The ionosondes provide virtual height information and density profile estimates from the bottomside ionosphere (also by bistatic soundings) with a cadence as small as 1 min, and follow the twilight and nighttime E-region to sounding frequencies of less than 0.5 MHz when implemented with suitable antennas. They also provide information about drifts, ionospheric tilts, and the “rms” amplitude and spectral index of density fluctuations by a phase structure function method. Five ionosondes with co-located flux-gate magnetometers will be placed equidistantly and nearly aligned with the magnetic flux tube intersecting the magnetic equator at 70° W. In our plan, one ionosonde will be installed at Tabatinga, Brazil located near Leticia, Colombia and another near Antofagasta, Chile, to observe the E- and F-region densities. Field lines intersecting 100 km altitude over these two stations map to the equator at 250 and 260 km respectively. A third ionosonde will be placed very close to the magnetic equator in Puerto Maldonado. Two more ionosonde will be located at 19-20° away from the magnetic equator, near the crest caused by the equatorial ‘fountain’. Data from all 5 ionosonde, magnetic fields from the co-located magnetometers, TEC values from the nearby GPS receivers, and the Kalman filter-based assimilation will provide several geophysical parameters (winds, electric fields and densities) from the E and F regions, and will also fill in the regions between the sites. This will be the first time that a numerical model of the equatorial ionosphere can be fully constrained by data collected on both sides of the magnetic equator and for a range of altitudes that includes the E region.