Search Comments and Ratings

go

   
Date File Comment by Comment Rating
21 Feb 2015 Convert ECI to ECEF Coordinates Transform ECI position, velocity and acceleration to ECEF position, velocity & acceleration. Author: Darin Koblick

Darin Koblick (view profile)

Manu

Manu (view profile)

I think the routine is wrong. As mentioned by drake in 2012, there needs to be a precession matrix to go from J2000 to current epoch of ECEF, and that involves a change of the z-axis. The routine computes the new position through a simple rotation around the z-axis. I have compared the results from this routine to conversions using other algorithms (in particular JPL NAIF SPICE routines) and I find differences of ~ 20 km in x, y and z coordinates for times in the year 2015. I am not sure where the differences come from, but the absence of precession is likely the problem.

1
19 Feb 2015 Vectorized Solar Azimuth and Elevation Estimation Predict the topocentric solar position defined by geodetic lat, lon, Alt, and a universal time Author: Darin Koblick

Darin Koblick (view profile)

L. He

L. He (view profile)

very nice program. I compare it with
http://www.mathworks.com/matlabcentral/fileexchange/4605-sun-position-m

the result is almost same. That one is more accurate,but not Vectorized yet.

Note: please change this line
jd = juliandate(datestr([y,mo,d,h,mi,s],'yyyy/mm/dd HH:MM:SS'),'yyyy/mm/dd HH:MM:SS');
do not use datestr but use date_num directly.
this will boost the speed, a lot

5
15 Dec 2014 2000 ASTM Standard Extraterrestrial Spectrum Reference E-490-00 Vectorized MATLAB code which will compute the solar flux given a wave length. Author: Darin Koblick

Darin Koblick (view profile)

Tang

Tang (view profile)

5
15 Dec 2014 2000 ASTM Standard Extraterrestrial Spectrum Reference E-490-00 Vectorized MATLAB code which will compute the solar flux given a wave length. Author: Darin Koblick

Darin Koblick (view profile)

Tang

Tang (view profile)

5
12 Dec 2014 Gauss-Jackson Eighth-Order ODE Solver (Fixed Step Size) Gauss-Jackson Eight-Order MultiStep Predictor-Corrector using ODE113 in its startup procedure. Author: Darin Koblick

Darin Koblick (view profile)

Christophe Lauwerys

Nice contribution.

One remark: number of states is hard-coded to 3.

Please replace these references to a variable number of states that you, for instance, can get from y0 at run time.

Thanks

Christophe

4
11 Aug 2014 Convert Azimuth and Elevation to Right Ascension and Declination Algorithm will convert Az/El angles to RA /DEC using a topocentric coordinate frame Author: Darin Koblick

Darin Koblick (view profile)

Darin Koblick

Darin Koblick (view profile)

You should reference Vallado pg. 162 for additional information on "topocentric coordinate frame". It is a Geocentric equatorial coordinate system with the origin translated from the center of the Earth to the origin of the observer.

Comment only
08 Aug 2014 Convert Azimuth and Elevation to Right Ascension and Declination Algorithm will convert Az/El angles to RA /DEC using a topocentric coordinate frame Author: Darin Koblick

Darin Koblick (view profile)

Mehdi

Mehdi (view profile)

What is 'topocentric coordinate frame'? Is it the same as spherical celestial frame?

Comment only
08 May 2014 Lunar Azimuth and Altitude Estimation Algorithm Predict the Lunar Azimuth and Altitude within +/- .2 deg of any lat and lon for a given UTC Author: Darin Koblick

Darin Koblick (view profile)

Leo

Leo (view profile)

5
23 Apr 2014 Efficient Vector Rotation Matrix Routine Efficient Method to Determine a Matrix Needed to Rotate One Vector to Another Author: Darin Koblick

Darin Koblick (view profile)

Darin Koblick

Darin Koblick (view profile)

Alexander, you are correct. I went ahead and changed the vector angle check to be closer to 1 instead of 0.99. Also, I found that I needed to add the case where vectors where close to parallel (i.e. abs(c) > 1-1e-13) and two or more components had the same values. Thank you for pointing out the problem to me.

Comment only
22 Apr 2014 Efficient Vector Rotation Matrix Routine Efficient Method to Determine a Matrix Needed to Rotate One Vector to Another Author: Darin Koblick

Darin Koblick (view profile)

Alexander

Thank you for submission. But if cosine of angle between vectors is >.99 (by module), calculation is incorrect.
A pair f=[1 0 0], t=[0.9904 0 -0.1380] can be used as an example.

