U.S. Department of the Interior

Bureau of Reclamation September 2013

Technical Memorandum 86-68260-13-03

Aerial Missions with Small 

Unmanned Aircraft Systems to 

Monitor Sediment Flow and 

Changing Topography Resulting 

from the Removal of Dams on the 

Elwha River 

Elwha River Restoration, Washington

Pacific Northwest Region

Mission Statements

The mission of the Department of the Interior is to protect and 

provide access to our Nation’s natural and cultural heritage and 

honor our trust responsibilities to Indian Tribes and our 

commitments to island communities.

The mission of the Bureau of Reclamation is to manage, develop, 

and protect water and related resources in an environmentally and 

economically sound manner in the interest of the American public.
U.S. GEOLOGICAL SURVEY 

National Unmanned Aircraft Systems (UAS) Project Office

BUREAU OF RECLAMATION

Technical Service Center, Denver, Colorado

Emergency Management and GIS Group, 86068260

Technical Memorandum No. 86-68260-13-03

Aerial Missions with Small Unmanned 

Aircraft Systems to Monitor Sediment 

Flow and Changing Topography 

Resulting from the Removal of Dams on 

the Elwha River

Elwha Dam

Olympic National Park (Washington)

Douglas Clark, Ph.D. 12 November 2013 

Preparer Date

Physical Scientist, USBR, Emergency Management and GIS Group, 86-68260

Alan Bell 12 November 2013 

Preparer Date

Physical Scientist, USBR, Emergency Management and GIS Group, 86-68260

Jeff Sloan 12 November 2013 

Preparer: (type in name) Date

Cartographer, USGS, National UAS Project Office, MS-980

Mark Bauer 12 November 2013 

Preparer: (type in name) Date

Geospatial Analyst, Parallel Inc. USGS National UAS Project Office, MS-980

Susan Goplen 12 November 2013 

Preparer: (type in name) Date

IT Specialist, USGS, National UAS Project Office, MS-980
Elwha UAS Study

iii

Bruce K. Quirk, Ph. D. 29 October 2013

Peer Reviewer (type in name) Date

UAS Liaison, USGS, Advanced Systems Center, MS-562

Title, Agency, Group, Mail code

Section Reviewed: All

Michael E. Hutt 29 October 2013

Peer Reviewer (type in name) Date

Cartographer, USGS, UAS National Project Office, MS-980

Title, Agency, Group, Mail code

Section Reviewed: All

Lance Brady 29 October 2013

Peer Reviewer Date

UAS Operator Fire Management Specialist, BLM, National Operations Center

Title, Agency, Group, Mail code

Section Reviewed: All

Jerry Freilich, Ph.D. 3-Sept-2013 

Peer Reviewer Date

Research Coordinator, NPS, Olympic National Park, 600 East Park Avenue 

Port Angeles, WA 98362

Section Reviewed: National Park Service (NPS) Permitting Process

Tommy Noble 29 October 2013 

Peer Reviewer Date

Physical Scientist, BLM, National Operations Center, Geospatial Section, OC-534

Denver, CO

Section Reviewed: Data Accuracy, Results, Recommendations

Neffra Matthews 29 October 2013 

Peer Reviewer Date

Supervisory Cartographer, BLM, National Operations Center, Geospatial Section, OC534 Denver, CO

Section Reviewed: Data Accuracy, Results, Recommendations
Contents

Page

Table of Contents

Background ........................................................................................................... 1

Project Objectives................................................................................................. 1

Methods and Equipment National Park Service (NPS) Permitting Process. ... 2

The FAA Certificate of Authorization Process................................................. 5

The Department of the Interior Office of Aviation Services - UAS Operational 

Procedures Memorandum (OPM) No. 13-11.................................................... 6

Unmanned Aircraft System Platform................................................................ 6

Aircraft Onboard Sensors ................................................................................. 7

Flight Planning.................................................................................................. 8

Flight Missions................................................................................................ 12

Field Operations.............................................................................................. 12

Data Processing to Produce Orthorectified Photography and Digital Elevation 

Models............................................................................................................. 13

Data Processing Assessment........................................................................... 15

Interior Orientation ................................................................................... 15

Absolute Orientation................................................................................. 16

Data Accuracy................................................................................................. 17

Testing the Accuracy of the Acquired Data and the Derived Products.... 17

Digital Orthophoto.................................................................................... 18

Digital Elevation Model............................................................................ 20

Results.................................................................................................................. 21

UAS vs. Conventional Aerial Photography vs. Satellite Imagery .................. 22

Conventional Commercial Aerial Photography.............................................. 22

Satellite Imagery ....................................................................................... 23

Recommendations........................................................................23

Bibliography ........................................................................................................ 25

Appendix A...............................................................Error! Bookmark not defined.

Appendix B. Raven RQ-11A Camera Specifications......................................... 33
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Background

The Elwha River Restoration Project involves the largest dam removal project in 

U.S. history. The restoration effort, coordinated by the Department of the Interior 

(DOI), includes federal, state, local, and tribal support. Dam removal will allow 

for renewed salmon, trout, and char spawning, and ecosystem restoration 

throughout Olympic National Park. Removing the Elwha and Glines Canyon 

Dams will expose over 20 million cubic meters of sediment that is presently 

trapped in the reservoirs behind both dams. 

Erosion and transport of this sediment by the river will cause major geomorphic 

changes not only to the reservoir deltas, but also to the downstream river and 

shoreline. Tracking the erosion of the reservoir deltas and downstream sediment 

movement is a high priority for managers and scientists who will monitor the 

Elwha River restoration. The research results of the Elwha work will contribute

significantly to other future dam-removal projects. Because this is the first dam 

removal on such a large scale, there are presently uncertainties about how rapidly, 

and in what patterns, sediment will erode from the reservoirs and move 

downstream. A monitoring program has been established to track the sediment, 

but funding limitations have not allowed for a complete overall picture of 

sedimentation processes. The UAS flights were designed to support this 

monitoring effort. A secondary purpose of this research was to test whether these 

data gaps could be answered by using aerial over-flights, including those from 

unmanned aircraft systems (UAS), to monitor changes in the reservoirs and river 

channels. 

The United States military made several AeroVironment Raven RQ-11A 

unmanned systems available to DOI in 2008. The U.S. Geological Survey -

National UAS Project Office and the DOI Office of Aviation Services, which 

oversees all aviation activities within DOI, are leading the effort to train DOI 

employees in UAS safety and operational procedures to test the utility of UAS for 

DOI image capture missions, and coordinate national airspace issues with the 

Department of Transportation Federal Aviation Administration (FAA).

Project Objectives

The use of the DOI unmanned systems for monitoring the Elwha River changes 

took place in two separate image acquisition flights in June and September of 

2012. The cooperative effort with the Bureau of Reclamation (BOR), the 

National Park Service (NPS) and the U.S. Geological Survey (USGS) combined 

the skills of UAS operators, hydrologists, biologists, and geographic information 
Elwha UAS Study

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systems and remote sensing experts. The proof-of-concept missions set out to 

discover the capabilities of the new technology for mapping topography. The 

benefit of the project is far reaching in terms of the timeliness and type of data 

acquired. The aerial imagery collection provides data for on-going studies, future 

research, and development of an historical record. This project had the following

objectives:

 Outline the permitting and authorization processes involved with flying 

within the National Airspace System over the DOI, National Park Service 

lands.

 Outline and describe the process of UAS mission operations, data 

acquisition and data processing.

 Conduct a data and accuracy assessment of the derived orthoimagery 

products and elevation models from the UAS acquired data over the 

accessible portion of the former Lake Aldwell lake bed.

