ATP-3-09-12 Field Artillery Counterfire and Weapons Locating Radar Operations Download
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AN/TPQ-53 Weapons Locating Radar System Characteristics and Employment 26 October 2021 ATP 3-09.12 H-3 SITE REQUIREMENTS H-5. The choice of a site for the radar set is dictated primarily by the tactical situation, the area to be observed, and the terrain restrictions. There are no restrictions on the location of the OCS except that it must be within 1000m of the MEG due to the length of the fiber optic cable. The OCS can be entrenched, sandbagged, or located among trees. The OCS should be located in a protected area and never in the line-of- sight of the antenna. H-6. Generally, the following should be considered when selecting a site for the MEG: The slope of the ground (must be equal to or less than 5 degrees) with the prime mover positioned facing down slope. The ground should be of adequate strength and consistency. The terrain mask angle. The height and density of foliage or trees relative to the antenna. Other radar sets operating in the area. The site selected should have adequate drainage. H-7. The slope of the ground should be such that the prime mover and the antenna transceiver group can be leveled. The bubble level located on the prime mover dashboard must indicate that the vehicle is on ground that falls within the capabilities of the leveling system. The area in front of the antenna should be clear of nearby clutter that will weaken (attenuate) the radar beam. Solid objects and heavy foliage within 300m should not extend above the bottom of the antenna. The slope of the ground should be such to minimize possible multipath errors. Multipath errors are caused mainly by ground reflections. To minimize multipath errors, the terrain should not exceed 2-3m in height from the terrain height at the antenna for a distance of 200-250m. H-8. The system should be emplaced on man-made or natural ground which provides adequate strength for stability. Such man-made surfaces include, but are not limited to: concrete, asphalt, dirt roads, and gravel pads. Acceptable natural ground conditions should be of consistency and moisture content that does not allow the soil to noticeably flow under the sand pads during emplacement. The ground should be as free of organic content for example logs, branches, peat as possible, as this can lead to settling. Care should also be taken to prevent washout conditions from eroding soil from beneath emplaced sand pads. H-9. The angle from the antenna to the top of the nearest obstruction, above which the radar set provides search coverage is the terrain mask angle. Two conflicting requirements influence mask angle: enemy radar jamming and direction finders; and detection of enemy projectiles. To be effective, radar jamming and direction finders generally require a line-of-sight to the antenna of the WLR. H-10. A high mask angle is useful against ground-based jamming and direction finders because the jamming must be located at a point above the mask angle. As the jammer or direction finder is forced up in height, the number of suitable sites is generally reduced. Also, because the radar set detects projectiles to determine the weapon location, the radar set does not require a line-of-sight to the weapon emplacements. Therefore, a mask angle that masks off the line-of-sight to the weapons location reduces the effectiveness of enemy jamming and direction finding located in the vicinity of the weapons. H-11. Enemy weapon locations generally tend to require lower radar mask angles. Maximum allowable mask angles decrease with increasing weapon location range, lower weapon location elevations, and lower weapon velocity. However, the radar set does not require a line-of-sight to the weapon location. The radar set must track the enemy projectile for a sufficient elevation arc before the projectile reaches the highest points of its trajectory (apogee). Considering the requirements for effectiveness against jamming, while maintaining adequate detection capability of projectiles, a lower mask angle (dependent upon the QE and velocity of the rounds fired) will provide the specified performance when the WLR and the weapons are at the same altitude. H-12. Another factor which influences site selection is the height and density of foliage or trees relative to the WLR antenna and the AO. Radar signals may be weakened (attenuated) by more than 1 decibel per meter of heavy foliage. Therefore, foliage more than a few meters deep can severely reduce or inhibit the WLR effectiveness. The WLR effectiveness is evident when the operator looks at the AO with the clutter map function enabled and raw video displayed. If the remote control display unit shows a lot of white area, then