Unexpected result...

[Tomi]

Just tried to compile (and to make fun for myself ) the following sequence (the snippet calculates the distance between two points and converts SiRF x,y,z coordinates of a GPS to longitude, latitude and height coordinates).
And after downloading believe or not, the right numbers appeared on the LCD !

float distance,atm;
float x,y,z,a,b,e,ee,N,p,th,fi;

distance = 0.0;
atm = gXPos - gRefXPos;
atm *= atm;
distance += atm;
atm = gYPos - gRefYPos;
atm *= atm;
distance += atm;
atm = gZPos - gRefZPos;
atm *= atm;
distance += atm;
distance = sqrt(distance);
DeltaD = distance;

x = gXPos;y = gYPos;z = gZPos;
a = 6378137.0; b = 6356752.31424518; // Earth constants
e = sqrt((a*a-b*b)/a/a);
ee = sqrt((a*a-b*b)/b/b);
p = sqrt(x*x+y*y);
th = atan(z*a/p/b);
if (fabs(x) > 1.0e-40) Lon = atan(y/x)/PI*180.0;
else Lon = 90.0;
fi = z + ee*ee*b*sin(th)*sin(th)*sin(th);
fi /= p - e*e*a*cos(th)*cos(th)*cos(th);
fi = atan(fi);
Lat = fi/PI*180.0;
N = a/sqrt(1-e*e*sin(fi)*sin(fi));
N = p/cos(fi) - N;
Height = N;


___________________________
This message was ported from CCS's old forum
Original Post ID: 13154

[Sherpa Doug]

:=Just tried to compile (and to make fun for myself <img src="http://www.ccsinfo.com/pix/forum/smile.gif" border="0"> ) the following sequence (the snippet calculates the distance between two points and converts SiRF x,y,z coordinates of a GPS to longitude, latitude and height coordinates).
:=And after downloading believe or not, the right numbers appeared on the LCD !
:=
:= float distance,atm;
:= float x,y,z,a,b,e,ee,N,p,th,fi;
:=
:= distance = 0.0;
:= atm = gXPos - gRefXPos;
:= atm *= atm;
:= distance += atm;
:= atm = gYPos - gRefYPos;
:= atm *= atm;
:= distance += atm;
:= atm = gZPos - gRefZPos;
:= atm *= atm;
:= distance += atm;
:= distance = sqrt(distance);
:= DeltaD = distance;
:=
:= x = gXPos;y = gYPos;z = gZPos;
:= a = 6378137.0; b = 6356752.31424518; // Earth constants
:= e = sqrt((a*a-b*b)/a/a);
:= ee = sqrt((a*a-b*b)/b/b);
:= p = sqrt(x*x+y*y);
:= th = atan(z*a/p/b);
:= if (fabs(x) > 1.0e-40) Lon = atan(y/x)/PI*180.0;
:= else Lon = 90.0;
:= fi = z + ee*ee*b*sin(th)*sin(th)*sin(th);
:= fi /= p - e*e*a*cos(th)*cos(th)*cos(th);
:= fi = atan(fi);
:= Lat = fi/PI*180.0;
:= N = a/sqrt(1-e*e*sin(fi)*sin(fi));
:= N = p/cos(fi) - N;
:= Height = N;
:=

There is no better way to astonish yourself than to try something really stupid... and have if work!
As written it seems the problem is solved at compile time.

___________________________
This message was ported from CCS's old forum
Original Post ID: 13158

[Ron]

Maybe for your next challenge you should try these calculations:

<a href="http://ralph.bucher.home.att.net/project.html" TARGET="_blank">http://ralph.bucher.home.att.net/project.html</a>

If it doesn't work, I certainly hope the American Navy is not using CCS on their Tomahawks!

Ron

:=Just tried to compile (and to make fun for myself <img src="http://www.ccsinfo.com/pix/forum/smile.gif" border="0"> ) the following sequence (the snippet calculates the distance between two points and converts SiRF x,y,z coordinates of a GPS to longitude, latitude and height coordinates).
:=And after downloading believe or not, the right numbers appeared on the LCD !
:=
:= float distance,atm;
:= float x,y,z,a,b,e,ee,N,p,th,fi;
:=
:= distance = 0.0;
:= atm = gXPos - gRefXPos;
:= atm *= atm;
:= distance += atm;
:= atm = gYPos - gRefYPos;
:= atm *= atm;
:= distance += atm;
:= atm = gZPos - gRefZPos;
:= atm *= atm;
:= distance += atm;
:= distance = sqrt(distance);
:= DeltaD = distance;
:=
:= x = gXPos;y = gYPos;z = gZPos;
:= a = 6378137.0; b = 6356752.31424518; // Earth constants
:= e = sqrt((a*a-b*b)/a/a);
:= ee = sqrt((a*a-b*b)/b/b);
:= p = sqrt(x*x+y*y);
:= th = atan(z*a/p/b);
:= if (fabs(x) > 1.0e-40) Lon = atan(y/x)/PI*180.0;
:= else Lon = 90.0;
:= fi = z + ee*ee*b*sin(th)*sin(th)*sin(th);
:= fi /= p - e*e*a*cos(th)*cos(th)*cos(th);
:= fi = atan(fi);
:= Lat = fi/PI*180.0;
:= N = a/sqrt(1-e*e*sin(fi)*sin(fi));
:= N = p/cos(fi) - N;
:= Height = N;
:=
:=
___________________________
This message was ported from CCS's old forum
Original Post ID: 13179

[Ron]

Maybe for your next challenge you should try these calculations:

<a href="http://ralph.bucher.home.att.net/project.html" TARGET="_blank">http://ralph.bucher.home.att.net/project.html</a>

If it doesn't work, I certainly hope the American Navy is not using CCS on their Tomahawks!

Ron

:=Just tried to compile (and to make fun for myself <img src="http://www.ccsinfo.com/pix/forum/smile.gif" border="0"> ) the following sequence (the snippet calculates the distance between two points and converts SiRF x,y,z coordinates of a GPS to longitude, latitude and height coordinates).
:=And after downloading believe or not, the right numbers appeared on the LCD !
:=
:= float distance,atm;
:= float x,y,z,a,b,e,ee,N,p,th,fi;
:=
:= distance = 0.0;
:= atm = gXPos - gRefXPos;
:= atm *= atm;
:= distance += atm;
:= atm = gYPos - gRefYPos;
:= atm *= atm;
:= distance += atm;
:= atm = gZPos - gRefZPos;
:= atm *= atm;
:= distance += atm;
:= distance = sqrt(distance);
:= DeltaD = distance;
:=
:= x = gXPos;y = gYPos;z = gZPos;
:= a = 6378137.0; b = 6356752.31424518; // Earth constants
:= e = sqrt((a*a-b*b)/a/a);
:= ee = sqrt((a*a-b*b)/b/b);
:= p = sqrt(x*x+y*y);
:= th = atan(z*a/p/b);
:= if (fabs(x) > 1.0e-40) Lon = atan(y/x)/PI*180.0;
:= else Lon = 90.0;
:= fi = z + ee*ee*b*sin(th)*sin(th)*sin(th);
:= fi /= p - e*e*a*cos(th)*cos(th)*cos(th);
:= fi = atan(fi);
:= Lat = fi/PI*180.0;
:= N = a/sqrt(1-e*e*sin(fi)*sin(fi));
:= N = p/cos(fi) - N;
:= Height = N;
:=
:=
___________________________
This message was ported from CCS's old forum
Original Post ID: 13182