a commercial of the shelf components for a...

Section Name

A COMMERCIAL OF THE SHELF COMPONENTS FOR A UNMANNED AIR

VEHICLE PHOTOGRAMMETRY

Pawel Burdziakowski

Jakub Szulwic

Faculty of Civil and Environmental Engineering, Gdansk University of Technology, Poland

ABSTRACT

A photogrammetry from a unmanned aerial vehicle (UAV) can be understood as a new

measurement tool. Is introduces a low-cost alternatives for a traditional aerial

photogrammetry. A commercial off-the-shelf products (COTS), that are commercially

available for a costumers, are the standard manufactures products, not custom. COTS

products are available in the commercial market and can be bought and used under

government contract. That fact makes it cheaper and available for all. Motivations for

using COTS components is a reduction of overall system-development and costs and

long-term maintenance costs. An aviation offers a different types of aircraft. Aircraft

may be classified by different criteria, such as lift type, aircraft propulsion. All those

types offers different attributes, that are more or less desirable for UAV

photogrammetry. A methodology for determining a platform type was developed in this

research, and the most suitable platform for a photogrammetry measurements was

chosen. In order to build a UAV platform for photogrammetry tasks, products available

on commercial market were analyzed with characteristics and technical data.

Keywords: COTS, UAV, photogrammetry, methodology

INTRODUCTION

Commercial off-the-shelf (COTS) products can be defined as an items, including

services, sold in the commercial marketplace. This is a standard manufactures products,

not specially designed for custom purposes. This item is commercially available, leased,

licensed and sold to the general public. COTS products not require special modification

or maintenance over its life cycle. It means that all components can be purchased on the

market, connected and programed for a final product.

Unmanned aerial vehicle (UAV), also called drone, is defined as a generic

aircraft design to operate with no human pilot onboard. Initially, UAV systems and

platforms were designed for a military applications. Military UAV are very

complicated, specially designed for a military operations. UAV technology was

unavailable to a wider community. During recent years UAV technology was

commercialized. Nowadays, it is possible to purchase small, simple and cheap drone

for a home usage. So called professional drones, but still commercial, are available on

the market and equipped with more advanced technology, better cameras, represents

better stability, endurance and maneuverability during flight. All components are

available on markets, can be replaced, modified, upgraded. It means, that UAV

technology becomes very popular and affordable for community.

16th International Multidisciplinary Scientific GeoConference SGEM 2016

UAV PHOTOGRAMMETRY

Fig. 1 Measurement methods and techniques – relationships between object size and accuracy [1] [4] [7]

Fig. 2 Geomatics techniques, sensors and platforms fo 3D recording purposes, according to the scene

dimensions and complexity [1][6]

UAV photogrammetry should be understood as a new photogrammetric

measurement tool. This technology opens a new applications in the close range domain,

combining aerial and terrestrial photogrammetry, but also introduces low-cost

alternatives to the classical manned aerial photogrammetry. UAV photogrammetry

Section Name

describes photogrammetric measurement platforms, which operate as either remotely

controlled, semi-autonomously, or autonomously [1].

Recent years showed that a the range of measurement technique published in [7]

and modified in [4], now can be revised again (Fig. 1), since NASA launched

X-37 project, also known as the Orbital Test Vehicle (OTV), which is a reusable

unmanned spacecraft. Since that moment unmanned aerial vehicle are enable to operate

in outer space.

Based on this information, new classification of geomatics 3D measurement

technique found in [6] should be revised as well (Fig. 2). Since UAV reached the space,

its capability to take a photogrammetry measurements reach ability close to

measurements taken from satellites.

UAV PLATFORMS

UAV platform (body) can be considered as a mechanical structure, typically

including a fuselage, wings and the propulsion system and aviation electronics,

excluding payload. Platforms design is a field of aerospace engineering that combines

aerodynamics, materials technology and manufacturing methods to achieve balances of

performance, reliability and cost. UAV platforms can be categorized using the main

characteristics of aircrafts. Table 1 shows a classification of the UAV platforms, which

can be used for photogrammetric applications.

Tab. 1 Classification of UAV according to the class [4]

Aerostat Aerodyne

Flexible wing Fixed wing Rotary wing Unpowered Balloon Hang glider Gliders Rotor-kite

Paraglider Kites

Powered Airship Paraglider Propeller Single rotors

Jet engines Coaxial Quadrotors

Multi-rotors

Fig. 3 UAS functional blocks.

