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The GNSS integer ambiguities: estimation and validation

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can be derived:<br />

<br />

<br />

<br />

L = {2h(x) T Q −1 (y − b) + h(x) 2 }fˆb|â (y|x)fâ(x)dxdy<br />

z∈Z n<br />

<br />

= {2h(q) T Q −1 (y − b) + h(q) 2 } <br />

fˆb|â (y|q + z)fâ(q + z)dqdy<br />

<br />

=<br />

S0<br />

S0<br />

{2h(q) T <br />

−1<br />

Q<br />

<br />

= {2h(q) T Q<br />

z∈Z n<br />

z∈Z n<br />

<br />

(y − b)fˆb|â (y|q + z)dy<br />

+ h(q) 2 } <br />

<br />

fˆb|â (y|q + z)dy}fâ(q + z)dq<br />

−1 <br />

z∈Z n<br />

z∈Z n<br />

(E{ ˆb|q + z} − b)fâ(q + z) + h(q)<br />

S0<br />

<br />

F (q)<br />

<br />

F (q)<br />

= {h(q) +<br />

G(q) − b2 F (q)<br />

− <br />

G(q) − b2 }G(q)dq<br />

S0<br />

F (q)<br />

L is minimized for h(q) = − G(q)<br />

periodic.<br />

2 <br />

z∈Z n<br />

fâ(q + z) }dq<br />

<br />

G(q)<br />

+ b, which is an admissible solution since F (q)<br />

G(q) is<br />

Note that ˆ T in (C.10) is the BIE unbiased estimator if fâ(x + a) is symmetric with<br />

respect to the origin.<br />

If the float estimators are normally distributed the BIE baseline estimator, ˜ b, follows<br />

from equation (C.10) as:<br />

˜ b = ˆ b + b −<br />

= ˆ b + b −<br />

<br />

E{ ˆb|â + z} exp{− 1<br />

2x − z2Qâ }<br />

<br />

z∈Zn exp{− 1<br />

2x − z2 Qâ }<br />

<br />

z∈Z n<br />

z∈Z n<br />

b + Qˆ bâ Q −1<br />

â (â − z) exp{− 1<br />

2 x − z2 Qâ }<br />

<br />

z∈Z n<br />

exp{− 1<br />

2 x − z2 Qâ }<br />

= ˆb − Qˆbâ Q −1<br />

â (â − ã) (C.11)<br />

where the BIE ambiguity estimator of equation (C.4) is used.<br />

Best <strong>integer</strong> equivariant unbiased baseline <strong>estimation</strong> 157

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