fly/fgdata
1
0
Fork 0
Code Activity

Tentative improvements to semi-analytical model for orbital targets

Browse source
This commit is contained in:
Thorsten Renk 2019-05-28 12:21:41 +03:00
parent 5ffcc3f2cc
commit 7ce5cd0267
1 changed files with 36 additions and 5 deletions
Show stats Download patch file Download diff file Expand all files Collapse all files

41
Nasal/orbital_target.nas
View file

@ -29,10 +29,22 @@ var orbitalTarget = {
t.running_flag = 0;
t.elapsed_time = 0.0;
t.delta_time = 0.0;
t.label = "";
t.node_drift = -4361.26 * 1./math.pow(t.radius/1000.0 ,2.0) * math.cos(t.inc_rad);
#print ("Drift rate: ", t.node_drift);
# Coefficients for the J3 altitude variation
var inc_var = t.inclination/60.0;
#print ("inc_var:", inc_var);
t.coeff1 = (10268. - 0.99579 * (t.altitude / 1000.0)) * inc_var;
t.coeff2 = 0.212 * 2.0 * math.pi;
#t.node_drift = -4361.26 * 1./math.pow(t.radius/1000.0 ,2.0) * math.cos(t.inc_rad);
t.node_drift = -2.16732e+9 /math.pow(t.radius/1000.0, 3.48908) * math.cos(t.inc_rad);
print ("Drift rate: ", t.node_drift);
return t;
},
@ -163,9 +175,28 @@ var orbitalTarget = {
compute_inertial_pos: func (anomaly_rad, nl_rad) {
# J3 variation around radius
while (anomaly_rad > 2.0 * math.pi)
{
anomaly_rad = anomaly_rad - 2.0 * math.pi;
}
while (anomaly_rad < 0.0)
{
anomaly_rad = anomaly_rad + 2.0 * math.pi;
}
var r_corr = me.coeff1 * math.exp(- math.pow(((anomaly_rad - math.pi)/ me.coeff2),2.0));
#print (r_corr);
# movement around equatorial orbit
var x = me.radius * math.cos(anomaly_rad);
var y = me.radius * math.sin(anomaly_rad);
var x = (me.radius + r_corr) * math.cos(anomaly_rad);
var y = (me.radius + r_corr) * math.sin(anomaly_rad);
var z = 0;
# tilt with inclination