V.N. Bondarenko - Dr.Sc. (Eng.), Professor, «Radioelectronic Systems» Department, Engineering Physics and Radioelectronics Institute, Siberian Federal University, Krasnoyarsk. E-mail: vbondarenko@sfu-kras.ru
R.G. Galeev - Ph.D. (Eng.), General Director, NPP «Radiosvyaz», Krasnoyarsk. E-mail: KRTZ@mail.ru
V.F. Garifullin - Engineer, «Radioelectronic Systems» Department, Engineering Physics and Radioelectronics Institute, Siberian Federal University, Krasnoyarsk. E-mail: vadimgar@mail.ru
T.V. Krasnov - Engineer, «Radioelectronic Systems» Department, Engineering Physics and Radioelectronics Institute, Siberian Federal University, Krasnoyarsk. E-mail: krasnovtv@ya.ru

A quasi-coherent accumulation algorithm is proposed for time delay search of bicomponent spread spectrum signal consisting of pilot and information components. Input mixture is processed in quadrature splitter and then each of constituents is converted within reference pseudorandom sequence (PRS) at fixed delay. Convertions are accumulated upon PRS periods becoming quadrature correlations. Then pilot and information component quadrature correlations are separately accumulated through n PRS periods. Information component quadrature constituents inverse modulation is eliminated within data estimation formed upon coherent accumulation of pilot component at each signal period. Each component quadrature constituents accumulations are combined resulting in quadrature correlations that used to compute the correlation modulo. Signal delay estimation is produced upon selecting the maximal correlation modulo from others. Analysis of proposed quasi-coherent accumulation algorithm used as abnormal error probability criteria is provided. Analysis shows that the algorithm provides significant noise immunity advantages in compare with pilot-component-only algorithm: in signal-to-noise ratios of practice interest, equivalent gain is more than 2,5 dB.

1. Bondarenko V.N., Kokorin V.I. Shirokopolosnye radionavigacionnye sistemy s shumopodobnymi chastotno-manipulirovannymi signalami / Novosibirsk: «Nauka». 2011.
2.       Bondarenko V.N. Optimal'nyj algoritm poiska shumopodobnogo signala s minimal'noj chastotnoj manipuljaciej / Radiotehnika i jelektronika. 2008. T. 53. № 2. S. 238-244.