reference_file:       a_ex.nav
           refabs_output:        a_ex.ref
           output:               a_ex.sm
           filter_hwidth=        0.0208
           min_filter_fraction=  0.5
           max_gap_ratio=        0.05
           max_gap_distance=     50
           max_gap_time=         30            /* 0.5  minutes */
           ensemble_time=        120
           max_speed=            5.0
           min_speed=            1.0
           iterations=           5
           fix_to_dr_limit=      0.00050