In radar and lidar, adjustment of the received power to compensate for the divergence of radiant flux density with range. The received power is multiplied by (r/r₀)², where r is the range and r₀ is an arbitrary reference range (e.g., 1 km). This normalization assumes that a distributed target fills the pulse volume at range r (See beam filling) so that the size of the scattering volume increases with r² even as the incident flux density decreases with r². The normalization in effect corrects for the flux divergence on the return trip from the scattering volume to the receiver. See lidar equation, radar equation.