LANTIRN stands for Low Altitude Navigation and Targeting Infrared for Night. This system consists of two pods hung under the air intakes – the AN/AAQ-13 navigation pod under the right intake and the AN/AAQ-14 targeting pod under the left intake. Since LANTIRN pods are in use with other platforms (A-10, F-16) where they have other hanging points, adaptor units are needed to fix them on the F-15E. The adaptor units are the ADU-576/A for the navigation pod and ADU-577/A for the targeting pod. This is the only place on the F-15E for them and they cannot be exchanged. Although both of the pods are capable of working alone, most of the time they come in pair, an F-15E with only one LANTIRN pod is a rare sight.

LANTIRN pods are manufactured by Lockheed Martin (originally Martin Marietta) and over 1.400 of them is currently in service in the air forces of 10 countries. The cost of the LANTIRN system is around $4.6 million ($1.4 million for the navigation pod and $3.2 million for the targeting pod). Although a newer and much more potent targeting pod (the Sniper pod) is available now for the Strike Eagle, LANTIRN pods are still widely used and this will not change for at least a couple of years to follow.

Navigation Pod

The development of the navigation pod began in September 1980 and its initial operation test and evaluation was successfully completed in December 1984. The first production pod was delivered to USAF on 31st March, 1987 and made its combat debut in Operation Desert Storm in early 1991.

The navigation pod is 78.2 inches long, 21.8 inches high, 13.7 inches wide, and weighs 470 pounds. It is integrated with the jet’s other systems and they communicate via the standard MIL 1553B data bus. It's onboard software can be easily updated whenever the need arises, and many of its components are designed to LRU's (line replaceable units, meaning that its replacement can be carried out by maintenance personnel on the field). It contains a terrain-following ( TF) radar, a forward-looking infrared ( FLIR) sensor, plus a control computer, a power supply (the pod uses power from the aircraft's power system) and an environmental control unit (see the following diagram).

Both the TF radar and the FLIR are aimed at allowing the F-15E to make a high speed, low altitude penetratation of enemy airspace at night and/or in adverse weather conditions. These two systems give a powerful edge to the Strike Eagle when it comes to deep interdiction missions, thus making the jet an extremely capable night flying platform.

Terrain-Following Radar

The AN/APN-237A terrain-following radar is located behind the round radome forming the forward end of the pod. It is a KU band radar manufactured by Texas Instruments. When operating, it constantly scans the terrain in front of the jet and combining it with using altitude and airspeed data, it is able to generate inputs to the autopilot to maintain its pre-set altitude thus making the jet follow the contours of the terrain totally 'hands off', that is without inputs from the pilot. When the autopilot is not in use the TF radar is able to generate maneuvering cues for the pilot to avoid ground obstacles.

Advanced signal processing solutions result in a wide azimuth coverage, which means that the system is able to give directional commands as well, not just simple 'fly up' commands. Although the system works flawlessly (no F-15E ever was lost due to TF radar fail) it must be a bit eerie feeling for the aircrew to blast over a rugged terrain at night at high speeds with their life depending on a couple of electronic circuitry.

The TF system has its limits however. Obviously it is not able to safely maneuver the aircraft in every possible situations. But since the working of the system is critical for the safety of the jet and its crew, the system immediately issues several warnings to the aircrew upon reaching its operational limits. When this happens, the aircrew hears a series of beeps plus a synthesized female voice (called ' Bitching Betty') saying ' TF fail'. Parallel to this a dedicated warning light illuminates under the glareshield of both the pilot and the WSO, plus a short text appears flashing in the middle of the HUD stating the reason why operational limits were reached (if limits are reached in more than one aspect, only the highest priority aspect is displayed). The following texts can appear on the HUD:

The TF radar system receives data from the aircraft's FCC (Flight Control Computer), radar altimeter and navigation system. Incoming terrain is displayed to the crew by utilizing a so called E-scope page, which can be called up on one of the multi-purpose displays. Since this display is somewhat difficult to understand (at least for first sight), we dedicate a separate chapter for the explataion of how it works. See chapter 'Reading the E-scope Display' below.

