ABSTRACT

Using Unmanned Aircraft Systems (UAS) for photogrammetric 

aerial mapping provides surveyors and other geospatial 

professionals with a revolutionary tool for collecting data 

that was once reserved for large photogrammetry specialists. 

Trimble is creating the standard for Aerial Imaging Solutions by 

simplifying a once complex and time-consuming process. Aerial 

Imaging Solutions allow survey and geospatial professionals to 

collect large amounts of data (several square kilometers) in a 

short time (less than one hour) from a safe location for use in 

a variety of applications – rapid, safe, flexible.

WHITE PAPER

Dr P. Cosyn & R. Miller

Trimble Survey, Westminster, CO, USA 

Survey & Engineering Division, 10368 Westmoor Drive, Westminster, CO 80021-2712, USA

© 2013, Trimble Navigation Limited. All rights reserved. Trimble, the Globe & Triangle logo, Trimble Access are trademarks of Trimble Navigation Limited, registered in the United States Patent and 

Trademark Office and in other countries. All other trademarks are the property of their respective owners. Last updated May 2013. PN 022543-549 (09/12)

Trimble’s UX5 Aerial Imaging Solution is an ideal and innovative 

tool that can be utilized for survey, open-pit mine, oil & gas, 

landfill, and environmental applications such as; topographic 

surveys, site & route planning, progress monitoring, volume 

calculations, disaster analysis and as-builts, along with a wide 

variety of other applications.

TRIMBLE UX5 AERIAL IMAGING SOLUTION

A new standard in accuracy, robustness and performance 

for photogrammetric aerial mapping

WWW.TRIMBLE.COM/UAS
INTRODUCTION

Digital imaging is a rapidly expanding and highly valuable 

technology for geospatial professionals. Imagery is often 

used to visualize job site conditions, review survey & mapping 

observations, measure points & features, and create twodimensional & three-dimensional deliverables. In some cases, 

the imagery itself could be the desired deliverable. Imaging 

can be accomplished from both the terrestrial perspective 

as well as the aerial perspective. Both terrestrial panoramic 

and overhead point-of-views have advantages for given 

applications. The aerial perspective is optimal for documenting 

and measuring large horizontal sites, while the terrestrial 

perspective is ideal for documenting and measuring vertical 

structures such as buildings and bridges. Because many sites 

have a combination of both horizontal and vertical objects 

that need to be surveyed, there is a benefit to collecting both 

forms of imagery and merging them. 

Trimble prides itself on being a leader in innovation. By setting 

new industry standards to improve our users’ efficiencies and 

deliverables, we are proud to provide even more breadth and 

depth to our portfolio by offering the first and only complete 

Aerial Imaging Solution specifically designed for surveyors 

and geospatial professionals. The system is comprised of 

the Trimble UX5 Aerial Imaging Rover for collecting aerial 

photography; Trimble AccessTM Aerial Imaging application 

for mission planning, pre-flight checks and flight monitoring; 

and Trimble Business Center Photogrammetry module for 

processing aerial images and creating deliverables. This white 

paper discusses Trimble’s complete UAS photogrammetric 

mapping solution and simplified deliverable generation that 

make it the preferred solution for any demanding aerial 

surveying or mapping task.

IMAGE ACQUISITION METHODOLOGY

Being successful with aerial mapping is predicated on the 

planning of flights and the desired deliverables. The typical 

phases for image acquisition are:

f Mission planning: In the office (and in the field) users can 

define the mission area, add background maps, and define 

avoidance zones if required. The software estimates the total 

flight time needed to cover the mission area and allows the 

user to split the area into multiple flights when required 

because of the size of the area. 

f Flight planning: For each flight, the pilot identifies the wind 

direction, takeoff location, and the landing location, so that 

the duration of the flight can be re-calculated based on the 

field conditions at the time of the flight. The launcher is set 

up and the pre-flight checklist is completed to ensure that the 

system is ready for flight. 

f Flight operation: After launching the Trimble UX5 Aerial 

Imaging Rover, the flight is monitored using the ground 

control station. No manual interventions are required unless 

the user wants (or needs) to abort the flight. After the Trimble 

UX5 Aerial Imaging Rover lands, the post-flight checklist is 

completed to transfer the data to the computer.

f Analysis: This process allows for a completeness check of the 

data. It ensures that the user is confident that he heads home 

with data he can process to his deliverables.

