Minimum Variance Unbiased Estimation - Study Guide | ECE 531, Study notes of Electrical and Electronics Engineering

Material Type: Notes; Class: Detection and Estimation Theory; Subject: Electrical and Computer Engr; University: University of Illinois - Chicago; Term: Spring 2011;

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2011/2012

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Estimation: chapter 2+3
Minimum variance unbiased estimation + the CRLB
Natasha Devroye
http://www.ece.uic.edu/~devroye
Spring 2011
Find a few estimators
Estimation: a first example
Estimate the DC level, A, of a signal given noisy measurements x[0], x[1], ... x
[N-1] where
x[n] are samples of this!
Compare their performance { mean?
variance?
pdf?
pf3
pf4
pf5
pf8
pf9
pfa
pfd
pfe

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Estimation: chapter 2+

Minimum variance unbiased estimation + the CRLB

Natasha Devroye

[email protected]

http://www.ece.uic.edu/~devroye

Spring 2011

  • Find a few estimators

Estimation: a first example

  • Estimate the DC level, A, of a signal given noisy measurements x[0], x[1], ... x

[N-1] where

x[n] are samples of this!

  • Compare their performance
  • mean?
  • variance?
  • pdf?

Estimation: a first example

  • Estimators of the DC level, A

Estimation: definitions

Minimum variance unbiased estimation

Give a counter-example! (b1pg.20)

The Cramer-Rao Lower Bound

  • the CRLB give a lower bound on the variance of ANY UNBIASED estimator
  • does NOT guarantee bound can be obtained
  • IF find an estimator whose variance = CRLB then it’s MVUE
  • otherwise can use Ch.5 tools (Rao-Blackwell-Lehmann-Scheffe Theorem and

Neyman-Fisher Factorization Theorem) to construct a better estimator from

any unbiased one - possibly the MVUE if conditions are met

The Cramer-Rao Lower Bound (CRLB)

  • Use?
  • Intuition?

The Cramer-Rao Lower Bound (CRLB)

CRLB T or F

What is I(θ)?

  • Why “information”?
    • non-negative
    • additive for independent observations

Vector form of the CRLB

Vector form of the CRLB

Vector CRLB for transformations

Example of vector CRLB with transformation

CRLB for General Gaussian Case

  • When observations are Gaussian and one knows the dependence of the

mean and covariance matrix on the unknown parameters, we know the

closed form of the CRLB (or Fisher information matrix):

CRLB for Gaussians examples

Example: range estimation

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