Acquisition time frames

Find out how order parameters affect the time frames of your tasking order.


Overview

When ordering a tasking collection, you need to specify start and end dates for the acquisition. Different collections accept these dates differently — some allow for a shorter acquisition window, and some require a longer lead time.

The actual time frames for completing a tasking order are determined by a feasibility study. Some parameter values can lead to a longer acquisition time, while others can help speed up the process and lead to an order being completed earlier than expected.

Minimum time frames for acquisition

  • Earliest start date

    This value indicates the first day from today that a tasking acquisition can be scheduled. A value of 0 means you can select today.

  • Minimum interval

    Depending on the selected start date, this value represents the number of days required between the selected start and end dates, including the end date.

Affecting parameters

AOI

  • Width

    If the width of an area of interest (AOI) is greater than the swath width of the chosen collection, the sensor will need to do multiple passes over the area. The more passes the sensor has to do, the longer it takes to complete the order.

  • Shape and complexity

    A standard bounding box is considered a simple-shaped AOI, while a long corridor with many vertices is considered a complex shape. More complex polygons may take longer to capture. If the AOI is non-rectangular, it may take multiple rectangular assets to cover the shape, increasing the amount of time needed.

  • Orientation

    The orientation of the AOI compared to the sensor’s orbit can affect the time frames of an order acquisition. Most sensors are sun-synchronous, so a North-South oriented polygon will be covered by the swath of the satellite orbit, and will be captured faster than an East-West oriented polygon.

  • Latitude

    A sensor can quickly capture an AOI close to the poles because it will pass over this region more often. Meanwhile, an AOI close to the equator will require more attempts.

Cloud coverage

Whether a sensor can successfully capture an AOI in any given pass depends largely on the climate in the geographic area of the AOI at a certain time of interest. If there are a lot of clouds, the sensor will need to do another pass.

Cloud coverage is the percentage of clouds covering an AOI or a full scene, depending on how the data is delivered in a chosen collection. The optimal cloud coverage is 10%. For cloudy climates, it can be up to 30%. If the chosen cloud coverage is less than the optimal value, the sensor will need more passes to capture imagery with the required parameters.

Incidence angle

The smaller the incidence angle is, the more difficult it is to task a sensor. For example, a 30° incidence angle will require fewer attempts than a 20° incidence angle.

Acquisition mode

The mono acquisition mode is the easiest one to capture. Stereo and tri-stereo modes require a sensor to turn while operating. Considering the complexity of the operation, the attempt might not be successful, and the sensor will need to do another pass.