Comment only
05 Dec 2013 Vectorized Clohessy-Wiltshire Hill Linear Propagation A Demonstration of Linear Satellite Orbit Propagation Using Clohessy-Wiltshire Equations of Motion. Author: Darin Koblick

Darin Koblick (view profile)

juyoung Son

5
01 Sep 2013 Convert ECI to ECEF Coordinates Transform ECI position, velocity and acceleration to ECEF position, velocity & acceleration. Author: Darin Koblick

Darin Koblick (view profile)

Darin Koblick

Darin Koblick (view profile)

Chad,

The two code lines you are referencing are trying to find the midnight that occurs before the provided Julian Date.

As written, the first check will be true if the Julian date occurs after midnight and 12+ hours before the time.

As written, the second check will be true if the Julian date occurs after midnight and less than 12 hours before the time.

If both checks are true, the code will use the last midnight that occurred. This is the desired functionality.

Because I am rounding down on the Julian date and subtracting a half day, there is no possible way that jd could be less than jdMin.

-Darin

Comment only
29 Aug 2013 Convert ECI to ECEF Coordinates Transform ECI position, velocity and acceleration to ECEF position, velocity & acceleration. Author: Darin Koblick

Darin Koblick (view profile)

Chad Hawes

5
29 Aug 2013 Convert ECI to ECEF Coordinates Transform ECI position, velocity and acceleration to ECEF position, velocity & acceleration. Author: Darin Koblick

Darin Koblick (view profile)

Chad Hawes

Darin,
In your JD2GMST function, I have a question related to the following two lines:

jd0(jd>jdMin) = jdMin(jd>jdMin);
jd0(jd>jdMax) = jdMax(jd>jdMax);

This appears to be limiting the Julian day between a lower bound and an upper bound. Don't you want the first line to be:

jd0(jd<jdMin) = jdMin(jd<jdMin);

Otherwise, it would appear that no actual lower bounding occurs...

Chad

Comment only
31 Jul 2013 Vectorized Picard-Chebyshev Method Vectorized Picard-Chebyshev Method used for the analysis of the 2012 ASME Conference paper 87878 Author: Darin Koblick

Darin Koblick (view profile)

Chris Binz

5
31 Jul 2013 Vectorized Clohessy-Wiltshire Hill Linear Propagation A Demonstration of Linear Satellite Orbit Propagation Using Clohessy-Wiltshire Equations of Motion. Author: Darin Koblick

Darin Koblick (view profile)

Chris Binz

5
08 Apr 2013 Vectorized Solar Azimuth and Elevation Estimation Predict the topocentric solar position defined by geodetic lat, lon, Alt, and a universal time Author: Darin Koblick

Darin Koblick (view profile)

Per

Per (view profile)

Very useful function. With a few updates it can handle vector time input. I would prefer the use of matlab UTC time input in order to speed up.

4
27 Mar 2013 Convert ECI to ECEF Coordinates Transform ECI position, velocity and acceleration to ECEF position, velocity & acceleration. Author: Darin Koblick

Darin Koblick (view profile)

João Carneiro

Darin,
I have been importing some ECI data from the OrbitTools C++ library and have stumbled upon some weird behavior.

In MATLAB I am using your functions to transform ECI to ECEF and then using the MATLAB function, ecef2geodetic to transform into normal azimuth/elevation/height coordinate space.

The weird behavior is that despite having smooth ECI data (smooth as in no jumps in the data) as inputs, I am getting discontinuous ECEF data (graph for r_ECEF(1,:) and r_ECEF(2,:) looks like saw). This is happening for GOES-8 and GOES-15 satellite data.

What is weirder is that on a macro scale (ignoring variations, including the sudden discontinuities), the position of the satellite in the mapa mundi seems to be correct.

5
10 Jan 2013 Efficient Vector Rotation Matrix Routine Efficient Method to Determine a Matrix Needed to Rotate One Vector to Another Author: Darin Koblick

Darin Koblick (view profile)

Jan Simon

Jan Simon (view profile)

There is some potential for accelerations:
1. Avoid calculatin ~idx 35 times, but use a temporary variable instead.
2. Matlab's CROSS and DOT implementations are very slow, so better calculate them inlined.

