’s air-to-air radar functionality. A much
more detailed discussion of the various A-A modes and how to use them will be
gone over later on in the Air Combat course. Several of the slides in this lesson
have additional info that will appear as you click your mouse to continue. Links to
different sections are also provided and will look like this. Just click them with your
mouse and you’ll be taken to the specific topic.
Radar
- Overview & General Description
- Use, Functionality & Operation
HUD & HSD
- Radar related info displayed on the HUD & HSD
AN/APG-68 Radar
Display, Use, Functionality & Operation
- Overview
-Fire Control Radar (FCR) Display
- Range
- Azimuth
- Bar Scan
- Elevation
- Locking Targets
- Target Information
AN/APG-68 Radar
Overview & General Description
Before we get into radar mechanization and symbology “in the pit”, a basic
overview of the radar and how it operates is in order. I’ve found going over the
basics of how the radar actually works, helps pilots better understand and
operate the complex avionics systems in Falcon 4.0.
All current USAF combat ready F-16’s use the AN/APG-68v9 radar or
equivalent upgraded unit. As far as I can determine the radar version modeled in
current patch versions of Falcon 4.0 is a blend of the older AN/APG-68v5 and the
v9.
In Falcon the fighters you’ll encounter will be equipped with either a Pulse
(older aircraft such as the Mig-21) or Pulse Doppler (newer aircraft such as the
MiG-29, Su-27, F-18) type radar unit. The AN/APG-68 used in the Viper, is a
Pulse Doppler type radar. In layman's terms the difference between the two
types is that the older Pulse radars do not have “look down” capability while
Pulse Doppler types do. In other words an aircraft equipped with a Pulse radar
cannot discriminate targets at lower altitudes against the ground clutter picked up
by the radar. Pulse Doppler radars have a “gate” that filters out ground clutter
and slow moving objects. This gives them a “look down” capability enabling
tracking and firing on targets at lower altitudes. One advantage the older Pulse
radars have over the Pulse Doppler, is high resistance to notching techniques.
Notching against a Pulse radar equipped aircraft rarely yields the desired results.
Pulse Doppler radars by contrast are susceptible to notching tactics. I’ll go over
notching in much more detail later on in this lesson series.
Primary radar units in fighter aircraft are mounted in the nose of the jet. The
nose is made of special fiberglass assembly which is designed to be “invisible” to
radar waves, and provides a window so to speak, for the radar to look through. The
F-16’s radome is made of filament wound fiberglass (as are radomes on all modern
U.S. fighters) which provides superior “look through” characteristics. As a point of
interest, when I repair radomes, special care and training comes into play to ensure
the repair is done so as not to impair the radomes ability to let radar waves pass
through seamlessly. If not done properly a repair could affect radar capability.
Typically motors move the antenna assembly left and right and up and down to
provide maximum coverage of airspace in front of the aircraft. This is commonly
referred to as radar sweep. If you reference the pictures provided earlier in this
lesson you can see how the antenna in the Viper is mounted, and the swivel
assembly and motors that allow the antenna to move up and down and left and
right.
Radar assemblies consist of the antenna and motor assemblies as well as
hardware and software that is used to send out and receive radar energy, interpret
and display target returns, as well as control scan area, volume and scan intensity.
In the F-16 Air to Ground and Air to Air radar returns and info are displayed on
either one of our MFD’s. You can tell you are in a radar display mode by checking
the bottom of your left (default for radar display) MFD where you’ll see FCR (Fire
Control Radar) highlighted. The radar for both A-G and A-A modes ties into, or
communicates with several other interfaces available to us such as the HSD, HMS,
and certain weapons/display pages.
The AN/APG-68 has a total coverage area of 120 degrees left and right and up and
down.
You’ll commonly see this referred to as
+ or - 60 degrees azimuth (left and right)
and + or - 60 degrees vertical (up and down).
The radar does not scan it’s complete area of possible coverage at all times. It’s
important to remember that the radar has to sweep or move left and right and up and
down to scan airspace. This takes time and there are many controls and modes
available for you to use to tailor the radars scan pattern to optimize it to your needs at
any given moment. All Air-Air radar modes have an azimuth and vertical (Bar Scan)
mode setting they default to. You have options to tailor these to your needs in almost
all main radar modes. You can tilt the radar antenna up or down, adjust the width
(azimuth) of the scan, slew the radar left and right and set the volume of space
covered vertically (Bar scan). In simplest terms this means that you can set the radar
to scan specific larger or smaller areas of the sky. Larger lets you “see” more, and
smaller means a quicker scan. This is an extremely important concept to grasp. Most
virtual pilots do not know how to get the most out of their radar equipment. When going
up against an experienced air combat pilot who does….more often than not they
inevitably find themselves blown out of the sky, and/or dangling in their chute.
