Military


Chapter 11

Meteorological Techniques


Met techniques described in this chapter allow a unit to account for the effects of nonstandard conditions and achieve first round fire for effect.


Section I

Principles


Understanding the applications of met techniques requires basic knowledge of registration and met principles.

11-1. Purpose and Use of Met Techniques

a. Nonstandard Conditions

(1) Accurate fires can be placed on targets of known location without adjustments. Under standard conditions, the firing table data would achieve the desired results. However, it is valid to assume that standard conditions will not exist. Corrections need to be applied to firing table data to compensate for the nonstandard conditions of weather, position, and material. The most accurate means of determining these corrections is by registering. Registration corrections are only valid within transfer limits and for a specified period of time. However, conducting a registration may not be an option. Therefore, techniques are needed to mathematically determine corrections and compensate for changing nonstandard conditions. The met techniques are used to measure deviations from standard conditions and to compute corrections for them.

(2) The firing tables used to determine firing data for artillery weapons are based on an arbitrary set of standard conditions of weather, position, and material. The standards for weather are established by the ICAO (International Civil Aviation organization). (See Figure 11-1.)

(3) The first seven columns of Table F of the TFT are based on one of two conditions occurring:

    • Standard conditions are in effect.
    • The sum of the corrections for all nonstandard conditions in effect equals zero.

It is obvious that the first will never occur and the second has a minimal chance of occurring. Therefore, if a unit wants to provide surprise and massed fires, it must consider the effects of nonstandard conditions in some way. The best solution to correct for all nonstandard conditions in effect is to register. This allows a unit to achieve first round FFE on an accurately located target. To correctly determine registration corrections and the effects of nonstandard conditions as they change over time, a unit must follow the five steps to improve firing data. (See Table 11-1.)

11-2. Position Constants

a. When a unit displaces to a new position and cannot register, the position constants from the last position may be used as a basis for determining a GFT setting by solving a subsequent met. The use of this technique may cause slight inaccuracies, but it will produce the most accurate data possible until the unit can conduct another registration or met + VE with a check round. Once new position constants are determined, the old position constants are not used.

b. The position deflection correction generally accounts for errors in survey and chart construction. The position deflection correction should only be transferred if common survey exists between positions.

c. The position fuze correction should be considered a fuze characteristic and not a correction for existing weather conditions. The position fuze correction should only be applied to the same lot of fuzes.

d. The position velocity error is expressed in meters per second. It is the position constant which accounts for all range errors not accounted for by met data, muzzle velocity variation, and propellant temperature. Therefore, it will include any errors in survey and should only be transferred if common survey exists. However, the position VE is a constant for projectiles within the registering projectile family.

e. Part of the position VE and position deflection correction are charge independent, specifically errors in the firing chart and survey. The position fuze correction is charge independent because it is a fuze characteristic. Since position constants are relatively small and a portion of the position constants are charge independent, it is possible to compute a GFT setting for other charges and lots. The GFT setting will not be as accurate as a GFT setting derived from a registration, but it will be more accurate than firing with no GFT setting.

11-3. Met Messages

a. Among the nonstandard conditions that affect the projectile after it leaves the tube is the atmosphere (weather conditions) through which the projectile passes. The three properties of the atmosphere that the artillery considers in its gunnery computations are wind (both direction and speed), air temperature, and air density.

(1) Wind. The effects of wind on a projectile are easy to understand. A tail wind causes an increase in range and a head wind causes a decrease in range. A crosswind blows the projectile to the right or left, which causes a deflection error. The FDC converts ballistic wind measurements into range and deflection components and applies corrections to the deflection and elevation of the howitzer.

(2) Temperature. Variations in air temperature cause two separate effects on a projectile. One effect is caused by the inverse relationship between density and temperature. This effect is compensated for when density effects are considered. The second effect is regarded as the true temperature. It is the result of the relationship between the speed of the projectile and the speed of the air compression waves that form in front of or behind the projectile. These air compression waves move with the speed of sound, which is directly proportional to the air temperature. The relationship between the variation in air temperature and the drag on the projectile is difficult to determine. This is particularly true for supersonic projectiles, since they break through the air compression waves after they are formed. As firing tables indicate, an increase in air temperature may increase, decrease, or have no effect on achieved range, depending on the initial elevation and muzzle velocity of the weapon.