Comment only
20 Oct 2012 Convert UTC to Solar Apparent Time Convert a time given in UTC to Solar Apparent or Solar Mean Time Author: Darin Koblick

Darin Koblick (view profile)

Darin Koblick

Darin Koblick (view profile)

Brandon,

Also, if you are trying to compare the Solar Apparent Time, (SAT) be sure to input the longitude in degrees (W < 0, E > 0).

You can see that this function will match the solutions (almost exactly ... depending on the year) to those solutions in Example 4 of the ASTRONOMICAL INFORMATION SHEET No. 58 http://astro.ukho.gov.uk/nao/services/ais58.pdf

Comment only
20 Oct 2012 Convert UTC to Solar Apparent Time Convert a time given in UTC to Solar Apparent or Solar Mean Time Author: Darin Koblick

Darin Koblick (view profile)

Darin Koblick

Darin Koblick (view profile)

Brandon,

Latitude and Longitude are needed to determine the input time value to the equation of time (UT). They aren't needed to determine the equation of time ... it has nothing to do with latitude and longitude. Perhaps you should compare to a location with a 0hr local time offset.

See this document for a description of what the equation of time is, you can also compare results to this as an "example". I don't guarantee any specific accuracy with EoT as it depends on the mean anomaly of the sun which is obviously a first/second order approximation.

http://www.ips.gov.au/Educational/2/1/14

Comment only
18 Oct 2012 Convert UTC to Solar Apparent Time Convert a time given in UTC to Solar Apparent or Solar Mean Time Author: Darin Koblick

Darin Koblick (view profile)

Brandon

The code does not appear to be working properly for me. I am trying to calculate the solar time of the ISS, and the solar day takes about 2.75 hours instead of 1.5 as expected. I further checked my results by plugging time and longitude into a converter on the NOAA website. It returned an Equation of Time that differed by 4%. Any ideas? Do you have some examples of where it works.

Comment only
11 Aug 2012 Convert ECEF to ECI Coordinates Take any vector or series of vectors in the ECEF Coordinate frame and convert them to ECI. Author: Darin Koblick

Darin Koblick (view profile)

Darin Koblick

Darin Koblick (view profile)

John,

35 leap seconds since 1972 sounds like that is indeed what you are seeing in STK. As you know, ECEFtoECI.m takes in a Julian date, so the correction would not be internal to this particular conversion routine.

In fact, I don't think Mathworks attempts to address this issue with their juliandate.m routine. You would more than likely want to make the leap second correction when converting UTC to Julian date.

Are you able to check for the estimated position differences using Julian date in STK instead of UTC? Perhaps this should make the comparisons a little more accurate as well.

Truthfully, unless you are trying to use this routine in high-precision satellite mission operations, as long as you are consistent with your coordinate frame conversions (i.e. always using these conversion routines), it really shouldn't matter if there are minor discrepancies with STK (it is all relative motion anyway).

-Darin

Comment only
03 Aug 2012 Convert ECEF to ECI Coordinates Take any vector or series of vectors in the ECEF Coordinate frame and convert them to ECI. Author: Darin Koblick

Darin Koblick (view profile)

John

John (view profile)

Correction: JDate above should be: 2455728.92361111

Comment only
03 Aug 2012 Convert ECEF to ECI Coordinates Take any vector or series of vectors in the ECEF Coordinate frame and convert them to ECI. Author: Darin Koblick

Darin Koblick (view profile)

John

John (view profile)

Hello Darin,
I was comparing the results to STK for the simple case of ECEF positon:
r_ECEF = 6378.137, 0, 0
Which is 0,0,0 Lat / Long /Alt. At a time of 6/16/2011 10:10:00 UTC (JDate = 2455728.61111) I am seeing:
STK: ECI: 3503.040, 5330.040, -3.964
ECEF2ECI: 3488.874, 5339.325, 0.0

I noticed that if I offset my time by 35 sec. in your function I get a much better agreement. That looks like it may be a leap second issue?
The Z coordinate discrepancy I was wondering about - never see Z=0 in STK for ECI J2000 coordinates.
The function is very useful - any comments you have would be great. Thanks.

5
28 Jun 2012 Convert ECI to ECEF Coordinates Transform ECI position, velocity and acceleration to ECEF position, velocity & acceleration. Author: Darin Koblick

Darin Koblick (view profile)

Darin Koblick

Darin Koblick (view profile)

Drake,

J2000 is factored into the ECI to ECEF conversion routine through the call to JD2GAST.m (converts Julian Date to Greenwhich Apparent Sidereal Time). In order to do this, the effects of nutation are considered, and depend on the correct number of Julian centuries since J2000.

