AN/APG-70 A2A modes

[Geier]

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Edited May 29, 2019 by Geier

[Geier]

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Edited May 29, 2019 by Geier

[Pilotasso]

As far as I can tell the APG-63 had NCTR early on. The APG-70 improved on that, in adition for much higher resolution ground mapping and other radar modes.

[FVMAD]

Those modes are really sweet...:bounce:

[Geier]

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Edited May 29, 2019 by Geier

[D-Scythe]

As far as I can tell the APG-63 had NCTR early on.

 

No.

[Geier]

No.

Summing the information I've found I can say that you are right;)

[GGTharos]

I'm fairly certain most F-15C's had NCTR capability after their MSIP upgrade ... but I can't recall where I got that impression.

[GGTharos]

Those modes are really sweet...:bounce:

 

And it doesn't even list all the submodes ... and there's plenty of those too.

[Geier]

And it doesn't even list all the submodes ... and there's plenty of those too.

 

Can you describe them? It seems to be very interesting:)

[GGTharos]

To give you an example, there are some TWS submodes like, DTWS (designated target track), HDTWS (high data rate TWS - faster updates) and a bunch of funky things I likely know nothing about :)

 

Why is there a special 'double target' TWS mode? I'll tell ya what my guess is ... in DTWS you track one target, and the radad scan zone is centered on it - your second target is not taken into consideration when pointing the antenna. So you have this special mode to help you keep both targets in the scan zone, automatically (in LOMAC, it doesn't even center on a single!)

 

 

Of course, I might be completely wrong, too! :)

[TucksonSonny]

AN/APG-70 has the following A/A modes:

 

Range While Scan (RWS) modes: The RWS mode provides all-aspect (nose-on, tail-on) and all-altitude (look-up, look-down) target detection. This is the most commonly used mode upon nearing a hostile environment. It is a good balance of wide volume, and fairly rapid scan. This mode is used to resolve (detect) multiple targets separated by less than the antenna beam-width, at long range. There are three RWS modes, depending on what pulse repetition frequency (PRF) is used for emitting radar energy. In RWSH mode high PRF is used, while in RWSM mode medium PRF is used. High PRF's are better to detect distant contacts with high closure rates with the risk of low or no-closure contact not showing up on the radar screen. Medium PRF's are not very good on long ranges since they are subject to clutter when receiving returns from long ranges, but they are useful for detecting medium-range low closure targets or targets which are below the radar water line. A good mixture of high and medium PRF's is realized in RWSI mode (interlaved RWS) when the radar emits eneregy alternating between high and medium PRF's as it scans through bars.

 

Range Gated High (RGH) mode: This mode uses a single PRF somewhere between those used in RWSH and RWSM modes. Returns are processed electronically to find low and high closure targets. This mode may not as accurate as RWSI, but can find certain targets more quickly. Note that this mode can detect targets up to a 160 nm range, but it is sensitive to altitude, it can be confused by ground clutter below 4000 feet.

 

Velocity Search (VS) mode: This mode is specifically for detecting medium and high closure targets, with the cost of not detecting low and no-closure targets at all. This mode displays targets on the radar screen by azimuth and velocity instead of by azimuth and range. Note that sometimes a fast moving part of the target (a turbine blade for example) can make VS mode detect a speed much higher than the actual speed of the target itself. This phenomenon is called Jet Engine Modulation (JEM).

 

Vector (VCTR) mode: The scan rate for this mode is half as normal, about 35 degrees per second. This means that a full scan takes twice the time, but the computer uses this time to make extra work, thus enhancing the detection of objects which have a low radar cross section (RCS). Lower RCS contacts are picked up from greater distances by using VCTR mode. This mode uses high PRF's only.

 

Track While Scan (TWS) modes: Track-while-scan means that the radar does its normal right-to-left, left-to-right scanning while it is actively tracking a couple of targets. TWS uses either high or medium PRF's. In TWS mode the radar beam covers an area much smaller than the maximal 120 degrees, but this way the target updates are much quicker. In takes around 2 seconds for the radar to complete a full scan. The arc and number of bars covered by TWS scan can be set to different settings: 'wide' (60 degrees with 2 bars), 'medium' (30 degress with 4 bars) and 'narrow' (15 degrees with 6 bars). See diagram below.

TWS mode scan options

Since the radar normally can cover a 120 degree arc in front of the jet, it can be manually slewed in TWS mode, which means that the actually scanned area (15, 30 or 60 degrees) can be placed anywhere within the 120 degree limits.