 Conduct an overall assessment and feasibility of using low-altitude UAS 

data collection capabilities for topographic mapping.

 Provide readers with an overview of mission planning, mission operations, 

and data processing 

 Make recommendations as to the utility of UAS to meet or extend the 

Bureau of Reclamation remote sensing capabilities.

Methods and Equipment

National Park Service (NPS) Permitting Process DOI 

UAS flights that launch or land in a U.S. National Park must obtain a park permit 

and pilots must contact the NPS Aviation Manager. (See: 

http://inside.nps.gov/waso/contacts.cfm?lv=3&prg=359). If the UAS will fly over 

a park, but not launch or land in the park, pilots should also contact the NPS 

Aviation Manager and park management. Flights in National Parks are subject to 

NPS policies, Office of Aviation Services policies, and to FAA regulations. 

 http://inside.nps.gov/waso/custommenu.cfm?lv=3&prg=359&id=11288) 

 http://oas.doi.gov/library/ib/library/FY2013/IB1305.pdf

 http://www.faa.gov/about/initiatives/uas/reg/
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To apply for a scientific or research permit to conduct UAS flights, applicants 

should go to: http://science.nature.nps.gov/research (Figure 1). Click the button "Create 

a new Permit Application." After the applicant fills in contact information and 

indicates the park in which work will be conducted, a link will appear where 

he/she can upload a project statement. The website also hosts a document that 

presents the requirements for such permits with detailed information on the level 

of detail needed in the research proposal. Generally speaking, very detailed 

information about the formal project statements is only required for very large, 

very complex, or very invasive projects. For small scale projects, a project 

statement of 2-3 pages is usually sufficient. It should focus on essential project 

 Figure 1: National Park Service Research and Reporting System

elements, (e.g., how many samples, how many visits) rather than the theoretical 

underpinnings of the work). Submitted proposals will be entered into the NPS 

database and also to NPS administrators. After filling out the main form there is a 

place to add additional parks to the application, so that the same application may 

be used for any or all parks in the NPS system.

The following information is required to successfully complete the application 

process. 

 Project title 

 Purpose of study 

 Study start and end dates 
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 Identification of any federal funding agencies

 Location of activity in the park

 Method of access

 Names of co-applicants

 If researchers will be collecting specimens, contact information of 

repositories

 A copy of the study proposal

 A copy of all peer reviews

 Study title

 Study purpose

 Summary of methods

 Activity type:

o Research

o Education

o Inventory

o Monitoring

o Other

 Funding source 

 Name of the park

 Location within the park where work will occur

 Field research start and end dates

 Study start and end dates

 List of Co-Investigators

 Location of maps, data, and photography after the research is finished

Each application the NPS receives is peer reviewed. To speed the application 

process it is advisable to contact an NPS staff member in the project subject area 

(aviation, biology, geology, etc.) for advice. Average review and processing time 

is typically three to four weeks, so it is a good idea to start the process as early as 

possible.

Occasionally, if the proposed UAS work is deemed to be out of the ordinary (eg. 

significantly different from the routine work conducted in the park) or if the work 

is to be conducted in a designated Wilderness Area, a Minimum Requirements 

Analysis Worksheet may be required. In such cases, management actions, 

including research efforts, must comply with the minimum requirements mandate 

set forth in the Wilderness Act, Section 4(c). The purpose of the minimum 

requirements concept is to reduce the effects of an action on the wilderness 

character and values. The minimum requirements process involves a 

determination of whether a proposed research or management action is 

appropriate and necessary for the administration of the area as wilderness and 

does not pose a significant impact to its wilderness resources or character. 

Worksheets can be obtained at: 

http://www.nps.gov/ever/upload/EVERMinimumToolInstruct.pdf .
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The FAA Certificate of Authorization Process 

The Certificate of Authorization (COA) is an approval issued by the FAA - Air 

Traffic Organization to a public operator requesting permission to fly a specific 

UAS activity over a specific area for a defined period of time. UAS missions are 

reviewed on a case-by-case basis. After a complete application is submitted, the 

FAA conducts a comprehensive operational and technical review. If necessary, 

provisions or limitations may be imposed as part of the approval to ensure the 

UAS can operate safely with other airspace users.

The COA includes, but is not limited to, the operational plan, risk management, 

airworthiness, airspace, pilot qualifications, radio frequency and communication 

plan, and should be developed and submitted using the COA online system found 

at the following internet address: https://ioeaaa.faa.gov/.

From a period beginning in 2009 to the present time of this publication (2013), 

the FAA has required several documented approvals. Included in the request for 

flight authorization are the following:

 Project description

 Project flight operations

 Class of airspace to be flown

 Date of operation

 Radio frequency spectrum analysis approval

 Notice to Airmen (NOTAM)

 Flight operations plan including maps and authorized area extents

 Special circumstances (special use permits)

 UAS system descriptions

 Performance characteristics (launch/recovery)

 Airworthiness

 Operating procedures (emergency, lost link, lost communications)

 Flight aircrew qualifications (medicals, training, currency and proficiency)

Once the request has been drafted by the requesting agency, it is then internally 

reviewed by the agency’s Bureau Aviation Manager and the Office of Aviation 

Services UAS Coordinator. The request is then sent to the FAA and the approval

or denial process begins. The current 2012-2013 procedural timeline set in place 

by the FAA is based on three review phases; the commit phase, the validation 

phase, and the activation or release phase. 

The commit phase involves the FAA administrative review. The validation phase 

begins a 60 business day detailed review. The determination of the review results 

in the release of the COA for additional edits by the submitting agency, or the 

activation for operational use of the UAS by the requesting agency per the 

parameters in the request. The COA can be renewed or extended on a case-bycase basis, or allowed to expire if no additional flight missions are required.
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The Department of the Interior Office of Aviation 

Services - UAS Operational Procedures Memorandum 

(OPM) No. 13-11.

The Department of the Interior Office of Aviation Services outlined a 

memorandum in 2009 that initiated the operational procedures for use of UAS 

within the agencies. The memorandum and subsequent updates, further define the 

agency authority, policies, procedural guidelines, pilot qualifications and 

limitations beyond what is described by the FAA requirements and specific 

mission COA (Appendix A). Included with these guidelines are:

 Approval of the Bureau Aviation Office

 Possession of a valid and current COA from the FAA

 Exercise operating limitation within the defined geographical boundary, 

COA and OPM provisions

 Meet the Department of the Interior UAS Pilot/Mission Operator/Observer 

training and certification

 Operator letter of authorization specifying the UAS vehicle that is 

approved to be used

 Visual Flight Rules are used regardless of the UAS operational airspace

Unmanned Aircraft System Platform

The RQ-11A Raven (Figure 2) is a hand-launched, battery operated, unmanned 

aerial vehicle. The vehicle is 36 inches in length and has a 55 inch wingspan. 

The typical operating altitude is 100 – 400 feet above ground level (AGL) with an 

average speed of about 20-30 mph, a flight range of approximately 10 km, and a 

flight duration length of about one hour. Two persons are required for flight 

operations of the Raven; one for piloting the aircraft and another to serve as the

mission operator on the navigational laptop computer. In addition, one or more 

trained observers must maintain visual line of sight of the aircraft at all times, 

based upon current FAA UAS operation regulations.

Figure 2 AeroVironment Raven 

RQ-11A
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Aircraft Onboard Sensors

The Raven UAS carries a payload of either an electro-optical video camera with a 

forward and side-looking view or an infrared thermal video camera with only a 

forward view or a side view. Including the Raven UAS nose cone, each camera 

weighs approximately 6.5 oz. The Department of the Interior agencies are also 

testing the use of higher resolution cameras such as the GoPro Hero2. With the 

permission of OAS, the new camera can be retrofitted onto the system in order to 

take advantage of more recent developments in camera and sensor technologies

(Figures 3). 

