Tuesday, April 17, 2012

Remote Sensing at the Consumer End

The day has come when every university, mapping agency could collect their own remote sensing imagery.. No, I am not talking about purchasing high resolution imagery, I am talking about collecting such images using their own sensors! UAV RS has arrived.

Deciding which UAV system to use can be just as confusing as deciding which cell phone to buy. There are so many of them. Recently I complied a list of Unmanned Aerial Vehicle (UAV) platforms for civilian use suitable for remote sensing purposes and am presenting it here. Some of these systems are specifically designed for mapping while some other are more versatile capable of additional tasks. Below is the table listing a few UAV systems.

CryoWing Norway, oboard GPS, 3 axis gyros, RS payloads
From Norway. Fixed wing airplane, with on-board computer. GPS. Satellite uplink, cell phone tower uplink. Capable of several sensors including hyperspectral, LiDAR
Welcome page of the company 
DragonFly Pictures Inc.
Un-assisted take-off and landing. I assume the rest needs controller. Not much info on payloads.
Aeryon, Canada. Quadrocopter.
Vertical take-off and landing, aerial intelligence, real time streaming, fly beyond line of sight, pre-planned flight. Optical, video, thermal payloads.
Yamaha R Max.
Probably the closest to UAV RS. Helicopter, GPS, internal combustion engine instead of a motor, operator controlled,
Looks like it cannot be bought for use in the US.
Sensefly, Swiz. Specifically made for RS application. Fixed wing aircraft
Autonomous take-off and landing and flight with on-board IMU and GPS. Flight planning and live viewing software.  12MP optical camera. Server based software to prepare orthomosaics and DEMs.

The camera looks like a typical autofocus commercial camera. It does not have off the shelf capability for thermal or NIR or hyperspectral imaging. I am not sure of the payload capacity.

Microdrone, Germany.  4 winged helicopter
Helicopter, pilot operated. Designed for surveillance. Modular design allows different payloads.
Micro-hyperspec , Headwall Photonics
This is not a UAV, but a light weight hyperspectral sensor for aerial platforms.
VNIR, NIR capable. Imager comes with GNSS and storage.
Picture of the Sensor mounted on a UAV
Gatewing, Belgium
Autonomous flight, fixed wing aircraft, post processing software (client as well as cloud based) to create DEM, orthophotos, mosaics.
Company Homepage
U Penn, micro UAV
Micro UAV designed at UPenn Mechanical Department. No sensors. But a bigger UAV with MS Kinect is possible. These are totally autonomous. No human controller. Algorithms take care of flight.
(The above two are TED talks by the prof)
GRASP lab at UPenn is the link to the lab in UPenn

From my experience in aerial imaging, a commercial user would require the following characteristics in a UAV system
  • Platform stability - highly stable platforms are needed for acquiring clear images and maintaining the flight course. Of course, we would fly them only when the sky is calm.
  • Knowledge of platform attitude (roll, pitch and yaw) in addition to precise location of the UAV system
  • Knowledge of the direction (in solid angles) where the sensor is pointed, if it is capable of off-nadir viewing
  • Versatility with different payloads. I would like to do repeat flights with different sets of imagers attached.
  • Computing facility - the UAV system should have a flying computer capable of precisely actuating the imager, storing the data and perhaps transmitters to downlink the data live. The OS of the UAV should provide SDK to develop our own software for doing all of the above.
  • A super capable battery - this battery should power the aircraft, power the navigation system, imaging system, data storage system and also run its on-board computers. The battery should also be light weight.
These can be too much to ask for, and systems listed here many not provide them all. But it is becoming clear that innovation in this front is at break-neck speed. Its only the aviation policies of governments that is keeping these UAVs from wide spread use. However this is set to change soon as the industry matures and products become more reliable, and sufficient data is gathered about their safety, design standards etc.
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