 

The AN/APG-70 stores tracking information of up to 10 targets in TWS mode. This track record serves as a defense against loosing radar contact - if a target disappears from the screen, the system extrapolates from its track records and tries to predicts where the target should be next and then tries to re-acquire the target at the predicted spot. Additionally TWS provides speed and heading information to targets. Screen symbology of speed and heading information are small 'vector sticks' to point from the dot representing the target. The vector stick points to the heading of the target (the top of the screen meaning a heading of north) while the length of the stick illustrates the speed of the target. This is very useful for the aircrew to get a quick overall impression of the tactical situation. In TWS mode it is possible to put the designation cursor over a target to get important data of it (altitude, range, closure rate, heading, aspect angle, true airspeed) without locking up the target - this way triggering the target's RWR systems can be avoided.

 

There is a sub-mode in TWS which is called High Data Rate TWS (HDTWS). This mode halves the 2 second time needed for a full scan to 1 second at the price of halving the number of bars scanned. In HDTWS mode the radar scans either a 30 degree arc with 2 bars (called 'high data' TWS) or a 15 degree arec with 3 bars (called 'three-bar HD' TWS). Slewing is also possible in both HDTWS submodes.

 

The AN/APG-70 provides another sub-mode within TWS, other than HDTWS sub-modes. This sub-mode is designed to help target sorting, that is to make a difference between two or more targets that are flying very close to each other.

 

Single Target Track (STT) mode: If the pilot marks a single target for tracking, then the radar enters STT mode and begins tracking that specific target. This tracking uses a 3 degree mini-raster of radar energy centered on the target with very quick scans thus rapid target updates. If STT mode is entered from any of RWSI, RWSH, RWSM, RGH, VS or VCTR modes, then all other contacts disappear from the screen. If STT mode is entered from TWS or from HDTWS mode, all other targets remain on the screen. In STT mode exact data of this single target are are immediately available, such as altitude, range, closure rate, heading, aspect angle and true airspeed.

 

STT mode gives special aids to AIM-7 Sparrow usage (considered now obsolete). The Sparrow is a SARH (Semi-Active Radar Homing) missile, which means it has no radar of its own, but instead uses returns of radar signals originating from the launching F-15E for homing. Normally by entering into STT mode, the radar tries to switch to a medium PRF if it used a high PRF before. If the pilot places the Sparrow in priority, the radar tries to switch back to high PRF when the target enters into missile range. The Sparrow needs the high PRF for homing, since high PRF provides a more intensive signal exchange between the jet and the missile, hence makes homing easier. Since the SARH Sparrow requires continuous radar lock until impact, a numerical value is also displayed for the pilot giving the maximum angle (in degrees) that is allowed to steer without reaching radar gimbal limits, thus breaking lock for the Sparrow.

 

Dual Target Track (DTT) mode: This is the same as STT mode, but it tracks two targets simultanously. This mode supports the AIM-120 AMRAAM only (it is able to receive guidance from the F-15E in its non-active phase of flight) and provides no support for the AIM-7 Sparrow. Not that practically no one uses DTT mode, since TWS mode is much better from practically every aspects.

 

Auto Acquisition modes: All the modes above are for detecting targets while target designation is done manually by the pilot. Sometimes the situation dictates otherwise. To aid the pilot in snap-locking a target, there are five modes of the AN/APG-70, all of which are designed to acquire and designate the target automatically, within the limits of the given mode. These modes are the following:

 

-- Super Search (SS) mode: SS mode projects a 20 degree circle onto the center of the HUD. The radar locks up the first target within 500 feet and 10 nm that enters this circle.

 

-- Boresight (BST) mode: BST mode projects a 4 degree circle onto the center of the HUD. The radar locks up the first target within 500 feet and 10 nm that enters this circle.

 

-- Long Range Boresight (LRBST) mode: LRBST mode projects a 4 degree circle onto the center of the HUD. The radar locks up the first target within 3000 feet and 40 nm that enters this circle.

 

-- Vertical Scan (VTS) mode: In VTS mode the radar beam covers a vertical area of about 7,5 degrees azimuth and of an elevation between 5 degrees and 55 degrees above the nose of the F-15E. The radar locks up the first target within 500 feet and 10 nm that enters this area. This mode is useful for targeting enemy aircraft in a turning fight.

 

-- Guns (GUNS) mode: Despite its name GUNS mode has nothing to do with the built-in gun of the F-15E. It is just a moderate range and wide scan auto ACQ mode of the radar. In GUNS mode the radar scans a 60 degree azimuth and a 20 degree elevation area (that is 30-30 degrees to the left and right and 10-10 degrees up and down). The radar locks up the first target within 3000 feet and 15 nm that enters this area.

 

Electronic Attack (EA) modes: In EA modes, the radar automatically reconfigures itself when inevitable signs of enemy jamming activity are detected. Facing enemy ECM activity, the radar tries to select special search and tracking modes which are the least sensitive to enemy jamming.