The TF system has several operating modes, selected by the pilot based on weather, topographical or tactical conditions. These modes are the following:

Normal mode: This mode is used most often as this is the basic operating mode of the TF radar. This mode is used in good weather with no jamming activity by the enemy. In this mode the radar perform one 8-bar scan every 2.5 seconds and this scan covers an area ranging from +10° to -20° of elevation. A pre-defined set of altitude values (called 'set clearance plane', or SCP) is available to select from: 200, 300, 400, 500 and 1,000 feet AGL. In normal mode the TF system is able to handle at most 60° banks and 5.5° per second turn rates.

ECCM mode: ECCM stands for Electronic Counter-Countermeasures. As its name says, it provides protection against enemy RF (radio frequency) jamming at the cost of reducing TF performance. In ECCM mode the TF scan range is only 15.000 feet (instead of 10 miles) and the upper limit of scan elevation is +5° (instead of +10°). ECCM modes uses special circuitry to pick real radar return from the jammed signals flooding the receiving end of the TF radar. The TF can be programmed to filter out returns from chaff bundles dropped by enemy (or friendly for that matter) aircraft operating in the same area.

WX1 mode: WX1 stands for Weather 1. This mode is used under light rainy conditions (in this case 'light' means no more than 10 mm/hour). Since raindrops tend to reflect radar energy, WX1 mode decreases the sensitivity of the system somewhat in order that radar returns from raindrops should not be mistaken with ground returns. In WX1 mode the TF scan range is only 15.000 feet (instead of 10 miles) and the upper limit of scan elevation is +5° (instead of +10°).

WX2 mode: WX stands for Weather 2. This mode is used in heavy rain. Like WX1 mode it too decreases the sensitivity of the system, but in this case the level of decrease is quite significant. In WX2 mode the TF scan range is only 15.000 feet (instead of 10 miles) and the upper limit of scan elevation is +5° (instead of +10°) and SCP selection is limited to 500 and 1000 feet AGL. Because its inherent insensitivity, this mode cannot be called 'safe' by any means, hence it is never used in peacetime. In wartime however, there are sometimes more important things to consider than safety...

LPI mode: LPI stands for Low Probability of Intercept. Emitted radar energy can be detected by the enemy quite easily, even from much longer distances than the useful range of the radar. To prevent early detection the TF radar features LPI mode. In this mode the normal 8 bar scan is reduced to only 1 bar and after the scan the radar pauses a bit then does the next scan. Additionally the system automatically adjusts radiated radar energy to the minimum level necessary to create TF commands. Some ECCM features are also included in this mode.

VLC mode: VLC stands for Very Low Clearance. It introduces a new minimum SCP value as low as 100 feet AGL. Since this is a very low altitude, upon entering this mode the system automatically performs a self-test of each of its components and mode selection is valid only if all of the tests results in no errors.

Reading the E-scope Display

The E-scope display shows raw radar returns, thus presenting the aircrew a good overview of a 'slice' of terrain in front of the aircraft (see photo below) up to 10 miles. Though not easily readable for a first sight, it provides a bunch of useful information only at a quick glance of a trained eye (see diagram below).

On the edges of the screen, aligned to the pushbuttons sorrounding each MPD/ MPCD, there are menus and settings by which the aircrew can modify the operating parameters of the navigation pod.

On top of the screen, the available set of SCP's are displayed (1), the pilot can select from them by pushing the appropriate button. The selected SCP value is boxed. Remember, SCP is the altitude (in feet) the TF system is supposed to keep.

Below this selection two critical flight parameters (2) are displayed: one of them is actual radar measured altitude (beginning with letter 'R'), the other is the aircraft's ground speed (beginning with letter 'G') that is the speed of the aircraft relative to the ground.

On the left side of the screen, TF radio frequency ( RF) channel is displayed (5), the pilot can change the channel up or down by pushing the appropriate pushbutton. Below this (in the bottom left corner of the screen) riding comfort setting is displayed (6), this setting can be changed by pushing the corresponding pushbutton. Available values are 'SOFT' and 'HARD'. This value tells the TF system, how intensive course changes it is allowed to initiate.

