  Continuous burst mode VLF measurements were recorded on the RBSP/Van Allen
Probes satellites and are analyzed to detect pulses from the Russian Alpha
(RSDN-20) ground-based navigational system. Based on the wave characteristics
of these pulses and on the position of the spacecraft, the signals propagated
mostly in ducted mode in the plasmasphere. Knowledge of the propagation path
allowed us to carry out a monochromatic wave propagation inversion to obtain
plasmaspheric electron densities. We compared the obtained densities with
independent in-situ measurements on the spacecraft. The results show good
agreement, validating our inversion process. This contributes to validating the
field-aligned density profile model routinely used in the inversion of
whistlers detected on the ground. Furthermore, our method can provide electron
densities at regimes where no alternative measurements are available on the
spacecraft. This raises the possibility of using this method as an additional
tool to measure and monitor plasmaspheric electron densities.
