Analysis of openloop conical scan pointing error and variance estimators
Abstract
General pointing error and variance estimators for an openloop conical scan (conscan) system are derived and analyzed. The conscan algorithm is modeled as a weighted leastsquares estimator whose inputs are samples of receiver carrier power and its associated measurement uncertainty. When the assumptions of constant measurement noise and zero pointing error estimation are applied, the variance equation is then strictly a function of the carrier power to uncertainty ratio and the operator selectable radius and period input to the algorithm. The performance equation is applied to a 34m mirrorbased beamwaveguide conscan system interfaced with the Block V Receiver Subsystem tracking a Kaband (32GHz) downlink. It is shown that for a carriertonoise power ratio greater than or equal to 30 dBHz, the conscan period for Kaband operation may be chosen well below the current DSN minimum of 32 sec. The analysis presented forms the basis of future conscan work in both research and development as well as for the upcoming DSN antenna controller upgrade for the new DSS24 34m beamwaveguide antenna.
 Publication:

The Telecommunications and Data Acquisition Report
 Pub Date:
 November 1993
 Bibcode:
 1993tdar.nasa...81A
 Keywords:

 Carrier To Noise Ratios;
 Conical Scanning;
 Deep Space Network;
 Downlinking;
 Error Analysis;
 Extremely High Frequencies;
 Variance (Statistics);
 Algorithms;
 Beam Waveguides;
 Pointing Control Systems;
 Position Errors;
 Radio Tracking;
 Waveguide Antennas;
 Communications and Radar