Comment only
25 Jun 2012 Convert ECI to ECEF Coordinates Transform ECI position, velocity and acceleration to ECEF position, velocity & acceleration. Author: Darin Koblick

Darin Koblick (view profile)

drake

drake (view profile)

Dear Darin,

It seems that this code considers the rotaion about Z-axis, or the earth's rotation axis only. However, the most commonly used ECI frame is J2000 which is defined at 1 January 2000, so I believe the effects of precession and nutation should be considered in the conversion between ECI(J2000) and ECEF.
Please let me know your opinion.

Comment only
28 May 2012 Convert ECI to ECEF Coordinates Transform ECI position, velocity and acceleration to ECEF position, velocity & acceleration. Author: Darin Koblick

Darin Koblick (view profile)

Darin Koblick

Darin Koblick (view profile)

Johan,

You are correct, thank you for spotting that mistake. I should have left everything in degrees since the mean obliquity of the ecliptic is referenced directly in the final computation.
The new parameters for the mean obliquity should be:

EPSILONm = 23.439291-0.0130111.*T - 1.64E-07.*(T.^2) + 5.04E-07.*(T.^3);

This corresponds to the estimates contained in Vallado, Fundamentals of Astrodynamics and Applications, Second edition, (EQ 3-53). 2001.

Thank you again for double checking my work.

Comment only
22 May 2012 Convert ECI to ECEF Coordinates Transform ECI position, velocity and acceleration to ECEF position, velocity & acceleration. Author: Darin Koblick

Darin Koblick (view profile)

Johan

Johan (view profile)

This function is great.
Although i think i found a mistake in your JD2GAST file.
When calculating the EPSILONm shouldn't the first number be 84381.448 and not 84381448 to make sure EPSILONm is calculate in arcseconds.
Shouldn't you convert EPSILONm from arcseconds to degrees like you did with dPSI and dEPSILON?

5
25 Apr 2012 Convert Keplerian Orbital Elements to a State Vector Convert orbital elements to a state vector, or a state vector back to orbital elements. Author: Darin Koblick

Darin Koblick (view profile)

vlas

vlas (view profile)

oops, forgot the comment, here it goes:
was about to write eci conversion functions myself, glad i've found these ones first!

Comment only
25 Apr 2012 Convert Keplerian Orbital Elements to a State Vector Convert orbital elements to a state vector, or a state vector back to orbital elements. Author: Darin Koblick

Darin Koblick (view profile)

vlas

vlas (view profile)

5
15 Apr 2012 Convert Right Ascension and Declination to Azimuth and Elevation Algorithm will convert topocentric RA/DEC Angles to Azimuth and Elevation Author: Darin Koblick

Darin Koblick (view profile)

Artik Crazy

5
11 Apr 2012 Vectorized Analytic Two Body Propagator (Kepler Universal Variables) Analytic propagation routine uses universal variables to solve a single formula for all orbit types Author: Darin Koblick

Darin Koblick (view profile)

Darin Koblick

Darin Koblick (view profile)

John,

The zip file seems to unzip without problems. Try using either the default windows zip utility, the MATLAB command unzip(), or the free 7zip utility. If all else fails, you can view the source code here:

http://www.mathworks.com/matlabcentral/fileexchange/35566-vectorized-analytic-two-body-propagator-kepler-universal-variables/content/keplerUniversal.m

Comment only
11 Apr 2012 Vectorized Analytic Two Body Propagator (Kepler Universal Variables) Analytic propagation routine uses universal variables to solve a single formula for all orbit types Author: Darin Koblick

Darin Koblick (view profile)

John Fuller

John Fuller (view profile)

Downloaded but can't seem to unzip. Not sure if the file is corrupted, may want to check.

