X-Band EOS System > Technical Summary

The antenna system automatically tracks X-Band satellites and receives direct broadcast RF transmissions which are focused into the scalar feed horn by the parabolic dish, amplified by the low-noise amplifier, then fed to the block down-converter. This converts the signal to a lower frequency to minimise cable loss and feeds it to the XDC programmable downconverter in the receiver rack, where it is converted to a common frequency and fed to the high-rate demodulator.

The demodulator converts the RF signal back to a binary data stream which is then Viterbi decoded, byte-aligned and transferred via USB to the Polar Orbiter Ingester software running on the ingest PC. This detects the attached synchronisation markers (ASMs) in the data stream and extracts the CCSDS frames, which are then derandomised, Reed-Solomon decoded and demultiplexed into virtual channel data units (VCDUs).

In the case of Terra, Aqua and Suomi-NPP, the VCDUs are automatically transferred via a TCP socket to the RT-STPS software running on the processor PC, which processes them live and displays a preview in the Simulcast software. The IPOPP software automatically processes the resulting data sets into level 0, 1 and 2 data and products.

FengYun-3 data is assembled into a file which is automatically transferred via a LAN connection to the FY3L0pp and FY3L1pp software running on the processor PC, which automatically produces level 0 and 1 data and products.

Antenna and rotator specifications

Radome 2m diameter, low-loss composite, hydrophobic coating
Antenna type Parabolic dish, solid spun aluminium
Diameter 1.5m
F/D ratio 0.364
Gain @ 8200MHz 39.3dBiC including 0.4dB radome loss
Feed Scalar horn
Frequency range 7200–8500MHz
Axial ratio 2dB max
Polarisation RHC/LHC, software remote-controlled
Control By ingester PC via MAD XPA controller
Movement 0–360° azimuth, 0–180° elevation
Speed 48°/sec azimuth, 10°/sec elevation
Mechanical tolerance ±0.15°
Tracking accuracy ±0.1°

Low-noise amplifier (LNA) specifications

Noise figure 0.5dB (35K) typical, 0.691dB (50K) maximum
Input frequency 7700–8500MHz
Gain 50dB min
Gain flatness ±1dB max

Block downconverter (BDC) specifications

Noise figure 16dB typical
Input frequency 7750–8400MHz
LO frequency 6950.00MHz
IF output frequency 800–1450MHz
Gain variation within 30MHz ±0.4dB max
Gain variation over band ±3dB max
Conversion gain 0dB typical
Image rejection >60dB
LO stability ±2.5ppm (–40 to +60?C)
LO oscillator type Internal PLL locked to TCXO
Phase noise –90dBc/Hz @ 10kHz typical
–95dBc/Hz @ 100kHz

XDC programmable downconverter specifications

Noise figure 3dB maximum
Input frequency 800–1450MHz
Output frequency 720MHz
Output bandwidth 3dB @ 120MHz
Frequency step size 100kHz
LO stability ±5ppm
Oscillator phase noise –100dBc/Hz @ 10kHz typical
IF filter SAW
IF filter bandwidth 120MHz
Conversion gain 20dB typical
Output 1dB compression point >+19dBm
Control interface RS-232 serial

High-rate demodulator specifications

Input frequency 720MHz (from XDC programmable downconverter)
RF input bandwidth 75MHz
Demodulator modes BPSK, QPSK, SQPSK, OQPSK
Demodulator implementation loss <0.2dB typical
Supported symbol rates 1–40Msps
Baseband filter Root raised cosine (RRC) with variable alpha
Convolution decoding Viterbi, K=7, rate ½, dual-channel, G1=171, G2=133
Coding gain 5.2dB @ 1:105 BER
Control/data interface USB 2.0
Supported modes Terra Direct Broadcast
Aqua Direct Broadcast
Suomi-NPP Direct Broadcast
JPSS (NPOESS) Direct Broadcast
FengYun-3 Direct Broadcast
Typical system G/T performance 19.4dB/K @ 8200MHz

Combined X/L-Band Option

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