Hello RG.
Can a position/distance error be represented as frequency error or Doppler in antenna systems?
Thanks in advance.
Regards
he challenges of severe Doppler effects in high-speed railway are considered. By building a cooperative antenna system, an algorithm of joint channel estimation and Doppler frequency offset (DFO) estimation is proposed based on Ricean channel model. First, a maximum likelihood estimation (MLE) algorithm for DFO is designed, showing that the Doppler estimation can be obtained by estimating moving velocity of the train and the path loss with the exploitation of pilots that are placed inside the frame. Then a joint detection algorithm for the receiver is proposed to exploit multi-antenna diversity gains. Last, the theoretical Crammer Rao bound (CRB) for joint channel estimation and DFO estimation is derived. The steady performance of the system is confirmed by numerical simulations. In particular, when the Ricean fading channel parameter equals 5 and the velocities of train are 100 m/s and 150 m/s, the estimation variances of DFO are very close to the theoretical results obtained by using CRB. Meanwhile, the corresponding signal to noise ratio loss is less than 1.5 dB when the bit error rate is 10-5 for 16QAM signals
Dear Mohammed,
The distance traveled by an electromagnetic wave L = c t where c is the velocity of light and t is the propagation time. If these is an error in the distance then there will be an equivalent error in time dt such that dL=c dt. Accordingly, this will be equivalent to statistical variations of the symbol arrival time. From this simple thinking, one can treat statistical distance errors as statistical delay time in the symbol time. Most probable it will cause statistical delay errors that may cause inter symbol interference.
Frequency offset requires a change in the rate of change of the propagation distance with time.
Best wishes
Please read the book
Airborne Doppler Radar
by
Martin Schetzen
This book is documentation of the Apollo 11 project
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