Utilizing short-wave two-dimensional antenna arrays

the HF backscatter sweep frequency-elevation ionogram is obtained for the first time in China. In this paper combining genetic algorithm and Otsu for the signal extraction of the group-frequency-energy three-dimensional ionogram. Using the connected domain marking to eliminate discrete point noise

obtain the clean signal

and use the Canny detetion method to obtain the nearest and farthest distance of each frequency in the echo signal. On the group-frequency-elevation three dimensional ionogram

the elevation-group data of each frequency is acquired

Fitting the points by the polynomial fitting

logarithmic fitting of the elevation and logarithmic fitting of the group

Finally performing error analysis of the fitted curve through the vertical detection data of the Qingdao observation station. The result show that the logarithm of the group obtained curve is in good agreement with the target curve. The validity of the extraction method is proved.