(3) Air density. Density of the air through which a projectile passes creates fiction, which affects the forward movement of the projectile. This affects the distance a projectile travels. The density effect is inversely proportional to the projectile ranges; that is, an increase in density causes a decrease in range.

b. The met section is responsible for sampling the weather conditions at various altitudes. Data determined by these samples are converted, manually or by computer, to provide specific weather information at specific altitudes. These weather data are transmitted to artillery units in fixed formats called met messages. The field artillery uses the following four types of met messages:

(1) Ballistic met message. This message is used by cannon units, rocket units, mortar units, and air defense artillery.

(2) Computer met message. This message is used by artillery computer systems.

(3) Fallout met message. This message is used in nuclear and chemical fallout predictions.

(4) Target acquisition met message. This message is used by radar platoons of the target acquisition battery (TAB).

NOTE: Only the ballistic and computer met messages will be described in the following paragraphs.

11-4. Ballistic Met Message

The ballistic met message is a coded message containing information about current atmospheric conditions. There are two types of ballistic met messages provided for artillery. Type 2 messages (surface to air) are used in air defense artillery and type 3 messages (surface to surface) are used by FA cannon and rocket units. Type 3 messages are used in solving DA Form 4200 (Met Data Correction Sheet). Type 3 messages are used for all elevations, for all charges, and for all howitzers in manual FDC operations. The ballistic met message is recorded on DA Form 3675 (Ballistic Met Message) and is divided into an introduction and a body.

a. The introduction of the ballistic met message consists of four six-character groups.

(1) Group 1. The first three letters (MET) in group 1 identify the transmission as a met message. The next letter (B) indicates that it is a ballistic met message. The next digit (3) indicates the type of met message (surface to surface). The last digit (1) designates the octant of the earth in which the met station is located. (See Figures 11-2 and 11-3.) In Figure 11-3, octant 1 indicates that the met station is located between 90° W and 180° W longitude and is north of the equator.

(2) Group 2. This group designates the center of the area in which the met message is valid. This is expressed in tens, units, and tenths of degrees of latitude and longitude (347 = 34.7 and 985 = 98.5°). When the longitude is 100 or greater, the initial digit (1) is omitted. If the number 9 is used to designate the octant, the six digits or letters represent the coded location (in latitude and longitude) of the met station that produced the message. (See Figure 11-3.)

(3) Group 3. The first two digits (27) in group 3 represent the day of the month that the met message is valid. The next three digits (125) indicate the hour in tens, units, and tenths of hours (125 = 12.5 hours = time 1230) the met message is valid. The hours refer to Greenwich Mean Time (GMT). The last digit (0) in group 3 indicates the number of hours the message will remain valid. The US does not try to predict the length of time a met message will remain valid. Therefore, the last digit in group 3 of a ballistic met message will always be 0. Some allied nations predict the length of time a met message will remain valid. These predictions vary from 1 to 8 hours. Code 9 indicates 12 hours. (See Figure 11-3.)

(4) Group 4. The first three digits (055) in group 4 indicate the altitude of the met station (MDP) above mean sea level in multiples of 10 meters (055 = 550 meters). The next three digits (972) indicate the atmospheric pressure at the MDP (972 = 97.2 percent). When a value is equal to or greater than 100 percent the initial digit (1) is omitted (012 = 101.2 percent). (See Figure 11-3.)

b. The body of the met message can consist of 16 met message lines (00-15). Each line consists of two six-number groups. Each line contains the ballistic data for a particular altitude zone. Ballistic data are the weighted average of the conditions that exist from the surface up through the altitude zone, indicated by the line number, and back to the surface. (See Figure 11-4.)

(1) The first two digits in the first group on each line identifies the altitude zone (00 [surface] through 15 [18,000 meters]). (See Figure 11-4.) Line 02 is used as an example. (See Figure 11-5.)

(2) The next two digits in the first group (59) indicate the direction from which the ballistic wind is blowing. It is expressed in hundreds of mils true azimuth (59 = 5900). (See Figure 11-5.)

(3) The last two digits of the first group (17) indicate the wind speed of the ballistic wind in knots (17 = 17 knots). (See Figure 11-5.)

(4) The first three digits of the second group (008) indicate the ballistic air temperature expressed as a percentage (to the nearest 0.1 percent) of the ICAO standard (008 = 100.8). (See Figure 11-5.)

(5) The last three digits of the second group (958) indicate the ballistic air density expressed as a percentage (to the nearest 0.1 percent) of the ICAO standard density (958 = 95.8). (See Figure 11-5.)