The current retrofit procedures for 

utilizing the new cameras involve 

removing one of the existing (sidelooking) video cameras in the nose cone. 

A new hole is drilled in the bottom of the 

nose cone for the camera enabling it to be 

pointed straight down (nadir) to better 

collect vertical images required for 

mapping purposes. The camera is 

surrounded by packing material or other 

means of firmly securing it into position. 

The nose cone is then ready for use again in flights just as it was originally used 

(Figures 4 and 5). The images are stored on-board a micro secure digital (SD) 

card with the camera setting on video or still frame capture at an approximate one 

to three second timed interval. The imagery is copied from the SD card upon 

landing to a computer hard drive to complete the data collection. 

These sensors should weigh the same as the existing cameras to minimally affect 

existing UAS flight characteristics. Specifications of the existing cameras and the 

GoPro Hero2 retrofitted cameras can be found in Appendix B.

Figure 4. GoPro Hero2 integrated into the Raven nose cone.

Figure 1. GoPro Hero2 with 5.4 mm and 2.5 

mm lenses.
Elwha UAS Study

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Figure 5. GoPro Hero2 in the nose cone reattached and used as it was 

originally designed.

Flight Planning

Aerial photography flight planning is a way of predetermining the most efficient 

method of flying over a geographic area of interest to collect a series of 

overlapping images that can be used for scientific mapping, surveying or 

monitoring. Photogrammetry is the scientific method of using the aerial images 

for accurate measurements and creation of three dimensional models. Flight 

planning utilizes a variety of mathematical computations, such as flight height, 

cameral focal length, and camera sensor sizes to achieve the best results for 

proper image collection to later develop elevation models and rectified images.

The traditional flight height, grid patterns and overlap requirements used by aerial 

photography companies can also be implemented by a UAS airframe and are 

desirable for achieving the best results in the post-processing of the data in 

photogrammetric software. Flight height planning and direction of flight must be

determined in advance as well as, the method of flight that will be used, such as 

autonomous or manual modes of controlling the aircraft in a grid or linear pattern. 

A minimum of a 60% forward and 30% side overlap between flight paths are 

desired in order to collect sufficient stereo image overlap required to derive a 

three dimensional model and obtain full coverage of the area. Camera collection 

trigger time such as one to three seconds between exposures on average is 

optimal for overlapping photo coverage but, this can vary due to flight height,

ground speed and wind conditions. The faster photo interval will greatly increase 
Elwha UAS Study

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or decrease the amount of overlapping data and the amount of data volume 

collected.

A standard formula for calculating the sensor pixel size, ground sample distance 

and photo footprint on the ground can be useful for flight planning as described 

by a commercial vender providing UAS data processing services (DroneMapper 

2013. See: http://dronemapper.com/):

GSD = PS * FH / FL

Where:

GSD = Ground Sample Distance

PS = Pixel Size (Sensor Size / Image Width or Height)

FH = Flight Height (Above Ground Level (AGL))

FL = Focal Length

Once the camera information is known, flight path, camera exposure timing, 

altitude and overlapping transect patterns can be determined. For the Elwha River 

Restoration Project utilizing the GoPro Hero2 camera, the flight plan parameters 

were as follows:

Example of GoPro Hero2 Parameters:

Image Width = 3840 pixels

Image Height = 2880 pixels

Megapixels = 11 mp

Sensor Size (width) = 6.20 mm

Sensor Size (height) = 4.60 mm

Pixel Size (width) = .0016 mm/pixel

Pixel Size (height) = .0016 mm/pixel

Flight Height (AGL) = 400 feet (122 meters)

Focal Length = 4 mm

GSD = .0016 mm * 122 m / 4 mm = 4.88 cm

With the parameters calculated, additional information can then be used in the 

flight planning of the mission. This would include best estimate for flight heights, 

direction, transect spacing for overlap and flight pattern (Figure 6).
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Figure 6. Flight planning calculations for the GoPro Hero2 at 100 ft. intevals above ground level 

(AGL).

Photo Footprint on the Ground:

(width) 3840 pixels * 4.88 cm = 187.3 m (614.5 ft)

(height) 2880 pixels * 4.88 cm = 140.5 m (460.9 ft)

Figure 7. Still frame capture from the GoPro Hero2 with calculated ground dimensions at a flight 

altitude of 400 feet (AGL).

In-track flying requires an image to be captured at a spacing that would 

accomplish a minimum of a 50% sidelap and 60% overlap relative to the ground

(Figure 8):

(Image height) 615 feet * 50% = 310 feet on the ground

(Image width) 460 feet * 60% = 276 feet on the ground
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Figure 8. Still frame capture from the GoPro Hero2 with optimal overlap collection parameters.

The transecting pattern based upon the flight planning calculations can then be 

used to determine the actual autonomous or manual flight patterns. The interval 

of the automatic photo exposure timing can also be determined and set on the 

camera based upon the projected speed and height of the aircraft (Figure 9).

Figure 9. Flight plan based upon GoPro Hero2 camera parameters at a flight altitude of 400 feet 

(AGL). 60% forward overlap and 50% side overlap are optimal collection parameters. The boxes 

represent individual images collected in a linear flight path. In this example, five flight paths are 

required to cover the area with sufficient overlap of the area photographed both in line and on the 

side between the flight strips.
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Flight Missions

The planning of UAS missions can follow traditional flight collection methods,

however many missions must be altered to some degree in the field due to 

exaggerated effects of wind speed and direction on the small aircraft and 

constraints within the terrain being flown. Flexibility with flight missions is

necessary to ensure safety and success in interpreting all external factors involved 

in operating lower altitude flights, the lighter weight of the aircraft, and the lack 

of stability with the smaller UAS airframes. For example, if a flight mission plan 

is initially designed to fly north and south in a ‘lawn mowing’ pattern, but the 

wind is from the northeast at 15 mph, the fight plan would need to be changed to 

collect photo strips into the wind for stability and slower flight speeds in order to 

collect the most stable and clear images (Figure 10).

Figure 10. Flight plan transects can be altered to aid in collecting a consistent pattern of data.

Instability of the lighter weight aircraft and effects of wind conditions may require one-directional 

collection versus a more efficient bi-directional acquisition.

Field Operations

Once all logistics planning is in place, actual field operations can commence with 

minimal set up and time required for the actual UAS flights and imagery 

acquisition (Figure 11). Video imagery is captured via an analog downlink from 

the aircraft to the ground station. In addition, higher resolution still frame images 

are captured on-board through a data storage card within the GoPro Hero2

camera.
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Figure 11. Field operations require minimal set up for ground station navigation (laptop and 

uplink/downlink antennas) with hand- launch and deep stall landing recovery of the small Raven 

UAS.

Data Processing to Produce Orthorectified 

Photography and Digital Elevation Models

Refined geometric correction for ultimate use in geospatial applications with 

geographic information systems or other types of decision management systems

can be accomplished using various types of commercial data processing software 

packages. One approach used in some of these packages provides for the 

photogrammetric three-dimensional reconstruction of cultural objects and land 

models utilizing imagery captured from hand-held or metric cameras and sensors. 

