[Spice_discussion] spkezr vs Geocentric Solar Ecliptic (GSE) Frame
William T Bridgman
william.t.bridgman at nasa.gov
Fri Jan 29 09:05:21 PST 2016
I just browsed the rbsp kernel file and it looks like MEAN_ECLIP is the
same as Bill's ECLIPDATE
\begindata
FRAME_MEAN_ECLIP = -362913
FRAME_-362913_NAME = 'MEAN_ECLIP'
FRAME_-362913_CLASS = 5
FRAME_-362913_CLASS_ID = -362913
FRAME_-362913_CENTER = 399
FRAME_-362913_RELATIVE = 'J2000'
FRAME_-362913_DEF_STYLE = 'PARAMETERIZED'
FRAME_-362913_FAMILY = 'MEAN_ECLIPTIC_AND_EQUINOX_OF_DATE'
FRAME_-362913_PREC_MODEL = 'EARTH_IAU_1976'
FRAME_-362913_OBLIQ_MODEL = 'EARTH_IAU_1980'
FRAME_-362913_ROTATION_STATE = 'ROTATING'
\begintext
So is the lack of this definition in Bill's test the cause of the fail?
Tom
On 1/29/16 11:51 AM, William Thompson wrote:
> I tried using these three different definitions of GSE in SPKEZR. When
> I put Earth in for both the target and the observing body, I get all
> zeros for all three definitions, as you would expect. When I then try
> to put in a different body than Earth for the target, I get an error
> message for the Van Allen definition:
>
> % CSPICE_SPKEZR: SPICE(NOTRANSLATION):
> [spkezr_c->SPKEZR->SPKEZ->SPKGEO->FRMCHG->FRMGET->ZZDYNFRM->ZZDYNFID]
> The kernel
> variable FRAME_-362930_SEC_FRAME used to define frame
> BRIDGMAN is assigned the character value MEAN_ECLIP.
> This value was expected to be a reference frame
> name, but NAMFRM cannot translate this name to a frame ID
> code.
> % Execution halted at: $MAIN$
>
> (I renamed GSE to BRIDGMAN or LINTON to allow all three definitions to
> be loaded simultaneously.) The Van Allen definition must include a
> definition for MEAN_ECLIP frame. However, the same is true of the
> STEREO definition, which includes a reference to the ECLIPDATE frame
> defined below:
>
> \begindata
>
> FRAME_ECLIPDATE = 1803321
> FRAME_1803321_NAME = 'ECLIPDATE'
> FRAME_1803321_CLASS = 5
> FRAME_1803321_CLASS_ID = 1803321
> FRAME_1803321_CENTER = 399
> FRAME_1803321_RELATIVE = 'J2000'
> FRAME_1803321_DEF_STYLE = 'PARAMETERIZED'
> FRAME_1803321_FAMILY = 'MEAN_ECLIPTIC_AND_EQUINOX_OF_DATE'
> FRAME_1803321_PREC_MODEL = 'EARTH_IAU_1976'
> FRAME_1803321_OBLIQ_MODEL = 'EARTH_IAU_1980'
> FRAME_1803321_ROTATION_STATE = 'ROTATING'
>
> \begintext
>
> It's possible this is the same as MEAN_ECLIP in the Van Allen
> definition. I realize now that everything else in the STEREO and Van
> Allen definitions of GSE is the same.
>
> When I apply the Linton and STEREO definitions of GSE to Mars for the ET
> value in the original mail message, I get the following values:
>
> STEREO definition:
> 3.8803534e+08 54357681. 6945416.9 6.9416565
> -23.066438 0.37886396
>
> Linton definition:
> 3.8803534e+08 54357885. 6943816.8 6.9416565
> -23.066896 0.38321554
>
> Difference:
> 0.0000000 -204.42863 1600.1297 0.0000000
> 0.00045798140 -0.0043515797
>
> The light travel times are the same for both definitions.
>
> Bill Thompson
>
>
> On 01/29/16 11:17, William Thompson wrote:
>> The STEREO project has been using a different definition for GSE.
