Simultaneous rocket and satellite measurements of the topside ionosphere

In view of the vast amount of data accumulating from Alouette, the Canadian topside sounder satellite [Chapman, 1963], it is highly desirable to establish the accuracy of this technique by comparing the electron density profiles obtained by Alouette with similar data obtained independently. This accuracy affects the geophysical interpretation of the data as well as the possibility of using the topside sounder to calibrate ground-based techniques such as the incoherent backscatter radar. There are two possible sources of errors in the electron density profiles derived from topside sounders. The first one is associated with the method of converting the observed ionograms to true-height profiles.