Module estimation 

Estimation module for orbit determination and state estimation.

Provides extensible estimation filters for processing measurements and determining spacecraft state. Supports multiple estimator types and user-defined measurement models.

Estimator Types

• Extended Kalman Filter (EKF): Sequential filter using linearized dynamics and measurement models. Leverages the propagator’s built-in STM for the prediction step.

• Unscented Kalman Filter (UKF): Sequential filter using sigma points to capture nonlinear behavior without linearization.

• Batch Least Squares (BLS): Accumulates all measurements and iteratively solves for the state correction. Supports weighted and constrained modes.

Measurement Models

Built-in models are organized by reference frame:

Inertial (ECI) frame — direct state observations:

• InertialPositionMeasurementModel: 3D inertial position (meters)
• InertialVelocityMeasurementModel: 3D inertial velocity (m/s)
• InertialStateMeasurementModel: 6D inertial state

GNSS (ECEF) frame — receiver outputs with ECI→ECEF conversion:

• EcefPositionMeasurementModel: 3D ECEF position (meters)
• EcefVelocityMeasurementModel: 3D ECEF velocity (m/s)
• EcefStateMeasurementModel: 6D ECEF state

Custom models can be defined by implementing the MeasurementModel trait in Rust or by subclassing MeasurementModel in Python.

Structs

BLSConfig

Configuration for Batch Least Squares.

BLSIterationRecord

Record of a single batch least squares iteration.

BLSObservationResidual

Per-observation residual from a batch least squares iteration.

BatchLeastSquares

Batch Least Squares estimator for orbit determination.

ConsiderParameterConfig

Configuration for consider parameters in batch estimation.

EKFConfig

Configuration for the Extended Kalman Filter.

EcefPositionMeasurementModel

GNSS position measurement model (ECEF frame).

EcefStateMeasurementModel

GNSS state measurement model (ECEF frame, position + velocity).

EcefVelocityMeasurementModel

GNSS velocity measurement model (ECEF frame).

ExtendedKalmanFilter

Extended Kalman Filter for sequential state estimation.

FilterRecord

Record of a single sequential filter update step.

InertialPositionMeasurementModel

Inertial position measurement model.

InertialStateMeasurementModel

Inertial state measurement model (position + velocity).

InertialVelocityMeasurementModel

Inertial velocity measurement model.

Observation

A single observation (measurement) at a specific epoch.

ProcessNoiseConfig

Process noise configuration for sequential filters.

UKFConfig

Configuration for the Unscented Kalman Filter.

UnscentedKalmanFilter

Unscented Kalman Filter for sequential state estimation.

Enums

BLSSolverMethod

Solver formulation for Batch Least Squares.

DynamicsSource

Dynamics source for estimation filters.

Traits

MeasurementModel

Trait for defining measurement models used in estimation.