The state of the art in 1993. The first generation system used a mechanical gyro from the autopilot system of a DC-6. The aircraft is Keith Echelmeyer's PA-12 with the 160 hp engine.
The 2nd generation altimetry instrumentation: A survey range-finder and a fiber optic "gyro" from crossbow.
The mounting system: A rigid frame holds the two instruments, and second frame with shock mounts hangs from a cross brace over the PA-12's baggage area.
Keith Echelmeyer's PA-12, with 180 hp engine upgrade. Keith did all the tremendously challenging glacier flying for this project up until 2002 in this PA-12.
Keith's PA-12 was flown by Paul Claus in 2003, 2004. In 2005 we moved the instruments over to this Cessna 185. Paul's father bought this plane brand-new in 1976. It was getting some major work on it at this time, including a new engine and re-wiring.
Some major work....
We installed the instrument package in the aft baggage compartment, just behind this door.
This is where a hole was cut so the laser can shoot down.
Instruments installed in the baggage floor.
Another view
Another view. Although you can clearly see that this is a hard working bush plane, it is very well maintained.
To install the GPS antenna directly above the laser (along the optical axis), we leveled the aircraft by raising the tail. This placed the aircraft in "level flight". It was actually nice to not have the engine on the airframe, because at some point, the airplane can tip over! With the weight of the engine off, this was not an issue.
The system uses two GPS antennas. The large green one aft of the cabin is a L1/L2 antenna for the kinematic positioning of the aircraft. The small white antenna near the right hand wing root is for the real time navigation used to follow the flight paths.
Another view
Yet another view...
3rd Generation System: In 2006, we installed a complete new system with all new instruments. The complete system is miniaturized to fit on a single platform.
Another view of the new system. The laser is made by optech (red). To either side are two computers, one for data packet timing and concatenation and one for data storage and real time display.
Another view, this from behind. The gold cube in the center of the platform is a crossbow nav420 inertial navigation unit, which we have been very happy with. 0.2 deg accuracy, confirmed, in dynamic settings.
Complete system including the operator display and interface. The small LCD is a touch screen, and most of the commands needed while flying a profile do not need the keyboard. The black cable reaches up to where the system operator sits in the airplane.
Cessna 185 extended baggage compartment. The system mounts on the four vibration isolators, with the laser hanging over the square hole in the floor.
Belly of the Cessna 185 showing the laser port. There is a belly pod for extra fuel, which needed slight modification near the laser port. This belly pod also holds the survival gear, which keeps it away from the laser system as survival gear is usually keep in the extended baggage.
Looking up.
In May 2007, we installed the system in the Super Otter. This aircraft has a 1000 hp turboprop, and behaves like something in-between a helicopter and a big super cub. Paul is being a little goofy for Hombi. Ruedi Homberger photo.
Looks lonely back there...
The otters came with a photo hatch, for a REALLY BIG camera. Might be able to drop fifty-five gallon drums through there.
We mounted the antenna up here.
Close up of the antenna installation. The center of the antenna is marked with the small hole just aft of the cable.
GPS Antenna, just aft of the beacon.
Preflight planning and preparing navigation files. Ruedi Homberger photo.
Sandy in the instrument operator's seat. The system screen is on her lap, and the trimble 4000 ssi GPS receiver is in front of her.
Sandy keeping things organized. Ruedi Homberger photo.
System screen. The laser height is shown in feet, which is read aloud to the pilot while profiling. Ruedi Homberger photo.
Navigation screen. Ruedi Homberger photo.
Close up of the navigation screen, showing the moving map and the path along the glacier. Precise flying is need to keep the new flight path within a few meters of the previous flight paths. Ruedi Homberger photo.
Paul has a lot to pay attention to on these flights! Ruedi Homberger photo.
End of the mission, we take out the instruments. All smiles after a good data haul. Ruedi Homberger photo.