Differences between revisions 5 and 30 (spanning 25 versions)

TestF3G - Results

Definitions

CompareOBJ RMS: The root mean square of the distance from each bigmap pixel/line location to the nearest facet of the truth OBJ.
SCOBJ: The S/C position vector from the center of the asteroid.

Comments

The results show no significant difference in the final S/C position (SCOBJ) and model accuracy (as measured with CompareOBJ RMS) with respect to the magnitude of S/C position and pointing perturbation within the ranges tested, indicating that the SPC-driven modeling is immune to S/C position and pointing perturbation up to three standard deviations.

It should be noted that S/C position perturbation was divided equally between the SCOBJ components, resulting in a distance from the truth position which was a multiple of the standard deviation of 6.4m. Therefore:

maximum lateral perturbation was a multiple of 3.7m (6.4m/sqrt(3));
maximum normal perturbation (wrt body center) was 3.7m (6.4m/sqrt(3)).

It is assumed that the worst case scenario is a 3 x sigma (19.2m) lateral perturbation. The maximum possible lateral perturbation tested was 3 x 3.7m = 11.1m.

In all cases, the final SPC-derived S/C position is within 8m of the true S/C position, but in only two cases is within 2m of the true S/C position. The actual distance from the true S/C position is not dependent on the initial perturbed position - for example in the 0.25 x sigma case, the SPC-derived S/C position (distance from truth: 1.6m to 6.9m) in most cases moves further away from the true S/C position than its initial position (distance from truth: 1.6m).

The final SPC-derived S/C positions appear to be clustered around an incorrect solution 2m-8m distant from the true S/C position.

CompareOBJ RMS

CompareOBJ does not appear to be affected by the magnitude of S/C position and pointing perturbation within the ranges tested.

CompareOBJ Optimal Translations:

Sub-Test	Perturbation Magnitude	Translation (cm)
F3G7	0.25 x sigma	85.0698	62.3596	-14.3765
F3G6	0.50 x sigma	84.5538	61.6624	-15.3434
F3G5	0.75 x sigma	95.8438	59.9313	-21.6901
F3G3	1.00 x sigma	106.4870	58.2162	-27.3527
F3G4	1.50 x sigma	79.1224	63.2865	-19.6432
F3G2	2.00 x sigma	110.1339	58.9454	-23.2403
F3G1	3.00 x sigma	93.5937	61.6997	-26.8422

Image Footprints

The first graph shows footprints for all Detailed Survey PolyCam pictures which were included in the model. The second graph shows the four pictures down-selected due to their coverage of the 20m x 20m evaluation region, and their almost complete containment within the iterated 100m x 100m region.

Distance SCOBJ(truth) to SCOBJ(solution)

The distance of the final SPC-derived S/C position from the true S/C position is plotted for the full Detailed Survey PolyCam image set for each magnitude of perturbation. The evaluation images are plotted in red.

3D graphs of final SPC-derived SCOBJ and true SCOBJ are then plotted for each picture. The first four are the down-selected evaluation pictures, the rest of the image set is included for comparison.

The pattern of final SPC-derived SCOBJ is broadly consistent across magnitudes of perturbation. The position correction is mostly a normal correction with lateral movement, bringing the modeled S/C position within an approx. 8m-radius sphere around the true position (or, in the case of perturbations<8m, pushing SCOBJ outwards up to 8m).

Evaluation Pictures

Example nominal SCOBJs:

Final solution SCOBJs:

-  ⇤ ← Revision 5 as of 2016-03-22 16:52:42 → 
  Size: 1525
  Editor: DianeLambert
  Comment:
+   ← Revision 30 as of 2016-04-27 13:10:27 → ⇥
  Size: 4460
  Editor: DianeLambert
  Comment:
-Deletions are marked like this.
+Additions are marked like this.
 Line 2:
+== Definitions ==

'''CompareOBJ RMS:''' The root mean square of the distance from each bigmap pixel/line location to the nearest facet of the truth OBJ.<<BR>>
'''SCOBJ:''' The S/C position vector from the center of the asteroid.

