Mortar as a typical representative of "intermittent artillery", its aiming method is similar to other indirect aiming artillery, and the intermittent aiming method is more flexible and diverse.
Indirect aiming of artillery in general.
Generally speaking, indirect aiming of artillery means that the scope cannot be seen with the target unit, and it is necessary to calculate the observed azimuth, gauge, height and other shooting elements before installation. In an idealized state, as long as the parameters of the firing elements are relatively accurate, the cannon can be firedHowever, in the process of practical operation, because the stability of the artillery itself is relatively poor, the recoil force is large, and it is easy to cause the displacement deviation after the gun, so modern artillery shooting generally needs a measuring angle instrument similar to the "theodolite" used in civil engineering (as shown in the figure below) to assist the stable coordinate system of the component for accurate shooting.
This auxiliary measuring instrument is generally arranged at the rear of the position, can be convenient to observe (see) the position of the target, first use the pointing needle to accurately adjust the orientation of the azimuth, and then use this measuring instrument to aim at the sight of the artillery, carry out the measurement angle and division, the surveyor will measure the data to inform the artillery aimed, the aimer aims at the auxiliary measuring instrument of the rear with the artillery sight according to the data, because the two use the same angle division, the artillery firing line at this time is parallel to the azimuth of the aiming line of the auxiliary measuring instrument, and can shoot accurately。 (It's a bit of a twist here, but it's true, the gun's scope is aimed at the auxiliary gauge behind the position, and the muzzle is forward, so when you actually operate, you can observe that the gun sight and the muzzle direction are reversed, not aimed at the target, as shown below).
Indirect targeting of mortars.
What we have said above is the basic aiming principle of intermittent artillery, and for mortars, which are relatively lightweight, intermittent artillery, they can rely on auxiliary measuring instruments for aiming, but most of the time because the measuring instruments are inconvenient to carry, and because mortars are generally used on the front line of the battlefield, the measuring instrument for mortars sometimes needs to be set in front of the position, which is easy to be exposed. Therefore, when using mortars, there is no need for auxiliary measuring instruments, but instead of shooting rods, usually two poles are used (modern portable poles are generally two thick and thin, and the thin poles can be inserted into the thick poles when carrying, which is convenient to carry). When in use, the pole is inserted in front of the gun position, and after identifying the target position and aligning it with the naked eye, the pole is inserted into the ground, and the mortar is set in a suitable position behind the pole. In wartime, it can also be used as a benchmark using wooden sticks and other materials (as shown below).
The mortar operator behind first uses the mortar to aim at the pole in the distance in front of him, and the muzzle moves with the scope during the aiming processThen use the scope to divide the near mark, and only adjust the mirror without moving the muzzle during the differentiation process;Finally, use the scope to aim at the distant mark, and then move the muzzle with the scope;Through these three steps, the precise direction of the mortar is basically established. The significance of the three-step action is that the first time aiming at the distant benchmark is equivalent to an azimuth to zero;The second aiming of the approach rod is to reverse the delineation (you may not understand this professional term, simply put, the reverse is a trigonometric elevation measurement, the observation from A to B is called direct viewing, and then the observation from B to A is called reverse viewing, which is an observation technique);The third step is to aim at the far pole again in order to adjust the muzzle to the exact direction of the shot. (Of course, if there is an obstacle between the mortar and the target, and the target cannot be visually seen with the benchmark alone, it is necessary to aim with the compass, which provides the reference bearing, and then uses the principle of the far and near poles to determine the direction of the shot).
Due to the complex and changeable battlefield environment, what we talked about earlier is the "regular opening method" of mortar direction finding, and this gun itself as a portable fire strike tool, of course, has more operation methods (to meet the needs of wartime). If the position of the artillery gun and the position of the target can be directly seen with the naked eye, then there is no need for a benchmark, no auxiliary measuring instruments, and direct shooting can be done directly using the mortar sight. Of course, this method is also very dangerous, when you can look directly at the target, the target can also see you, and it is vulnerable to direct attacks. When encountering an emergency and being close to the target, you can shoot directly at the target with the gun body without any auxiliary measuring instruments, sights, gun carriages, base plates and other tools, which requires quite skilled operation and rich experience, and the "master" can accurately hit the target within hundreds of meters, as shown in the figure below:
Problems with the ranging of mortars.
Above we have talked about the direction finding problem of mortars, and now we will talk about the ranging problem, the modern army is basically equipped with laser rangefinders, which makes it very easy to determine the target distance:
We know that the more modern, high-precision equipment is, the more likely it is to be damaged on the battlefield or affected by environmental and climatic factors. Ranging is very important for mortar aiming, and when the laser rangefinder is damaged or unusable, we still need to use conventional ranging methods, which are also compulsory courses for gunners. The well-known "eye-skipping method" that uses two eyes to take turns to observe is not practical because of its great limitations. For artillerymen, the most commonly used is "thumb ranging", after extending the thumb, the number of targets blocked by the thumb is estimated according to the principle of similar triangles, and the corresponding distance of the target unit is calculated.
Of course, in addition to the thumb distance measurement method, for a target at a specific distance, it is also necessary to use the fist, finger or palm to assist in measuring the angle, and the thumb distance measurement method is assisted. All in all, a qualified artilleryman needs to master a lot of skills and tools to operate.