This methodology is based upon computer vision technology and can work well 

with low altitude imagery captured from a small UAS. Computer vision is based 

upon artificial intelligence and image processing utilizing images from the real 

world. It is most commonly applied in the field of robotics in which automated 

processes and image analysis is interpreted or learned by processing millions of 

mathematical computations to aid in visual perception and machine or robotic

learning. In the field of photogrammetry and remote sensing, this same idea can 

be applied to aid in the derivation of three-dimensional modeling from real world 

aerial imagery. These are the building blocks to highly accurate base geographic

data creation. 

The UAS platform is best utilized for creating this type of data when imagery is 

captured at near vertical angles; however, it is also possible for use with oblique 

imagery for creating models. Fast moving advances in camera technology is 

greatly aiding this method of data collection for deriving highly accurate models 

from currently available off the shelf cameras that are integrated into the UAS. 

The Agisoft PhotoScan software, developed in St. Petersburg, Russia is one 

package that has shown great potential for processing the data captured from 

small UAS. This software was utilized for the imagery captured over the Elwha 

River Restoration Project (Figure 12). The general processing steps include:

 Adding and aligning the overlapping images (preferably from different 

heights and flight directions)
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 Adding any ground control point information

 Constructing a point cloud model based on intersecting vectors

 Building the geometry of the model

 Constructing an elevation model

 Draping the imagery to fit the model

 Exporting out the photogrammetrically rectified products

Step 1. Select, load and align all images to be used. Step 2. Generate a 3D point cloud.

Step 3. Build the geometry and elevation model. Step 4. Drape the imagery over the model.

Step 5. Export the elevation model. Step 6. Export the rectified orthophoto.

Figure 12. A systematic process of geometric correction and three dimensional reconstruction of 

the river model over the Lake Aldwell area. Steps include selecting, loading and aligning the UAS 

acquired images, point cloud creation with horizontal and vertical derivations, elevation modeling

and draping of the images, and export of the geographic products.
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Data Processing Assessment

The PhotoScan software generates graphic and tabular photogrammetric reports 

(Figure 13) that can be used as a general assessment of the quality of the data 

processing inputs and outputs. The report analyzes the various input parameters, 

the data adjustment and variable used in constructing a model. The results reveal 

the level of errors it is able to generate and provide an indication of the quality of 

the final data products. Processing the September 24, 2012 Lake Aldwell area 

UAS Raven aerial photos of the Elwha River Restoration Project included using 

202 images collected by the GoPro Hero2 camera with a 4mm lens on board the 

UAS.

Interior Orientation

No. of Images 202

Flying Altitude 169.329 m

Ground Resolution 0.0268237 m/pix

Coverage Area 0.928812 sq. km

Camera Stations 202

Tie Points 418301

Projections 1141317

Error 3.61681 pix

Figure 13. Camera photo center locations (black dots) and number of correlated images (number 

indicated by a color ramp) from the PhotoScan software. The values >9 would indicate a correlation of 

at least 9 photos and usually many more shown in blue would show a strong tie between multiple 

images. Those <3 shown in the yellow-red colors would represent a much weaker or less accurate 

correlation between fewer photos.
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Absolute Orientation

For image mosaic control input, 27 ground control points (GCPs) were captured 

from existing orthorectified imagery collected from in an August 30, 2012 aerial 

flight. The imagery was photogrammetrically corrected using surveyed field 

ground control panels that were placed before imagery acquisition. In addition to 

the panel control points, other image points that were identifiable on both the 

existing orthoimage and on the UAS individual images were selected and used as 

input into the PhotoScan photogrammetric model. Horizontal latitude and 

longitude points were recorded along with vertical elevation measurements of the 

same points using an October 16, 2012 LIDAR over flight (Figure 14). 

Figure 14. Photo identifiable points are selected from an existing orthomosaic image with 

elevation measurements from a LIDAR collection for input into the photogrammetric model.

The geometric errors are adjusted after the refinements were made both manually 

and automatically by the software to try to derive the best correction for the image 

rectification and three dimensional model (Table 1).
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Control Points:

Pts X Error Y Error Z Error Error (m) Projections Error (pix)

1 0.011509 -0.002797 -0.0003 0.011848 6 2.743731

2 0.005945 -0.086896 0.049093 0.099982 10 2.055259

3 0.028374 -0.037907 0.222039 0.227032 5 3.308647

4 -0.131484 0.017945 -0.019401 0.134113 10 3.440058

5 0.00186 0.048201 -0.010797 0.049431 8 1.917636

6 0.026642 0.137322 -0.145721 0.201994 4 3.415554

8 0.009655 -0.04433 -0.159079 0.165422 10 5.86506

11 0.015884 -0.051131 0.630114 0.632385 9 4.537753

12 0.023414 0.024461 0.427391 0.428731 9 4.310678

13 -0.212929 -0.185384 -0.424605 0.509898 3 3.562857

14 0.004879 -0.10091 -0.348916 0.363248 12 5.973536

15 -0.078203 0.168483 0.283648 0.339055 10 4.989952

17 0.47803 0.774976 -0.802429 1.21367 2 3.538357

18 -0.55626 -0.130476 0.204615 0.606891 3 5.146252

20 0.032793 0.070225 -0.58447 0.589586 14 7.185184

21 -0.111523 -0.241071 0.828853 0.870373 11 7.543617

22 -0.029096 -0.039477 -0.476022 0.478541 5 3.224689

23 0.032769 0.038926 0.229853 0.235417 13 6.151782

24 -0.043736 -0.005594 -0.042114 0.060973 7 2.708866

25 0.052492 0.258153 -0.317136 0.412279 8 3.170312

26 -0.05569 -0.131894 0.199826 0.24582 6 2.79061

27 -0.005314 -0.002189 -0.110629 0.110779 6 5.061313

Table 1. Photomosaic ground control points used as input into the PhotoScan photogrammetry 

software for rectifying the image. Image correlation (projections) between photos creates the 

geometry necessary for three dimensional modeling. Ground control errors in the horizontal and 

vertical positioning are refined and the errors are distributed across the mosaic to derive the best fit 

to the ground.

Data Accuracy

Testing the Accuracy of the Acquired Data and the Derived Products

Initially, before the UAS Raven over flights, the Bureau of Reclamation had 

planned to collect, and panel/target, up to 35 ground control points (GCPs) within 

the Lake Aldwell project area. Plans called for 20 GCPs to be withheld from the 

photogrammetric process and used as independent check points for the final 

orthophoto and digital elevation data sets, with the remaining GCPs used for 

absolute orientation of the UAS Raven acquired aerial photos.

However, as time drew nearer during the spring of 2012 to collect the GCPs, it 

became apparent during discussions with Reclamation engineers that were to 

survey the GCP locations, that plans to collect up to 35 GCPs were not feasible. 

The rapidly draining Lake Aldwell had left behind a very rough and unstable 

surface across large portions of the former lake bed, creating dangerous drops of 
Elwha UAS Study

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six feet or more, particularly in the vicinity of the very active and shifting river 

channels. In effect, these hazardous conditions restricted access to a much 

smaller area of the former lake bed for both the survey and ground control panel 

crews. During late May 2012, the survey crews could safely reach and survey 

only 14 of the planned GCP locations to pin their locations. Prior to the first UAS 

Raven overflight in June 2012, ground panel crews could safely reach, recover or 

panel only seven of the planned GCP locations for Lake Aldwell. In effect, these 

hazardous on-site conditions had derailed Reclamation plans to acquire an 

independent source of higher accuracy data to be used for checking the UAS 

Raven derived data sets.

