Space Ground Link Subsystem TT&C Transponder

TOR Compliant, S-Band TT&C Transponder

The Space Ground Link Subsystem (SGLS) TT&C Transponder is a space-qualified, TOR-compliant, S-band transponder that provides compatibility with the Air Force Satellite Control Network (AFSCN) SGLS telemetry and command formats in a single, highly reliable unit. This transponder has been designed for the demands of space including missions in low Earth orbit (LEO), medium Earth orbit (MEO) and geosynchronous Earth orbit (GEO).

  • Fully Aerospace TOR compliant (parts, materials, and processes)
  • Radiation Hardened for the harsh Medium Earth Orbit (MEO) and for use in Strategic nuclear environment
  • Operating modes commanded via latching relays for reliable operation

Further customization is available, please contact us to discuss your unique requirements.


The Space Ground Link Subsystem (SGLS) TT&C Transponder operates at uplink command rates of 1 kbps and 2 kbps (automatically detected) and provides downlink telemetry data rates up to 32 kbps on a 1.7 MHz subcarrier. Coherent operation, including ranging, is selectable via command, as is rate 1/2, constraint length 7 convolutional encoding. For signal security the unit provides interfaces to the KG-327 cryptographic unit for uplink decryption and downlink encryption. Being fully compliant to Aerospace Parts, Materials and Processes TOR requirements* results in lower life-cycle costs by reducing the probability of parts issues impacting spacecraft integration and test efforts.

Receiver Features

  • Operating mode: SGLS/ AFSCN including Ternary FSK
  • Noise figure:< 4.0 dB
  • Operating Frequency: 1760 to 1840 MHz
  • Acquisition: Auto acquisition (± 100 kHz)

Transmitter Features

  • 7W TX power
  • Operating Frequency: 2200 to 2300 MHz
  • Data Rates: up to 32 kbps on 1.7 MHz subcarrier
  • Meets NTIA mask
  • Can be configured as a non-coherent transceiver or coherent transponder
  • R 1/2, K=7 convolutional encoder
  • Coherent ranging
  • Automatic Transmitter Turn On capability with uplink signal



Space Ground Link Subsystem (SGLS) TT&C Transponder Data Sheet



View Document


Interface 1553B SV interface
RF connectors are SMA-F
Non-RF connectors are sub-miniature D
Digital interfaces are differential RS-422 compatible line drivers and receivers
Operating modes commanded via latching relays
DC power
68-71 VDC: < 15 Watts receive-only mode, < 45 Watts full duplex
Analog telemetry: Voltage Monitor, Receiver AGC, RX frequency offset,
Temperature Monitors (passive thermistors), RF Output Power Monitor
Hard-line baseband command interface for spacecraft checkout
Interface to standard cryptographic equipment (e.g, KG327)
Size 8.7” x 7.6” x 6.9” (Including mounting feet, connectors and semi-rigid cables)
Weight 17.5 lbs.
Radiation Radiation hardened for natural and man made environments


  • 100 kRad
  • EMP Tolerant
  • Prompt Dose


Vibration 17.2 Grms (Qualification level)
Shock 1123 G Peak, 1723 Hz
Temperature -34° C to +71° C