On the bottom of the screen, the available TF operating modes are displayed (12). These modes were discussed earlier in this article. The selected value is boxed. Note that WX2 mode (never used in peacetime) cannot be seen in the selection, it can be selected by selecting WX1 mode first, then by pushing the same pushbutton again.

Two more important indicators are included in this screen. One is the aircraft pitch and attitude indicator in the top left corner of the screen (3) which shows the pitch and bank attitude of the aircraft by using standard HUD symbology. In the picture above, the aircraft is in level flight and is slightly banked to the right.

The other is the TF radar scan position indicator in the top right corner of the screen (7), this shows the current scan position of the TF radar. The horizontal scale represents TF radar azimuth range, while the small blip just above the scale represents the current azimuth the TF radar beam is actually pointing to. As the TF radar performs its scanning, this small blip continuously moves from left to right, then right to left.

These values explained we can now get to the most interesting, middle part of the screen: this area is reserved for different lines and graphs which will be discussed below. All of them are displayed in a coordinate-system with range on the X axis and altitude on the Y axis. Range (in nautical miles) represents the terrain in front of the aircraft. Range values are displayed on a non-linear scale (11), with smaller values (terrain closer to the aircraft) having more space on the screen, thus being able to represent more details. The range scale ends at 10 nm, this is the maximum range of the TF radar.

Altitude values are not explicitly displayed, they are indicative in nature. There is however one important altitude value, which is displayed to be easily seen. This is the SCP value and it is displayed by a horizontal line  (9) , called the SCP line. If everything goes well, this is the altitude the aircraft is ought to be at.

The thick and grainy graph occupying the center of the screen shows raw radar returns (10). These are the RAW (not normalized) values received from radar energy reflected from the terrain. The display shows only a slice of terrain at a bearing the aircraft is currently travelling at. Imagine the aircraft as sitting on the left edge of the screen with its nose pointing right, towards the middle of the screen. As the aircraft advances, this raw radar return graph scrolls to the left and changes according to the terrain scanned by the radar. Places where no radar returns are acquired from (for example lakes or rivers) show as gaps in the graph - such a gap can be seen in the middle of the graph. Note that the SCP line represents the flight path of the aircraft and will always remain fixed on the screen. If the aircraft pitches up, the raw return graph moves towards the bottom of the screen, and if the aircraft pitches down, it will rise on the screen. It's obvious that this line should be kept above the raw return graph to avoid hitting the ground.

Since the range scale is non-linear, this graph is somewhat tricky to interpret. The picture above actually shows a FLAT terrain with the aircraft travelling at 200 feet AGL. Note that the more we go to the left (towards more close ranges) on the graph, the bigger the vertical gap between the SCP line and the raw radar return graph. It is obvious that close terrain details have more vertical space on the graph to be shown than distant terrain details. This is the reason why the graph is non-linear - terrain right in front of the jet is more important to be observed in detail than terrain several miles away.

It should be noted that raw returns are displayed for informational purposes, they themselves do not affect the behaviour of the jet. The system generates synthesized 'terrain points' from raw returns, these are the points which the TF system thinks the ground should be. These point can be seen as small blips on the 'ridge' of the raw return graph. These points are which do have actual effects to issuing TF commands.

The ZCL, or zero command line (8) represents the 'maximum climb path' the aircraft will take by autopilot should an obstacle be needed to be cleared. If the raw return graph scrolling from right to left hits the ZCL, the system will issue a fly up command to the autopilot and the aircraft will begin to climb at the preset G-loading.

The obstacle warning line (4) serves as a 'last line of defense'. It represents an agressive climb path to clear an obstacle - such intensive climb cannot be initiated by the TF system driven autopilot, it always requires pilot manual intervention. For example if an obstacle (which generates a peak in the raw return graph) cannot be cleared by the autopilot, based upon ZCL-originated commands, then the raw return graph will scroll further left and the terrain peak will scroll into the obstacle warning line. In this case the TF system automatically displays a 'FLY UP' message on the HUD and issues audio warnings to the aircrew that manual intervention and a relatively high-G climb is needed.

