Ranging accuracy is an important indicator to assess the performance of satellite autonomous integrity monitoring receivers in the threat environment. Analytical expressions of the relationship between the accuracy of code tracking loop and the parameters of International Civil Aviation Organization 2nd-order step threat model when employing coherent early-late processing in the satellite autonomous integrity monitoring receiver were presented. Theoretic analysis and simulation results show that the code phase estimator output curve will be biased under the digital failure model and the failure parameters will rarely impact the ranging variance. While the analog failure will distort the cross-correlation function and the code phase estimator output the curve, the curve is almost unbiased, and the ranging variance is affected by the analog failure parameters and receiver parameters such as front-end filter bandwidth and early late code space.