DOI: 10.22027/amdc2
title: Advanced Mock Data Challenge 1

description: The data set is the results of a pure dynamic orbit integration. Gravitational force and Non-gravitational force models were used for orbit integration. The characteristics for the gravitational force model are a static gravity field of degree and order between 75 and 95, an Ocean tide model (eot11a) up to degree and order 80, direct tides of the Moon and Sun using NASA Jet Propulsion Laboratory (JPL)DE405 ephemeris and solid Earth tides according to IERS 2010. For the non-gravitational force model characteristics are the atmospheric drag model and the solar radiation pressure model. The Advanced MDC 2 provides the following simulated instruments data: Simulated GPS positions and velocities are the output of the orbit integrator with added GPS error in ITRF. They can be considered as kinematic orbit. The orbit products contain 16 columns just similar to the official GRACE GNV1B products. The entries for each daily file are: GRACE time, satellite ID, coordinate frame, x, y, z, sigmax, sigmay, sigmaz, vx, vy, vz, sigmavx, sigmavy, sigmavz, quality flag. The standard deviations are formal errors for the orbit positions and the velocities. Simulated K-Band Ranging System (KBR) ranging data is derived from error free GPS positions and velocities with added KBR error. The ranging products contain 16 columns just similar to the official GRACE KBR1B products. The first four columns are: GRACE time, range, rangerate, rangeaccl.  Columns 5 through 8 shall not be used and contain zero values for different corrections. These columns are kept in the daily files to maintain the consistency with the official GRACE KBR1B format.  Columns 9 to 11 are antenna phase center range correction, antenna phase center range rate correction, antenna phase center range acceleration correction which should be added to the KBR range, range rate and range acceleration respectivly, just like using GRACE KBR1B ranging products. Columns 12 to 15 are the value 700 for K and Ka SNR; and the 16th column is the quality flag.  Simulated Laser Ranging Instrument (LRI) ranging data is derived from error free GPS positions and velocities with added LRI error. The LRI ranging products contain 17 columns. The first four columns are: GRACE time, range, rangerate, rangeaccl. Columns 5 through 7 shall not be used and contain zero values for different corrections. These columns are kept in the daily files to maintain the consistency with the official GRACE KBR1B format. Columns 8 to 10 are vertex point range correction, vertex point range rate correction, vertex point range acceleration correction which should be added to the LRI range, range rate and range acceleration respectivly, just like using GRACE KBR1B ranging products. Columns 11 to 12 are DWS pitch and yaw angles for GRACE A and columns 13 to 14 are DWS pitch and yaw angles for GRACE B. Columns 15 to 16 are the value 700 for LRI SNR; and the 17th column is the quality flag. Simulated star (SCA) quaternions, are derived from the simulated roll, pitch and yaw angles with added errors. The star camera products contain 9 columns just similar to the official GRACE SCA1B products. The entries for each daily file are: GRACE time, satellite ID, star camera ID, quatangle, quaticoeff, quaticoeff, sigmaquat, quality flag. The standard deviations are formal errors for the quaternions. Simulated linear accelerations (ACC) are calculated from the non-gravitational accelerations acting on the satellites. The error free simulated star camera quaternions were used to transform the linear accelerations from the ICRF to the satellite frame (SF). The angular accelerations are calculated from the simulated star camera quaternions. The accelerometer products contain 12 columns just similar to the official GRACE ACC1B products. The entries for each daily file are: GRACE time, satellite ID, linacclx, linaccly, linacclz, angacclx, angaccly, angacclz, sigmalinacclx, sigmalinaccly, sigmalinacclz, quality flag.  The standard deviations are formal errors for the linear accelerations.  All data provided in daily files with 5-second sampling rate.