NOTE: When the air temperature or air density is equal to or greater than 100 percent, the initial digit (1) is omitted. A completed ballistic met message recorded on DA Form 3675 is shown in Figure 11-5.

11-5. Computer Met Message

Like the ballistic met message, the computer met message is a coded message that reports the atmospheric conditions in selected layers starting at the surface and extending to an altitude that will normally include the maximum ordinate of field artillery weapons that use these data. Unlike the ballistic met message used in manual computations (in which the weather conditions existing in one layer or zone are weighted against the conditions in lower layers and reported as percentages of standard), the computer met message reports actual average wind direction, wind speed, air temperature, and pressure in each layer. The computer met message is used by the battery computer system (BCS) in the computation of the equations of motion used in the computer program. The computer met message is recorded on DA Form 3677 (Computer Met Message) and is divided into two parts--an introduction and a body.

a. The introduction of the computer met message consists of four six-character groups.

(1) Group 1. The first five letters (METCM) identify the transmission as a computer met. The last digit (1) designates the octant of the earth in which the met station is located. The octant code key is the same as that for the ballistic met message. (See Figure 11-6.)

(2) Group 2. This is the same as group 2 of the ballistic met message. (See Figure 11-6.)

(3) Group 3. This is the same as group 3 of the ballistic met message. (See Figure 11-6.)

(4) Group 4. The first three digits (049) of group 4 indicate the altitude of the met station MDP above sea level in tens of meters (049 = 490). The last three digits (987) indicate the atmospheric pressure, in millibars, at the met station. When the pressure value is greater than 999, the first digit (1) is omitted. (For example, 009 = 1009). (See Figure 11-6.)

b. The body of the met message can consist of 27 met message lines (00-26). Each line consists of two eight-number groups. Each line contains the actual average weather data for a particular zone. (See Figure 11-6.)

(1) The first two digits in the first group on each line identifies the altitude zone (00 [surface] through 26 [20,000 meters]). Line 00 is used as an example. (See Figure 11-6.)

(2) The next three digits in the first group (260) indicates the direction from which the wind is blowing. It is expressed in tens of mils true azimuth (260 = 2600). (See Figure 11-6.)

(3) The last three digits of the first group (018) indicate the wind speed expressed in knots (018 = 18 knots). (See Figure 11-6.)

(4) The first four digits of the second group (2698) indicate the actual air temperature expressed in degrees Kelvin (K) to the nearest tenth of a degree (269.8° K). (See Figure 11-6.)

(5) The last four digits of the second group (0987), indicate the actual air pressure, in millibars, to the nearest millibar (987 millibars). (See Figure 11-6.)

11-6. Met Message Checking Procedures

a. When the FDC receives a met message, it should be checked to ensure that it is valid. Any peculiarities noted in the message should be questioned. If the timeliness or validity of a met message is doubted, that also should be questioned and referred to the artillery met section, whose personnel are qualified to explain message variations or to correct message transmission errors. Verbal transmission of met messages may cause copying errors, particularly if the message is copied down on something other than the standard (ballistic or computer) met form. FDC personnel should use the guidelines in subparagraphs b through e below when checking met messages.

b. Check the ballistic or computer met message heading as follows: (See Figure 11-7 or 11-8.)

(1) Check message type, octant, and location entries for correctness.

(2) Check date-time entries to ensure data are current. If the met message is more than 4 hours old, consult with the met section to determine message validity (date-time entries are expressed in Greenwich mean time).

(3) Map-spot the altitude of the MDP by using the latitude and longitude from the location block in the header of the met message. (See FM 21-26 for additional information on how to plot a latitude and longitude. An error of 50 meters or more will affect air temperature and density and/or pressure corrections applied to firing data.)

c. Check the ballistic met message body as follows: (See Figure 11-7.)

(1) Ballistic wind direction should trend in a fairly uniform manner. Question drastic changes (1,000 mils or greater) or sudden reverses of wind direction from line to line, particularly if wind speeds are more than 10 knots. Direction changes greater than 1,000 mils are common when wind speeds are 10 knots or less.

(2) Question severe increases or decreases (10 knots or greater) in wind speed from line to line.

(3) Ballistic temperatures and densities normally show an inverse relationship; that is, as temperature increases, density should decrease.

(4) Check for drastic changes (2 percent or more) in density or temperature. Ballistic temperature and density should change smoothly between zones.

d. Consecutive messages should show a trend that relates to the actual weather conditions unless weather conditions have changed during sunrise or sunset transition periods or because of a frontal passage, rain, snow, or a rapid increase or decrease in cloud cover.

e. Check for errors in the computer met message as follows: (See Figure 11-8.)