FIGURE 2 Trimble AccessTM mission operation

FIGURE 1 Trimble AccessTM mission planning

DELIVERABLES

Orthophotos, contour maps, three-dimensional (3D) photos, 

point clouds, digital surface models (DSMs), and feature 

maps can easily be created from aerial imagery from Trimble 

Business Center. Trimble has created a new standard for 

processing UAS aerial imagery by incorporating more than 30 

years of experience in photogrammetry from Inpho, a Trimble 

software solution, into streamlined workflows in the recently 

released Trimble Business Center Photogrammetry module.

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FIGURE 4 Contour map produced with Trimble Business Center 

Photogrammetry module

FIGURE 6 Panorama image in Trimble Business Center, taken with the 

Trimble VX Spatial Station

FIGURE 5 3D image colored by elevation produced with Trimble 

Business Center Photogrammetry module

FIGURE 7 True-color point cloud in Trimble RealWorks, taken with the 

Trimble TX5 3D Laser Scanner

measurements can be taken from, but this type of data cannot 

be used to measure vertical structures such as buildings or 

bridges. By combining data collected with Trimble’s leading 

edge vision technology, such as the Trimble UX5 Aerial 

Imaging Rover, Trimble VX Spatial Station, and Trimble TX5 3D 

Laser Scanner, users can visualize their project from multiple 

perspectives, measure points within the images and create 3D 

models of the infrastructure and terrain.

FIGURE 3 Orthophoto produced with Trimble Business Center 

Photogrammetry module

IMAGE QUALITY & PERFORMANCE 

The quality of the deliverables is dependent on the quality 

of the photogrammetric equipment used. The innovative 

Trimble UX5 Aerial Imaging Rover has been designed to 

follow the latest developments in the ‘prosumer’ camera 

market, ensuring optimal image quality along with maximum 

photogrammetric accuracy. 

Trimble selected the Sony NEX-5R mirrorless camera because 

of its large APS-C (CMOS) sensor with 16.1 megapixel count. 

While the 1/1.7” sensor of the Ricoh GRD IV camera used in 

the Trimble Gatewing X100 was already 1.5 times larger than 

other compact cameras in the market, the surface area of the 

Sony NEX-5R sensor is nearly 9 times that of the Ricoh GRD 

IV. In addition to the significant increase in the pixel count, 

the size of each individual pixel with the Sony NEX-5R is more 

than 5x the Ricoh GRD IV pixels. This class-leading pixel size 

is important because it allows for a sharp increase in light 

In addition to producing these typical photogrammetric 

deliverables from Trimble Business Center, the aerial imagery 

data can be combined with Trimble VISION products such as 

the Trimble VISION total stations and Trimble 3D laser scanners 

for a one-of-a-kind solution in the market. Orthophotos are 

primarily used to create scaled images of a site that accurate 

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FIGURE 9 Sony NEX-5R camera and Voigtländer lens used in the 

Trimble UX5 Aerial Imaging Rover

sensitivity, dynamic range, and signal to noise ratio resulting 

in drastically reduced noise even at high ISO values. Combined 

with the much shorter ISO determination time of a system 

camera compared to a compact camera, it allows the user to 

use a fixed shutter speed and an automatically adjusted ISO 

ranging between 100 and 3200, yielding sharp, contrast rich 

images with a constant brightness, even in adverse and rapidly 

changing light conditions and shadow areas. This eliminates 

the need for users to judge brightness and manually set both 

the shutter speed and ISO to a fixed value throughout a flight. 

 From a photogrammetric perspective, the biggest advantage of 

the Trimble UX5 camera compared to using a compact camera 

in Aerial Imaging Rovers is the external lens. External lenses 

inherently offer a more stable internal geometry resulting in 

a more reliable camera calibration than that of a retractable 

lens. For the UX5, a light-weight 15 mm fixed focal length 

Voigtländer lens featuring mechanical focus and aperture ring, 

was chosen. To further increase the stability of the internal 

geometry, a custom adapter was designed by Trimble to replace 

the standard camera and lens mounts, which allow rotational 

movements of the principal point, by a two-part screw mount 

adapter. Additionally, the lens is fitted with a locking screw to 

fix the focus ring in the manufacturer-recommended position. 