UAV is a part of system named Unmanned Aerial System (UAS). A typical

UAS consists of an unmanned aerial vehicle, ground control station (GCS) and

a communication and control link (C2) between GCS and UAV. Critical UAV modules

are placed on board unnamed platform, such as navigation module (NM), flight control

module (FCM), mechanical servos. Depends on UAV main purpose and tasks payload

is different. In case of photogrammetry and remote sensing, payload could be defined as

a data acquisition module (DAM) (Fig.3).GCS can be defined as a stationary or


transportable devices to monitor, command and control the unmanned aircraft. Ground

control station can operate form ground, sea or air. It is a connection between machine

and an operator. The design of a GCS for UAV are to have a certain functional

requirements. Crucial functionalities are [5]: air vehicle control – a capability to

effectively control and fly the UAV during is mission, payload control – ability to

operate sensors from ground, mission planning – functionality that aids UAVs operator

in planning the mission providing required knowledge inputs concerning capabilities

and UAVs limitations, payload data analysis and dissemination – capability to

disseminate the data form payload to an eventual users, system/air vehicle diagnostics –

automatic test facility for UAV and GCS effective maintenance and deployment,

operator training – facility to train he air vehicle controller in handling the aircraft,

practicing mission plans and emergency procedures, post-flight analysis – capability to

store flight data and payload data and to analyses it after the flight.

NM is most critical module on board UAV. Navigation module repeatedly

provide the aircraft’s position, velocity and altitude to FCM. Navigation module

feeding FCM with a crucial data to guide unmanned platform. NM is equipped with

navigation systems (NS) to fix a platforms position (usually uses GNSS) and orientation

system (OS) with motion sensors (accelerometers) and rotation sensors (gyroscopes) to

continuously calculate orientation and velocity (direction and speed of movement) of a

platform (inertial measurement unit – IMU). Where NM (NS+OS) and FCM are

integrated in one module can be called autopilots.

FCM is defined as a devices commanding a flight, means leading UAV to

designated position and putting on the right orientation and speed. FCM consists of two

main parts: data analysis – this part is receiving commands from system operator and

current flight parameters form NM, analyses I and prepare commands for an executive

part in order to correct flight parameters. Second part is an executive part with

mechanical servos, engine electronic speed controller, designed to move all control

surfaces and regulate speed of engines.

DAM includes optical remote sensing instruments. Depends on characters of

desirable data the data acquisition module can be equipped with different type of sensor

including airborne image acquisition systems (from visible band to the near infrared

(NIR) up to the thermal infrared (TIR)), microwaves systems, active and passive

ranging instruments.

METHODOLOGY

In order to select the most suitable platform for a photogrammetry task platform

a parameters matrix was developed (Tab. 2). According to the classification (Tab.1)

a specified parameters have been assigned with an appropriate weight. The weights

range is 1 to 5. The weights for each type of platform have been developed on the basis

of own experience and research results [4] [6]. The parameter values varies from 0 to 2,

with 0 being the lowest characteristics (ability) platform in the specified parameter,

while the 2 highest. The result for the type of platform, was calculated from the

expression:

N

n

nn pwR1

. (1)

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Tab. 2 Evaluation of UAV platforms employed for photogrammetry applications.

Parameter (pn)

Platform type

Pay

load

Win

d resistan

ce

Min

imu

m sp

eed

Fly

ing

auto

no

my

Po

rtability

Lan

din

g

distan

ce

Ran

ge

En

du

rance

Man

euv

erability

Stab

ility

Resu

lt (R)

Parameter weight (wn) 3 2 4 5 3 2 3 3 2 4

Un

po

wered

Balloon 2 0 2 0 2 2 0 2 0 1 34 Hang glider 1 2 2 0 2 2 1 0 0 1 32

Gliders 1 1 1 1 2 1 1 1 1 2 38 Rotor-kite 1 1 1 1 2 1 1 1 1 1 34

Kite 1 1 1 1 2 1 1 1 1 2 38 Paraglider 1 1 1 1 2 1 1 1 1 1 34

Po

wered

Airship 2 1 2 2 2 2 2 2 0 1 52 Motor glider 2 2 1 2 2 1 2 2 1 2 54

Aircraft 2 2 1 2 2 1 1 1 1 1 44 Jet 2 2 0 2 2 0 0 1 1 0 31

Single rotors 2 1 2 2 2 2 1 1 2 1 50 Coaxial 2 1 2 2 2 2 1 1 2 1 50

Quadrotors 2 1 2 2 2 2 1 0 2 1 47 Multi-rotors 2 1 2 2 2 2 1 0 2 1 47

Hang Moto Glider 2 1 1 2 2 1 2 2 1 1 48 Moto Paraglider 2 1 1 2 2 1 2 2 1 1 48

As a results present, the most suitable platform for a photogrammetry task, with

specified parameters, is motor glider with result 54 points. According to a "FAI

Sporting Code" moto-glider is a fixed-wing aerodyne equipped with a means of

propulsion (MoP), capable of sustained soaring flight without thrust from the means of

propulsion. Motor gliders are equipped with a propeller, which may be fixed, feathering,

or retractable. Motor with fixed or full feathering propellers can take off and cruise like

an airplane or soar with power off, like a glider. Self-launching retractable propeller

motor gliders have sufficient thrust and initial climb rate to take off without assistance,

or they may be launched as with a conventional glider.

