Askania
Encyclopedia
Askania Cinetheodolite is a camera
-based system that measures and records azimuth, elevation
, and time data on 35mm film along with an image of a target. Multiple cinetheodolites generally operated together and each system is slewed in azimuth and elevation to track the target. The Askania systems typically operate at one frame per second and are synchronized by a central timing system to fire at the same instant. At the end of a tracking mission the rolls film from each site are photographically developed. Data are extracted from the film frames, and the data from each frame are processed to resolve the target's position in 3D.
Given the following:
The 3D position (latitude
, longitude
and elevation) of each theodolite
is known.
There are at least three cinetheodolites tracking the target.
The frames from each cinetheodolite can be time correlated using the time data on the film.
The target image is in each frame and the target's azimuth and elevation from each site can be obtained.
Then the data can be processed/computed to resolve the target's 3D position by triangulation
. An Askania cinetheodolite's data, allows position resolution that far exceeds the resolution of radar
. However, the radar provides position resolution in real-time. Whereas, Askania data must be post processed.
The Askania system is operated by a crew of two, one controlling azimuth and one controlling elevation. The operators manually crank hand wheels to slew the theodolite and track the target. Accurate tracking requires skill and coordination, since the target is typically a high-speed aircraft
that sometimes flies close to the site, requiring high slew rate
s. Askania systems have telescopic lenses that reduce the field of view and further challenge the crew.
Camera
A camera is a device that records and stores images. These images may be still photographs or moving images such as videos or movies. The term camera comes from the camera obscura , an early mechanism for projecting images...
-based system that measures and records azimuth, elevation
Elevation
The elevation of a geographic location is its height above a fixed reference point, most commonly a reference geoid, a mathematical model of the Earth's sea level as an equipotential gravitational surface ....
, and time data on 35mm film along with an image of a target. Multiple cinetheodolites generally operated together and each system is slewed in azimuth and elevation to track the target. The Askania systems typically operate at one frame per second and are synchronized by a central timing system to fire at the same instant. At the end of a tracking mission the rolls film from each site are photographically developed. Data are extracted from the film frames, and the data from each frame are processed to resolve the target's position in 3D.
Given the following:
The 3D position (latitude
Latitude
In geography, the latitude of a location on the Earth is the angular distance of that location south or north of the Equator. The latitude is an angle, and is usually measured in degrees . The equator has a latitude of 0°, the North pole has a latitude of 90° north , and the South pole has a...
, longitude
Longitude
Longitude is a geographic coordinate that specifies the east-west position of a point on the Earth's surface. It is an angular measurement, usually expressed in degrees, minutes and seconds, and denoted by the Greek letter lambda ....
and elevation) of each theodolite
Theodolite
A theodolite is a precision instrument for measuring angles in the horizontal and vertical planes. Theodolites are mainly used for surveying applications, and have been adapted for specialized purposes in fields like metrology and rocket launch technology...
is known.
There are at least three cinetheodolites tracking the target.
The frames from each cinetheodolite can be time correlated using the time data on the film.
The target image is in each frame and the target's azimuth and elevation from each site can be obtained.
Then the data can be processed/computed to resolve the target's 3D position by triangulation
Triangulation
In trigonometry and geometry, triangulation is the process of determining the location of a point by measuring angles to it from known points at either end of a fixed baseline, rather than measuring distances to the point directly...
. An Askania cinetheodolite's data, allows position resolution that far exceeds the resolution of radar
Radar
Radar is an object-detection system which uses radio waves to determine the range, altitude, direction, or speed of objects. It can be used to detect aircraft, ships, spacecraft, guided missiles, motor vehicles, weather formations, and terrain. The radar dish or antenna transmits pulses of radio...
. However, the radar provides position resolution in real-time. Whereas, Askania data must be post processed.
The Askania system is operated by a crew of two, one controlling azimuth and one controlling elevation. The operators manually crank hand wheels to slew the theodolite and track the target. Accurate tracking requires skill and coordination, since the target is typically a high-speed aircraft
Aircraft
An aircraft is a vehicle that is able to fly by gaining support from the air, or, in general, the atmosphere of a planet. An aircraft counters the force of gravity by using either static lift or by using the dynamic lift of an airfoil, or in a few cases the downward thrust from jet engines.Although...
that sometimes flies close to the site, requiring high slew rate
Slew rate
In electronics, the slew rate represents the maximum rate of change of a signal at any point in a circuit.Limitations in slew rate capability can give rise to non linear effects in electronic amplifiers...
s. Askania systems have telescopic lenses that reduce the field of view and further challenge the crew.