Paveway II Delivery Profiles - Ground Lasing (15/x)

In our previous discussions on Paveway II employment, we explored all the self-lasing delivery profiles (level, dive, pop-up, loft, and toss). These methods have all in common that they require precise aircraft handling and sensor management to acquire target and guide the bomb, in a potentially high threat environnement.

However, modern combat operations often involve distributed responsibilities to enhance survivability, reduce workload, and leverage joint assets. This brings us to ground lasing, a tactic where designation shifts to a ground-based asset (generally a JTAC), allowing the pilot to prioritize flight parameters and survivability.

Unlike self-lasing, where you control the entire chain, ground lasing introduces variables like JTAC line-of-sight limitations and designation timing, all of which must be mitigated through disciplined phraseology and pre-briefed tactics.

We'll cover here the general ground lasing procedures, and we'll detail the main risks and difficulties of ground lasing tactics, as described in official documents like JP 3-09.3 "Close Air Support" and ATP-3.3.2.1 "Tactics, Techniques and Procedures for Close Air Support and Air Interdiction".

I. Fundamentals of Ground Lasing for Paveway II

I.1 - Getting the correct LASER code

First of all, as you are now well aware, keep in mind that the bomb's LASER code is defined once and for all on the ground before take-off. It means that, just as you have to set up the correct code for you TGP, the ground party will have to receive your LASER code one way or another before the attack.

The most common means of transmission is by voice, on the radio: in a CAS scenario, it's usually done by voice during the check-in brief: you detail LASER code and bomb fuze settings when you describe your available weapons.

ATP-3.3.2.1 detailing the ordnance in the check-in brief, and LASER code details that have to be passed to the JTAC.

Another alternative way to pass the LASER code is via the ATO: each flight has an assigned LASER code assigned at the operational level. An aircraft checking-in "as fragged" implies that its LASER code matches the one assigned in the ATO. But this method is only valid if the JTAC has a reliable access to the ATO, which is not always the case.

Older version of JP 3.09 stating the ATO as a means to get the aircraft's LASER code.

More commonly, the LASER code can be passed directly during the planning phase, during a direct briefing between the crew and the ground party, if such a briefing is possible. It will most certainly be the case during the most sensitive missions, like special operations, where radio comms need to be minimized in order to remain electronically discreet.

Nowadays, with Digitally Aided CAS (DACAS), such information can also be transmitted via messages, generally in free text. Several DACAS systems now exist, and you can see below that VMF is the most common system, enabling safe data exchanges in direct line of sight (LOS). Beyond Line of Sight (BLOS) systems like SADL and Link-16 generally require more sophisticated equipment, that can not be carried in the field as easily as LOS equipment.

Table of DACAS equipement compatibility for US aircraft and JTAC systems.

Note: as explained in the buddy-lasing phraseology detailed in an earlier post, the LASER code will also be stated when the aircraft orders "LASER ON". It's obviously too late for the JTAC to enter the code in the ground designator, but it serves as a last second verification, that still enables an "ABORT" if a discrepancy in LASER codes is detected. That's a reason why continuous LASER is preferred: a LASER code error can be detected before the bomb is flying.

I.2 Getting within target's line of sight.

Ground lasing introduces an additional challenges in maintaining line-of-sight (LOS) to the target. Unlike Type 1 control, where the JTAC must visually acquire both the aircraft and target, Types 2 and 3 do not mandate JTAC visual confirmation of the target, allowing reliance on non-visual targeting data such as coordinates or third-party inputs. In these scenarios, the JTAC may coordinate with a joint fires observer (JFO) or other forward elements to acquire target information and execute lasing if the JTAC lacks direct LOS. However, the lasing party, whether JTAC or JFO, must still achieve unobstructed LOS to illuminate the spot accurately.

Terrain relief and vegetation often exacerbate LOS issues, masking the target and requiring repositioning that exposes ground personnel to threats or delays engagement. In mountainous or forested environments, valleys, ridges, or dense foliage can block the laser beam, necessitating elevated observation posts or JFOs closer to the target. For mobile targets, LOS becomes time-sensitive: the window for designation may be fleeting, demanding rapid coordination to align the lasing party with the target's movement before it relocates or enters cover.

Ground laser designator used during OEF. Using elevated positions enables better line of sight, especially in a mountainous environnement.

This contrasts sharply with airborne lasing, where elevation provides inherent LOS advantages, allowing designators to overlook terrain obstacles. Airborne challenges center more on avoiding pod self-masking during maneuvers, with clouds being the primary barrier to spot acquisition and weapon guidance.

Note: even if from a ground perspective the weather seems to be excellent (perfect visibility, no precipitations), you have to remembrer that ceiling is a critical factor for ground lasing. Operations require a ceiling of at least 5,000 ft above the target to ensure the bomb has sufficient clear-air time (at least 8 seconds) for guidance. If the ceiling is lower, the bomb emerges from clouds closer to impact, delaying laser spot acquisition and potentially preventing adequate trajectory correction, leading to ballistic fallback or misses.

II. Risks and Difficulties of Ground Lasing

II.1 Risks: fratricide

The primary risk in ground lasing is fratricide, driven by the physics of the Paveway II guidance system. The bomb does not “know” the target, it only homes on the coded laser energy reflected back within its seeker field of view. If the designator inadvertently paints a foreground object, or if the geometry makes the designator itself appear more attractive than the intended spot, the weapon will guide toward that reflection. This phenomenon is well documented and is the reason why laser safety zones and carefully briefed attack headings are mandatory.

