Estimating fluid related quantities of a first fluid compartment and a second fluid compartment disposed in or connected to a moveable platform. Measurements from the first fluid level sensor, the second fluid level sensor, the third fluid level sensor, the fourth fluid level sensor are combined into a unified calculation. The fluid related quantities are calculated from the unified calculation, the fluid related quantities comprising all of: (1) a fluid orientation estimate which is common to both the first fluid compartment and the second fluid compartment, (2) a first fluid height estimate for the first fluid compartment, and (3) a second fluid height estimate for the second fluid compartment, whereby (1), (2), and (3) form a set of results.