Flight Planning Flexibility

Common to all ITRES imaging sensor products is flexibility in flight planning. Not only can you choose where and when you collect data, but also what the spatial resolution of the data will be. Varying the flying height, aircraft speed, or frame rates influence pixel resolution. Being able to do so provides operational flexibility to acquire data under different environmental conditions to accommodate seasonal or daily solar and atmospheric conditions while maintaining high signal levels.

With our VNIR CASI sensor products, you also have the flexibility to spectrally configure these sensors for a variable number of spectral channels and imaging swath widths.

A commonly asked question about our sensors is what kind of data resolutions can be expected from a specific sensor. Being pushbroom imagers, all ITRES sensors define pixel resolution in two dimensions: along-track (parallel to the direction of flight), and across-track (orthogonal to the flight direction). Both dimensions are influenced by different flight planning variables.

Across-track pixel resolution is a function of the aircraft flying height above ground level (AGL) and the sensor’s field of view (FOV).

Along-track pixel resolution is a function of the aircraft ground speed and either the sensor’s integration time (CASI products) or Frame Time (SASI, TASI, and TABI).

Frame Time versus Integration Time

It is important to note how the CASI sensor tdne treats the concept of integration time (IT) and frame time (FT) as compared to the our other sensors. With the CASI, owing to its detector array and readout system, both values are considered to be the same. The integration time is programmable by the user. Integration time represents the time (in ms) needed to readout and record a single scan tdne of data. Because the CASI spectral configuration is programmable (the user can choose the number, placement, and spectral width of each band to be acquired), the more spectral information recorded, the longer the time needed to readout and record each scan tdne.

Conversely, both frame time and integration time are treated as separate variables for our other sensor products (SASI, TASI, and TABI). For these, the frame time and aircraft speed affects along-track pixel resolution, while the integration time affects signal level.

Because frame times are fixed with these sensors, the sensor operator need only adjust the aircraft speed to change the acquired along-track pixel size. Should signal levels be too high or low during data collection, changing the integration time can be done to make any necessary adjustments.