The glider (sailplane) is characterized by a high aerodynamic efficiency, much

higher than in other platform types. Currently the technology of building the gliders is

based on composite materials (carbon and glass fibers) formed in CNC milled molds.

That technology enables engineers to produce the wings and fuselages with a very high

precision accurately determined by numerical models, resulting in a lightweight yet

extremely rugged structure. The composite material forms complex shapes at relatively

low cost, and can exhibit incredible strength and stiffness.

The propulsion system in motor glider type UAV platforms consists of brushless

electric motor with electronic speed controller (ESC) powered by a Lithium-polymer

batteries. That configuration is the most efficient for UAV and can be assembled

completely of low-cost commercial-off-the-shelf products.

DATA ACQUISITION MODULE

Data acquisition module integrates in one physical element all sensing

instruments and auxiliary elements. As for the sensing elements for photogrammetry


tasks we concentrated only on commercial visible light, spectral and thermal cameras

with weight less than 1500 g, basing on [8] (Tab. 3). An auxiliary elements are mainly

active or passive stabilization system, additional data storage, and optionally recovery

system.

In case of chosen platform type (motor glider) DAM components should closed in

be housing or placed within fuselage, in order to diminish an aerodynamic drag. In that

particular platform aerodynamic drag forces can negatively influence on gliders overall

performance. On the other hand, that problem is minimalized on different platform type

typical vertical takeoff and landing (VTOL) like single of multirotor copters.

Tab. 3 Commercial cameras

Company, model Resolution [px] Size [mm] Pixel size

[m] Spectral range

Frame rate (fps)

Weigh [g]

Remarks

Visible light cameras

Phase One IXU 180 10328 x 7760 53.7 x 40.4 5.2 visible 0.37 930 FMC -TDI

Trimble Aerial Camera

IQ180

10328 x 7760 53.7 x 40.4 5.2 visible N/D 1500 True FMC

Hasselblad A5D-60

8956 × 6708 53.7 × 40.2 6.0 visible 0.42 1360

Phantom Miro Airborne HD

1920 x 1080 N/D 5.5 visible 335 1140

Sony Nex-7 6000x4000 23.5 x 15.6 3.92 visible 10 550

GoPro Hero 4 Black 4000x3000 N/D N/D visible 2 89

Spectral cameras

Tetracam's Ultra-light 90 Gram

2048 x 1536 6.55 x 4.92 3.2 520 – 920 nm 0.5 -7.5 90

Tetracam's ADC Lite 2048 x 1536 6.55 x 4.92 3.2 520 - 920nm 0.5 -7.5 200

Quest Innovations

Condor-3 C3-VNN-692-UAV-SD

1280x720x3 5.19 x 2.92 4.06 400-1000 nm

(3 bands) 5 350

Quest Innovations

Condor-5 C5-UAV-sCMOS

1360x1024x3 8.77x6.60 6.45 400-1000 nm

(5 bands) 5/30 1450

Thermal cameras

Flir Quark 2 640 640x512 10.8x8.7 17 7.5-13 m 25 18.3 LWIR VOx

Flir Tau 2 640 640x512 10.8x8.7 17 7.5-13 m 25 72 LWIR VOx

Flir Neutrino 640x512 9.6x7.6 15 3.4-5.1 m 25 450 MWIR InSB

Flir TAU 15xRH 640x512 9.6x7.6 15 0.6-1.7 m 25 101 SWIR InGaAs

Flir Lepton 80x60 1.36x1.02 17 8-14 m 8.6 0.55 LWIR

NAVIGATION AND ORIENTATION MODULE

Form the photogrammetric point of view NM and OS are responsible for camera

extrinsic parameters determination. Geodetic-grade light-weight GNSS modules are

available on the commercial market (Tab. 4) with weight less than 100 g. Unfortunately,

light-weight geodetic-grade IMUs are not yet available [3]. A light-weight IMU

modules are based on MEMS (microelectromechanical systems) technology, therefore

are not able to provide very accurate data, in compare to a heavy weight FOG IMU

system (Fiber Optic Gyro). Commercial IMU for navigation purposes, with weight less

than 250 g are presented in Tab. 5. Tables 6 and 7 presents an integrated modules -

autopilots and hybrid navigation units (HNU) with weight less than 250 g.