(1) Question drastic wind direction changes (1,000 mils or greater) or sudden reverses of wind direction from line to line, particularly if wind speeds are more than 10 knots. Direction changes greater than 1,000 mils are-common when wind speeds are 10 knots or less.

(2) Question severe increases or decreases (10 knots or greater) in wind speed from line to line.

(3) Question a severe increase or decrease (over 20° K) in temperature from line to line.

(4) Check for differences in identification line pressure and surface pressure; both should match.

(5) Check for increases in pressure. Pressure should decrease smoothly from line to line. Pressure will never increase with height.

11-7. Met Message Space and Time Validity

a. Space Considerations. The accuracy of a met message may decrease as the distance from the met sounding site to balloon and sensors increases. Local topography has a pronounced effect on the distance that met data can reasonably be extended. In mountainous terrain, distinct wind variations occur over short distances. This effect extends to much greater heights than the mountain tops. Large bodies of water affect both time and space considerations of the met message because of the land and sea breezes and the effect of humidity on density. It would be impossible to compute an exact distance for every combination of weather and terrain. Met messages for artillery are considered valid up to 20 kilometers (km) from the balloon release point (met section). The validity distance decreases proportionately with the roughness of the terrain and the proximity of large bodies of water.

b. Time Consideration. The passage of time may decrease the accuracy of a message because of the changing nature of weather. With existent equipment, the artillery met section has difficulty in providing met messages more often than every 2 hours over an extended period of time. There are no specific rules for determining the usable time, since that determination depends on the following:

  • Characteristics of the atmosphere.
  • Periods of transition.
  • Met section movement.
  • Personnel.
  • Supplies and equipment.
  • Altitude of the met message (line number) required by the artillery firing units.

When the weather pattern is variable, the usable time is variable. If a frontal passage is forecast for the area, the met section will take a new sounding after passage of the front. When the weather pattern is stable and is forecast to remain so, time between messages may be extended to several hours or longer, depending on the time of day and existing weather conditions. (See Figure 11-9.)

c. Criteria for Use of Met Data. Results of many studies that are based on artillery firing and met data show that the order of preference of various sources of met data is as shown in paragraphs (1) through (3) below. A current met message is one that is less than 2 hours old unless an exchange of air mass has occurred since the met message was produced or unless periods of transition are involved.

(1) Current met message from a station within 20 kilometers of the midpoint of the trajectory (upwind is best).

(2) Current met message from the nearest station up to 80 kilometers from the midpoint of the trajectory. A 4-hour old met message may be used except when day-to-night transitions or frontal passages are occurring.

(3) Met messages over 2 hours old but from a station within 20 kilometers of the midpoint of the trajectory. A 4-hour-old met message may be used except when day-to-night transitions or frontal passages are occurring.


Section II

Concurrent Met Technique


A concurrent met is solved to isolate position constants. To perform a concurrent met technique, the firing unit must have total corrections determined from a registration and the met conditions that were valid at the time of the registration. Met corrections are determined and then subtracted from the total corrections to isolate position constants. Any errors in the met corrections and total corrections will be contained in the position constants. Every effort must be made to obtain the most accurate met corrections available.

11-8. DA Form 4200

The concurrent met technique is solved on DA Form 4200. There are two methods to solve a concurrent met technique. The first is the vowel rule. This follows the sequence of the tables in the TFT, and computations are completed after extracting data from a vowel table. Table 11-2 provides the abbreviated steps for this method. The second is the RATT rule. RATT is an acronym for record, apply, transfer, tables. This also follows the sequence of the tables in the TFT, but computations are completed after extracting data from each table. Table 11-3 provides the abbreviated steps for this method.

11-9. Solution of a Concurrent Met

Table 11-4 shows a detailed solution of a concurrent met using the RATT rule. The example uses the data shown in Figure 11-10.


Section III

Subsequent Met Technique


A subsequent met is computed to determine new total corrections. Total corrections determined from a registration will remain valid only as long as the met corrections do not change.

11-10. Overview

Whenever a met condition (weather, propellant temperature, projectile weight, or propellant lot) changes, the GFT setting derived from the registration is no longer valid. Registering every time one of the conditions changes is not feasible. To update registration corrections, a subsequent met can be solved to quantify new met corrections, which are added to the position constants determined from the concurrent met. The result is new total corrections that are used to determine a new GFT setting.

