analysis and simulation of reliable and robust uav data transmission through geo satellite using long code dsss with zp algorithm

Wireless communication is the major form of connection nowadays. in most cases it exploits the benefits of the spread spectrum techniques to overcome corruptions introduced by channel like doppler residual frequency, noise, interference and jamming. the purpose of this paper is to exchange secure information with unmanned aerial vehicle (uav) through geo satellites at low bit rates (kbps) with the aim of expanding the radius and operational coverage in the absence of los communications. in order to evaluate the possibility of communication, the link budget calculations are performed and minimum carrier to noise ratio (c/n) required to receive the signal at the receiver’s side is measured. basically, due to the information relay with geo-satellite, security of the link and the lack of access to information by unauthorized users is very important, therefore, direct sequence spread spectrum technique with long code has been used in physical layer to increase signal security and non-detectability. in order to detect the signal, different code acquisition techniques are examined and zero padding (zp) is shown to outperform the other existing techniques in terms of doppler effect tolerance and probability of detection in low snrs. the results show that the proposed method makes detection at snr levels as low as -14db possible with a probability of false alarm of 10-5 and pd>0.9.