Section Name

Tab. 4 Commercial satellite navigation modules

Company, model GNSS Wight

[g] L1 [m]

L1/L2

[m]

SBAS

[m]

DGPS

[m]

RTK

[m]

Terrastar-C

[m]

Veripos Apex

[m]

Novatel,

OEM 615

GPS L1/L2/L2C + GLONASS L1/L2

+ SBAS 24 1.5 1.2 0.6 0.4 0.01 N/D N/D

Novatel, OEM628


+ BeiDou + SBAS + L-Band 37 1.5 1.2 0.6 0.4 0.01 0.04 0.06

Novatel, OEM 625S


+ SBAS 56 1.5 1.2 0.6 0.4 0.01 N/D N/D

Novatel,

OEM638

GPS L1/L2/L2C + GLONASS L1/L2 + BeiDou + SBAS + L-Band 84 1.5 1.2 0.6 0.4 0.01 0.04 0.06

Cloud Cap

Technology,

DGPS FlightPak

Based on module

Novatel OEM 615 85 1.5 1.2 0.6 0.4 0.01 N/D N/D

Tab. 5 Commercial inertial navigation modules

Company, model Weight

[g]

BIAS

[deg/h]

Data Rate

[Hz]

RMS

[deg]

Roll Pitch Heading

Novatel. OEM-STIM300

55 0.5 125 0.015 0.015 0.080

Novatel.

OEM-HG1930 200 1 100 0.060 0.060 0.100

Novatel. OEM-ADIS-16488

48 5 500 0.035 0.035 0.150

AIMS.

uMotion 90 0.3 30 0.4 0.4 0.4

AIMS.

Motion 190 0.2 30 0.4 0.4 0.4

Tab. 6 Commercial Hybrid Navigation Units

Company, model GNSS

Weig

ht [g]

BIAS

[deg/h]

Data

Rate [Hz]

L1

[m]

L1/L2

[m]

SBAS

[m]

DGPS

[m]

RTK

[m]

Terrastar-C

[m]

Veripos Apex

[m]

Gladiator

Technologies,

LandMark 40 INS/GPS

GPS. GLONASS. BeiDou.

QZSS & SBAS (Galileo).

SBAS: WAAS. EGNOS. MSAS

160 6 100 2 N/D 2 N/D N/D N/D N/D

Imar Navigaion,

iuIMU-01 GPS/WAAS/EGNOS/MSAS 50 1 1000 1.5 2.5 N/D N/D N/D N/D N/D

Advanced navigation,

Spatial

GPS L1. GLONASS L1.

GALILEO E1. BeiDou B1 37 3 1000 2.0 N/D 1.0 0.6 N/D N/D N/D

Tab. 7 Commercial autopilots (Y- Available, N- no available)

Company, model Weight

[g] Gyro Accelerometer Magnetometer GPS DGPS RTK Radio Control Ground Station

Cloud Cap Technology,

Piccolo Nano 29 N N N Y Y N Y N

MicroPilot,

MP2128 24 Y Y N Y Y Y Y Y

ACS Sp. Z o.o., FCS-2

50 Y Y N Y N N N Y

PitLab Piotr Laskowski,

AutoPitLot bd Y Y Y Y N N N N

AirWare, Flight Core

74 Y Y N Y N N N N

ArduPilot,

3DR Pixhawk 38 Y Y Y Y N N N Y


CONCLUSION

As the results shows the moto glider is the most suitable platform for

a photogrammetry tasks. A crucial modules for navigation and data acquisition are

commercially available on the market with weight suitable for small UAV like moto

glider. Still, light-weight with geodetic-grade IMU modules are unavailable, however

in connection with sensor fusion or other navigation methods [1], a camera extrinsic

parameters can be determined with affordable accuracy.

REFERENCES

[1] Burdziakowski P., Przyborski, M, A. Janowski, Szulwic J., A vision-based

unmanned aerial vehicle navigation method., IRMAST 2015, 2015.

[2] Colomina, I., & de la Tecnologia, P. M., Towards A New Paradigm for High-

Resolution Low-Cost Photogrammetry and Remote Sensing. In The International

Archives of the Photogrammetry, Remote Sensing and Spatial Information Sciences,

ISPRS Congress, Beijing, China, XXXVII, 2008, Part B (Vol. 1, pp. 1201-1206).

[3] Colomina, I., & Molina, P., Unmanned aerial systems for photogrammetry and

remote sensing: A review. ISPRS Journal of Photogrammetry and Remote Sensing,

92, 2014, 79-97.

[4] Eisenbeiß, H., UAV photogrammetry. Zurich, Switzerland: ETH, 2009.

[5] Natarajan, G., Ground control stations for unmanned air vehicles (Review

Paper). Defence Science Journal 51.3, 2002, pp. 229-237.

[6] Nex, F., Remondino, F., UAV for 3D mapping applications: a review. Applied

Geomatics, 6(1), 2014, pp. 1-15.

[7] Luhmann, T., Robson, S., Kyle, S., & Harley, I., Close range photogrammetry:

Principles, methods and applications. Whittles, 2006, pp. 1-510

[8] RPAS YEARBOOK 2013, 13 edition

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