ISAtmosphere.jl

International Standard Atmospheric (ISA) model

The International Standard Atmosphere (ISA) is a static atmospheric model of how the pressure, temperature, density, and viscosity of the Earth's atmosphere change over a wide range of altitudes or elevations. It has been established to provide a common reference for temperature and pressure and consists of tables of values at various altitudes, plus some formulas by which those values were derived.

It is also known as the ICAO Standard Atmosphere, ISA is a standard against which to compare the actual atmosphere at any point and time. The real atmosphere differs from ISA in many ways. Sea level pressure varies from day to day, and there are wide extremes of temperature at all levels.

Only metric units are used.

Source: EUROCONTROL BADA 4 User Manual Chapter 2.2 Atmosphere Model

Source: www.skybrary.aero/index.php/InternationalStandardAtmosphere_(ISA)

Source: en.wikipedia.org/wiki/InternationalStandardAtmosphere

Geopotential pressure altitude [m] of Tropopause

Real gas constant for air [M²/(Ks²)]

Standard atmospheric temperature [K] at Mean Sea Level (MSL)

Speed of sound [m/s] at Mean Sea Level (MSL)

Graviation acceleration [m/s²] at Mean Sea Level (MSL)

Standard atmospheric pressure [Pa] at Mean Sea Level (MSL)

ISA temperature gradient [K/m] with altitude below the tropopause

Adiabatic index of air []

Standard atmospheric density [kg/m³] at Mean Sea Level (MSL)

AtmosConditions(Hp_m, T_K, ΔT_K, p_Pa, ρ_kg_m³, a_m_s)

Immutable STRUCT to keep a set of atmospheric conditions together. This struct can be used to also store an arbitrary set of atmospheric conditions. The function conditions can be used to create the struct.

Hp_trans_m(Vcas_m_s, M)

Return the transition altitude Hp_trans_m (also called crossover altitude) [m] between a given calibrated airspeed Vcas_m_s [m/s] and a Mach number M.

Source: EUROCONTROL BADA 4 User Manual eq. 2.2-27/28/29

M2Vcas(M, p_Pa, T_K)

Return the calibrated airspeed Vcas_m_s [m/s] as a function of the Mach number M at pressure level p_Pa [Pa] and with temperature T_K [K].

Source: EUROCONTROL BADA 4 User Manual eq. 2.2-26

M2Vcas(M, AtmosConditions)

M2Vtas(M, T_K)

Return true airspeed Vtas_m_s [m/s] as a function of the Mach number M and temperature T_K [K].

Source: EUROCONTROL BADA 4 User Manual eq. 2.2-26

M2Vtas(M, AtmosConditions)

T_K(Hp_m [, ΔT_K= 0.0])

Returns the atmospheric temperature [K] at pressure altitude Hp_m [m] and with temperature offset ΔT_K [K].

Source: EUROCONTROL BADA 4 User Manual eq. 2.2-13/16

Vcas2M(Vcas_m_s, T_K)

Return the Mach number M as a function of the calibrated airspeed Vcas_m_s [m/s] at pressure level p_Pa [Pa] and with temperature T_K [K].

Source: EUROCONTROL BADA 4 User Manual eq. 2.2-26 (reversed)

Vcas2M(Vcas_m_s, AtmosConditions)

Vcas2Vtas(Vcas_m_s, p_Pa, T_K)

Return the true airspeed Vtas_m_s [m/s] as a function of the calibrated airspeed Vcas_m_s [m/s] at pressure level p_Pa [Pa] and with temperature T_K [K].

Source: EUROCONTROL BADA 4 User Manual eq. 2.2-23

Vcas2Vtas(Vcas_m_s, AtmosConditions)

Vtas2M(Vtas_m_s, T_K)

Return the Mach number M as a function of the true airspeed Vtas_m_s [m/s] and temperature T_K [K].

Source: EUROCONTROL BADA 4 User Manual eq. 2.2-26 (reversed)

Vtas2M(Vtas_m_s, AtmosConditions)

Vtas2Vcas(Vtas_m_s, p_Pa, T_K)

Return calibrated airspeed Vcas_m_s [m/s] as a function of the true airspeed Vtas_m_s [m/s] at pressure level p_Pa [Pa] and with temperature T_K [K].

Source: EUROCONTROL BADA 4 User Manual eq. 2.2-24

Vtas2Vcas(Vtas_m_s, AtmosConditions)

a_m_s(T_K)

Return the speed of sound [m/s] at the temperature T_K [K].

Source: EUROCONTROL BADA 4 User Manual eq. 2.2-22

conditions(Hp_m[, ΔT_K = 0.0])

Create AtmosConditions struct with the atmospheric conditions T_K [K], p_Pa [Pa], and ρ_kg_m³ [kg/m³], and the speed of sound a_m_s [m/s] at a given altitude Hp_m [m] and ΔT_K [K] temperature offset.

p_Pa(Hp_m[, ΔT_K = 0.0])

Return the air pressure [Pa] at pressure altitude Hp_m [m] and with temperature offset ΔT_K [K].

Source: EUROCONTROL BADA 4 User Manual eq. 2.2-18/20

ρ_kg_m³(p_Pa, T_K)

Return the air density [kg/m³] at pressure level p_Pa [Pa] and temperature T_K [K].

Source: EUROCONTROL BADA 4 User Manual eq. 2.2-21