Novel Meteor Observations Using FM Radio Broadcast Over Gadanki, India

Abstract

A novel GNU radio-based software-defined radio receiver using USRP (universal serial radio peripheral) front end and YAGI antenna is developed to record meteor echoes in passive mode using FM broadcast. Pilot observations are made for four days in August-September 2020 to record FM signals at 103.2MHz, 104MHz, and 107.5 MHz with a varying sample rate of 8 KHz and 200 KHz. The in-phase and quadrature signals are processed to obtain the amplitude and phase of the received signals for identification of the meteor echoes. A new algorithm is developed to automatically detect the echoes using a normalized amplitude threshold and a minimum temporal separation between two echoes. Overdense meteor echoes with a plateau-like amplitude response are found using a ratio test and remaining echoes are rejected. Thus, the system is able to detect almost all types of meteor echoes reported earlier. Notably, signatures of fragmentation and background wind are also observed in form of different phase patterns. Histogram of the meteor counts shows a peak for shorter durations indicating larger populations of the smaller size of meteoroids. The log-log plot of the meteor duration versus count is found to exhibit a characteristic transition of the slope. An empirical estimate of the height of the echoes is obtained. The echoes show micro-meteoroid populations which may depend upon the transmitting-receiving setup and the geometry. Hence, an inexpensive, low-power, portable, passive and automated meteor detection system is demonstrated which can be highly useful for understanding the meteor phenomena and estimation of atmospheric parameters.