Abstract: A method, apparatus for reducing errors in a plurality of beacon beams is disclosed. The method comprises the steps of computing quantized channel weights {tilde over (W)}c from channel weights Wc for at least some of the channels; estimating the quantization error ?Ba for each of the beacon beams from a difference between the channel weights Wc and the computed quantized channel weights {tilde over (W)}c; and adding the estimated quantization error ?Ba to the beacon beams. Similarly, a beacon biases equivalent to the beacon asymmetry error can be computed by the ground beacon beam forming software and uploaded to the on-board software for error compensation. The apparatus comprises one or more means, such as a processor communicatively coupled to a memory storing instructions for performing these operations.

Abstract: A method and apparatus for correcting a beam error is disclosed. One embodiment of the method comprises the steps of selecting beamweight coefficients based on the satellite orbital data, evaluating an effect of quantization of the beamweight coefficients on the beam error, and selecting beamweight coefficients based at least in part upon the evaluation of the effect of beamweight coefficient quantization on beam error. One embodiment of the apparatus comprises a beamweight correction module for selecting beamweight coefficients based on satellite orbital data, for evaluating the effect of quantization of the beamweight coefficients on beam error, and for selecting beamweight coefficients based at least in part upon the evaluation of the effect of beamweight coefficient quantization on beam error. The beamweight correction module comprises a beamweight generator and a beamweight quantizer for quantizing beamweights from the beamweight generator.

Abstract: A method of correcting for beacon pointing errors is disclosed. A desired beacon value and a predicted measured beacon value are computed and used to generate the beacon correction. An antenna pattern calculator can be used to compute the predicted measured beacon value, and a beacon correction value generator can be used to compute the desired beacon value and to generate the beacon correction.

Abstract: A method and apparatus for estimating spacecraft momentum is disclosed. The method comprises the steps of generating a plurality of spacecraft momentum measurements, fitting the plurality of spacecraft momentum measurements to a parametric model of a spacecraft momentum profile having a time period of tp, determining the momentum of the spacecraft from the parametric model; and generating an estimate of the momentum to be removed from the spacecraft at least in part from the determined momentum of the spacecraft.

Abstract: A method, apparatus for reducing errors in a plurality of beacon beams is disclosed. The method comprises the steps of computing quantized channel weights {tilde over (W)}c from channel weights Wc for at least some of the channels; estimating the quantization error &Dgr;Ba for each of the beacon beams from a difference between the channel weights Wc and the computed quantized channel weights {tilde over (W)}c; and adding the estimated quantization error &Dgr;Ba to the beacon beams. Similarly, a beacon biases equivalent to the beacon asymmetry error can be computed by the ground beacon beam forming software and uploaded to the on-board software for error compensation. The apparatus comprises one or more means, such as a processor communicatively coupled to a memory storing instructions for performing these operations.

Abstract: A method, apparatus for reducing errors in a plurality of beacon beams is disclosed. The method comprises the steps of computing quantized channel weights {tilde over (W)}c from channel weights Wc for at least some of the channels; estimating the quantization error &Dgr;Ba for each of the beacon beams from a difference between the channel weights Wc and the computed quantized channel weights {tilde over (W)}c; and adding the estimated quantization error &Dgr;Ba to the beacon beams. Similarly, a beacon biases equivalent to the beacon asymmetry error can be computed by the ground beacon beam forming software and uploaded to the on-board software for error compensation. The apparatus comprises one or more means, such as a processor communicatively coupled to a memory storing instructions for performing these operations.

Abstract: A method, apparatus for reducing errors in a plurality of beacon beams is disclosed. The method comprises the steps of computing quantized channel weights {tilde over (W)}c from channel weights Wc for at least some of the channels; estimating the quantization error &Dgr;Ba for each of the beacon beams from a difference between the channel weights Wc and the computed quantized channel weights {tilde over (W)}c; and adding the estimated quantization error &Dgr;Ba to the beacon beams. Similarly, a beacon biases equivalent to the beacon asymmetry error can be computed by the ground beacon beam forming software and uploaded to the on-board software for error compensation. The apparatus comprises one or more means, such as a processor communicatively coupled to a memory storing instructions for performing these operations.

Abstract: A spacecraft power/sun acquisition method includes a pitch search phase in which the spacecraft is rotated about a pitch axis, stopped, quaternions reset to remember position, and yaw search phase is entered when a first TOA occurs from a first slit sun sensor, and a keyhole slew is performed when the first TOA does not occur. The method also includes yaw search phase in which a keyhole slew is performed by rotating the spacecraft about a yaw axis, stopping the spacecraft, and entering pitch search phase when the first TOA does not occur, and in which the spacecraft is rotated about a yaw axis, stopped, quaternions reset, and sun hold phase is entered when a second TOA occurs from a second slit sun sensor. Lastly, the method includes a sun hold phase in which the spacecraft is oriented to the sun and placed in spin at power safe attitude.