The paper considers monostatic sensing of the Earth's surface using a
satellite laser altimeter. Equations relating the echo-signal delay an
d duration to the satellite altitude and the variance of the heights o
f the Earth surface irregularities are derived. The calculation result
s are presented, which demonstrate the effect the lidar divergence ang
le, the sounding angle, the state of the Earth's atmosphere, and the v
ariance of the heights of the Earth surface irregularities on the alti
meter measurement data.