 

http://web.interware.hu/f15e/techinfo/an_apg-70_eng.htm

 

 

All (almost) these modes were implemented in Falcon…:P

 

RWS: 60° sweep / 10° sweep / 30° sweep

RWS-SAM (for 2 targets)

VS: 60° sweep / 10° sweep / 30° sweep

TWS: 25° sweep / 10° sweep (1-bar / 2-bar / 4-bar options)

ACM: HUD scan (acm 20)/ Vertical Scan (acm 60)/ Slewable Scan (acm slew)/ Boresight Scan (acm bore)

gun mode

[GGTharos]

I'm actually fairly confident that the F-15C will happily put the radar in a 120deg 8-bar TWS mode ... sure it takes 8 sec to run through the entire volume, but when you can spot a MiG-29 against a mountainous background from 60-80nm away, you probably wouldn't worry about the 8 sec much.

[GGTharos]

http://forum.lockon.ru//showpost.php?p=26710&postcount=20

 

http://forum.lockon.ru//showpost.php?p=26729&postcount=23

 

The entire thread:

 

http://forum.lockon.ru//showpost.php?p=26729

[SwingKid]

No.

 

Does Combat Tree count?

 

-SK

[GGTharos]

I'd say that 'Non-Cooperative' does not apply to Combat Tree.

I mean, I'm sure they'd prefer their IFF systems to NOT cooperate, but they are, whether they like it or not ;)

[SUBS17]

All (almost) these modes were implemented in Falcon…:P

 

RWS: 60° sweep / 10° sweep / 30° sweep

RWS-SAM (for 2 targets)

VS: 60° sweep / 10° sweep / 30° sweep

TWS: 25° sweep / 10° sweep (1-bar / 2-bar / 4-bar options)

ACM: HUD scan (acm 20)/ Vertical Scan (acm 60)/ Slewable Scan (acm slew)/ Boresight Scan (acm bore)

gun mode

 

Thats correct same with Janes F/A-18, in OF you can engage 2 targets at once in TWS. The TTWS mode is also cool plus you can zoom and freeze the image and shoot at 2 aircraft at once. (IRL I think its more like 4 tgts at once for the F-16s later blocks)Of all the modes I think TWS and Vertical ACQ modes are the most used. You compare that to the modes on the F/A-18E/F where it can launch 8 120s at 8 targets at once. Also the data link in OF allows the passing of information between flights and aircraft. eg If I lock a Mig all the other aircraft in my data link group can see it and you can also pass this to other flights. In the F22 the pilots barely speak to each other as their DL also passes their cursor position so all pilots know whos shooting at what. One submode missing from that F-15E list allows the pilot the ability to see bad weather forgotten where I heard that one:D. Other handy features in OF you can mark targets locations and pass it to the flight through the DL and its very easy to call it up to drop JDAMs etc in the steerpoint. If you want to learn more read the MLU tapes 1 and 2, plenty of good stuff there.

[Geier]

Does Combat Tree count?

 

-SK

 

I'm sorry but what is "Combat Tree"?

[SUBS17]

Its an APX-81 that detects IFF transponder signals from enemy aircraft, IFF only says if the guy you are interrorgating is friendly or unknown. Combat Tree tells you that yes it definately is an enemy transponder signal from that aircraft. If only they had Aim54s back in Vietnam this system would have been a lethal combination.

[Pilotasso]

Thats correct same with Janes F/A-18, in OF you can engage 2 targets at once in TWS. The TTWS mode is also cool plus you can zoom and freeze the image and shoot at 2 aircraft at once. (IRL I think its more like 4 tgts at once for the F-16s later blocks)

 

Every plane of block 50/52, MLU and up have 6 on 6 AMRAAM capability.

[Geier]

Its an APX-81 that detects IFF transponder signals from enemy aircraft, IFF only says if the guy you are interrorgating is friendly or unknown. Combat Tree tells you that yes it definately is an enemy transponder signal from that aircraft. If only they had Aim54s back in Vietnam this system would have been a lethal combination.

 

Thx.

Is this system carried by every fighter or it places on AWACS? What types of planes does this System support ?

[D-Scythe]

Thx.

Is this system carried by every fighter or it places on AWACS? What types of planes does this System support ?

 

Pretty sure the Russians have realized their IFF codes have been hacked and changed them by now.

[Geier]

Pretty sure the Russians have realized their IFF codes have been hacked and changed them by now.

Of course... And what about the USAF?

[SUBS17]

Thx.

Is this system carried by every fighter or it places on AWACS? What types of planes does this System support ?

 

I don't think so as combat tree doesn't work with encrypted transponders from what I read. They most likely have something else that they use instead.

[SUBS17]

Of course... And what about the USAF?

 

Read the MLU tapes 1 and 2 and check out the F-16s IFF modes might give you an idea anyway.