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The GNSS integer ambiguities: estimation and validation

The GNSS integer ambiguities: estimation and validation

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with the weight function<br />

wz(â) =<br />

1 exp{− 2â − z2Qâ }<br />

<br />

exp{− 1<br />

2â − z2 z ∈ Zn<br />

}, Qâ<br />

z∈Z n<br />

<strong>and</strong> conditional posterior<br />

1<br />

pb|a(b|a, y) = <br />

|Qˆb|â |(2π) p<br />

2<br />

(3.99)<br />

exp{− 1<br />

2 ˆ b(a) − b 2 Qˆ b|â } (3.100)<br />

<strong>The</strong> Bayes baseline estimate can now be determined with equations (3.93) <strong>and</strong> (3.98)<br />

as<br />

<br />

<br />

ˆbBayes =<br />

(â − zwz(â)) (3.101)<br />

bp(b|y)db = ˆ b − Qˆ bâ Q −1<br />

â<br />

z∈Z n<br />

So, with the Bayesian approach the <strong>ambiguities</strong> are not resolved as <strong>integer</strong>s. Instead a<br />

weighted sum over all possible <strong>ambiguities</strong> is used with proper weights derived from the<br />

likelihood function. A discussion on the corresponding confidence regions can be found<br />

in Gundlich <strong>and</strong> Koch (2002) <strong>and</strong> Gundlich (2002).<br />

66 Integer ambiguity resolution

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