UAS Search Patterns - Revision history

Dmerrick: /* Overlapping Grid Search */

2019-02-07T06:38:00Z

‎Overlapping Grid Search

Dmerrick: /* Overlapping Grid Search */

2019-02-07T06:32:23Z

‎Overlapping Grid Search

Dmerrick: /* Overlapping Grid Search */

2019-02-07T06:30:51Z

‎Overlapping Grid Search

Dmerrick: /* Overlapping Grid Search */

2019-02-07T06:28:38Z

‎Overlapping Grid Search

Dmerrick: /* Overlapping Grid Search */

2019-02-07T06:27:11Z

‎Overlapping Grid Search

Dmerrick: /* Overlapping Grid Search */

2019-02-07T06:20:24Z

‎Overlapping Grid Search

Dmerrick: /* Parallel Track Search */

2019-02-07T06:03:48Z

‎Parallel Track Search

Dmerrick at 00:54, 26 August 2018

2018-08-26T00:54:32Z

Dmerrick at 00:47, 26 August 2018

2018-08-26T00:47:29Z

Dmerrick: /* Parallel Track Search */

2018-08-22T22:27:21Z

‎Parallel Track Search

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 With most software, the Overlapping Grid is programmed as two separate sorties or flights at the same altitude and overlap settings, with the second track path offset by approximately 90 degrees. When the datasets from the two flights are combined, each point on the ground is visible from at least two (typically four) oblique angles - allowing for better coverage under trees, obstacles, building eaves, etc.  This search pattern is typically overkill for creating a simple orthomosaic product, but can still be processed in this way.
-The Overlapping Grid requires more time to complete, analyze and process, so it should be used only in situations that warrant the additional resources.
+'''Effective Use Scenarios:'''  The Overlapping Grid requires more time to complete, analyze and process, so it should be used only in situations that warrant the additional resources. It is best in scenarios where tree cover is heavy, and extended coverage is required to maximize the POD. Operators and search managers should understand that tree cover may defeat an airborne search (manned or unmanned) and while this search technique may increase the odds of detection, the additional resources required (time) may indicate that other search techniques are appropriate.
 ===Track Line Search===

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 The Overlapping Grid Search is a modification of the Parallel Track Search (above).  When utilizing an oblique sensor angle, the Overlapping Grid provides additional views under canopy and other overhead concealment.
-With most software, the Overlapping Grid is programmed as two separate sorties or flights at the same altitude and overlap settings, with the second track path offset by approximately 90 degrees. When the datasets from the two flights are combined, each point on the ground is visible from at least two (typically four) oblique angles - allowing for better coverage under trees, obstacles, building eaves, etc.
+With most software, the Overlapping Grid is programmed as two separate sorties or flights at the same altitude and overlap settings, with the second track path offset by approximately 90 degrees. When the datasets from the two flights are combined, each point on the ground is visible from at least two (typically four) oblique angles - allowing for better coverage under trees, obstacles, building eaves, etc.  This search pattern is typically overkill for creating a simple orthomosaic product, but can still be processed in this way.
 ===Track Line Search===

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 </div>
 The Overlapping Grid Search is a modification of the Parallel Track Search (above).  When utilizing an oblique sensor angle, the Overlapping Grid provides additional views under canopy and other overhead concealment.
 ===Track Line Search===

@@ Line 60: / Line 60: @@
 </gallery>
 </div>
-sfsfsdfsdf
+The Overlapping Grid Search is a modification of the Parallel Track Search (above).  When utilizing an oblique sensor angle, the Overlapping Grid provides additional views under canopy and other overhead concealment.
 ===Track Line Search===

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 ===Overlapping Grid Search===
+<div style="float:right; padding-left: 10px;">
 <gallery>
 File:overlapping_grid_1.png|Sample overlapping grid search flight path, first pass (green lines)
 File:overlapping_grid_2.png|Sample overlapping grid search flight path, second pass (green lines)
 </gallery>
 ===Track Line Search===

← Older revision		Revision as of 06:20, 7 February 2019
Line 54:		Line 54:

	===Overlapping Grid Search===		===Overlapping Grid Search===
		+
		+	<gallery>
		+	File:overlapping_grid_1.png\|Sample overlapping grid search flight path, first pass (green lines)
		+	File:overlapping_grid_2.png\|Sample overlapping grid search flight path, second pass (green lines)
		+	</gallery>

	===Track Line Search===		===Track Line Search===

@@ Line 31: / Line 31: @@
 [[File:uas_grid_plan_sample1.png|thumb|Sample parallel track search flight path (green lines)]]The Parallel Track Search is the basic grid search - the sUAS is flown in a series of parallel 'tracks' or 'legs' covering an entire designated search area. sUAS Operators often refer to the Parallel Track Search as 'mowing the lawn' due to the resemblance of the search pattern to the path taken to mow the grass.
-The Parallel Track Search can be used to cover a large or small area, but it typically best on relatively flat terrain focused on the subject's last known point (LKP) or other datum. The search pattern requires post flight analysis of the captured imagery to increase effectiveness and generate the highest possible probability of detection (POD.
+The Parallel Track Search can be used to cover a large or small area, but it typically best on relatively flat terrain focused on the subject's last known point (LKP) or other datum. The search pattern requires post flight analysis of the captured imagery to increase effectiveness and generate the highest possible probability of detection (POD).
 This pattern is often employed by sUAS operators because it is the default pattern used by [[Glossary|commercial mapping software]]. These software programs will automatically generate a flight path appropriate for capturing [[Glossary|nadir images]] used to construct [[Glossary|ortho-mosaic photos]] or other [[Glossary|photogrammetry]] products.

