Table 1 Estimable unknown parameters and their interpretations in the short-baseline RTK model

\(d\tilde{t}_{12}^{*} (i) = dt_{12}^{*} (i) + d_{12,1}^{*} (i)\)

Receiver clock with code delays on \(j = 1\)

\(\tilde{d}_{12,j}^{*} (i) = d_{12,j}^{*} (i) - d_{12,1}^{*} (i)\)

Receiver differential code biases (DCBs), where \(j \ge 2\)

\(\delta_{ 1 2}^{ *} (i) = \delta_{ 1 2 , 1}^{*} (i) - d_{12,1}^{*} (i) + \lambda_{ 1} z_{ 1 2 , 1}^{{1_{*} }}\)

Receiver differential phase and code bias of the first frequency

\(\tilde{\delta }_{ 1 2,j}^{ *} (i) = \delta_{ 1 2,j}^{ *} (i) - \delta_{ 1 2,1}^{ *} (i) + \lambda_{j} z_{ 1 2,j}^{{1_{ *} }} - \lambda_{ 1} z_{ 1 2, 1}^{{1_{ *} }}\)

Receiver differential phase biases (DPBs), where \(j \ge 2\)

\(\tilde{z}_{12,j}^{{1_{*} s_{*} }} =z_{12,j}^{{s_{*} }} - z_{12,j}^{{1_{*} }}\)

Double-differenced (DD) integer ambiguities