Comment only
08 Apr 2012 Convert ECI to ECEF Coordinates Transform ECI position, velocity and acceleration to ECEF position, velocity & acceleration. Author: Darin Koblick

Darin Koblick (view profile)

Darin Koblick

Darin Koblick (view profile)

The following ECI coordinate information

rECI = [-2392.11241452386
-17078.1233608647
19945.4195944851];

vECI = [3.27682054057320
-1.79903293168245
-1.11948244495650];

t = 2453937.82777778;

Will yield an ECEF position and velocity of

rECEF = [-15615.6915464865
-7322.85945823539
19943.173494021];

vECEF = [-0.253618011215938
-2.5887912909949
-1.1194824449565];

This was obtained using the routines provided by CelesTrak found from http://www.celestrak.com/software/vallado-sw.asp

The ECItoECEF.m routine I posted on the FileExchange comes very close to this with the following vectors:

rECF = [ -15618.7911316673
-7310.12058163083
19945.4195944851];

vECF = [-0.253618011215938
-2.5887912909949
-1.1194824449565];

The problem is your ECEF position and velocity vectors do not correspond to each other.

A very easy way to check this is to compute the magnitude of your position vectors.

The magnitude of the first ECI position vector you have provided is: 26,366.726420485 km

The magnitude of the ECEF solution should be exactly the same as the magnitude in the ECI reference frame.

The magnitude of your ECEF position vector is 31,124.2960748149 km.

Hopefully this solves your problem.

Comment only
08 Apr 2012 Convert ECI to ECEF Coordinates Transform ECI position, velocity and acceleration to ECEF position, velocity & acceleration. Author: Darin Koblick

Darin Koblick (view profile)

Muhammad Shaikh

I am only posting here first five values of each of the vectors you asked for. They are actually long arrays of more than 1000 values.

GPS XYZ Position in ECI:
-0.239211241452386 -1.707812336086469 1.994541959448508
-0.238883560243254 -1.707992218920763 1.994429990702043
-0.238555873840528 -1.708172064621368 1.994317978585847
-0.238228182457349 -1.708351873071436 1.994205923172916
-0.237900485894857 -1.708531644380220 1.994093824395386

GPS XYZ Velocity in ECI:
3.276820540573197 -1.799032931682451 -1.119482444956503
3.276872512702608 -1.798661610033275 -1.119916159551723
3.276924413465574 -1.798290250160732 -1.120349848764825
3.276976242828717 -1.797918852306742 -1.120783512313681
3.277028000823877 -1.797547416246293 -1.121217150461423

GPS XYZ Position in ECEF:
2.486257771277870 -0.525992080845330 1.796962071713202
2.486219408921021 -0.526173379273422 1.796962071713202
2.486181033343849 -0.526354674903637 1.796962071713202
2.486142644546566 -0.526535967734976 1.796962071713202
2.486104242529370 -0.526717257766510 1.796962071713202

GPS XYZ Velocity in ECEF:
-1.932463623657266 -1.485322200484253 -1.119482444956503
-1.933172003035996 -1.485054282646371 -1.119916159551723
-1.933880318496407 -1.484786276830892 -1.120349848764825
-1.934588569639623 -1.484518183130969 -1.120783512313681
-1.935296756821210 -1.484250001479990 -1.121217150461423

Juliandate Vector:
2.453937827777778
2.453937827789352
2.453937827800926
2.453937827812500
2.453937827824074

Comment only
07 Apr 2012 Convert ECI to ECEF Coordinates Transform ECI position, velocity and acceleration to ECEF position, velocity & acceleration. Author: Darin Koblick

Darin Koblick (view profile)

Darin Koblick

Darin Koblick (view profile)

The MATLAB function juliandate.m should be fine. Can you please post the epoch, the position/velocity vector in ECI coordinates, and your ECF solution?

Comment only
07 Apr 2012 Convert ECI to ECEF Coordinates Transform ECI position, velocity and acceleration to ECEF position, velocity & acceleration. Author: Darin Koblick

Darin Koblick (view profile)

Muhammad Shaikh

Thanks Darin for your reply.
I am using matlab function 'juliandate' to convert my time to julian date format. I have searched whether it is a J2000 format but could not find anything on Mathworks page. Can you please help me for this as well.

Comment only
05 Apr 2012 Convert ECI to ECEF Coordinates Transform ECI position, velocity and acceleration to ECEF position, velocity & acceleration. Author: Darin Koblick

Darin Koblick (view profile)

Darin Koblick

Darin Koblick (view profile)

Check to make sure your time vector is in J2000 format, not Unix Time (epoch should be starting 01/01/2000 12:00:00).

Comment only
04 Apr 2012 Convert ECI to ECEF Coordinates Transform ECI position, velocity and acceleration to ECEF position, velocity & acceleration. Author: Darin Koblick

Darin Koblick (view profile)

Muhammad Shaikh

I am having some problems in calculating ECEF data. In my calculations, the satellite positions are calculated at the wrong side of Earth (globe) in the same plan they are now being calculated. Can you guide me for this please? Note, the data I am giving to the function is verified and I can easily say that my calculations can wrong, the data can't be. Please help.