This position is fixed using a collimator during production, 

ensuring not only sharp imagery across the flying height range 

(75 - 5000 m), but also a more stable focal length throughout 

all projects. The improved stability of the camera directly results 

in an increased accuracy of the deliverables, especially areas 

between the ground control points. 

Mounted in front of the APS-C sensor, the focal length 

expressed as 35mm-equivalent of the UX5 camera is 22.5mm, 

yielding a wide field of view. This means that, at a flying height 

of 150 m, the Trimble UX5 produces an image footprint of 235 

m by 157 m which is 40% larger than other UAS. Combining 

this field-of-view with the increased shutter speed, the Trimble 

UX5 has a larger overlap of the images than other systems, 

resulting in better accuracy of the DSM that is generated 

from the photos. The combination of these photogrammetric 

advancements means that the Trimble UX5 can cover 50-75% 

more area per flight hour than the X100 and most other UAS 

products at the same flying height. This translates to greatly 

enhanced work efficiency and reduced operational costs.

At a flying height of 150 m, the Trimble UX5 produces a GSD 

of 4.8 cm. In addition, the Trimble UX5 is capable of flying 

as low as 75 m above ground level (AGL) and producing a 

GSD of 2.4 cm. Flying at such a low height requires faster 

shutter speeds on the camera to prevent forward motion blur. 

The Sony NEX-5R camera used in the Trimble UX5 is capable 

of using the higher ISO values necessary to compensate the 

darkness resulting from the fast shutter speeds while keeping 

noise to acceptable levels for photogrammetric applications.

FIGURE 10 comparison X100 coverage and UX5 coverage

UX5 coverage

X100 coverage

WWW.TRIMBLE.COM/UAS 4
RELIABLE & RUGGED DESIGN

The new Trimble UX5 Aerial Imaging Rover builds on the 

standards set by its predecessor, the first commercial aerial 

imaging rover on the market, the Trimble Gatewing X100. 

Key features of the Trimble Gatewing X100 are also available 

in the Trimble UX5, such as all-weather flight capability, while 

surpassing its design of the airframe, making it a heavy-use, 

all-terrain device with the best accuracy and image quality 

available. 

FIGURE 11 UX5 top view

The Trimble UX5 Aerial Imaging Rover is based on a production 

method patented by Trimble. The base structure consists of a 

carbon frame inside expanded polypropylene foam. The frame 

ensures torsional stiffness and rigidity while the foam has 

exceptional pressure resistance and no memory-effect, which 

means that it will ‘bounce back’ to its original shape after 

impact. The exterior foam protects the internal electronics on 

impact and reduces the likeliness of any (physical) damage in 

case of an incident. 

The Trimble UX5 has a longer life expectancy than many other 

similar aircraft and is considered a wing suitable for heavy use. 

This new wing design produces a more rigid aircraft without 

compromising flight efficiency. Parts used in the motor 

assembly, the container for the flight electronics (also called 

‘eBox’) and servos are made of impact resistant plastics. The 

composite fiber parts of the elevons, the moving and fixed 

parts of the trailing edge of the wing, are light-weight and 

have an internal matrix structure that absorbs energy. The 

vertical winglets are made of a composite that allows bending 

in one direction to absorb energy during rough landings. 

Further, the Trimble UX5 belly plate is uniquely designed to 

absorb energy during landing as well as reduce abrasion from 

rough terrain such as rocks or tarmac.

FIGURE 12 UX5 bottom view

Due to its structural strength and additional energy absorption, 

maintaining the Trimble UX5 is easy. The Trimble UX5 offers 

operators a user-friendly design with replaceable parts such as 

vertical tails and propellers. The wing component is extremely 

durable and ideal for tough terrain. Some users will be able 

to work with just one airframe (or wing component) for 

years. This level of durability results in low yearly operation 

and maintenance costs of the Trimble UX5, which makes it a 

favorable system for the frequent (daily or weekly) use.

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ACCURATE LANDINGS

The Trimble UX5 starts its final landing phase at the a height 

above ground level (AGL) of 75 m only 200 m from the 

designated landing location. The touch down is, on average, 

within a 10 m (radius) circle of the designated location. Offsets 

that double this value are extremely rare. 

