In an embodiment, a quantity smoother includes a first stage and a second stage. The first stage is operable to receive a sequence of raw samples of a quantity and to generate from the raw samples intermediate samples of the quantity, the intermediate samples having a reduced level of fluctuation relative to the sequence of raw samples. The second stage is coupled to the first stage and is operable to generate from the intermediate samples resulting samples of the quantity, the resulting samples having a reduced level of fluctuation relative to the sequence of intermediate samples. For example, such a quantity smoother may be part of a target-ranging system on board a fighter jet, and may smooth an error in an estimated target range so that the fighter pilot may more quickly and confidently determine in his head a range window within which the target lies.