iXA Case Study

GPS Aerial was founded in Ormond Beach, Florida by Kenny M. Creed and specialized in aerial data acquisition in the Caribbean, Central America, and Eastern United States. It was also a supplier of imagery to the U.S. Geological Survey for the National Aerial Photography Program (NAPP).

In 1995, Kenny decided to expand the operation to the Alaska market. By 2004, Kenny moved the entire operation to Alaska, fulfilling his dreams and at the same time, the state slogan, "Beyond your dreams, within your reach."

Phase One Phase One is based in Denmark with offices in New York, London, Cologne, Tokyo, Hong Kong, Shanghai, Sydney and Tel Aviv. The Phase One iXA 180 and iXA-R 180 are 80 MP medium format aerial cameras with innovative features such as large image sensors of 10,328 pixel cross track coverage, forward motion compensation, fast shooting speeds, wide selection of central shutter lenses, low weight and low power consumption, providing high performance efficiency and accurately geo-referenced images. The Phase One aerial cameras are creating new possibilities in photogrammetry, remote sensing and mapping applications.

GPS Aerial: Alaska — Beyond Your Dreams, Within Your Reach

Transition from Film to DigitalGPS Aerial keeps busy with large scale photogrammetric mapping projects, typically two foot contour interval mapping (GSD 6 cm). Many of their clients were using scans made from color film. One of their clients asked them to capture a large project with a digital camera. After they saw the results they only wanted digital imagery.

After doing their research on various digital medium format systems, GPS Aerial turned to SoftNav Systems, a Canadian-based company, which provides software and hardware solutions for remote sensing systems, advanced flight navigation software, GNSS, IMU integration and other custom aeronautical applications.

SoftNav systems are installed on almost any type of aircraft including UAVs, ultra-lights, single and multi engine aircraft and helicopters, often times using SOMAG AG Jena's mounts. SoftNav partners with Phase One and integrates the iXA, iXA-R and the iXU camera systems for all types of aerial mapping projects.

Choosing a Camera

GPS Aerial chose to switch to the Phase One iXA 180, which is built with an 80 MP sensor, because it is best able to replicate the typical scan resolutions of their clients using color film. Digital imagery, combined with IMU measurements, also enabled GPS Aerial to take advantage of the automation available in aerial triangulation.

The ability to change the ISO, aperture and shutter speed with a keystroke and shoot in overcast conditions, while maintaining good dynamic range of the imagery proved to be a great advantage in their more difficult operations in the Aleutian Islands. Weather days there can be limited to 1-3 days in an entire summer in some areas.

Switching to the iXA 180 also gave GPS Aerial a lot more than just compatibility with their clients' systems. The 150 kg reduction in weight was immediately noticeable in aircraft performance. The ability to easily exceed the exposure count of film rolls was a plus, and of course, the huge savings in film cost, processing, shipping, editing, and annotation were a big factor in keeping costs down, even as fuel costs increased over the last several years. The ability to map to the edges without fiducial interference was a plus.

Kenny said, "The lack of film costs allow us to shoot everything at 80 percent overlap, greatly increasing the possibility to edit clouds out of photos due to the alternative stereo model set. This is a great advantage when difficult weather conditions exist such as in Alaska.

"We find that the CSM 130 gyro stabilized mount controlled by SoftNav's FMS keeps the Phase One iXA camera in perfect line alignment, even in high winds, and gust conditions in the difficult terrain and wind effects of the Aleutian Islands."

Forward Motion Compensation

GPS Aerial needed a camera with forward motion compensation (FMC) to handle their missions. Kenny said, "We had to have an FMC camera to meet specifications for government jobs. They absolutely required an FMC camera. So when Phase One added FMC to the iXA camera, it made it one of very few choices. And, of course, you know, cost wise, there was no comparison to the competition."

The FMC option on the iXA offsets the forward motion of the aircraft, while the camera sensor captures the image. The system operator can plan flight missions with a smaller Ground Sample Distance (GSD) and at greater flight speeds compared to aerial cameras without FMC. Kenny added, "Because of our high operational flight speed, the Phase One iXA FMC is a necessary option for high quality imaging and reduces flight time, which translates to overall cost savings."

The SoftNav FMS updates the iXA camera's FMC settings during the flight with the actual aircraft ground speed and GSD parameters. The camera calculates if it needs to activate the FMC during image capture by using these parameters, which results in a motion blur free image.

Patrick H. Doyon, Product Manager of SoftNav Systems commented, "The iXA's specially designed secure lens holder fixes the lens to the camera body and locks the focus ring necessary for calibration stability. Each camera is submitted through our in-door metric calibration process to determine the Interior Orientation Parameters (IOP) of the iXA camera system. The high stability of the iXA insures it is a truly metric camera, perfect for use in very precise mapping projects.

iXA 180 Sample Images

Specs:Camera: iXA 180

Lens: 55 mm

Shutter speed: 1/250 s

Altitude: 975 m AGL

GSD: 9.5 cm

Specs:Camera: iXA 180

Lens: 55 mm

Shutter speed: 1/250 s

Altitude: 1700 m AGL

GSD: 16.7 cm

aerial.phaseone.com

Specs:Camera: iXA 180

Lens: 55 mm

Shutter speed: 1/320 s

Aperture: F/8.0

Altitude: 1000 m

GSD: 10 cm

iXA 180 Sample Image

aerial.phaseone.com