Minimal detectable biases of GPS data

In this contribution closed-form expressions are given for the minimal detectable biases of singleand dual-frequency pseudo-range and carrier-phase data. They are given for three di€erent single-baseline models. These are the geometry-free model and two variants of the geometry-based model, namely the roving and stationary variants. The baselines are considered to be suciently short such that orbital uncertainties in the ®xed orbits and residual ionospheric and tropospheric delays can be assumed absent. The stochastic model used is one that permits cross-correlation and the use of di€erent variances for individual GPS observables, including the possibility to weigh the observables in dependence on which satellite is tracked.