Incoherent scatter multiple‐pulse measurements at Arecibo

The important points governing the design of a multiple-pulse measurement of the incoherent scatter autocorrelation function in the E region are discussed. Since the requirements for good signal-to-noise ratio and good resolution are contradictory, compromises must be made. These considerations dictated the choice of two multiple-pulse schemes which are now being used at the National Astronomy and Ionosphere Center in Arecibo, Puerto Rico. These schemes, one involving five pulses and one involving seven, are described and a few typical examples of the results obtained are presented. The data show that it is now practical during the day, or at night in reasonably strong sporadic-E layers, to make accurate measurements of the complex autocorrelation function in the E region with an altitude resolution of the order of 1 to 3 km in a time of less than 10 min. The number of heights which can be studied simultaneously is limited only by computer capabilities. In the measurements reported here ten altitudes were sampled.