Affordable, high-performance solution for receiving and processing X-Band EOS data from Terra/Aqua (MODIS), Suomi-NPP, JPSS-1 and FengYun-3A/B/C satellites.

X-band Earth Observation Satellite (EOS) data is essential for accurate monitoring of global weather and climate patterns. It is also invaluable for remote sensing work, such as monitoring ocean currents, detecting forest fires and mapping land use.

However, X-Band EOS reception systems have always tended to be very expensive to purchase and maintain. They also normally require specialised installation procedures and building works.

The Dartcom X-Band EOS System changes that, bringing X-Band within reach of universities, research institutions and other organisations with limited budgets and restricted installation sites.

It was developed from the outset as a lower cost X-Band system which still offers performance and features competitive with much more expensive products.

Dartcom has achieved this with a smaller antenna, state-of-the-art RF components, tight tolerances and advanced software.

Land-based and marine antenna options are available.

Brochure

Key Features

Automatic data reception from Terra, Aqua, Suomi-NPP, JPSS-1 and FengYun-3A/B/C (FY-3) X-Band Earth observation satellites.

Complete end-to-end solution with automatic data processing to level 0, 1 and 2 (currently level 0 and 1 only for FY-3).

Affordable to meet the limited budgets available for X-Band systems in universities and research institutions.

Simple installation with minimal civil engineering works.

1.5m antenna system enclosed in a radome to allow normal operation at wind speeds up to 185km/h (100kt or 115mph).

State-of-the-art RF components, allowing good data reception from 15° satellite elevation. In practice good quality data can be received from Terra, Suomi-NPP and JPSS-1 at 7° elevation and from Aqua and FY-3 at 5°.

Automatic daily prediction data updates from the internet.

Optional temperature monitoring for radome and equipment rack with automatic tracking lockout if limits exceeded.

All external components designed and treated to survive tropical and marine environments, with at least IP65 protection rating.

Comprehensive hardware and software diagnostics at all levels.

Modular construction for easy maintenance and future upgrades.

Comprehensive hardware and software diagnostics at all levels.

Cost-effective migration path for existing L-Band systems to the next generation of X-Band Earth observation satellites.
Combined X/L-Band option allowing reception from X-Band and L-Band satellites using the same antenna system.

Descriptions

Outdoor equipment

  • 2m diameter radome with hydrophobic coating to minimise signal loss caused by standing water during rainfall.
  • 1.5m prime focus aluminium parabolic dish antenna.
  • Rotator/pedestal and controller (land-based and marine options).
  • Scalar feed horn and low-noise block downconverter (LNB).
  • Rugged, weatherproof GPS antenna (mounted outside radome).
  • Optional radome environmental control unit for hot climates.

All outdoor equipment is housed in the radome, except the GPS antenna which is mounted externally.

Indoor equipment

  • Modular receiver rack.
  • Demodulator.
  • Uninterruptible power supply (UPS).
  • Optional temperature sensor unit.
  • Ingest and processor PCs.
  • Optional visualisation PC.

All units are rack-mountable and can be supplied in an optional floor-standing cabinet for a complete rack-mounted system.

The indoor equipment comprises the following:

  • Modular receiver rack (4U rack mount) containing:
    • LNB power supply.
    • Programmable downconverter.
    • USB hub and serial adapters.
    • GPS receiver.
    • Switch mode power supply.
    • Optional USB interfaces for reception of L-Band services.
  • High-rate demodulator (1U rack mount).
  • 2kVA UPS (tower or 2U rack mount).
  • Optional temperature sensor unit (1U rack mount).
  • Ingest PC (midi-tower or 4U rack mount) running 64-bit Windows with Dartcom Polar Orbiter Ingester software.
  • Processor PC (midi-tower or 4U rack mount) running NASA RT-STPS, Simulcast, IPOPP and CMA FY3L0pp/FY3L1pp software.
  • Optional visualisation PC (midi-tower or 4U rack mount).
  • 6U desktop or optional 22U floor-standing cabinet.

Antenna specifications

Radome2m diameter, low-loss composite, hydrophobic coating, white or grey
Antenna typePrime focus parabolic dish, solid spun aluminium, white powder coated
Diameter1.5m
F/D ratio0.364
Gain @ 8200MHz39.3dBiC including 0.4dB radome loss
FeedScalar horn
Frequency range7200–8500MHz
Axial ratio2dB max
PolarisationRHC/LHC, software remote-controlled
Wind speed185km/h (100kt) operational
240km/h (130kt) survival

 

High-rate demodulator specifications

Input frequency720MHz (from XDC programmable downconverter)
RF input bandwidth75MHz
Demodulator modesBPSK, QPSK, SQPSK, OQPSK
Demod. impl. loss<0.2dB typical
Supported symbol rates1–40Msps
Baseband filterRoot raised cosine (RRC) with variable alpha
Convolution decodingViterbi, K=7, rate ½, dual-channel, G1=171, G2=133
Coding gain5.2dB @ 1:105 BER
Control/data interfaceUSB 2.0
Supported modesTerra Direct Broadcast
Aqua Direct Broadcast
Suomi-NPP Direct Broadcast
JPSS (NPOESS) Direct Broadcast
FengYun-3 Direct Broadcast
Typical system G/T19.4dB/K @ 8200MHz

