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Regenerative Pseudonoise Ranging (784 words) |
 | Pseudonoise binary sequences have been used before in turnaround ranging of spacecraft because they offer a desirable combination of high ranging resolution, low ranging ambiguity, and no need for receivers to "know" when pseudonoise sequences started. |
| If the pseudonoise sequence could be regenerated in the transponder with proper timing instead of being simply turned around along with the uplink noise, then it could be retransmitted without the uplink noise, thereby increasing the ranging-signal-to-noise ratio. |
| The nature of the pseudonoise sequence would be such that the tracking phase error would average out to zero in the long term, and the effect of the tracking phase error could be diminished through low-pass filtering. |
| Coherent spread spectrum pseudonoise tracking loop - Patent 4538280 (5958 words) |
| pseudonoise signal generator means for generating a pseudonoise sequence signal which corresponds to a pseudonoise signal component of the received spread data signal. |
| A demodulator is included in the first channel for correlating the pseudonoise signal component of the received spread spectrum signal with the pseudonoise sequence signal generated by the local generator to thereby generate a detected recovered signal. |
| The control signal is applied to the local generator for controlling the phase of the pseudonoise signal sequence to lock the phase of the pseudonoise sequence signal to the phase of the pseudonoise signal component of the received spread spectrum signal. |
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