The tiny ionospheric photometer (TIP) and GPS occultation experiment (GOX) onboard FORMOSAT-3/COSMIC (F3/C) are employed to measure the OI 135.6 ran intensities in the nadir direction and the total electron content (TEC) between the F3/C and GPS satellite in the ionosphere, respectively. Due to its very high sensitivity similar to 600 counts/Rayleigh and rather narrow nadir pointing 3.8 degrees circular field-of-view, the TIP provides accurate characterization of ionospheric electron density gradients in the horizontal direction. Meanwhile, a technique of the low earth orbit (LEO) tomography is applied to analyze the GOX data obtaining the 3D distribution of ionosphere electron density. Here, we combine the two observations to carry out the LEO-TIP tomographic inversions, and demonstrate that the peak electron density (NmF(2)) retrieved from the TIP combined together with the peak altitude (hmF(2)) information from the LEO tomography profiles provides more realistic electron density.
