Implement atmosphere and dynamics data

code/getRho.m

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+function [acousticSpeed,rho] = getRho(state)
+% Compute atmospheric properties from mean sea level altitude.
+g = 9.8066; % m/sec^2
+lapserate = -0.0065; % K/m
+R = 287.05; % J/kg-K
+gamma = 1.4; % adiabatic constant for air
+z0 = 0; % mean sea level reference altitude (m)
+T0 = 288.15; % sea level temperature (K)
+P0 = 1.01325e5; % sea level pressure (Pa)
+
+z = state(3); % altitude above mean sea level (m)
+
+if z <= 11000
+    T = T0 + lapserate*(z-z0);
+    P = P0*(T/T0)^(-g/(lapserate*R));
+else
+    T = T0 + lapserate*(11000-z0);
+    P11k = P0*(T/T0)^(-g/(lapserate*R));
+    P = P11k*exp(-g*(z-11000)/(R*T));
+end
+
+rho = P/(R*T);
+acousticSpeed = sqrt(gamma*R*T);
+end