 

Low-noise block downconverter (LNB) specifications

Noise figure0.69dB (50K) maximum
0.6dB (43K) typical
Input frequency7700–8500MHz
LO frequency6950MHz
IF output frequency800–1450MHz
Gain variation within 30MHz±0.4dB maximum
Gain variation over band±2dB max
Conversion gain55dB minimum
Image rejection40dB minimum
Local oscillator stability±1.5ppm (–40 to +80°C)
Local oscillator typeInternal 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 figure3dB maximum
Input frequency800–1450MHz
Output frequency720MHz
Output bandwidth3dB @ 120MHz
Frequency step size100kHz
LO stability±5ppm
Oscillator phase noise–100dBc/Hz @ 10kHz typical
IF filterSAW
IF filter bandwidth120MHz
Conversion gain20dB typical
Output 1dB compression point>+19dBm
Control interfaceRS-232 serial

Combined X/L-Band Option

L-Band Pre-LNA filter specifications

Type3-pole cavity filter
Passband1680–1710MHz
Passband loss0.15dB
Bandwidth–3dB ±86MHz centred on 1705MHz
Stopband loss300MHz: –80dB
1200MHz: –35dB
1570MHz: –10dB
1866MHz: –10dB

L-Band LNA specifications

TypeSingle stage advanced E-PHEMT technology
Noise figure0.65dB typical
Gain14dB minimum
IP333.5dBm typical
Operating temperature–40 to +85°C

L-Band post-LNA bandpass filter specifications

Type4-pole, Combline
Insertion loss1.5dB max
Bandwidth1690–1710MHz

L-band feed specifications

Type4 dipoles with quad hybrid combiner
PolarisationRHC

L-Band block downconverter specifications

Noise figure0.75dB typical
Input frequency1682–1710MHz
LO frequency1553.500MHz
Output frequency126.5–154.5MHz
Converted bandwidth50MHz @ 3dB typical
Conversion gain>50dB, 55dB typical
Image rejection>60dB
Input/output impedance50Ω
Output 1dB comp. point>+14dBm
LO stability±2.5ppm (–30 to +60°C)
LO typeInternal PLL locked to TCXO
Phase noise–103dBc/Hz @ 10Hz typical
–130dBc @ 100kHz
Input voltage10–15V DC @ 350mA typical powered via IF output cable
Operating temperature–40 to +60°C
Operating humidity100%

L-Band low-rate demodulator specifications

LRD-100LRD-200B
Signal input range–90dBm to –20dBm–90dBm to –20dBm
IF conversionDirect 70MHz, up to 50Msps, 10-bit resolutionDirect 70MHz, up to 50Msps, 10-bit resolution
IF bandwidthProgrammableProgrammable
Supported symbol rates0.1–3.5Msps0.1–3.5Msps
Demodulator modesBPSK, QPSK, PSKBPSK, QPSK, PSK, 8PSK, 16QAM
BPSK/QPSK performanceBPSK/QPSK within 1dB of theoretical, 0.5dB typicalBPSK/QPSK within 0.4dB of theoretical, 0.2dB typical
Convolution decodingViterbi, rate ¾Viterbi, rates ½ and ¾
RF inputsSimulator or signal, selectableSimulator or signal, selectable
Outputs50Ω TTL clock and NRZ data50Ω TTL clock and NRZ data
DisplayLCD, 16-character × 2 lineLCD, 16-character × 2 line
Control interfaceRS-232 serial via USB serial adaptorRS-232 serial via USB serial adaptor

Marine antenna

  • Active-stabilised pedestal to compensate for pitch, roll and yaw.
  • X-Y with continuous movement to eliminate cable wrap problems without needing slip-rings or a rotary joint.
  • Automatically controlled via a TCP/IP link from the ingest PC by the Dartcom Polar Orbiter Ingester software.
  • Waveguide bandpass filter fitted between the scalar feed horn and LNB to prevent interference and damage from X-Band radar.

Marine antenna pedestal specifications

ControlX-Y controller with active stabilisation
Movement limitsNone (continuous)
Vessel motion:
    Roll±30° @ 8 sec
    Pitch±15° @ 8 sec
    Yaw±80° @ 50 sec
    Surge±0.2g
    Sway±0.2g
    Heave±0.2g
    Turning rate10°/sec
Weight180kg (including radome)
Power requirements110/220V AC (±5%)
50/60Hz (+0, –3%)
660W
Wild heat660W
Operating temperature–10°C to +70°C unheated
–40°C to +70°C with optional heater
Survival temperature–35°C to +75°C
Humidity95% @ 40°C
EMI/RFIMIL-STD-461
VibrationDesigned to meet MIL-STD-167-1
ShockDesigned to meet MIL-STD-901

Marine antenna radar filter specifications

Passband7750–8400MHz
Insertion loss at band edges0.25dB maximum
VSWR1.2:1 maximum
Rejection from 9300–9500MHz100db minimum
Operating temperature–10°C to +50°C