BALLISTIC COMPUTER - ARTILLERY

[sketchh 11]

I created a ballistic computer (spreadsheet) for artillery.  The difference between what I created and what I have seen elsewhere is that I added a calibration function.  The concept is that you provide the initial inputs and fire the first round, then input the coordinates of where that round impacts, and the sheet automatically updates the yellow cells for the adjusted bearing and elevation.  This calibration is valid as long as you consider the following assumptions:

1. As you drive the vehicle, any change in position AND/OR change in elevation will throw off your calibration by the same amount.

2. The calibration value is most accurate at the bearing you used during the calibration process, and your results deviate more as your turret deviates from that initial bearing (if you target something 90° from the original target, don't get mad when it's not accurate). 

 

All of the testing was completed using the M4 Scorcher, however the M5 MLRS and the MK6 Mortar is included in the file.  The equations don't change, only the muzzle velocity values, so if there is any issue with the results start by verifying the velocity values.  Using the M4 Scorcher, I drove to a distance of 5.6km, entered my cords and the cords of the target, fired the first round, entered the impact cords, and put rounds on target consistently after that.

 

Remember, the performance of the computer is dependent on the accuracy of the data entry.

 

Calibration process:

NOTE: ONLY CHANGE VALUES IN THE GREEN CELLS.

1. Enter your vehicle type in cell B6.

2. Enter your cords in cells B7:B9, using the 4-digit format.

3. Enter the target cords in cells B10:B12.

4. Adjust your firing mode according to the value shown in cell B17.

5. Adjust your bearing according to the value shown in cell B18.

6. Select an elevation value to use for your calibration shot; in theory the "high" value will result in a more accurate calibration (this isn't real life btw), although in practice the difference seems small.  Fire your calibration shot.

7. Determine the impact cords of the calibration shot, either by watching the map (King of the Hill) or by utilizing a forward observer.

8. Enter the impact cords of the calibration shot as follows:

         a. If you fired the calibration shot using the "high" elevation value, enter the impact cords into cells E10:E12.

         b. If you fired the calibration shot using the "low" elevation value, enter the impact cords into cells F10:F12.

9. The calibrated bearing and elevation values automatically populate into the yellow cells B18:B20.  Adjust your turret to the corrected bearing and elevation values and fire at will.

 

Notes:

-Re-calibrate any time the vehicle is moved, or if you change target cords and the bearing changes changes more than a couple degrees.

-If you can't get the system to work and you are following the steps above, verify that you are in the correct firing mode by pointing at something far away and cycling firing mode until you locate the short range mode, then cycle forward from there.

-The computer is set up such that:

       -You can keep the same calibration values in E10:F12 and change to different targets in cells B10:B12 without affecting the calibration.  Remember the assumptions listed above when doing this.

       -You must clear all of the contents in cells E10:F12 before you can accurately RE-calibrate your firing. (Actually clearing the contents from cells E10 and F10 will remove the calibration effect from the yellow cells, if you are in a hurry).

       -The computer will return an error message if there are values present in BOTH cells E10 and F10 at the same time.

 

Click on the link below to go to the (locked) public version of the spreadsheet, click on File, and Download As, then Microsoft Excel.  If you want, re-upload this file to Google Docs and share the link with your friends, then you can all see the same data if you are in the same vehicle or working together as a crew.

 

Link below.

 

https://docs.google.com/spreadsheets/d/1rQhx9mfsRJQRfSk-24Sj2fH3Efh1zojJ-ErFZBqjwF8/edit?usp=sharing

[lex__1 422]

Thanks for the calculator.

In line 13 - RANGE(m), the cell formula B13 = 10 * SQRT ((K29 ^ 2) + (K30 ^ 2)) is changed to = 100 * SQRT ((K29 ^ 2) + (K30 ^ 2)). This will show the result in meters.