Application In GPS Signal Denoising And Multipath Based On SSA,EMD And ICA

GPS is widely used in the field of Surveying and mapping.GPS measurement technology has many advantages compared with conventional measurement technology.However,the GPS measurement is affected by various errors when receiving the satellite signal to determine the location of the station.Most of the systematic errors can be eliminated by means of correction model,dual-frequency observations and differential measurements.However,accidental errors such as random noise and multipath effects are difficult to eliminate because they do not have spatial correlation and regularity.These errors are attached to the GPS signal and ultimately affect the positioning accuracy.The development of measurement technology requires higher observation accuracy,GPS signal denoising becomes very necessary.The main work of this article is as follows:1.Analysis of signal denoising method.The principle and research status of signal denoising methods such as SSA,EMD and ICA are summarized,and their advantages and disadvantages are analyzed.A joint denoising method is proposed for modal aliasing of EMD and ICA can only handle multi-channel observations,which combines the advantages of both,It is called EMD-ICA.2.Denoising analysis of GPS random noise.Through the denoising experiment of GPS simulation signal,we verify the denoising ability of the three methods of SSA,EMD and EMD-ICA.The experimental results show that the three methods can effectively extract the random noise in GPS signal.SSA is obviously better than the other two methods.EMD-ICA is slightly better than EMD,It indicates that EMD-ICA can overcome the modal aliasing problem of EMD to a certain extent.3.Analysis of GPS multipath effect.Extraction and correction of GPS multipath effect by stellar day filtering method.First,we use SSA,EMD and EMD-ICA to denoise the three day coordinate sequence to establish the multipath error model of each day.Then,we use the first day multipath correction model to correct the other days coordinate sequence.The results show that SSA is better than EMD and EMD-ICA for denoising and multipath error correction.