Hudson
Research Inc has recently entered the field of Artificial Intelligence (AI) and Unmanned
Autonomous Vehicles (UAV) as a result of requirements associated with our Space Shuttle Program
(G-301). The Get-Away-Special (GAS) program imposes many unique requirements on the system
controller. In this program, astronaut involvement is minimal, primarily limited to
turning the instrument on at some random point shortly after launch and arrival in orbit
and turning the instrument off towards the end of the mission. The G-301 Hyperspectral Imaging
Spectroscope (HIS) experiment is one of the most complex experiments to be
carried under this program. The experiment utilizes an advanced uncooled Infra-red
hyperspectral imaging sensor controlled by an artificial intelligence program with an
embedded Global Positioning System (SatNav; GPS) capability. The mission specifications
call for the instrument to have continuous awareness of its geographic position in order
to determine when to turn the imaging system on to acquire images. The host must be able
to store a large number of potential targets and camera setup information associated with
them and be able to compare its position to the target database. Once it has been
determined that a target is in acquisition range, the host then transmits instrument setup
data specific to that target to the camera controller.
The situation is complicated by two issues:
(1) Shuttle orientation relative to Earth
(2) Cloud cover over the target
This problem has been resolved by use of an artificial intelligence program
developed in-house specifically for this application. In order for acquisition to occur,
three positive votes must be cast in the AI sub-routine. They are position and two factors
derived from scene content.
Target Determination (TD) Program: This is the highest
level program. It receives data from several sources and based on a set of rules
determines whether the image acquisition sequence should be activated and what the
specific camera settings should be. The TD program receives data from the Navigation
program (NAV) and compares it to a list contained in the Target database. Each target is
listed as a set of geographic coordinates. When a current value from the NAV program falls
within the values of a predetermined target region, then a positive vote is cast in the
Polling sub-routine. This causes the frame grabber to acquire a frame from the imager.
This frame is then analyzed in the Polling sub-routine described below.
Polling Sub-Routine: The thermal content of the frame is
examined for determination of the percentage of deep space visible to the imager.
Determination is made on the basis of the average temperature of the scene. The average
temperature of a deep space image is almost always negative whereas the average
temperature of an earth view falls within a narrow band of positive values. If the average
temperature falls within this range, a second positive vote is cast to the DM subroutine.
A second analysis is performed on the data to determine if there are clouds in
the field of view. This analysis is a combination of water vapor content in the image
field in proportion to the percentage of whiteness. If the cloud analysis is acceptable
then a third positive vote is cast to the DM routine. The accumulation of three positive
votes causes the activation of a targeting sub-routine. The selected target profile is
read from the target database and those values are fed to the camera interface. The camera
is activated for a pre-determined period and scan configuration, and time, cloud cover
data, position data from the GPS are recorded in the interframe intervals onto the hard
disks.
Navigation (NAV) Program: The navigation program receives
periodic position and time data from the GPS receiver. It uses this data combined with a
priori knowledge of the predicted orbital track to calculate a continuously updated
position. The predicted values are used to extend the position in the absence of GPS
signals. This is an important aspect since the GPS satellites will not be continuously
visible to the antenna. It provides output to the Target Determination Program. When GPS
data is available the fix is updated.
Target & Rules Database: The Target Database contains
a listing of the exact geographical coordinates of each a target, the acceptable position
guard band, and camera set-up information. The Rules Database is realized as a set of
batch files. It contains a listing of all the decision making rules.
Figure 1 G-301 Artificial Intelligence Architecture
The interrelationship of the hardware and software components of this system
are shown in Figure 1 . For further information or if you have an application you would
like to have us analyze and develop, CONTACT US
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