# Covariance Matrix Utilities

Utility functions for constructing and validating covariance matrices from standard deviations, diagonal vectors, upper-triangular packed arrays, or full matrices.

These are used by measurement models, process noise configuration, and other estimation components.

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::: brahe.diagonal_covariance
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## See Also

- [Measurement Models](../estimation/measurement_models.md) - Built-in models using these utilities
- [Custom Models Guide](../../learn/estimation/custom_models.md) - Using covariance helpers in custom models
- [Mathematics Module](index.md) - Mathematics module overview