The Long Wavelength Array (LWA) is a new telescope/interferometer facility being established to do astrophysical observations in the frequency range 10 MHz to 80 MHz. As such, measurements will be strongly affected by the ionosphere. In fact, part of the LWA mandate is to make highly precise measurements of the ionosphere. The work will require a combination of active and passive measurements, detailed modeling and improvement of existing telescope “self-calibration” techniques. This presentation will give an overview of the requirements, with the aim of stimulating discussion in the ionospheric community on how to address these issues. We will also present measurements and 3D reconstructions of the ionosphere over the LWA core site obtained from a recent experiment using the COSMIC satellite constellation, the Very Large Array 74 MHz system and GPS measurements.