Forward Looking Infrared

The LANTIRN navigation pod contains a fixed, wide file of view (21x28 degrees), advanced 3rd generation mid-wave (8-12 micron) forward looking infrared ( FLIR) sensor. The window of this sensor can be found directly above the TF radome.

This FLIR sensor generates an infrared image of the terrain in front of the aircraft and projects it onto the pilot’s HUD. This way the pilot is able to see the terrain in front of him through the HUD in shades of green even in total darkness or in adverse weather conditions. Seeing the terrain the pilot can easily fly at high speeds very close to the ground, thus using terrain features (mountains, valleys) to avoid enemy detection. The WSO can view the same image on one of his multi-purpose display, by calling up the HUD-repeater page. Note that the repeated FLIR image is available for the WSO regardless of whether the pilot had actually chosen to put the FLIR image on the HUD or not.

Image quality is 640 x 512 pixels, not something you can call as high quality, but it gives the pilot more than enough sense of depth and contours to be able to navigate the jet with confidence. Moisture in the air (rain, fog, smoke) however degrades the performance of the FLIR system.

The FLIR is capable for a snap-look and look-into-turn ( LIT) modes, which means that the pod is temporarily able to slew its field of vision to show the pilot (on the HUD) a section of terrain not directly in front of the jet. This enhances aircrew situational awareness ( SA) and helps the pilot to make drastic course changes safely. The pod can cover a 56x78 degree field by slewing, although only a 21x28 degree section of this field (called field of regard) can be viewed at a time.

By snap-look the ground-stabilized field of vision can be slewed 9 degrees up or down, and 25 degrees left or right.

Look-into-turn ( LIT) mode actually covers two modes: a manual and an automatic mode, both of them horizon-stabilized. Manual mode allows the pilot a 6 degree slewing in the direction of the turn, it is initiated by the pilot by pressing the coolie switch on his stick. To use this feature the aircraft must be in a bank of at least 5 degrees. Automatic mode can be set via the UFC and if engaged, the pod automatically slews its field of view in the direction of the turn by 6 degrees, once the aircraft's banking exceeds 33 degrees. The pilot can engage snap-look while LIT is active, this way he can add 19 more degrees of slewing, thus reaching a maximum slew angle of 25 degrees in the direction of the turn. Once the aircraft returns to below 3 degrees (in manual LIT mode) or below 20 degrees (in automatic LIT mode) of bank, the field of view automatcally gets boresighted again.

It should be noted that however useful snap-look and look-into-turn modes are, they have a drawback of projecting an offset image to a not offset HUD. Flying at high speeds, close to the ground in darkness, pilots have to think fast, and this offset image can sometimes be rather disorienting. This is the reason why snap-look and look-into-turn (especially its automatic mode) are seldom used by F-15E pilots (especially if they are equipped with nigh vision goggles).

As with other infrared systems the pilot can toggle between 'white hot' and 'black hot' display modes (the hotter terrain features display lighter in 'white hot' modes and darker in ‘black hot’ mode), although that the image is monochromatic green.

Navigation Pod Usage

The first and most important process when fitting a pod to an aircraft is boresighting. Should the pod not be properly boresighted, errors in navigation may occur and at high speeds and low altitudes even small margins of error could prove fatal. After fitting, the pod is boresighted mechanically by adjusting its fitting in pitch, yaw and roll directions. These adjusments values are then entered into the central computer of the F-15E to be able to compensate for them during pod usage. The angle values are down to tenths of milliradians, which gives you a feeling of the preciseness and importance of this process. Note that this calibration process are repeated from time to time even when the pod is not removed from the jet, since the normal wear and tear caused by flying (especially high G loads) can alter these mechanical values a bit.

An even finer, electronical tuning is also possible: in this case the pilot (during flight) can compare the FLIR image to the real world in his HUD. Using the target designator switch on the throttle quadrant, he can perfectly align the FLIR image to the real world image.