11-11. Solution of a Subsequent Met

Table 11-5 shows a detailed example of the solution of a subsequent met technique. It uses the previously completed concurrent met (Figure 11-27) and assumes the battery and MDP have not moved.


Section IV

Subsequent Met Applications


Subsequent met applications include eight-direction met, met to a met check gauge point, met to a target, and met + VE. These are called subsequent met techniques but they do not necessarily require met conditions that were subsequent to a registration nor are position constants required. They are listed under subsequent met techniques because they are used to determine new GFT settings or new total corrections. These techniques would also be used if the jive requirements for accurate predicted fire were being met or registration corrections were not available. The procedures would be identical to solving a subsequent met technique, with the exception that all position constants would be zero.

11-12. Eight-Direction Met

a. Certain combat conditions may require a firing unit to provide accurate artillery support throughout a 6,400-mil zone. Transfer limits define an area within which total corrections are-assumed to be valid. These transfer limits place a severe limitation on a 6,400-mil firing capability. Total corrections could be obtained by conducting a registration in each 800-mil sector of the unit's area of responsibility. Such registrations, however, would be costly and would endanger unit survivability. An alternative to registering in each 800-mil sector is the use of the eight-direction met technique.

b. The eight-direction met technique provides corrections to range, deflection, and fuze setting to compensate for the effects of ballistic wind direction and speed and for rotation of the earth throughout the firing unit's area of responsibility. These corrections are combined with the position constants determined in the concurrent met by solving a subsequent met in each 800-mil sector or selected 800-mil sectors. (See Figure 11-32.)

c. Lateral transfer limits can be eliminated for ranges of 10,000 meters or less by solving an eight-direction met. For ranges greater than 10,000 meters, because the lateral transfer limits are valid 4,000 meters left and right of the battery registration point, there will be areas between the 800-mil segments that are not covered by valid corrections. When needed, corrections to cover these areas must be computed by using the met-to-target technique.

d. The eight-direction met technique consists of two steps:

  • Solution of a concurrent met technique to determine the position VE correction, position deflection correction, and position fuze correction.
  • Solving for met corrections for other 800-mil segments by use of the met + VE technique and the position constants to determine GFT settings for those octants.

NOTE: The direction of fire will be different for each octant. The value used for altitude of target is the altitude of the registration point. The FS ~ ADJ EL will be determined on the basis of the computed adjusted elevation. The eight-direction met technique could be solved without registering. The procedures would be identical to solving a subsequent met technique, with the exception that all position constants would be zero.

11-13. Solution of an Eight-Direction Met Technique

NOTE: This example illustrates how to solve the eight-direction met following the solution of the concurrent met.

a. All known data remain the same as the concurrent met except for the direction of fire. The direction of fire must be determined for the new octant by applying 800 mils to the original direction of fire.

b. The steps shown in Table 11-6 give a detailed example of the solution of an eight-direction met technique.

11-14. Met to a Target

a. Because of the restrictions of transfer limits for the total corrections represented by a GFT setting, there are areas beyond 10,000 meters that are not covered by normal eight-direction met techniques. If a target that requires accurate surprise fires appears in one of the areas, a met to the target is solved. A met to target may also be solved for situations when the unit needs to fire a projectile that they did not register with (for example, M549A1 RAP). Because of the time needed to solve a met to a target, this technique is usually reserved for those situations requiring FFE fires against a "high-payoff" target.

b. The met-to-target technique consists of the two steps below.

(1) Solution of a concurrent met to determine the position VE, position deflection correction, and position fuze correction. If position constants are not available, use zero for these values.

(2) Solving for met corrections by using the chart range and direction to the target and the position constants to determine a GFT setting. The chart range used is the range to the target. The direction of fire is determined on the basis of the chart direction to the target. The met line number and complementary range are determined from Table B on the basis of the chart range to the target and the height of target above gun.

11-15. Solution of a Met-to-Target Technique

a. Target AB7450 is located outside the octants for which the GFT settings have been determined.

b. All known data remain the same as those for the concurrent met except for the following:

  • Target AB7450 is located at grid 440240, altitude 1120.
  • Chart deflection to the target is df 4155.
  • Chart range to the target is rg 5630.

c. Table 11-7 shows a detailed example of the solution of a met-to-target technique.

