Horizontal Coriolis Force: Calculation
Equation
To manually calculate horizontal Coriolis deflection, we only need to know the latitude of our position and how long our bullet will be in flight:
(.00007292 rad/s * cos(latitude°)) * (Time of flight) * 1000 = Horizontal deflection in MRADs
Where:
- positive outputs = right deflection
- negative outputs = left deflection
Data collection
Time of flight can be found in the ATragMX under the “RC” button in the top right of the screen or derived in an online ballistics program. As the ATragMX suite is not available in situations where manual ballistics are relevant, time of flight information should be recorded prior to operation start.
Map latitude in Arma 3 does not always correlate with real word locations, rather this information is manually populated by map makers and is persistent for an entire map. Latitudes for common UNITAF campaigns are listed below:
| UNITAF Campaign | Map Name | Latitude |
|---|---|---|
| Operation Black Flag | Takistan, Takistan Mountains | 35° |
| Operation Deadlock | Lingor v3.9.5 | -4° |
| Operation Everglade | Rosche, Germany (2.0) | 53° |
| Operation Everyman | Armavir | 44° |
| Operation Fault Line | Lythium | 34° |
| Operation Fulcrum | Uzbin Valley | 34° |
| Operation Guardian Angel | Island Panthera | 46° |
| Operation Hetman | Livonia | 54° |
| Operation Honeybadger | Reshmaan Province | 35° |
| Operation Polaris | Altis | 40° |
| Operaton Quantum | Kingdom of Regero | 39° |
| Operation Steadfast Resolve | G.O.S. Al Rayak | 36° |
| Operation Valiant Guardian | Beketov | 55° |
Calculation Example
Equation limitations
This equation will serve well under most conditions and the small degree of inherent error will not impede operations in target rich environments even in hand with poor atmospheric conditions.
In high value target environments, or when the effects of a single shot must be guaranteed, it should be noted that atmospherics are not considered in the equation, and under extreme examples this additional variable can create relevant error when compounded with other unknowns. As air resistance increases (typically due to lower temperatures, altitudes and humidities, or with higher pressures), our bullet loses its inherited rotational velocity more quickly (see Horizontal Coriolis: Introduction). This increases the horizontal deflection accumulated over time, up to around .05 MRADs at 1000m in unfavorable conditions.
When atmospherics are unfavorable, horizontal Coriolis holds need to increase.
