Compatibility of impulse modulation techniques with attitude sensor noise and spacecraft maneuvering

Three impulse modulation techniques, each of which provides precision control of spacecraft attitude together with excellent fuel economy during limit cycle operation, are evaluated comparatively in terms of compatibility with sensor noise and with maneuver (plus damping) requirements. Analog computation is used to efficiently simulate sensor noise and controller nonlinearities. Typical response plots demonstrate performance variations (attitude accuracy, rates, fuel economy, jet duty cycle, etc.) as functions of switching hysteresis, sensor noise spectrum, filter parameters and controller parameters. Based on analog results and theoretical correlation, design guides are evolved for selecting control system parameters and minimizing jet fuel usage in terms of mission performance requirements and sensor noise characteristics.