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Spacecraft Azimuth Variations

Eric E Palmer edited this page Oct 23, 2026 · 1 revision

Spacecraft Azimuth Variations

Aim and Objectives

Purpose of Test 11: To evaluate SPC's ability to represent a simplified 'boulder' which has a constant 20 degree slope.

Objective for Tests 11 F, G, H, I & J, Spacecraft Azimuth Variations

  • To investigate the effect of varying the combination of spacecraft azimuths with respect to a landmark contained in the image suite;
  • To investigate the effect of the number of images and viewing conditions.

Methodology

The 'boulder' was simulated by generating a simple axi-symmetric, flat-topped cone (peak) with a constant 20 degree slope. Multiple peaks and (simplified) craters are randomly placed in an otherwise flat landscape of width approx. 22.5m.

Entire Truth map: REGION.MAP

Bigmaps

The following TAG1 bigmaps were tiled/iterated and evaluated:

Starting topography defined from: START1.MAP at pixel/line location 49, 49 (= REGION.MAP at p/l 1125, 1125).

Step GSD Overlap Ratio Q Size Width Center
START.MAP 20cm - 49 20m REGION.MAP p/l 1125, 1125 (center)
10cm-Tiling 10cm 1.3 130 20m START1.MAP, p/l 49, 49
5cm-Tiling 5cm 1.3 250 20m START1.MAP, p/l 49, 49
5cm-Iterations 5cm - - 20m START1.MAP, p/l 49, 49
Portion Truth Map (011TRU.MAP) 1cm - 200 4m REGION.MAP, p/l 996, 1005

Tiling/Iteration Parameters

Auto-Elimination Parameters: 0, 60, .25, .25, 0, 3
Reset albedo/slopes NO
Determine Central Vector YES
Differential Stereo YES
Shadows YES

Tiling seed files: t11-10.seed , t11-05.seed

Iteration seed file : Piteate2StSh-woAYY

Data

  • Data was generated by Eric.
  • Image resolutions: 2cm/pixel.

Viewing Conditions

Name Sun S/C Az S/C Zenith Total Number of Images
Test11F 45, 0, -45 every 20 45 72
Test11G 45, 0, -45 every 30 45 48
Test11H 45, 0, -45 every 45 45 32
Test11I 45, 0, -45 every 60 45 24
Test11J 45, 0, -45 every 90 45 16

Test 11F Viewing Conditions

![](files/Spacecraft Azimuth Variations/sc_plotF.png) ![](files/Spacecraft Azimuth Variations/sun_plotF.png)

Test 11G Viewing Conditions

![](files/Spacecraft Azimuth Variations/sc_plotG.png) ![](files/Spacecraft Azimuth Variations/sun_plotG.png)

Test 11H Viewing Conditions

![](files/Spacecraft Azimuth Variations/sc_plotH.png) ![](files/Spacecraft Azimuth Variations/sun_plotH.png)

Test 11I Viewing Conditions

![](files/Spacecraft Azimuth Variations/sc_plotI.png) ![](files/Spacecraft Azimuth Variations/sun_plotI.png)

Test 11J Viewing Conditions

![](files/Spacecraft Azimuth Variations/sc_plotJ.png) ![](files/Spacecraft Azimuth Variations/sun_plotJ.png)

Results ( All with overlaps)

Test Over11FGHIJ Comparative Results

Test Over11F Results

Test Over11G Results

Test Over11H Results

Test Over11I Results

Test Over11J Results

IMPORTANT Note: The heat maps are made from CompMapVec where optimal translation and rotation is not used.

Heat Maps Discussion

Observing the heat maps show a clear tilt that is present since one side of the Effort's bigamp topography is always lower than the Truth's after the tiling step. Then, as iterations occur, SPC starts to bring the entire topography up to account for this tilt, but SPC overshoots the Truth leaving most of the Effort's topography now greater than the Truth. The heat maps also indicate the iterations where the Effort's topography best matches the Truth; which are 10 ,20, 20, 30, and 30 for Tests F, G, H, J , and I respectfully. This completely agrees with Figure 1 in the Test Over11FGHIJ Comparative Results Section.

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