The sensor instrument must be positioned within the scene in order to capture data. In the case of a 2D framing array type of system, the instrument might be placed at a single, static location and the image acquired. For scanning systems, the instrument may rely on the motion of the instrument through the scene to acquire some spatial dimension of the instrument. In the DIRSIG model, the instrument is always placed on a "platform" that can be positioned and oriented within the scene. This chapter focuses on the use of the platform model to position the imaging instrument either statically or as a function of time.
The position and orientation of the sensor is described in the POSITION section within the PLATFORM section of the DIRSIG Input Configuration File.
The platform modeling support in DIRSIG is very simple. The user can use one of six different methods to position and orient the platform. The first three are static positioning methods that allow the user to easily point the instrument at the scene using various descriptors:
Specify the platform location and target location to look at.
Specify the platform location and orientation angles.
Specify the target location, platform orientation angles and the range to the target.
The second three are dynamic position methods that allowed the user to move the platform and orient it as a function of time:
Specify the altitude, heading and speed of the platform.
Specify start and stop location of the platform.
Specify a file that contains a series of location and orientation angles.