>> I'll have to
>> take a look at how all these frames differ. The definition below is
>> in the file
>>
>> http://sohowww.nascom.nasa.gov/solarsoft/stereo/gen/data/spice/gen/heliospheric.tf
>>
>>
>> Bill Thompson
>>
>>
>> \begindata
>>
>> FRAME_GSE = 1803311
>> FRAME_1803311_NAME = 'GSE'
>> FRAME_1803311_CLASS = 5
>> FRAME_1803311_CLASS_ID = 1803311
>> FRAME_1803311_CENTER = 399
>> FRAME_1803311_RELATIVE = 'J2000'
>> FRAME_1803311_DEF_STYLE = 'PARAMETERIZED'
>> FRAME_1803311_FAMILY = 'TWO-VECTOR'
>> FRAME_1803311_PRI_AXIS = 'X'
>> FRAME_1803311_PRI_VECTOR_DEF = 'OBSERVER_TARGET_POSITION'
>> FRAME_1803311_PRI_OBSERVER = 'EARTH'
>> FRAME_1803311_PRI_TARGET = 'SUN'
>> FRAME_1803311_PRI_ABCORR = 'NONE'
>> FRAME_1803311_SEC_AXIS = 'Z'
>> FRAME_1803311_SEC_VECTOR_DEF = 'CONSTANT'
>> FRAME_1803311_SEC_FRAME = 'ECLIPDATE'
>> FRAME_1803311_SEC_SPEC = 'RECTANGULAR'
>> FRAME_1803311_SEC_VECTOR = ( 0, 0, 1 )
>>
>> \begintext
>>
>>
>> On 01/29/16 10:24, William T Bridgman wrote:
>>> A tf file for the Van Allen probes has a different definition to
>>> build GSE:
>>>
>>> \begindata
>>>
>>> FRAME_GSE = -362930
>>> FRAME_-362930_NAME = 'GSE'
>>> FRAME_-362930_CLASS = 5
>>> FRAME_-362930_CLASS_ID = -362930
>>> FRAME_-362930_CENTER = 399
>>> FRAME_-362930_RELATIVE = 'J2000'
>>> FRAME_-362930_DEF_STYLE = 'PARAMETERIZED'
>>> FRAME_-362930_FAMILY = 'TWO-VECTOR'
>>> FRAME_-362930_PRI_AXIS = 'X'
>>> FRAME_-362930_PRI_VECTOR_DEF = 'OBSERVER_TARGET_POSITION'
>>> FRAME_-362930_PRI_OBSERVER = 'EARTH'
>>> FRAME_-362930_PRI_TARGET = 'SUN'
>>> FRAME_-362930_PRI_ABCORR = 'NONE'
>>> FRAME_-362930_SEC_AXIS = 'Z'
>>> FRAME_-362930_SEC_VECTOR_DEF = 'CONSTANT'
>>> FRAME_-362930_SEC_SPEC = 'RECTANGULAR'
>>> FRAME_-362930_SEC_FRAME = 'MEAN_ECLIP'
>>> FRAME_-362930_SEC_VECTOR = (0, 0, 1)
>>>
>>> \begintext
>>>
>>> It defines the secondary as z-axis rather than y-axis. I suspect
>>> your y-axis is
>>> not quite perpendicular to your x-axis which might be projecting some
>>> velocity
>>> in the x-direction.
>>>
>>> Tom
>>>
>>> On 1/27/16 7:33 PM, Donald F. Linton wrote:
>>>> I implemented the Geocentric Solar Ecliptic (GSE) Frame in the Frames
>>>> <http://naif.jpl.nasa.gov/pub/naif/toolkit_docs/FORTRAN/req/frames.html#Specifying
>>>>
>>>>
>>>>
>>>> a New Frame> reference:
>>>>
>>>> \begindata
>>>> FRAME_GSE = 314101
>>>> FRAME_314101_NAME = 'GSE'
>>>> FRAME_314101_CLASS = 5
>>>> FRAME_314101_CLASS_ID = 314101
>>>> FRAME_314101_CENTER = 399
>>>> FRAME_314101_RELATIVE = 'J2000'
>>>> FRAME_314101_DEF_STYLE = 'PARAMETERIZED'
>>>> FRAME_314101_FAMILY = 'TWO-VECTOR'
>>>> FRAME_314101_PRI_AXIS = 'X'
>>>> FRAME_314101_PRI_VECTOR_DEF = 'OBSERVER_TARGET_POSITION'
>>>> FRAME_314101_PRI_OBSERVER = 'EARTH'
>>>> FRAME_314101_PRI_TARGET = 'SUN'
>>>> FRAME_314101_PRI_ABCORR = 'NONE'
>>>> FRAME_314101_SEC_AXIS = 'Y'
>>>> FRAME_314101_SEC_VECTOR_DEF = 'OBSERVER_TARGET_VELOCITY'
>>>> FRAME_314101_SEC_OBSERVER = 'EARTH'
>>>> FRAME_314101_SEC_TARGET = 'SUN'
>>>> FRAME_314101_SEC_ABCORR = 'NONE'
>>>> FRAME_314101_SEC_FRAME = 'J2000'
>>>> \begintext
>>>>
>>>> Using the epoch: 2017-07-01T00:00:00
>>>> et = 5.521392681841135e8
>>>>
>>>> sv = spkezr( "SUN", et, "J2000", "NONE", "EARTH" )
>>>>
>>>> -2.41323e7 1.37774e8 5.97261e7 -28.9257 -4.24521 -1.83927
>>>>
>>>> then
>>>>
>>>> M = sxform("J2000", "GSE", et )
>>>>
>>>> -0.158671 0.905874 0.392703 0.0 0.0 0.0
>>>> -0.987331 -0.145594 -0.0630798 0.0 0.0 0.0
>>>> 3.26993e-5 -0.397737 0.9175 0.0 0.0 0.0
>>>> -1.90166e-7 -2.80422e-8 -1.21495e-8 -0.158671 0.905874
>>>> 0.392703
>>>> 3.0561e-8 -1.7445e-7 -7.56986e-8 -0.987331 -0.145594
>>>> -0.0630798
>>>> -6.6631e-11 -9.82553e-12 -4.257e-12 3.26993e-5 -0.397737
>>>> 0.9175
>>>>
>>>> M*SV yields
>>>>
>>>> 1.5209e8
>>>> 2.79397e-9
>>>> 7.45058e-9
>>>> 0.0217735
>>>> 6.64746e-15
>>>> 2.22045e-16
>>>>
>>>> I don't understand why I see 21.77 m/s of sunward velocity
>>>>
>>>>
>>>>
>>>>
>>>> _______________________________________________
>>>> Spice_discussion mailing list
>>>> Spice_discussion at naif.jpl.nasa.gov
>>>> https://naif.jpl.nasa.gov/mailman/listinfo/spice_discussion
>>>>
>>>
>>
>
--
Dr. William T."Tom" Bridgman Scientific Visualization Studio
Global Science & Technology, Inc. NASA/Goddard Space Flight Center
Email: William.T.Bridgman at nasa.gov Code 606.4
Phone: 301-286-1346 Greenbelt, MD 20771
FAX: 301-286-1634 http://svs.gsfc.nasa.gov/
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