Zobrazeno 1 - 10
of 20
pro vyhledávání: '"Srini H. Raghavan"'
Publikováno v:
2019 IEEE Aerospace Conference.
Subcarrier modulation, along with direct modulation, is typically used in telemetry, tracking, and command (TT&C) systems. The Space Ground Link Subsystem is an example of the TT&C system using a subcarrier and direct modulation together in a phase m
Autor:
Hubert Chew, Srini H. Raghavan
Publikováno v:
2018 IEEE Aerospace Conference.
Improving spectrum use to enable existing and upcoming modern communication and navigation services has increased the potential for interference. This potential is a critical issue that must be addressed carefully, to avoid degrading the performance
Publikováno v:
2018 IEEE Aerospace Conference.
The Space Ground Link Subsystem provides the telemetry, tracking, and command (TT&C) functions compatible with the Air Force Satellite Control Network (AFSCN). The ranging signal is made up of a 1 mega-chip-per-second pseudo-random code, directly mod
Publikováno v:
2017 IEEE Aerospace Conference.
Passive intermodulation (PIM) can degrade the transmitted signal quality by acting as an interference signal resulting from subsystem, components, material, poor mechanical connections, and sometimes the physical layout when they fall inside the rece
Publikováno v:
2016 IEEE Aerospace Conference.
Pseudorandom noise (PRN) sequences are used to provide a means to measure the ranging distance between a ground station and a satellite. Satellite Ground Link System (SGLS), Global Positioning System (GPS), and some radars are some of the examples th
Autor:
Srini H. Raghavan, Lance Williams
Publikováno v:
2012 IEEE Aerospace Conference.
The satellite control uplink waveform known as SGLS (Space-to-Ground Link System) for commanding satellites currently used by the U.S. Department of Defense (DOD), uses ternary frequency shift keying (FSK), which is amplitude modulated using a triang
Autor:
Srini H. Raghavan, Jack K. Kreng
Publikováno v:
2011 Aerospace Conference.
To mitigate intentional and unintentional in-band interference problems in today's navigation and communication frequency bands, spread-spectrum techniques such as direct sequence (DS) or frequency hopped (FH) systems are frequently used. 1 2 A key c
Autor:
Srini H. Raghavan, Thomas D. Powell
Publikováno v:
2011 Aerospace Conference.
It is well known that the available effective carrier-to-noise density ratio (C/N 0 ) effective to a GPS receiver is degraded to a greater degree due to spectral line effects than when spectral line effects are ignored for the Global Positioning Syst
Autor:
Jack K. Holmes, Srini H. Raghavan
Publikováno v:
2011 Aerospace Conference.
The process of removing the Doppler frequency of the input signal in the receiver on the input is performed by a Doppler removal circuit. The paper addresses the effects of quantizing the ideal sine waves for implementing the Doppler removal (a singl
Publikováno v:
2010 IEEE Aerospace Conference.
It is well known that spectral lines of the Global Positioning System (GPS) coarse acquisition (C/A) codes increase the amount of code division multiple access (CDMA) noise generated, occasionally far exceeding what is typically expected, depending o