The navigation pod features two BIT (built-in test) modes. One is automatic and runs every time the pod is given power from the aircraft, this test mode is called P- BIT (periodic built-in test). The other is run manually with the pod in standby, this mode is called I- BIT. This latter analyzes the pod more deeply, although it takes more time to run. Errors found by either BIT modes can be displayed on one of the multi-purpose displays by calling up the error page (there are 15 possible errors). Parallel to this a separate warning light is reserved for the LANTIRN on the master caution panel. Additionally, external BIT interface is provided for the ground crew, this uses small black buttons which change their color if an error occurs. I- BIT errors can be cleared from the system only if the pod gets removed from the jet and repaired.

Navigation Pod Technical Data

Targeting Pod

The initial operation test of the targeting pod was successfully completed in April 1986 and reached its full-scale production in early 1990, entering service just before Operation Desert Storm. Lockheed Martin created an improved version of the pod in 1995 mainly for the Navy's F-14 Tomcats. This pod integrated the navigation and targeting features in one unit, plus brought many improvements over the previous two-pod LANTIRN system. This LANTIRN ER pod (ER standing for Extended Range) however never made it to the F-15E. Being a strictly F-15E website, in the following we will discuss the 'old' version of the LANTIRN targeting pod.

The pod is 98.5 inches long, 15.0 inches in diameter and weighs 549 pounds. The pod itself is integrated with the jet's other systems and they communicate via the standard MIL 1553B data bus. It's onboard software can be easily updated whenever the need arises, and many of its components are designed to be LRU's (line replaceable units, meaning that its replacement can be carried out by maintenance personnel on the field), though not as much as of the less complex navigation pod. It contains a targeting laser, a targeting FLIR, plus an environmental control unit, a power supply (the pod uses power from the aircraft's power system), central electronics and a control computer (see the following diagram).

Note that the targeting pod is the longer from the two in such extend that the two countermeasure (chaff and flare) dispenser bays directly behind the pod are limited for chaff use only, since flares launched from here would damage the pod.

The targeting pod features a data-logging module ( DLM) which communicates with the pod's control computer to provide real-time data recording and logging. Data can be analyzed after landing by connecting a portable data terminal into the appropriate socket outside of the pod. The DLM system can be of great help for the ground crew when trying to find minor or lower-level errors.

Targeting Laser

The pod contains a laser designator/rangefinder to aid the delivery of precision guided munitions (PGM's) plus the software necessary to automatically track the selected target regardless of the maneuvering of its host plane. The designator is a four-digit PRF coded laser which can designate for the aircraft's own weapons and for the weapons of other aircraft as well (this latter technique is called 'buddy-lasing'). In case of unguided ('dumb') bombs the laser is used to determine target range and the pod feeds this input to the aircraft's fire control system.

To be able to follow the target within wide limits, the nose section (called NESA - Nose Equipment Support Assembly) of the targeting pod can rotate, thus giving the laser a 150 degree field of regard. When the system is not operating, the nose rotates the vulnerable sensors towards the belly of the jet, thus protecting it from elements (this is especially useful during takeoff and landing when ground debris could cause severe damages to the sensors).

The pod uses a Q-switched neodymium-doped yttrium garnet (Nd:YAG) laser, powered by ints own high-voltage power supply located within the pod's power supply unit. The laser can operate in two modes: training mode and combat mode. For training purposes the pod uses an eyesafe laser beam to avoid accidental damages to the eyes of people around the jet. It is an 1.54 micron, 8 millijoule laser. In combat the pod uses an 1.06 micron, 100 millijoule laser beam. The two modes can be selected by a switch mounted externally on the pod. Since the training version is much less powerful, it can be used on targets not further than 3.5 miles, under good visibility conditions.

Since more than one aircraft can be operating in the same area using lasers, confliction may occur. To avoid this, the laser can be coded to match the codes of the bombs the jet is carrying (this coding can be accomplished by the WSO using MPD and UFC).