The radar display in the F-16 is presented in what’s known as a B-Scope format
vs. the older arc or A-Scope type of format. The pie or A-Scope is a very straight
forward idea, it simply reproduces the radar returns inside a representation of the
horizontal (or vertical) coverage of the radar. The AN/APG-68 however uses the B
scope in the air to air modes. This carries with it the advantage that closer targets
do not clutter the display, making it easier to use in closer combat. The differences
between the two display types are shown below.
A-Scope
This type of radar display is popular because it
is very intuitive to use. However it’s main
disadvantage is that closer targets bunch up
together, making it difficult to discriminate
targets.
B-Scope
The most important thing to remember
with a B-Scope display, is that the entire
length of the bottom of the display
represents your aircrafts nose.
The B-Scope represents a limited overhead view of the volume of airspace that
your radar sweep pattern is covering. As shown previously the closer and narrower
part of the radars scan is stretched out along the bottom of the B-Scope display.
It’s important to realize how this works so that you can accurately interpret and
act on what you’re seeing on the B-Scope. Study of the picture above should
clarify how what the radar is “seeing” is displayed in the pit on the B-Scope.
Targets at the very bottom portion of the B-Scope display are either on or very
close to your nose even if they are all the way to the right or left of the display.
We covered previously the fact that the radar does not cover it’s entire possible
area of coverage all the time. Even if it did it would take literally forever (in air
combat terms) to complete the scan.
We do have the ability to define where the radar is looking in airspace, and
how much volume of that space is covered. Range settings are available to adjust
how far out the radar scans. Azimuth settings are available to adjust how wide an
area the radar is searching. Bar Scan settings are available to adjust how much
vertical space is covered, and Elevation settings are available to adjust the block of
airspace being searched up and down to search higher and lower.
To start off with we’ll look at the FCR display on the F-16 MFD and then Range,
Azimuth, Bar Scan and Elevation settings, explaining how each works and
graphically depicting how the settings you make affect the radars scan area and
volume. Finally we’ll take a look at how to lock targets and some of the info provided
and displayed with a lock.
FCR (Fire Control Radar) Display
Use the OSB adjacent to
a display item to change
the value or make
settings.
Range Settings
Targets range can be determined, even without a lock, at a glance
by noting where they are on the display. If in 40 mile range targets
at the top of the display would be 40 miles out. Half way down the
display would be 20 miles out. The 3 blue horizontal bars along the
right hand side of the display are a range scale to help you
determine target ranges. In the 40 mile range view above, the
middle bar equates to 20 miles, the top to 30 and the bottom to 10.
Range will double each time
you press the OSB to increase
range and halve each time you
press the OSB to decrease
range. The F-16 radar is
arguably the most reliable,
accurate, tenacious and precise
out there. However it’s ability
lock targets at extreme ranges
is limited compared to the likes
of the F-15 and F-14. Larger
targets such as bombers can
be picked up at 80+ miles. Non
jamming fighter sized targets
usually are not detectable until
inside of 60-40 miles,
depending on the RCS and
electro-magnetic emissions of
the target.
Azimuth Settings
When you first get in the jet your FCR Azimuth setting is to the full width of 120
degrees. This is expressed in degrees left and right. There are three Azimuth
settings possible in the default RWS mode: A6 is 60 degrees left and right (120
total), A3 is 30 degrees left and right (60 total), and A1 is 10 degrees left and right
(20 total). In the jet in FCR view on the MFD in RWS mode you’ll see A6 displayed
about half way down the left side. Pressing the OSB next to A6 will cycle through
to A3 and A1.
Here’s what each setting looks like in the jet.
Notice that the narrowed
scan is indicated by the large
gate lines. It’s important for
you to understand that these
gates are centered around,
and will move left and right
with, the radar acquisition
cursors.
The blue “T” at the bottom of
the display is an azimuth
indicator that shows in real
time where the radar is
pointing as it scans. The
Vertical green lines along the
bottom are an azimuth
reference scale in 10 degree
increments left and right of
center.
Only the area represented in
between the Azimuth gates is
scanned by the radar.
However when in A3 (Azimuth
30) and A1 (azimuth 10), you
can slew the radar/scan left or
right to the radars full gimble
limits to scan specific areas of
the sky. Note that in the
default A6 (Azimuth 60)
setting the radar is already
conducting a full scan up to
gimble limits, hence no gates.