== Comments ==

The results show no significant difference in the final S/C position (SCOBJ) and model accuracy (as measured with CompareOBJ RMS) with respect to the magnitude of S/C position and pointing perturbation within the ranges tested, indicating that the SPC-driven modeling is immune to S/C position and pointing perturbation up to three standard deviations.

It should be noted that S/C position perturbation was divided equally between the SCOBJ components, resulting in a distance from the truth position which was a multiple of the standard deviation of 6.4m. Therefore:
 * maximum lateral perturbation was a multiple of 3.7m (6.4m/sqrt(3));
 * maximum normal perturbation (wrt body center) was 3.7m (6.4m/sqrt(3)). 
It is assumed that the worst case scenario is a 3 x sigma (19.2m) lateral perturbation. The maximum possible lateral perturbation tested was 3 x 3.7m = 11.1m.

In all cases, the final SPC-derived S/C position is within 8m of the true S/C position, but in only two cases is within 2m of the true S/C position. The actual distance from the true S/C position is not dependent on the initial perturbed position - for example in the 0.25 x sigma case, the SPC-derived S/C position (distance from truth: 1.6m to 6.9m) in most cases moves further away from the true S/C position than its initial position (distance from truth: 1.6m).

The final SPC-derived S/C positions appear to be clustered around an incorrect solution 2m-8m distant from the true S/C position.
-Line 5:
+Line 23:
+CompareOBJ does not appear to be affected by the magnitude of S/C position and pointing perturbation within the ranges tested.
-Line 6:
+Line 26:
+'''CompareOBJ Optimal Translations:'''
||'''Sub-Test'''||'''Perturbation Magnitude'''||||||'''Translation (cm)'''||
||F3G7||0.25 x sigma||85.0698||62.3596||-14.3765||
||F3G6||0.50 x sigma||84.5538||61.6624||-15.3434||
||F3G5||0.75 x sigma||95.8438||59.9313||-21.6901||
||F3G3||1.00 x sigma||106.4870||58.2162||-27.3527||
||F3G4||1.50 x sigma||79.1224||63.2865||-19.6432||
||F3G2||2.00 x sigma||110.1339||58.9454||-23.2403||
||F3G1||3.00 x sigma||93.5937||61.6997||-26.8422||
-Line 9:
+Line 39:
-The first graph shows footprints for all Detailed Survey PolyCam images which were included in the model. The second graph shows the four images down-selected due to their coverage of the 20m x 20m evaluation region, and their almost complete containment within the iterated 100m x 100m region.
+The first graph shows footprints for all Detailed Survey PolyCam pictures which were included in the model. The second graph shows the four pictures down-selected due to their coverage of the 20m x 20m evaluation region, and their almost complete containment within the iterated 100m x 100m region.
-Line 17:
+Line 47:
-Distance magnitude is plotted for the full Detailed Survey PolyCam image set. 3D graphs of final SCOBJ and truth is then plotted for each image. The first four are the down-selected evaluation images, the rest of the set is included for comparison.
+The distance of the final SPC-derived S/C position from the true S/C position is plotted for the full Detailed Survey PolyCam image set for each magnitude of perturbation. The evaluation images are plotted in red.

3D graphs of final SPC-derived SCOBJ and true SCOBJ are then plotted for each picture. The first four are the down-selected evaluation pictures, the rest of the image set is included for comparison.

The pattern of final SPC-derived SCOBJ is broadly consistent across magnitudes of perturbation. The position correction is mostly a normal correction with lateral movement, bringing the modeled S/C position within an approx. 8m-radius sphere around the true position (or, in the case of perturbations<8m, pushing SCOBJ outwards up to 8m).
-Line 23:
+Line 57:
+'''Example nominal SCOBJs:'''
-Line 24:
+Line 60:
+''' Final solution SCOBJs:'''

{{attachment:P601293751G3_final_resized.png}}
-Line 34:
+Line 74:
-{{attachment:P601293751G3_final_resized.png}}