11-16. Computing a GFT Setting for an Unregistered Charge

a. When data from a registration and concurrent met are known, the FDC can derive a GFT setting for an unregistered charge.

b. Total corrections for the unregistered charge are determined by applying the position constants determined for the registered charge to the met corrections for the unregistered charge. This is done by using the following steps:

(1) Determine the range to a met check gauge point on the GFT for the unregistered charge. This will be used as the chart range on the met data correction sheet. The entry range will be the met check gauge point range expressed to the nearest 100 meters. The altitude of the target is the same as the battery altitude.

NOTE: All corrections from the TFT are based on the unregistered charge.

(2) Compute the total deflection correction as follows:

(a) Compute the met deflection correction by use of the met data correction sheet.

(b) Add the position deflection correction determined from the registered charge to the newly computed met deflection correction for the unregistered charge. The sum is the total deflection-correction for the unregistered charge.

NOTE: The position deflection correction generally accounts for errors in survey and chart construction. These errors are independent of charge in that they remain constant regardless of the charge fired. Therefore, it is valid to apply a position deflection correction determined for one charge to other charges.

(3) Compute total range correction and adjusted elevation as follows:

(a) Add the position velocity error for the registered charge determine the VE.

(b) Add the MVV correction for propellant temperature determine to the VE to determine the V for the unregistered charge.

(c) Multiply the V by the appropriate MV unit correction to determine the V range correction.

(d) Add the V range correction to the met range correction for the unregistered charge to determine the total range correction.

(e) Add the total range correction to the chart range (range to the met check gauge point) to determine the range corresponding to adjusted elevations.

(f) Set the adjusted range under the MHL of the GFT, and read the adjusted elevation for the unregistered charge.

NOTE: Position velocity errors caused by survey and chart errors are charge independent and, therefore, can be transferred to other charges. Muzzle velocity variations can be transferred to all preferred charges within the same charge group and lot.

(4) Compute the total fuze correction as follows:

(a) Determine the fuze setting corresponding to the adjusted elevation.

(b) Compute the met fuze correction.

(c) Add the met fuze correction to the position fuze correction determined for the registered charge. The sum is the total fuze correction. Apply this correction to the fuze setting corresponding the adjusted elevation to determine the adjusted fuze setting for the unregistered charge.

NOTE: The position fuze correction is a constant fuze characteristic. Fuze characteristics are independent of the charge fired. The position fuze correction is similar to a known fuze setting correction, which is determined historically by observing the performance of a particular lot of fuzes.

(5) Compute the GFT deflection correction by subtracting the drift correction corresponding to the adjusted elevation for the unregistered charge from the total deflection correction. The remainder is the GFT deflection correction for the unregistered charge.

11-17. Met to Met Check Gauge Point

a. The one-plot GFT setting determined by registering has limited range transfer limits. A more accurate GFT setting can be determined by using the data from a registration and one or more met + VE computations to met check gauge points. Solution of a met to met check gauge point using subsequent met techniques will yield total corrections at each met check gauge point range. The met check gauge points selected should be the ones farthest away, in range, from the registration chart range.

b. The met to met check gauge point technique consists of the following steps:

  • Solution of a concurrent met to determine the position VE, position deflection correction, and position fuze correction.
  • Solving for met corrections to the selected met check gauge points and adding the position constants to determine GFT settings for these ranges. The chart ranges will be the ranges to the selected met check gauge points and the line number of the met message will be determined on the basis of that range and a height of target above gun of 0. The altitude of target used will be the same as the battery altitude.

c. Combine the data from the registration and the met(s) to met check gauge points to determine a two-plot or multiplot GFT setting.

11-18. Met + VE

a. Registrations may not always be practical or necessary on the basis of the current situation and the factors of METT-T. If a battery is meeting the five requirements for accurate predicted fire (less accurate target location), there is still a need to improve the data read from the GFT. A GFT setting can be determined by solving a subsequent met by using the met + VE technique. The steps for working a met+ VE are similar to the subsequent met technique. Since no registration has been conducted and position constants were not isolated, position constants are not considered (use zero for these values).

b. For accuracy, the chart ranges used for the met + VE technique should correspond to met check gauge points, unless the met-to-target technique is being used. The altitude of target will be the same as the battery altitude unless the met-to-target technique is used.

c. The direction of fire will correspond to the chart direction to the center of the zone of responsibility or the target.

d. The values for position deflection correction, position velocity error, and position fuze setting will be recorded as zeros (0).




NEWSLETTER
Join the GlobalSecurity.org mailing list