By the time the joint DOI UAS Raven crew arrived for the first flight mission in 

June 2012, lake bed conditions in the north/lower end of former Lake Aldwell 

(nearer the Dam site) were determined to be unsuitable and unsafe for both the 

ground crew and UAS Raven operations. For safety reasons, an on-site decision 

was made to restrict the UAS Raven flights to only the southern/upper portion of 

the former Lake Aldwell lake bed. Only three of the paneled GCPs ended up 

being within the UAS Raven flight mission area and were visible in the 

September 2012 UAS Raven aerial photos taken with the higher resolution GoPro

Hero2 camera. These three GCPs were used for control/absolute orientation 

purposes, not as independent check points of higher accuracy.

In retrospect, ideally at least 20 stable-ground GCPs should have been collected 

and paneled a few days before the first UAS Raven flight missions in June 2012, 

then withheld from the photogrammetric process to serve as an independent check 

source of higher accuracy for UAS Raven derived data. Then, the x-y-z positions 

of the 20 GCPs would remain stable and unchanged between June and September 

2012, and re-paneled for use as check points for the second UAS Raven mission 

in September 2012. However, because of unstable and unsafe onsite conditions 

and budget considerations, we did not have an independent source of higher 

accuracy data, acquired near or at the time of UAS Raven aerial photo collection 

that we could use to independently check the accuracy of the UAS Raven data.

Digital Orthophoto

Accuracy assessments can be conducted in a number of ways. To ensure that end 

products from the cameras on board the UAS can reliably meet required 

resolution and positional accuracy, a standard validation process can be employed 

to check horizontal and vertical values against surveyed ground control or an

accepted base image from previous corrected data collection. The 1999 National 

Standard for Spatial Data Accuracy (NSSDA) provides a good framework for 

assessing the horizontal accuracy of an orthorectified image from a small UAS 

and for the creation of a positional accuracy statement (Figure 15).
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Figure 15. Test points selected on both the orthomosaic base image collected August 30, 2012 

and from the UAS Raven photogrammetrically derived orthophoto from September 24, 2012. 

Coordinates are collected with the measured differences calculated to derive a statistical average 

of the ground position error between the base image and newly derived UAS image mosaic.

Horizontal Accuracy Statistic Worksheet

Positional Accuracy Statement: 

Tested 4.365 meters horizontal accuracy at 95% confidence level 

Table 2. Twelve test points are selected on both the aerial photography orthophoto base and the 

UAS Raven GoPro Hero2 photogrammetrically derived orthophoto. An accuracy assessment is 

calculated following the National Standard for Spatial Data Accuracy method of measurement and 

accuracy reporting. Note: The base orthophoto had a ground sample distance of 3.96 inches 

(10.05cm) and the UAS orthophoto had a ground sample distance of 2.04 inches (5.18cm). Error 

in the measurement could be introduced in using the lower resolution base orthophoto in the 

statistical input. However, this was the highest resolution image available at this time and with 

lack of ground control, the only option for a similar comparison.
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Digital Elevation Model

For elevation accuracy assessments, a direct comparison can be made against the 

vertical elevations of the derived UAS elevation model from imagery collected on 

Sept. 24, 2012 and a LIDAR base elevation model from an over flight collected 

on October 16, 2012 - approximately 22 days later. Random points are selected in 

a distributed pattern and elevation measurements are collected for each data set 

over the exact same points. The vertical measurements are compared with an 

overall difference averaged and root mean square error analysis applied to derive 

the vertical accuracy statement (Figure 16). 

The specifications for the October 16, 2012 LIDAR data acquisition include a 

survey altitude of 900-meters above ground level, pulse rate of 106 kHz, 21 cm 

laser width at ground level, 26-degree field of view, an average of 8 pulses per 

square meter initial data collection, and a tested vertical accuracy over open 

terrain (bare earth) of approximately 15 cm. Twelve test points are selected on 

both the LIDAR base elevation model and the UAS Raven GoPro Hero2 elevation 

model and a vertical accuracy assessment is calculated following the National 

Standard for Spatial Data Accuracy method of measurement and accuracy 

reporting. Note: The LIDAR was the best available source to use and compare 

against the UAS photogrammetrically derived model. Error in the measurements 

could be introduced with the larger sampling area of the LIDAR in contrast to the 

much higher resolution of the data collected from the UAS (Table 3).

Figure 16. Random points are selected with latitude, longitude and elevation values recorded form 

both the October 2012 LIDAR collection (left) and from the UAS Raven GoPro Hero2

photogrammetrically derived elevation model (right). These values are then used in a statistical 

analysis to derive an average of the error difference between the two data sets in order to be able 

to produce a positional accuracy statement.
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Vertical Accuracy Statistic Worksheet

Positional Accuracy Statement: 

Tested 5.230 meters vertical accuracy at 95% confidence level 

Table 3. Twelve test points elevation values are recorded from both the LIDAR base elevation 

model and the UAS Raven GoPro Hero2 elevation model. The difference between the two 

datasets and a statistical average is calculated in order to produce a standard vertical accuracy 

statement.

Results

Although an image orthomosaic and elevation model was derived from the initial 

June 2012 UAS Raven flight missions, the results were not satisfactory. The 

imagery using the standard UAS Raven camera was lacking in adequate fidelity 

and resolution. As a result, the confidence level in the derived elevation data was 

not high. An immediate search was done for better camera options for the UAS 

Raven and due to payload weight limits, a limited selection of camera choices 

were available. The best option at the time was a GoPro Hero2 which delivered 

much higher resolution and clarity. This camera was then used for the subsequent 

September 2012 UAS Raven flight mission.

As described in this paper, significant progress was made by using the GoPro 

Hero2 camera for the September 2012 aerial photography mission. A useable 

orthophoto and digital elevation model were derived from the GoPro acquired 

aerial photos. However, the horizontal and vertical accuracy errors were higher 

than anticipated. These higher accuracy errors are likely due to several factors; 

1) The mix of GCPs used were not of sufficient horizontal and vertical accuracy 

to support the UAS derived higher resolution orthophoto and digital elevation 

data products - with the exception of the three GPS GCPs, the 27 other GCPs 
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likely contributed in degrading the UAS product accuracy. 

2) The GoPro Hero2 camera/optics was not of sufficient quality to ensure an 

adequate mapping level camera calibration and photogrammetric input. 

3) The steep canyon and surrounding tall trees in the Lake Aldwell project area 

did not allow for adequate perpendicular cross-flights over the project area. The 

additional flight passes likely would have strengthened the camera calibration and 

photogrammetric processing results.

Because of a lack of confidence in the initial June 2012 UAS Raven mission data, 

and a change in the camera configuration for the following mission, a valid 

comparison for sediment movement analysis between the June 2012 and 

September 2012 UAS Raven missions was not possible.

UAS vs. Conventional Aerial Photography vs. Satellite 

Imagery

Conventional Commercial Aerial Photography

In general, the FAA restricts commercial fixed wing aircraft to a minimum 

operational flight altitude of 1000 feet above the ground. In practice, and 

depending on the project terrain, most commercial aerial photography mapping 

contractors will not collect aerial imagery at a flight altitude of lower than 1200-

1500 feet above the ground. To meet higher resolution and larger scale elevation 

data requirements, a commercial contractor will likely conduct large format 

calibrated mapping camera acquired aerial photography flight missions, using a 

fixed wing aircraft in the range of 1200-2000 feet above ground level.

However, a helicopter can operate and acquire aerial photography and LIDAR at 

a much lower elevation, perhaps as low as 300-400 feet above ground level 

depending on project area terrain. There are medium format, photogrammetric 

quality digital cameras, professional grade digital SLR cameras and LIDAR 

systems that can be mounted in helicopters to acquire engineering level quality 

mapping data. For smaller project areas, this equipment along with advances in 

associated airborne GPS/IMU may offer better pricing when compared to fixed 

wing aircraft mission costs.