Note that the targeting pod automatically shuts itself down above 25.000 feet of altitude to avoid electrical arcing in thin air when firing the laser. The environmental control unit ( ECU) is also capable of shutting the pod down if for some reason it gets too hot.

The targeting laser system makes use of a very interesting feature, masking zone prediction. The reason behind is that while maneuvering with laser being fired, the aircraft can sometimes turn such a way, that parts of the airframe or parts of the ordnance hung on pylons can stand in the way of the laser. This would not be welcome of course, since with the laser blocked, the LGB already on its way to the target would fail to guide any further, not mentioning the danger of a laser operating in combat mode getting reflected from some part of the airframe and blinding the aircrew. To avoid this blocking, the pod contains a selection of 'masking profiles', each of the profiles referring to a particular weapon loadout arrangement. Before takeoff the appropriate profile can be selected via the PACS. There are 7 profiles for the left side and 3 profiles for the right side of the jet and if necessary, more than one profile can be selected. Using the selected masking profile and knowing both the laser's and the aircraft's attitude, the targeting pod can issue a warning to the pilot every time the laser gets close to a blocking situation. In this context 'close' means that the laser is less than 10 degrees from being blocked. The warning is issued by presenting a 'MASK' text over the targeting FLIR image on the MPD/ MPCD. This way the pilot has time to maneuver the aircraft to avoid laser blocking.

The targeting laser can be used to update INS information. Once the aircraft reaches a pre-defined steering point, the steering point ground feature (some building, a road intersection, a bridge, etc.) is designeted and then the laser is fired. The pod determines the range of the selected point and updates the INS based upon this very accurate, 'real-life' information. INS has the tendency to 'drift away', i.e. become more and more inaccurate as time progresses, so this feature comes very handy to keep the INS tight and precise.

Another feature, called MARK, works just the same. The aircrew can designate something on the ground, fire the laser and the system computes the coordinates of the point designated and stores it for future reference. The aircrew can recall this point later and can receive INS guidance and thus return to the point later.

Targeting infrared

The LANTIRN targeting pod contains a high-resolution, 8.0 inch aperture forward looking infrared ( FLIR) sensor for long range target acquisition. It can operate in a 5.87x5.87 degree wide field of view ( WFOV) mode, a 1.65x1.65 degree narrow field of view ( NFOV) mode and a 0.825x0.825 degree extra-narrow field of view ( ENFOV) mode. WFOV is used for target detection and tracking while NFOV and ENFOV are used for target selection. The WSO can switch the FLIR between air-to-ground and air-to-air modes, and both modes feature ground and aircraft stabilized operation. 'Ground stabilized' that the FLIR is looking at a specific point on the ground while the aircraft can maneuver, while 'aircraft stabilized' means the FLIR is looking at a fixed angle and azimuth relative to the aircraft, just like a fixed camera attached to it.

The pod features a missile boresight correlator for automatic lock-on of Maverick imaging infrared missiles. Integration with the Maverick is full, the pod is able to hand over the target info to the missile prior to launch, which means that the WSO designates the target via the targeting pod and then 'transfers' this designation point to the Maverick and from then on the missile is able to track and hit the target on it own. The image of the targeting FLIR (along with important data related to its operation) can be displayed on any of the seven multi-purpose displays in the cockpit of an F-15E.

The FLIR's optics is synchronized with the laser designator, so that the optics looks in the exact direction the laser is pointing. The targeting FLIR operates on the same 8-12 micron wavelength as the navigation FLIR does.

The targeting FLIR features four air-to-ground tracking modes. These are the following:

Point Track ( PTRK) mode: This mode is to track the designated target by recognizing contrast differences in the target's IR signature on each side of the target. This mode is often used when tracking single targets which stick out from their surroundings and the IR signature of which can be easily recognized by the pod's software. Typical targets for this mode are trucks, tanks, moving vehicles.

Area Track ( ATRK) mode: When the target's IR signature is blended into its surroundings, then ATRK mode is used. This mode utilizes an area correlation tracker to keep the crosshairs centered on the selected target. When a target is originally tracked by PTRK but its IR signature 'fades into' its surroundings, then the pod automatically switches to ATRK mode to maintain tracking.