As explained in the introduction video above, and as detailed in the official documents, attack from the same side of the LASER designator is mandatory, otherwise the bomb will probably identify the designator as a stronger source of energy than the target itself, all the more than the target will certainly hide most of the LASER reflection (cf. podium effect, described several time already). Even if the bomb might not be able to actually hit the designator itself (too far from the ballistic aim point), it will try to reach it, end up long and off target.

A similar phenomenon can occur when the weapon is dropped exactly above the LTL (LASER-to-Target Line), that's why a 10° safety zone on each side is also created.

Authorized attack sectors as described in JP 3.09.

One generally unknown tool for risk mitigation lies in the weapon’s pulse logic settings. Paveway II seekers can employ either Long Last Pulse Logic (LLPL) or Short Last Pulse Logic (SLPL), each optimized for different conditions.

SLPL and LLPL modes on the GBU-12 in Razbam's F-15E module. Source: Chuck's Guide.

• LLPL is less susceptible to obscurants such as fog, haze, dust, or smoke. Without LLPL, the seeker might lock on the obscurant itself rather than the intended target, causing the bomb to steer off target, sometimes back along the beam toward the ground designator. In a ground lasing scenario, that places the JTAC directly at risk.

• SLPL is used when the designator illuminates a target at long range and excess LASER energy “spills over” onto objects behind it (trees, buildings, ridgelines). If the seeker simply tracked the last return, it might ignore the target and guide on the background object. SLPL logic helps filter these weaker, more distant reflections and hold the weapon on the actual aimpoint.

Source: F-15 Aircrew Weapons Delivery Manual.

In other words: in most cases LLPL is the default setting if ground lasing is an option. Correct employment of these modes significantly reduces the probability of a bomb wandering off the intended spot and toward either friendlies or the designator itself.

II.2 – Difficulties: Coordination

II.2.a - Technical Factors

Transmission of LASER energy in the atmosphere is far from perfect. Diffraction, scattering, and absorption through haze, dust, smoke, or battlefield obscurants degrade the return signal. The Paveway II seeker requires a strong and stable reflection to make mid-course corrections. Later Paveway variants (III and Enhanced Paveway) were designed with better signal processing to mitigate these effects.

Another important effect is diffraction around obstacles. If the line of sight passes close to a hard edge, such as a building corner, treeline, or ridge-line, part of the LASER energy can scatter into unintended directions. From the seeker’s perspective, this creates false returns or weak, ambiguous signals. In practice, this can pull guidance slightly off-axis, degrading accuracy, or in the worst case, shift the weapon toward the diffracting obstacle itself. Unlike obscurants, diffraction often provides no obvious warning to the JTAC.

Example of diffraction effect at the edge of an obstacle.

The practical consequence of these two phenomenon is that ground lasing is only reliable under excellent conditions. In a high-intensity fight, every artillery burst, building strike, or vehicle kill adds smoke. What began as a clear geometry can quickly become below the threshold of acceptable conditions for ground lasing, forcing the JTAC either to reposition, delay, or hand off to another asset.

Enemy countermeasures also complicate the picture. Even low-tech adversaries can deploy smoke or aerosols once they detect laser designation. More sophisticated opponents may employ laser warning receivers or active jamming to disrupt weapon guidance. As a consequence, a balance must be found: too early, and the enemy can reacts; too late, and the bomb cannot acquire the spot.

II.2.b - Procedural Factors

The harder part, however, is not the physics but the human coordination.

• Perspective mismatch: the JTAC on the ground and the pilot overhead rarely share the same sight picture. Terrain that looks flat from above can hide ridges or tree lines from the ground. Conversely, what looks like a clear aimpoint to the JTAC may present clutter and competing reflections to the bomb’s seeker. Weather is also difficult to assess from the ground, and more particularly cloud ceiling.

• Threat environment: for the JTAC, exposure is often the limiting factor. To gain LOS, he may have to move to an elevated or forward position under fire. For the pilot, the threat is air defenses dictating altitude, run-in angles, or release ranges. These two threat perspectives rarely align, making compromise inevitable.

• Timing: unlike self-lasing, where you can start guidance at the optimal moment, ground lasing may involve delays. The JTAC may be under cover, waiting to break out and lase at the last possible second. Or, due to comms latency and procedural deconfliction, the bomb may spend several seconds unguided before spot acquisition. In low ceilings or short slant ranges (eg: pop-up), that margin can mean the difference between a hit and a miss...

For these reasons, doctrine is unambiguous: ground lasing requires very robust procedures. Shared phraseology, redundant checks of LASER codes and geometry, and disciplined timing are very important. This is why the same documents that warn about technical limitations also place heavy emphasis on the procedural backbone of CAS: the 9-line, remarks and restrictions, and the standardized LASER brevity set that we already discussed earlier.

Conclusion

Ground lasing with Paveway II remains a powerful tactic, but it comes with unique complexities that self-lasing pilots rarely face. Ground lasing is unforgiving of poor coordination and doctrinal safeguards like strict phraseology and precise timing of calls exist to ensure that bombs strike the intended target and not the designator or friendly forces. They are not “nice-to-have” procedures, but critical requirements.

Where ground lasing forces the JTAC to fight terrain, weather, and enemy threats for line-of-sight, airborne lasing offers different advantages and challenges. Altitude provides geometry and visibility that ground operators cannot match. That's why in a following part we will introduce airborne buddy lasing, beginning with high-altitude profiles.