In either case, commercial fixed wing aircraft or helicopter based aerial photo 

collection, the anticipated cost range for a one square mile project area, high 

resolution accurate ortho-image and elevation data, including ground control 

collection, would likely be $15,000-$20,000 price range for acquisition.
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Satellite Imagery

Currently, with the highest resolution commercial satellite imagery capable of 

capturing an image with a 46 cm ground sample distance, it would still not be able 

to meet a two foot or better elevation contour interval or a one foot or better pixel 

accuracy requirement for derived imagery products. A lower resolution three 

meter elevation model and an approximate 20 inch ground sample distance 

orthoimage requirement could be met using commercial satellite imagery with 

sufficient collected ground control. Cost would be in the $10,000 range for 

coverage over a 1-square mile project area.

Recommendations

The UAS Ravens were built for military operations, primarily for reconnaissance 

and surveillance. The standard equipped electro-optical video camera and 

thermal infrared sensors are not designed or suited for higher resolution 

photogrammetric mapping applications. The Ravens are limited in their payload 

sensor capacity, limiting DOI options for significant improvement in higher 

resolution cameras, optics, sensors, or IMU/GPS components. The UAS Raven 

and its standard camera package could be useful to Reclamation for certain 

surveillance and monitoring activities, and they are useful as an introductory 

learning tool for operating a UAS. In the event access to a Reclamation facility 

or associated infrastructure was blocked or prohibited due to a natural event 

(landslide, earthquake, or other adverse natural/weather event), or dangerous onsite conditions (fire, chemical, or radiation related event) a Raven or similar type 

UAS could be put into operation to gather imagery remotely. However, the UAS 

Raven is not recommended for use in Reclamation applications requiring more 

precise measurements or mapping products.

The military surplus acquired UAS Ravens were built for the Defense Department 

from 2002-2005. Most had experienced many hours of use from overseas 

operation before coming to DOI, and have now exceeded their useful lifespan. 

The UAS Ravens have not been produced since 2005, and spare parts are 

becoming harder to attain. The UAS Raven cannot be cost-effectively modified 

to make use of professional grade digital SLR cameras.

The UAS Raven flight management system can accommodate only a limited 

number of waypoints for flight planning, resulting in a cumbersome flight plan 

and operation that may result in gaps in area coverage or less desirable aerial 

photo overlap. Modern commercial UAS systems can plan for hundreds of 

waypoints, and account for wind speed and direction and adjust the flight plan

accordingly. This makes flight operations more efficient, effective, and results in 

better stereo overlap coverage, and will allow the execution of better aligned 
Elwha UAS Study

24

perpendicular cross-flights that will strengthen camera calibration results. The end 

result being more effective and efficient photogrammetric processing, and 

reducing the chances of having gaps in aerial photography coverage.

The GoPro Hero2 and other digital point-and-shoot type cameras are a vast 

improvement in resolution and usefulness, when compared to the standard UAS 

Raven cameras, particularly for mapping and measurement related applications. 

However, the best results for mapping and measurement related applications will 

be accomplished by a UAS utilizing higher resolution, professional grade (Nikon 

or Canon 20 MP and above) digital SLR cameras such as the Nikon or Canon 20 

megapixel models, which have better lenses and associated optical characteristics, 

resulting in sharper images, better camera calibration results, more precise 

measurements, and higher accuracy derived products. 

The DOI now has another UAS available from military surplus - the vertical 

takeoff and landing RQ-16 T-Hawk. It was first utilized in November 2012 and 

was not available at the time of the Elwha River Restoration Project. It has since 

been used several times by USGS for various projects, and does offer several 

advantages over the UAS Raven platform, although it is not powerful enough to 

incorporate a professional grade digital SLR camera as its primary sensor 

package.

Significant cost savings, compared to a commercial aerial mapping company, 

could be realized in using a UAS for imagery and elevation data acquisition and 

production for smaller project areas such as a few square miles. Using in-house 

UAS data acquisition and data processing capability, response time and data 

delivery timeframes can be significantly shortened as compared to a commercial 

acquisition. More modern UAS typically contain a smaller volume of related UAS 

control and flight operations (ground control station) related equipment, resulting 

in reduced travel and/or shipping related costs per mission. An aircraft number 

limit imposed on the DOI Office of Aviation Services currently limits our ability 

to acquire new UAS. The BOR, USGS, and Bureau of Land Management, have 

investigated several fixed and rotary (helicopter type) UAS within the past 12 

months. Several commercially available systems offer higher quality, 

professional grade aircraft and camera systems, along with more efficient flight 

planning (hundreds of waypoints) and flight management software than the Raven 

UAS. In addition, several rotary type UAS have the ability to incorporate a 

higher quality professional grade digital SLR camera as their imagery acquisition 

sensor, in addition to having better flight planning/management software.

As we near the FAA 2015 deadline for guidelines for UAS operations in the 

United States airspace, many commercial companies are expected to offer similar 

higher quality UAS. We strongly recommend that for applications requiring more 

precise measurements and higher resolution mapping related data that the Bureau 

of Reclamation and DOI invest in both a rotary type UAS with the capability to 

incorporate a professional grade digital SLR camera as its primary sensor package 
Elwha UAS Study

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and better flight planning/management software, and a fixed wing UAS that has 

camera/optics and flight planning/management system better suited to true 

photogrammetric applications.
Elwha UAS Study

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Bibliography

Federal Geographic Data Committee, 1998. Geospatial Positioning Accuracy 

Standards Part3: National Standard for Spatial Data Accuracy, FGDC-STD007.3-1998.

Minnesota Planning Land Management Information Center, 1999. Positional 

Accuracy Handbook: Using the National Standard for Spatial Data Accuracy to 

Measure and Report Geographic Data Quality.

Stoermer, Jon-Pierre. "DroneMapper Aerial Imagery Processing and 

Photogrammetry." DroneMapper Customer Documentation | DroneMapper 

Aerial Imagery Processing and Photogrammetry. Big Mountains Robotics, LLC, 

02 June 2012. Web. 03 Sept. 2013. <http://dronemapper.com/documentation>.
Elwha UAS Study

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Appendix A. 

DOI OPERATIONAL PROCEDURES (OPM) MEMORANDUM NO. 13-11

Subject: DOI Use of Unmanned Aircraft Systems (UAS) 

Effective Date: January 1, 2013 

Supersedes: OPM 11-11 issued on December 19, 2011 

Expiration: December 31, 2013 

1. PURPOSE. The purpose of this OPM is to provide guidance on the operations and 

management of Unmanned Aircraft Systems (UAS). 

2. AUTHORITY. This policy is established by the Director, Department of the Interior, 

Office of Aviation Services(OAS) in accordance with the provisions of Departmental 

Manual 112 DM 12, 350 DM 1; and Secretarial Order 3250 dated September 30, 2003. 

3. BACKGROUND. Current FAA policy is provided in Interim Operational Approval 

Guidance 08-01, Unmanned Aircraft Systems Operations in the U.S. National Airspace 

System (NAS). 

A. FAA retains the authority to approve UAS operations within the NAS in Class A, B, C, 

D, E and G airspace. 

B. When operating in Class A, B, C, D, E and G airspace, DOI UAS’s must be operated 

with a FAA Certificate of Waiver or Authorization (COA). 

C. COAs are not required in Restricted, Prohibited, or Warning airspace. However, UAS 

operations in these specific airspaces will be regulated and approved by the Controlling 

Authority (a.k.a. “Range Control”). 

