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'''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|| |
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));
- 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) |
||
0.25 x sigma |
85.0698 |
62.3596 |
-14.3765 |
|
0.50 x sigma |
84.5538 |
61.6624 |
-15.3434 |
|
0.75 x sigma |
95.8438 59.9313 -21.6901 |
|||
1.00 x sigma |
106.4870 58.2162 -27.3527 |
|||
1.50 x sigma |
79.1224 63.2865 -19.6432 |
|||
2.00 x sigma |
110.1339 58.9454 -23.2403 |
|||
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:
Remaining Detailed Survey PolyCam Pictures
