for various disturbances from 0 to 512 Hz. Simulation results demonstrate excellent performance relative to the pointing and pointing stability requirements, with LOS jitter for the isolated instrument platform of approximately 1 micro-rad. Attitude and attitude rate knowledge are provided directly to the instrument with an accuracy defined by the integrated rate error requirements. The data are used internally for motion compensation. The final piece of the INR performance is orbit knowledge, which GOES-R achieves with GPS navigation. Performance results are shown demonstrating compliance with the 50-75 m orbit position accuracy requirements. As presented in this paper, the GN&C performance supports the challenging mission objectives of GOES-R.Keywords Spacecraft attitude control · Spacecraft pointing · Spacecraft jitter · GPS at GEO GOES-R mission objectivesThe Geostationary Operational Environmental Satellite-R (GOES-R) is the first of a new generation U.S. geostationary weather satellites, and is scheduled for delivery in late 2015 with launch shortly thereafter. The program is managed collaboratively by the National Oceanic and Atmospheric Administration (NOAA) and the National Aeronautics and Space Administration (NASA). The GOES spacecraft have provided continuous Earth imagery and space weather data for nearly 40 years. The GOES-R series of spacecraft will provide continuity of service as delivered by the current generation of GOES satellites. As such, the mission includes hosting both Earth-observing and space weather instruments, as well as hosting a communication payload to deliver instrument data to the data processing Abstract The Geostationary Operational Environmental Satellite-R series (GOES-R) is the first of the next generation geostationary weather satellites. The series represents a dramatic increase in Earth observation capabilities, with 4 times the resolution, 5 times the observation rate, and 3 times the number of spectral bands. GOES-R also provides unprecedented availability, with less than 120 min per year of lost observation time. This paper presents the guidance navigation & control (GN&C) requirements necessary to realize the ambitious pointing, knowledge, and image navigation and registration (INR) objectives of GOES-R. Because the suite of instruments is sensitive to disturbances over a broad spectral range, a high-fidelity simulation of the vehicle has been created with modal content over 500 Hz to assess the pointing stability requirements. Simulation results are presented showing acceleration, shock response spectra, and line-of-sight (LOS) responses

We investigate the coronal imaging capabilities of the Solar UltraViolet Imager (SUVI) on the Geostationary Operational Environmental Satellite-R series spacecraft. Nominally Sun-pointed, SUVI provides solar images in six Extreme UltraViolet (EUV) wavelengths. On-orbit data indicated that SUVI had sufficient dynamic range and sensitivity to image the corona to the largest heights above the Sun to date while simultaneously imaging the Sun. We undertook a campaign to investigate the existence of the EUV signal well beyond the nominal Sun-centered imaging area of the solar EUV imagers. We off-pointed SUVI line-of-sight by almost one imaging area around the Sun. We present the details of the campaign conducted when the solar cycle is at near the minimum and some results that affirm the EUV presence to beyond three solar radii.

Time-varying spacecraft magnetic fields or stray fields are a problem for magnetometer systems. While constant fields can be removed with zero offset calibration, stray fields are difficult to distinguish from ambient field variations. Putting two magnetometers on a long boom and solving for both the ambient and stray fields can be a good idea, but this gradiometer solution is even more susceptible to noise than a single magnetometer. Unless the stray fields are larger than the magnetometer noise, simply averaging the two measurements is a more accurate approach. If averaging is used, it may be worthwhile to explicitly estimate and remove stray fields. Models and estimation algorithms are provided for solar array, arcjet and reaction wheel fields.

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The traditional approach to on-orbit gyro scale factor calibration has been to perform large angle rotations about each gyro axis. The maneuvers require the science instruments to be taken offline, reducing operational availability and require a significant amount of interaction from the ground. To increase operational availability and to reduce the burden on mission operators, a novel approach to gyro scale factor calibration was developed, modeled and successfully demonstrated on the Geostationary Operational Environmental Satellite (GOES-16) to estimate gyro scale factor errors to within 1500 parts per million (ppm) without taking the science instruments offline.