Contributions of each of the simulated signals to range measurements of the altimeter for the time span of one orbit of the MPO, using topography case 1. Libration, pointing, and orbit determination errors contribute to the depicted range measurements mainly through their lateral effect, sampling the topography at a slightly different location. Only measurements with a range < 1050 km are shown. During the depicted time frame, the spacecraft altitude ranges from 1050 km down to 400 km and back to 1050 km. Random noise contains the range error and the Gaussian noise representing small-scale topography. Signals vary for each orbit and each random realization.