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 ===Expanding Square Search===
 ===Shoreline Search===
 ===Barrier Search===

← Older revision		Revision as of 00:47, 26 August 2018
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	===Expanding Square Search===		===Expanding Square Search===
		+
		+	===Shoreline Search===

	===Barrier Search===		===Barrier Search===

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 [[Glossary#Sensor_angle|Sensor angle]] will should be set based on a variety of factors. For processing ortho-mosaics, a nadir or near-nadir sensor orientation should be used. However, in situations where there is significant tree canopy, [[Glossary#oblique_images|oblique images]] may be more effective at an angle up to 45 degrees from vertical. The angled sensor orientation mitigates some canopy or overhead coverage; oblique images can see 'under' some obstruction. To maximize coverage using oblique images, planners should narrow the track spacing, resulting in higher overlap and reduced coverage. However, the tighter track spacing allows a specific point on the ground to be seen from at least two oblique angles. Planners should also remember that calculated GSD is only valid for nadir imagery. When oblique imagery is utilized, the GSD becomes higher closer to the horizon.
-The Parallel Track Search is typically planned using automated software, typically [[Glossary#commercial_mapping_software|commercial mapping software]]; the parallel leg pattern is identical to the typical flight plan for mapping and photogrammetry. While mapping and photogrammetry may require a [[Glossary#sidelap|sidelap]] of 65% or greater, the sidelap in the Parallel Track Search could be considerably less (as low as 15%). Planners should understand that a flight with overlap less than 60% may be fine for search purposes but will not be sufficient for building [[Glossary#ortho-mosaic_photos|ortho-mosaic]] or mapping products.
+The Parallel Track Search is typically planned using automated software, typically [[Glossary#commercial_mapping_software|commercial mapping software]]; the parallel leg pattern is identical to the typical flight plan for mapping and photogrammetry. While mapping and photogrammetry may require a [[Glossary#sidelap|sidelap]] of 65% or greater, the sidelap in the Parallel Track Search could be considerably less (as low as 15%) to increase coverage per sortie. Planners should understand that a flight with overlap less than 60% may be sufficient for search purposes but will not be sufficient for building [[Glossary#ortho-mosaic_photos|ortho-mosaic]] or mapping products.
 As overlap decreases, the amount of area than can be covered in a single [[Glossary#sortie|sortie]] will increase. Planners should understand that the flight altitude will also affect sweep width and therefore coverage on a single sortie, but as altitude increases, the [[Glossary#ground_sample_distance|ground sample distance]] or [[Glossary#resolution|resolution]] will decrease. In other words, the flight should be planned at the highest altitude at which an appropriate GSD can be achieved. This will maximize coverage while still providing appropriate sensor performance.
-'''Products of the Parallel Track Search:''' The primary product of a Parallel Track Search is a list of potential targets or targets of interest. This list can be generated in one of two ways: [[Glossary#live_search|live search]] or [[Glossary#post-flight_search|post-flight search]]. Live search is less likely to result in a successful find, primarily due to environmental conditions including glare, poor screens, time pressure, and distraction. As a result of this, Parallel Track Search data should be reviewed using post flight analysis or 'the squint'.
+'''Products of the Parallel Track Search:''' The primary product of a Parallel Track Search is a list of potential targets or targets of interest. This list can be generated in one of two ways: [[Glossary#live_search|live search]] or [[Glossary#post-flight_search|post-flight search]]. Live search is less likely to result in a successful find, primarily due to environmental conditions including glare, poor screens, time pressure, and distraction. As a result of this, Parallel Track Search data should be reviewed using post flight search or 'the squint'.
 In addition to a target list, the search data can be processed into an ortho-mosaic or other GIS product(s) if there was sufficient coverage and overlap of nadir images.
-'''Integration of the Parallel Track Search:''' This search type can be utilized in conjunction with ground resources operating in the same [[Glossary#Division_area|division area]], or it can be performed before a ground team begins working that area. This [[Glossary#Leapfrog_strategy|leapfrog strategy]] allows the sUAS team to perform an initial search as well as produce near real-time maps and other information that can be provided to ground resources.
+'''Integration of the Parallel Track Search:''' This search type can be utilized in conjunction with ground resources operating in the same [[Glossary#Division_area|division area]], or it can be performed before a ground team begins working that area. This [[Glossary#Leapfrog_tactic|leapfrog tactic]] allows the sUAS team to perform an initial search as well as produce near real-time maps and other information that can be provided to ground resources.
 ===Overlapping Grid Search===