Offset Track ( OTRK) mode: This mode, however useful it may seem, is very rarely used in practice. It is designed to track a target with a very poor IR signature, but close to an object with a good IR signature. In this mode the WSO locks on the 'good' object, then slews the crosshairs to the target and fixes this offset. From that point on the pod's logic actually tracks the 'good' object, but keeps the crosshairs centered on the actual target. For this mode to be effective, both points (i.e. the 'good' object and the target itself) have to be within the field of view of the pod.

Non-Active Track (CMPT) mode: This (very rarely used) mode utilizes some line-of-sight rate extrapolation techniques to temporarily track under poor IR visibility conditions. If PTRK and ATRK modes both fail for some reason, then CMPT mode is automatically selected.

Note that despite the above array of automatic tracking modes available, the pod often encounters difficulties tracking the target. In this case the WSO can manually aid the pod in tracking by manually making small adjustments with his TDC (Target Designation Control). Being often unable to achieve good target tracking independently of each other, the WSO and automatic modes together can produce very steady tracking as it is often seen on targeting FLIR videos.

Besides the modes and features discussed above, the targeting pod possesses a very capable air-to-air mode, however this is classified stuff so information on this mode is not available.

Targeting Pod Usage

The first and most important process when fitting a pod to an aircraft is boresighting. Should the pod not be properly boresighted, errors in bomb delivery may occur which is obviously not desired. After fitting, the pod is boresighted mechanically by adjusting its fitting in pitch, yaw and roll directions. These adjusments values are then entered into the central computer of the F-15E to be able to compensate for them during pod usage. The angle values are down to tenths of milliradians, which gives you a feeling of the preciseness and importance of this process. Note that this calibration process are repeated from time to time even when the pod is not removed from the jet, since the normal wear and tear caused by flying (especially high G loads) can alter these mechanical values a bit.

Electronical boresighting is also possible, which can be accomplished during flight. In this case the WSO designates (i.e. marks for tracking) a target with the pod. The target should be at least one mile in front of the jet. The targeting point is represented by a tracking symbol in the pilot's HUD. The pilot then uses his target designator switch to align the tracking symbol with two concentric circles in the HUD. Once this accomplished, a commit button should be pressed and the pod's onboard computer does the math and re-aligns the pod. Note that this electronical boresighting degrades the pod's accuracy somewhat, which raises the importance of mechanical boresighting during installation of the pod.

The targeting pod features two BIT (built-in test) modes. One is automatic and runs every time the pod is given power from the aircraft, this test mode is called P- BIT (periodic built-in test). The other is run manually with the pod in standby, this mode is called I- BIT. This latter analyzes the pod more deeply, although it takes more time to run. Errors found by either BIT modes can be displayed on one of the multi-purpose displays by calling up the error page (there are 27 possible errors, but only 24 of them could be displayed simultaneously). Parallel to this a separate warning light is reserved for the LANTIRN on the master caution panel. Additionally, external BIT interface is provided for the ground crew, this uses small black buttons which change their color if an error occurs. I- BIT errors can be cleared from the system only if the pod gets removed from the jet and repaired.

Target designation can be done from the TSD (tactical situation display, or moving map display) by simply placing the cursor over the target and pressing a button - and the targeting pod immediately slews its optic to center on the selected target point. However TSD is not the only way to designate from. The same designation process can be done on the RBM (real beam map - showing ground radar returns) or HRM (high resolution map, or patch map - a synthetic aperture radar generated image) radar displays as well. Moreover the targeting pod can also be slaved to pre-programmed steerpoint (where the pod looks in the direction of the next steerpoint programmed into the EGI), and it can be slaved to the target designator diamond displayed on the pilot's HUD.

Targeting Pod Technical Data

Sources

• The F-15E Strike Eagle Forum (SEF), www.f-15e.info
• Lockheed Martin official website (www.lockheedmartin.com)
• Federation of American Scientists (www.fas.org)
• F-16.net (www.f-16.net)

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