Bar Scan Settings
There are three Bar Scan settings possible in the default RWS mode: 4 Bar, 2 Bar
and 1 Bar. The bar scans are pretty much what they sound like. The default is Bar 4,
shown on the FCR display as B4. B4 starts in a scan at the top of the selected
elevation range, then drops down 2.2 degrees and scans, drops and scans ect, for
a total of 4 sweeps, or bars. B1 just does one sweep, covering much less area, but
also taking much less time. It’s a trade off depending on your needs at the time and
is totally controllable by you. In the jet in FCR view on the MFD in RWS mode you’ll
see B4 displayed about half way down the left side below the Azimuth setting.
Pressing the OSB next to B4 will cycle through to B2 and B1.
Here’s what it looks like in the jet.
This chart graphically shows the Bar Scans as
well as the Azimuth settings.
The blue “T” located along the left side of
the display is a Bar Scan indicator that
shows in real time what bar of the scan the
radar is in. The Horizontal green lines
along the left side are a Bar Scan
reference scale.
Elevation Settings
Elevation settings adjust the block of airspace your radar is searching up and
down to the full gimble limits of 120 degrees. That’s 60 degrees up and 60 down.
You can do this on your keyboard or on your stick if you have the option. The
keystrokes are: F5=Down, F6=Center & F7=Up. Each time you press F5 or F7 you’ll
step the radar search incrementally up or down. F6 centers the scan back to the
default, or looking straight ahead. Depending on your altitude and radar range
setting, you may not be scanning to the ground. It’s usually best to have different
members of the flight scan different altitude blocks for total coverage.
Locking Targets
I’m sure everyone reading this knows how to lock a target on the radar display.
However not everyone knows what “Bugging” the target or locking in SAM or STT
means. Common terminology for these terms is “Soft Lock” and “Hard Lock”
respectively. Bugging, SAM & STT will be explained in detail later in this course. For
now we’ll just stick with the common terms and the basic differences between them.
A soft lock in RWS, the default A-A radar mode, is accomplished by designating a
target once with your joysticks “designate target” button, or the 0 key on your
keyboards number pad. Doing this will give you altitude and heading info on the soft
locked target. Your azimuth scan area will also automatically be reduced regardless
of initial setting. This is done to facilitate getting info on and tracking the soft locked
target. It takes extra time and radar energy to do this so azimuth is reduced so scan
and other target returns displayed can be accomplished in a timely manner. Again,
the various radar modes will be gone into in detail later on, but for now I’m going to
keep things very simple.
Advantages: Soft locking in RWS gives you the advantage of: staying more stealthy
and not tripping the targets RWR/TWS (Radar Warning Receiver/Threat Warning
System), getting info on the locked target while still being able to see/track other
targets, and being able to fire on the target undetected (when using missiles
capable of being fired in SAM) with high probability of maintaining a stealthy lock.
Disadvantage: The only real disadvantage is that a soft lock is a little less reliable
than a hard lock & and it’s easier for the bandit to break the lock vs. a hard lock.
A hard lock in RWS is accomplished by designating a second time. Doing this will
focus the radars scan and all it’s energy only on the target and nothing else. No
other targets will be displayed and no other volume of space is looked at except
that immediately around the hard locked target. Hard locking gives you the
advantage of an extremely solid lock and positional info.
Advantages: A little harder for the bandit to break lock, very good positional info.
Disadvantage: The bandit will know:
1) you have him locked,
2) when you have launched a radar missile
3) your general location if he has a RWR/TWS unit.
You will only see and get info on the hard locked target, all other returns will be
ignored and will not be displayed or tracked.
Target Information
I’m not going to get into absolutely all the information the radar gives you on
targets just yet. We’ll hit most of what’s displayed in RWS mode. What we don’t go
over here will be gone over later on and would only confuse things if explained right
now. The easiest way to do this is to show you where everything's at on the MFD
and what it means. I’ll do that using pictures and notes.
40,000 Feet
10,000 Feet
4 Target tracks at about 26-28 miles.
The altitude range being covered at the
acquisition cursors location of about 26
miles is 40,000 down to 10,000 feet. Notice
that when the acquisition cursors are
placed over a target track that the targets
altitude is shown just below. Current
altitude for the target with the cursors over
it is Angels 25, or 25,000 feet. Practice
moving the acquisition cursor to the top
and then bottom of the MFD and note how
the upper to lower altitude readings
change. Remember that your radars scan
is going out from your nose in a wedge
shape. Less area is covered closer to you
and more further out.