4. POLICY. UAS by definition are considered aircraft. While their size, method of 

control, and airspace utilization procedures are different than manned aircraft, the overall 

responsibility for management within the Department of Interior (DOI) rests with the 

Office of Aviation Services (OAS). Ownership of all aircraft, including UAS, is a function 

and responsibility of OAS. Additionally, OAS will coordinate with other federal agencies 

on use and cooperate with the FAA on existing and proposed rule making. Department of 

Interior bureaus shall employ the following procedures when using any UAS, either DOIowned or DOI contract vendor-owned and operated. 
Elwha UAS Study

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5. PROCEDURES AND GUIDELINES. 

A. UAS Project and COA Application: 

1. The OAS Alaska Regional Director, Harry Kieling is the DOI UAS Coordinator for FAA 

COA applications, harry_kieling@nbc.gov, 907-271-5626, 907-271-6569 (Fax).

2. The alternate UAS Coordinator is Alaska Region Aviation Safety Compliance 

Specialist, Rod Russell, rod_russell@nbc.gov. 907-271- 5004, 907-271-4788 (Fax). 

3. Only a U.S. (Federal/State/Local) government agency or university may apply for a 

COA. 

4. The COA includes, but is not limited to the operational plan, risk management, 

airworthiness, airspace, pilot qualifications, frequencies and communication plan, and 

should be developed and submitted using the COA online system 

(https://ioeaaa.faa.gov/oeaaaA/Welcome.isp). This web site is password protected. 

5. Initial feasibility discussions will be conducted between bureau unit, local bureau and 

National Aviation Manager and, if necessary, DOI UAS Coordinator. 

6. The local unit will prepare and submit a formal request to initiate a UAS COA. This 

proposal shall include the general purpose, objectives and justification for utilizing UAS. 

7. The request shall be routed through the bureau state/regional office to the bureau 

National Aviation Manager for review and approval/disapproval. 

8. If approved, the proposal will be forwarded to OAS and a request will be made for an 

on line COA account for the project. 

9. Following the establishment of the on line COA account, the bureau proponent will 

complete the detailed COA application. When the proponent feels the application is 

ready for review and submittal, it should be forwarded through bureau channels to the 

Bureau National Aviation Manager for approval and then to the OAS COA coordinator for 

committal to the FAA. 

10. Collaboration and agreement will occur prior to official commitment of the application. 

Status of the COA can be followed on the On Line web site. The COA, once issued, shall 

serve as the UAS Operations Plan. 

B. Restricted/ /Prohibited and Warning Area Utilization:

1. Operations conducted entirely within Restricted/Prohibited and Warning areas do not 

require a COA; however, an MOU for UAS use will be established between the using 

bureau/OAS and the controlling agency and the request process outlined above is still 

necessary, requiring Bureau National Office approval. 

C. Minimum Operational Requirements: The following requirements must be met prior 

to any operational use of UAS: 

1. Obtain approval from bureau National Aviation Office 

2. Obtain (1) a valid and current COA issued by the FAA or (2) MOU with the controlling 

agency for operations wholly within Restricted/Prohibited and Warning areas. 

3. Exercise operating limitations in accordance with the COA/MOU Range 

provisions/COA and this OPM. 

4. Meet DOI UAS Pilot/Mission Operator/Observer Training and Certification 

Requirements. DOI operators of UAS vehicles must first receive bureau authorization 

and concurrence and then must receive training in the specific vehicle to be operated. 

The using bureau and OAS will identify appropriate training. Personnel must possess 

training certificates from OAS or OAS-approved sources prior to receiving OAS 

certification. 
Elwha UAS Study

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5. Possess a DOI UAS Operator Letter of Authorization. The LOA must specify the UAS 

vehicle(s) that are authorized to operate. 

6. VFR cloud clearances and visibilities for Class E airspace will be used regardless of 

airspace the UAS is operating in, except when operating in Class Airspace where 14 

CFR Part 91.155 will apply. 

7. Operations outside of restricted areas, warning areas, prohibited areas, and /or Class 

A airspace may only be conducted during daylight hours, unless authorized in the Special 

Provisions Section of the COA. 

6. UAS Pilot Qualifications and Certification

A. General UAS Pilot Responsibilities: The pilot in command, (PIC) of a UAS is 

directly responsible for, and is the final authority as to the operation of that aircraft. 

1. One PIC must be designated for all flights. 

2. Pilots are responsible to perform a thorough preflight inspection of the UAS. 

3. Pilots, mission operators and observers will not have concurrent responsibilities during 

the mission. They may not perform more than one crew duty at a time (i.e. pilot/mission 

operator/observer). 

4. Per 350 DM 1.8, Reporting Requirements, an OAS 2 or OAS 23 will be required for 

each flight. 

B. UAS Pilot Certification Factors: Rating requirements for the UAS PIC depend on 

the type of operation conducted and fall into two categories. The requirement for the PIC 

to hold a pilot certificate is based on various factors including: 

1. Location of the planned operations. 

2. Mission profile. 

3. Size of the UA. 

4. Whether or not the operation is conducted within or beyond visual line of sight. Each 

application will be carefully reviewed to assess the feasibility of allowing that type of 

operation. 

C. Operations that require a FAA pilot certificate and Letter of Authorization:

1. All operations approved for use in Class A, B, C, D, and E airspace. 

2. All operations conducted under IFR (FAA instrument rating required). 

3. All operations approved for nighttime operations. Night operations are authorized in 

Restricted/Warning/Prohibited areas without a FAA pilot certificate unless prohibited by 

the Controlling Authority. Also the night operations without a FAA pilot certificate are 

permitted if specifically allowed in the Special Provisions Section of the COA. 

4. All operations conducted at joint use or public airfields. 

5. All operations conducted beyond line of sight. 

6. Operations above 400 feet AGL or with visual line of sight conducted greater than one 

NM from the UAS observer. A FAA pilot certificate may not be required for altitudes to 

1000 ft in Restricted/Warning/Prohibited areas if not prohibited by the Controlling 

Authority. Also, the higher altitude is authorized without a FAA pilot certificate if 

specifically allowed in the Special Provisions Section of the COA. 
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7. At any time the FAA (as specified in the COA) has determined the need based on the 

UAS’ characteristics, mission profile, or other operational parameters. 

8. For those operations that require a certificated pilot, the PIC, in order to exercise the 

privileges of his certificate, shall have flight reviews and maintain currency in manned 

aircraft per 14 CFR 61.56, Flight Review and 61.57, Recent Flight Experience: Pilot in 

Command.

9. For operations approved for night or IFR, the PIC shall maintain currency per 14 CFR 

61.57, Recent Flight Experience: Pilot in Command, as applicable. 

D. Operations requiring only a Letter of Authorization: The PIC may not be required 

to hold an FAA pilot certificate for the following operations: 

1. Approved and conducted solely within visual line of sight. 

2. In Class G or Restricted/Prohibited or Warning airspace. 

3. Conducted in a sparsely populated location. 

4. With visual line of sight conducted no further than 1 NM laterally from the UAS 

observer and at an altitude of no more than 400 feet above ground level (AGL) at all 

times. Altitudes to 1000 ft are authorized in Restricted/Warning/Prohibited areas unless 

prohibited by the Controlling Authority. Also, the higher altitude is authorized if specifically 

allowed in the Special Provisions Section of the COA. 

5. Conducted during daylight hours only. Night operations are authorized in 

Restricted/Warning/Prohibited areas unless prohibited by the Controlling Authority. Also 

the night operations are authorized if specifically allowed in the Special Provisions 

Section of the COA. 