5
27 Feb 2012 Convert ECI to ECEF Coordinates Transform ECI position, velocity and acceleration to ECEF position, velocity & acceleration. Author: Darin Koblick

Darin Koblick (view profile)

Martin Fuchs

Maybe something like this but I am not sure ???

if (~isempty(a_ECEF) && (~isempty(r_ECEF)) a_ECI = MultiDimMatrixTranspose(T3D(THETA))*a_ECEF' + 2*MultiDimMatrixTranspose(Tdot3D(THETA,omega_e))*v_ECEF' + MultiDimMatrixTranspose(Tdotdot3D(THETA,omega_e))*r_ECEF'; else a_ECI = []; end

function Tdot = Tdotdot3D(THETA,omega_e)
Tdot = zeros([3 3 length(THETA)]);
Tdot(1,1,:) = -omega_e^2.*cosd(THETA);
Tdot(1,2,:) = -omega_e^2.*sind(THETA);
Tdot(2,1,:) = -Tdot(1,2,:);
Tdot(2,2,:) = Tdot(1,1,:);

Comment only
27 Feb 2012 Convert ECI to ECEF Coordinates Transform ECI position, velocity and acceleration to ECEF position, velocity & acceleration. Author: Darin Koblick

Darin Koblick (view profile)

Martin Fuchs

Could you also provide accelerations ?

3
10 Jan 2012 Convert ECI to ECEF Coordinates Transform ECI position, velocity and acceleration to ECEF position, velocity & acceleration. Author: Darin Koblick

Darin Koblick (view profile)

Syed Zohaib Ali

Hi Darin

Now its working fine. I was passing JD argument in a wrong way.

Thanks
Zohaib

Comment only
09 Jan 2012 Convert ECI to ECEF Coordinates Transform ECI position, velocity and acceleration to ECEF position, velocity & acceleration. Author: Darin Koblick

Darin Koblick (view profile)

Darin Koblick

Darin Koblick (view profile)

Syed,

Send me your test case and I will take a look at it.

Thanks,
-Darin

Comment only
09 Jan 2012 Convert ECI to ECEF Coordinates Transform ECI position, velocity and acceleration to ECEF position, velocity & acceleration. Author: Darin Koblick

Darin Koblick (view profile)

Syed Zohaib Ali

Hi

I am facing problem in converting 1441 values of position and velocity vectors from ECI to ECEF. It seems that function works fine. When 93 out of 1441 values were passed to the function it gave values for x,y & z components which I thought are correct but when 186 out of 1441 values were passed to the function, the initial 93 x & y values were different from the one that I got by passing only 93 values, z components were the same. similarly when more values were passed the x&y were different except the z-component.
can you please guide what could be the problem?

Comment only
26 Nov 2011 Convert ECI to ECEF Coordinates Transform ECI position, velocity and acceleration to ECEF position, velocity & acceleration. Author: Darin Koblick

Darin Koblick (view profile)

lin yue

5
17 Oct 2011 Convert Azimuth and Elevation to Right Ascension and Declination Algorithm will convert Az/El angles to RA /DEC using a topocentric coordinate frame Author: Darin Koblick

Darin Koblick (view profile)

Artik Crazy

Nice code, thank you :)
Probably it is better to output Right Ascension in hours and not in degrees.

5
17 Dec 2010 Julian Date to Greenwich Mean Sidereal Time Convert a given Julian Date to Greenwich Mean Sidereal Time (GMST) in degrees. Author: Darin Koblick

Darin Koblick (view profile)

7ate9

7ate9 (view profile)

5
17 Dec 2010 Convert ECI to ECEF Coordinates Transform ECI position, velocity and acceleration to ECEF position, velocity & acceleration. Author: Darin Koblick

Darin Koblick (view profile)

7ate9

7ate9 (view profile)

Excellent function - fast, and I verified a limited number of test cases. Thank you!

5
01 Nov 2010 Convert ECI to ECEF Coordinates Transform ECI position, velocity and acceleration to ECEF position, velocity & acceleration. Author: Darin Koblick

Darin Koblick (view profile)

Ismail

Ismail (view profile)

Ok .. now it works fine !
Thanks Darin !

Comment only

Contact us