Bernese GPS Software Version 5.0 - Bernese GNSS Software

8.3 Ambiguity Resolution Algorithms
Figure 8.9: Options for ambiguity resolution strategy QIF.
8.3.4.3 Implementation of the QIF Strategy
Let us denote by b1i, b1i1 , b1i2 the (real-valued) double difference L1 ambiguities. Similarly
by b2j, b2j1 and b2j2 the corresponding L2 ambiguities. Now, we check whether the pair
or the pair
b1i1
b1i , b2j
− b1i2 , b2j1 − b2j2 ,
which, as a matter of fact, is a pair of double-difference ambiguities again, meets the requirements
to be close to integers and may be accepted as the correct pair of integer ambiguities.
Let us explain the procedure in more detail. We compute the rms error for each L3 ambiguity
bias ˜b3 associated with a pair b1i,b2j or with a pair of differences b1i1 − b1i2 , b2j1 − b2j2 :
where
σ = σ0 ·
β2 1 Q11 + 2 β1 β2 Q12 + β2 2 Q22 , (8.26)
Q11 = Q(b1i,b1i) , Q12 = Q(b1i,b2j) , Q22 = Q(b2j,b2j) (8.27)
in the case of pair b1i,b2j (Q(...) is an element of the cofactor matrix) or
Q11 = Q(b1i1 ,b1i2 ) − 2 Q(b1i1 ,b1i2 ) + Q(b1i1 ,b1i2 )
Q12 = Q(b1i1 ,b2j1 ) − Q(b1i1 ,b2j2 ) − Q(b1i2 ,b2j1 ) + Q(b1i2 ,b2j2 ) (8.28)
Q22 = Q(b2j1 ,b2j1 ) − 2 Q(b2j1 ,b2j2 ) + Q(b2j2 ,b2j2 )
Bernese GPS Software Version 5.0 Page 179