6. Conducted no closer than 5 NM from any airport or heliport. 

7. If the pilot in command (PIC) is not required to hold a FAA pilot certificate for such 

operations and stated in the approved COA he/she must have in lieu of a pilot certificate 

one of the following: 

a. Successfully completed an FAA private pilot ground instruction, and have passed the 

written examination, or 

b. Completed a tailored aviation course approved by DOI-OAS covering applicable 

sections of the FAR/AIM or other aviation publications that will enable the pilot to safely 

operate a specific UAS in the class of airspace desired. This training will include but not 

be limited to weather (as applicable to a UAS pilot), emergency procedures, aircraft 

mishap reporting, SAFECOM Program, lost link, Air Traffic Control (ATC 

communications) and NOTAM procedures, classes of airspace, system operating 

limitation all other applicable DMs and OPMs pertaining to aviation. 

E. UAS Specific Training and Certification for all UAS Pilots and Operators:

1. All UAS pilots/mission operators will complete the manufacturer’s UAS specific training 

or equivalent, be tested on their knowledge, and be certified to operate the UAS upon 

graduation. These courses will be monitored by OAS Tech Services/Alaska Regional 

Director. 

2. DOI-OAS or approved bureau inspectors will provide a Letter of Authorization (LOA) 

under the direction of the DOI-OAS Chief of Technical Services/Alaska Regional Director. 

The LOA will specify the UAS vehicle(s) that are authorized to operate. 
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F. Flight Currency:

1. PIC must demonstrate three takeoffs (launch) and landings (recovery) in the specific 

UAS in the previous 90 days. If currency is lost prior to a mission, operator must regain 

currency by flying three emergency scenarios in the UAS simulator or fly under the 

observation of a current UAS pilot. 

G. Medical Qualification: The PIC shall maintain, and have in their possession, at a 

minimum, a valid FAA Class 2 medical certificate issued under 14 CFR Part 67. For 

operations that are covered in paragraph 5G above, alternate medical certification that is 

as rigorous as the Class II, may be considered and approved on a case by case basis by 

the bureau National Aviation Manager and OAS. After approval this alternate certification 

must be listed on the COA.

H. General UAS Observer Responsibilities: 

1. Observer duties include but are not limited to the following:

a. Have a clear view of the area of operation.

b. Be in communications with the PIC either within speaking distance or with a portable 

radio/cell phone.

c. Keep the pilot advised of any possible hazards such as power lines, birds, other 

aircraft, rocks, and hazardous weather conditions.

d. The observer can also act as the launch person for a hand launched aircraft.

2. Observer Training: Observers must have completed sufficient training to communicate 

to the pilot any instructions required to remain clear of conflicting traffic. This training, at a 

minimum, shall include knowledge of the rules and responsibilities described in 14 CFR 

91.111, Operating Near Other Aircraft; 14 CFR 91.113, Right-of-Way Rules: Except 

Water Operations; and 14 CFR 91.155, Basic VFR Weather Minimums; knowledge of air 

traffic and radio communications, including the use of approved ATC/pilot phraseology;

and knowledge of appropriate sections of the Aeronautical Information Manual. This 

training will be reviewed and approved by the Chief of Tech Services/Alaska Regional 

Director.

3. Observer Medical Qualification: The provisions of Paragraph 5J above will apply to 

observers.

I. Maintenance: 

1. Maintenance inspectors will require the same qualifications (DOI/OAS 6700.202) as 

current OAS inspectors plus knowledge of UAS procedures. Until OAS can develop 

specific UAS maintenance inspection procedures, Mil Handbook 516, or similar 

document will be used. Initially Rod Russell, Alaska Regional Office, OAS, should be 

contacted to evaluate any specific UAS airworthiness questions.

2. A conditional Inspection must be performed during preflight and must be logged in the 

aircraft flight log for the first flight of each day as part of a continuing airworthiness 

compliance program. This entry should read “I have inspected this aircraft in accordance 

with (site the publication and reference) and have found it to be in condition for safe 

operation, and be signed and dated.

3. Log and maintain progressive flight hours of the aircraft in the aircraft logbook to 

validate inspection intervals, component times, and time life items i.e.; batteries.
Elwha UAS Study

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4. Record malfunctions (loss of link), damage (parts that require repair to be airworthy 

again), and serial numbered parts that require replacement (wings, tail booms, etc). 

Record serial number of the part coming off and serial number of the part going on.

5. Every twenty four months, a biennial airworthiness inspection and carding by qualified 

maintenance personnel will be performed. At this time a new OAS-36 Aircraft Data Card

will be attached to each aircraft within the system kit.

6. A maintenance inspector training and evaluation program will be developed for each 

system specific and in compliance with the POH. 

7. OAS inspectors will coordinate with the FAA to ensure airworthiness criterion has been 

approved if required. OAS inspectors will then issue an OAS 36A/36B for UAS aircraft.

J. Radio Frequencies: Radio frequencies to be used will be coordinated with the 

bureau’s Radio Office and the FAA and be included in the COA application. 

K. Cooperator Aircraft: This could include work with universities, other governmental 

agencies such as the Department of Defense, or multiple agency collaborative projects. 

Bureau involvement in these projects does not necessarily mean that the bureau has 

operational control; therefore it is important for field units to communicate with the bureau 

National Aviation Manager on all UAS projects to determine the extent of bureau 

responsibilities. UAS projects must have a COA (except those covered in paragraph 3c) 

and shall be obtained by the agency having operational control. Even if the COA is not 

requested by DOI (i.e. another government agency), it must be coordinated with Bureau 

aviation personnel and OAS COA administrator. 

1. Involvement in a UAS project but no operational control: DOI personnel collect data 

but do not own, operate, or participate directly in the UAS process. This will be handled 

similar to an end product contract, field units need only to advise the bureau aviation 

manager and DOI COA Administrator. However, because of the nature of the 

responsibilities associated with the COA application and approval process, the 

individual/organization with Operational Control must file the COA.

2. DOI has operational control but does not own or operate the UAS: Bureaus would 

follow the procedures to include the formulation of a Project Aviation Safety Plan (PASP) 

identifying all agencies involved in the project, outlining their responsibilities and level of 

involvement. Each project will be evaluated on its own merits of involvement, complexity, 

and standards of safety. Therefore, responsibilities will be determined on a case by case 

basis as determined by the bureau National Aviation Manager and DOI-OAS.

7. EXCEPTIONS, LIMITATIONS. Per 350 DM 1.9., Deviations from this OPM must be 

approved by the Director, Office of Aviation Services. 

Director, Office of Aviation Services /s/ Mark Bathrick
Elwha UAS Study

33

Appendix B. 

Raven RQ-11A Camera Specifications

Camera: Raven A Stock Electro Optical 2001

Sensor Type: Optical

Operational Band: Vis, 0.4-0.7 micrometers, color images

Detailed Sensor: Charged-Coupled Device (CCD) 

Resolution: 768 x 494

Collection Medium: Fixed Hard Drive on laptop

Camera: Raven A Stock Electro Optical 2001

Sensor Type: Thermal - IR

Operational Band: Near IR – Far IR 700nm – 1mm

Detailed Sensor: Charged-Coupled Device (CCD) 

Resolution: 160 x 120

Collection Medium: Fixed Hard Drive on laptop

Camera: GoPro Hero2 Black (4 mm lens) 

Sensor Type: Optical

Operational Band: Visible, 0.4 - 0.7 micrometers, color images

Detailed Sensor: 11 Megapixel (CMOS) 

Processor: Digic 4

Resolution: 3840 x 2880 still frame, 1080p at 30 frames/sec (video) 

Collection Medium: Non-volatile memory card,

 high capacity ultra-high speed class 10