Ranking

The following parameters can be configured

Ranking: The process of optimization consists in selecting the subset of acquisitions among a larger set of candidates to compose a coverage fulfilling the target requirements. This selection begins with a ranking of candidates in a ranking list. The candidates are tested for suitability to be part of the optimized solution by scanning the ranking list starting from the first in the list. Ranking is done according to priority, and then by a second criteria. You may select the second ranking criteria as follows:

FIFO (First in First Out): Simple ranking according to start time. Earlier acquisitions are ranked first.
SPREAD: Ranking according to start time, but such that the list is spread in time as uniformly as possible in the optimization period selected. This is ranking is deterministic and repeatable.
RANDOM: Ranking is done randomly The purpose is to test numerous solutions to be fed in a MonteCarlo algorithm with the goal of optimize a given figure of merit. This ranking is non-deterministic, and repeatable or not depending on the setting of the Fix Seed parameter. With a fix seed the raking will be repeatable, which is useful for testing.
RANDOM_FIRST: The first item in the ranking list will be selected randomly, and the rest in FIFO sequence following the first item.
LOW_OVERLAP: Reduce the swath overlap in the final solution, with a strategy of privileging swaths with highest coverage, independently of their start time.

When selecting RANDOM or RANDOM_FIRST the user may access to advanced settings to configure the iterative loop:

Action: MINIMIZE or MAXIMIZE the selected Figure of Merit

Target figure of merit, used when iterating random solutions until the value is reached, or a time-out is generated. Select one of these:

Overlap: Overlap percent between swaths of the same coverage. The overlap is the ratio between area occupied by a collection of swaths and the sum of the areas of each swath individually.
Area: Area of the swaths of the same coverage, made up by adding the individual areas of each swath.
Frames: Number of frames, or scenes, contained in the solution swaths.
Latency: Average latency of the swaths in the solution. The latency is the time spanning between sensing and first downlink opportunity.
OZA: Average Observation Zenith Angle (OZA) of the swaths in the solution. The OZA, also known as incidence angle, is measured at the centre of the swath.
Time: Span time of the swaths in the solution, made up by adding the individual time span of each swath.
Data takes: Number of data takes (swaths) that compose the final solution.
Cloud Forecast: Cumulative cloud probability of the swaths in the solution, estimated from a FORECAST source for the period [now, now + 16 days]. Out of that period the source will always be STATISTIC.
Cloud Statistic: Cumulative cloud probability of the swaths in the solution, estimated from a monthly STATISTIC source.

Time out: defines the maximum iteration elapsed time. If the target figure of merit is not achieved before the time out, or if the use Aborts the process (Tools / Abort or ESC key) the iteration will be interrupted and the best solution produced so far will be recovered.

Fix seed: Selecting a fix seed for the randomiser allows to obtain repetitive results, useful for testing.