Predictions for LROJan McGarry

Will most likely be generated by LRO Orbit Determination Team. We will ask the LOLA Science Team to also generate predictions – at least initially – as check.

Will request predictions be in CPF format.

To synchronize with LOLA laser fire we will need:

- Determination of range-rate (compute from positions and/or velocities). - LRO UTC offset and LRO oscillator drift (embedded in CPF Header

Type 4 - Transponder Info). - Delay of range window relative to T0:

use transponder transmit delay field or generate new field???

One LOLA detector does both earth uplink and lunar surface

Two range windows in one detector: 8 msec earth and 5 msec lunar.

Need to minimize the earth events in the lunar surface window to prevent on-board signal processing algorithm from following the wrong signal.

This can be achieved by synchronizing the ground laser fires to LOLA (LRO timing and range-rate of spacecraft), OR by low frequency laser fire rates.

EARTH RANGEWINDOW (8ms)

LUNAR RWIN(5ms)

35.7 msec (28 Hz)

Start of LOLA laserfire period (T0)

Start of next LOLA laser fire period

LOLA laser fires(~ 9ms after T0)