A traditional landing for an Aerial Imaging Rover has limitations 

that must be considered and addressed: the glide slope and 

landing speed. An efficient aircraft with good range and 

coverage has a disadvantage over an aircraft that consumes 

a lot of energy to stay aloft: the glide angle is rather small. A 

steeper approach would be means to reduce this offset but 

would result in a higher approach speed. 

75 m

ø 200 m

300 m

The Trimble UX5 has been engineered to overcome the 

limitations of a traditional landing with the addition of 

an advanced control method and improving the height 

measurement resulting in accurate and predictable landings. 

The advanced control method included in the Trimble UX5 is a 

thrust reversal on approach. During thrust reversal, the motor 

and propeller direction is reversed. This has the same effect as 

using a propeller with opposite pitch. By reversing the thrust, 

the propeller starts pulling air instead of pushing it. This gives 

the aircraft a means to counteract the speed increase that 

results with a steep descent. 

Thrust reversal (or also called ‘reversed thrust’) allows for an 

advanced control method that relies on changing the propeller 

from forward to reversed speed. This challenges aerodynamics, 

electronics and control algorithms. It challenges aerodynamics 

because applying a pulse of reversed thrust can result in stall 

effects of wing and elevons. It challenges electronics because 

FIGURE 13 Landing pattern UX5

having smooth control from forward to reverse is difficult for 

electronic speed controller (ESC). And it challenges control 

algorithms because it needs to cope with limits set by the 

aerodynamics and electronic speed controller and non-linear 

behavior because of asymmetry in the reversed and forward 

mode. A propeller that turns in reversed mode delivers thrust 

but also creates torque and aerodynamic effects that need to 

be monitored and controlled.

AUTOMATED CHECKS & IMPROVED WORKFLOWS 

The new Trimble Access Aerial Imaging application is a single 

software tool for planning Trimble missions, performing 

pre-flight checks and monitoring flights – all with intuitive 

workflows that ensure reliable results and safety of the 

individuals involved.

Trimble Access Aerial Imaging application offers mission 

planning that can be performed in the office or on the Ground 

Control Station (GCS). The project area and avoidance zones 

are drawn on top of an industry-standard map interface. The 

flight height above ground level (AGL), Ground Sample Distance 

(GSD) and photo overlap are defined and Trimble Access 

calculates the number of flights, flight pattern and duration 

of flight(s). The locations for takeoff and landing are proposed 

and then the project is taken to the field for the flight. 

FIGURE 14 Trimble AccessTM 

In the field, the operator is guided through the pre- and 

post-flight sequences with step-by-step digital checklists. 

Many of the Trimble UX5 checks are automatically verified 

by the software and sometimes run in the background (selfcheck routines) and do not require any interaction from the 

operator. This makes the setup process (before launch) and 

data recovery (after landing) easy and reliable. 

With these wizard-like digital checklists, it is impossible for the 

operator to forget or bypass a critical step, ensuring reliable 

and safe flights. The software also requires the operator to 

follow a fixed post-flight procedure for downloading the data 

and verifying the data. This safeguards that the user does not 

leave the field with a dataset that is incomplete or inconsistent. 

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Some examples of automated pre-flight checks are:

f battery connection and status

f ground control station connection and status

f aircraft parameter self-check (when arming the system)

f camera trigger check

f elevon response check

f sensor and gps checks

FIGURE 15 pre-flight check

CONCLUSION

The Trimble UX5 Aerial Imaging Solution sets a new standard 

in accuracy, robustness and performance for photogrammetric 

aerial mapping. The imaging performance of the Trimble 

UX5 Aerial Imaging Rover and the streamlined workflows of 

Trimble Business Center Photogrammetry application allow for 

the creation of professional deliverables with unprecedented 

accuracy and quality. Costs for data acquisition are drastically 

reduces when compared to collecting the same level of detail 

using traditional methods and technologies.

What was once reserved for large photogrammetry specialists 

is now available for a variety of geospatial applications. 

Trimble’s innovation in aerial photography can now be used 

to generate very detailed and useful deliverables by itself, 

however, by coupling UAS technology with other survey 

technologies such as GNSS, imaging total stations and 3D 

laser scanners, Trimble offers an unparalleled way to visualize 

and measure the world.

For more information visit trimble.com/uas