Citation
Abstract
A new telemetry playback scheme promises to maximize telemetry return for deep-space missions. For a given effective isotropic radiated power from the spacecraft, the received P /N and, hence, the supportable bit rate vary during a trackT 0 ing pass as the elevation angle changes. In the past, spacecraft would use just one bit rate or perhaps a few different bit rates during a pass. However, large bit-rate changes sometimes cause the ground receiver to go out of lock. The new scheme, which is examined here, allows the spacecraft to change its bit rate in frequent, small steps to "match" the P /N profile. Because the rate changes are small, the T 0 ground receiver will be able to remain in lock. This has been validated through numerical analysis and through limited tests in the Telecommunications Development Laboratory (TDL). Analysis shows that this scheme can increase telemetry return by approximately 1 to 2 dB over the best single-rate approach for a wide range of bit rates, having minimum impact on the spacecraft and DSN.
Keywords
Details
- Volume
- 42-137
- Published
- May 15, 1999
- Pages
- 1–17
- File Size
- 413.4 KB