WSF_ORBIT_DETERMINATION_FILTER

filter WSF_ORBIT_DETERMINATION_FILTER

filter <name> WSF_ORBIT_DETERMINATION_FILTER
   ... Commands ...
end_filter

Overview

Implementation of an Unscented Kalman Filter (UKF) for orbital determination and tracking. Like the Kalman Filter, the WSF_ORBIT_DETERMINATION_FILTER accepts input locations (from range, bearing, elevation, or location measurements), and it produces an estimate of the tracked target’s location and velocity, as well as a state and covariance. Unlike the WSF_KALMAN_FILTER, the WSF_ORBIT_DETERMINATION_FILTER filter produces state and covariance estimates appropriate for orbital motion. It provides these estimates differently depending on whether the filter is stabilized (typically, after three measurements have been received). Before stabilization, the filter relies on either a linear extrapolation (used when explicitly added in a filter definition), or an explicit orbital propagation of the filtered state (used internally in Orbit Determination Fusion). Once the filter stabilizes, state and covariance predictions are computed through a nonlinear (unscented) transform using orbital propagators.

Note

This filter is used by the orbit determination track fusion method. Do not combine use of this filter in a track_manager definition with the orbit determination fusion method.

Commands

process_noise_sigmas_XYZ <X-value> <Y-value> <Z-value>

Defines the filter’s noise standard deviation for the three directions. The values correspond with accelerations in the entity coordinate system (ECS) of the tracked platform.

Default: 0 0 0

propagator <propagator-type> propagator-commands … end_propagator

Specifies the propagator type that will be used to track the target.

Default: The tracked target’s propagator type, if a truth target type is available from the track; otherwise, WSF_KEPLERIAN_PROPAGATOR.

Note

The initial state of the propagator will be provided using provided track updates; any provided initial state configuration (initial orbital elements or orbital state) of the propagator will be ignored.

range_measurement_sigma <length-value>

Defines the standard deviation that is applied to the measurement’s range prior to filtering.

Note

This input is usually not needed. It is only used if there is no range error on the associated track.

Default: 0 m

bearing_measurement_sigma <length-value>

Defines the standard deviation that is applied to the measurement’s bearing prior to filtering.

Note

his input is usually not needed. It is only used if there is no bearing error on the associated track.

Default: 0 deg

elevation_measurement_sigma <length-value>

Defines the standard deviation that is applied to the measurement’s elevation prior to filtering.

Note

This input is usually not needed. It is only used if there is no elevation error on the associated track.

Default: 0 deg

debug

When specified, writes filtered measurements data and filter performance data to the file KFILT_DEBUG.out.