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 and amplified by the low-noise block downconverter. 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, Suomi-NPP and JPSS-1, 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 specifications
Radome 2m diameter, low-loss composite, hydrophobic coating, white or grey
Antenna type Prime focus parabolic dish, solid spun aluminium, white powder coated
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
Wind speed 185km/h (100kt) operational
240km/h (130kt) survival
High-rate demodulator specifications
Input frequency 720MHz (from XDC programmable downconverter)
RF input bandwidth 75MHz
Demodulator modes BPSK, QPSK, SQPSK, OQPSK
Demod. impl. 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 19.4dB/K @ 8200MHz
Low-noise block downconverter (LNB) specifications
Noise figure 0.69dB (50K) maximum
0.6dB (43K) typical
Input frequency 7700–8500MHz
LO frequency 6950MHz
IF output frequency 800–1450MHz
Gain variation within 30MHz ±0.4dB maximum
Gain variation over band ±2dB max
Conversion gain 55dB minimum
Image rejection 40dB minimum
Local oscillator stability ±1.5ppm (–40 to +80°C)
Local oscillator type Internal Phase Locked Loop (PLL) locked to Temperature Controlled Crystal Oscillator (TCXO)
Phase noise –90dBc/Hz @ 10kHz typical
–100dBc/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

Combined X/L-Band Option

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