The Bullseye reading is for wherever the
acquisition cursors are currently located. In this
situation the cursors are soft locked on the target and
the bullseye reading is for the targets location.
Bullseye is read heading and miles from bullseye. For
this situation it would be “target locked at bullseye
060 for 125”.
Once you have a target soft or
hard locked, various information will
be displayed about that target. This
includes target speed and the
closure rate between you and the
target. In the picture to the left you
can see that the target lock is
indicated by the target track being
depicted as a triangle instead of a
solid yellow square. Notice as well
that there is a line (known as a
vector line) coming out of one
corner of the triangle. This indicates
which way the target is heading
and the faster the targets speed the
longer the line. In this example the
bandit is heading toward you. The
targets current speed, and closure
rate between you and the target,
are shown in the upper right of the
display as labeled. This is all critical
info that will gain importance for
you as we move further along in
this course.
HUD
Symbology & Use
This section will go over information in the HUD as relates to targets you have
locked on the A-A radar. I’ll go over most information, but the info that is related to
weapons and their employment will be gone over in another lesson block. I’ll also
go over info that’s displayed on your HSD.
Miles to selected
steer point
This is what you’ll see when in the A-A master mode without a radar lock. Radar range is
set to 40 miles. The acquisition gates are at around 34 miles and the current radar scan
elevation at that range and the current altitude of angels 25, is from angels 46 down to angels
4.
DLZ Bracket
This indicates when
you’re in range to fire
the selected missile.
When the > is within
the bracket you’re in
range.
In this view a target is soft locked. Notice that a TD Box is displayed around the locked target in the HUD. If the
target is far enough to the left or right to fall outside the HUD a target locator line will be displayed coming out of the
flight path marker and pointing in the direction of the locked bandit. The targets current range from you is also
displayed as noted. In this situation the range to target is 26.2 miles. A graphic depiction of the current horizontal
area being scanned by your radar is displayed on the HSD, as well as any targets you or your flight have locked.
Here’s an expanded view of the
HSD to better show the target you
have locked and the target your
wingman has locked. This is
extremely useful info for sorting
targets, helping to avoid fireing
missiles at the same targets and at
times giving you info on target
locations when you can’t find targets
on the radar but a flight member has
targets locked.
The HSD in Falcon 4.0 simulates Link 16 capabilities enjoyed by many U.S. and
NATO aircraft. Link 16 is basically a system that gives aircraft the ability to
communicate with each other via data modem and integrates with A-A and A-G radar
and certain weapons to provide info from and send info to other friendly aircraft “on
the link”. Info is displayed on the HSD as well as radar and HMCS (if used) display.
The HSD in Falcon 4.0 is an approximation of this technology. Exactly how it
works and how info is displayed in game depends on the patch version you’re flying.
It’s an incredible SA building tool that provides useful info in an easy to understand
display. Grasping just how important this tool is to your combat flying, and then
implementing the knowledge and skills gained in reference to incorporating the HSD
into your operations, is an important objective of this course.
Putting It All Together
The AN/APG-68 has amazing flexibility, controllability and functionality. You have
at your finger tips an extremely powerful tool, especially once you learn just what it’s
capable of and how to control it. You’ll develop your own style and technique for
working the radar. You don’t have to use all the options all the time, but knowing
what you can do, how and when to do it, and how to interpret what you are seeing,
will make you a much better and much more deadly virtual Fighter Pilot.
Remember that reducing the scan volume in either Azimuth or Bar Scan, can be
useful by reducing the time it takes the radar to search, but that you’re also looking
at a lot less airspace. There are times to do a full scan and times to narrow things
down. The skill is learning when to do what. A good example of when you might
want to narrow your search is when you know where the bandits are already.
Another is when you need to clear a specific area of the sky. Experiment and
practice and you’ll start to get the hang of things and develop your own technique.
To the right is a listing of all
the A-A radar modes and submodes and the available Azimuth
and Bar Scan settings in each.
Note that in ACM (commonly
referred to as Dogfight mode)
Azimuth and Bar Scan are set
and not adjustable. All of these
modes will be discussed in detail
later on in the Air Combat Course
56th Air Combat Course and Presentation
by:
th
56 VFW
Thumpper
56th Virtual Fighter Wing
www.56thvfw.com
Vipertown
Send questions and comments to:
USA
freycat@yahoo.com
ICQ 56609485