RF Beam Control
This chapter discusses the detection and control of the position of the radio frequency (RF) beam. The position of the beam is slightly different from the antenna position as measured by the encoders. This happens due to structural deformations caused either by loads (e.g., gravity, wind) or by the temperature gradient, atmospheric distortion, or azimuth track unevenness. We also discuss how the beam position is detected and controlled to minimize pointing error.
First, the RF controller to be used in the RF control is selected. Next, the monopulse detection and control technique are analyzed, showing its performance in its linear and nonlinear models. Finally, the scanning techniques, such as conical scan, Lissajous, rosette, and sliding window conical scan are discussed.
Selecting the RF Beam Controller
KeywordsRadio Frequency Power Variation Wind Gust Spacecraft Position Position Controller
- 1.Alvarez L. (1993). Analysis of Open-Loop Conical Scan Pointing Error and Variance Estimators. TDA Progress Report 42-115, Jet Propulsion Laboratory, Pasadena, CA. Available at http://ipnpr.jpl.nasa.gov/progress_report/42-115/115 g.pdf
- 2.Biernson G. (1990). Optimal Radar Tracking Systems, Wiley, New York.Google Scholar
- 4.Damonte JB, Stoddard DJ. (1956). An Analysis of Conical Scan Antennas for Tracking. IRE National Convention Record, 4(1).Google Scholar
- 5.Dutton K, Thompson S, Barraclough B. (1997). The Art of Control Engineering. Addison-Wesley, Harlow.Google Scholar
- 6.Eldred DB. (1994). An Improved Conscan Algorithm Based on Kalman Filter. TDA Progress Report 42-116, Jet Propulsion Laboratory, Pasadena, CA. Available at http://ipnpr.jpl.nasa.gov/progress_report/42-116/116r.pdf.
- 7.Gawronski W. (1995). Wind Gust Models Derived from Field Data. TDA Progress Report 42-123, Jet Propulsion Laboratory, Pasadena, California, pp. 30–36. Available at http://ipnpr.jpl.nasa.gov/progress_report/42-123/123G.pdf.
- 8.Gawronski W, Craparo E. (2002). Antenna Scanning Techniques for Estimation of Spacecraft Position. IEEE Antennas and Propagation Magazine, 44(6).Google Scholar
- 9.Gawronski W, Gudim MA. (1999). Design and Performance of the Monopulse Control System. IEEE Antennas and Propagation Magazine, 41(6).Google Scholar
- 10.Lee HP, Hwang HY. (1997). Design of Two-Degree-of Freedom Robust Controllers for a Seeker Scan Loop System. Int. J. Control, 66(4).Google Scholar
- 11.Ohlson JE, Reid MS. (1976). Conical-Scan Tracking with 64-m Diameter Antenna at Goldstone. JPL Technical Report, 32-1605, Jet Propulsion Laboratory, Pasadena, CA.Google Scholar
- 12.Wan H, Liang Z, Zhang Q et al. (1996). A Double-Band Infrared Image Processing System Using Rosette Scanning. Detectors, Focal Plane Arrays, and Applications, SPIE Proceedings, vol. 2894.Google Scholar