On the power spectral density of SGLS and USB waveforms

Conference Paper · February 1999with87 Reads
DOI: 10.1109/AERO.1999.793154 · Source: IEEE Xplore
Conference: Aerospace Conference, 1999. Proceedings. 1999 IEEE, Volume: 2

    Abstract

    Most of the DoD satellites utilize the Space-to-Ground Link
    Subsystem (SGLS) for tracking, telemetry, and command (TT and C)
    controls. The standard SGLS waveform uses a phase modulation (PM) scheme
    on the combined PCM/FSK/AM signal and pseudo-random noise (PRN) square
    wave signal for command and ranging, respectively. The SGLS uplink
    operates in the 1755-1850 MHz (L-band), while the downlink operates in
    the 2200-2290 MHz (S-band). On the other hand, the non-DoD satellites
    for other various governmental agencies primarily use Unified S-Band
    (USB) for their TT and C links. Two waveforms, PCM/PSK/PM and
    PCM/PM/Bi-Phase, are mainly used in the USE for command along with
    either PRN squarewave or sinusoidal tone for ranging. Due to a high
    demand of utilizing the L-band for the mobile satellite services, the
    government has been thinking of migrating its SGLS uplink from L-band to
    USB to avoid the increasing radio frequency interference (RFI) from/to
    other mobile satellite systems. Such a migration raises a concern with
    respect to interference between the immigrated and existing links. To
    study the RFI impact, the power spectrum density (PSD) of both SGLS and
    USE waveforms and their respective bandwidth efficiency need to be
    studied. This paper derives the PSD for the SGLS and USB waveforms and
    compares their respective occupied bandwidths