RF Channel Simulators add Hardware-in- the-Loop Test Capability to STK Steve Williams, RT Logic

2 RF Channel Simulation  Whenever a transmitter and receiver are in motion with respect to one another, flight and ground COMMS systems must be tested against many conditions, both nominal and worst-case:  Carrier and Signal Doppler Shift  Delay  Losses  Noise  Interference  Intentional  Unintentional  Terrain & overhead obscuration  Natural and man-made atmospheric conditions  Flight paths, orbits, ground paths, ground locations  Transmitter characteristics  Receiver characteristics  Antenna patterns  Etc… True for: satellites, UAVs, aircraft, missiles, targets, ships, rockets, ground vehicles, ground locations, etc.

3 RF Channel Simulation  STK provides superb simulation, analysis, reporting and visualization tools  STK provides easy-to-use scenario creation and modification tools  STK provides a solid physics engine Results in high confidence that the COMMS system should work. At some point though, hardware-in-the-loop testing must occur with the actual COMMS systems devices. This is not a departure from STK, but rather a hardware add-on to it.

4 Example: Adaptive Coding and Modulation (ACM) Modem Test ACM Satellite Modem (or components) under test Ethernet TxRxTxRx May include in- band ACM control signals

5 Satellite Replaced by Channel Simulator ACM Satellite Modem (or components) under test Ethernet TxRxTxRx RF Channel Simulator STK Scenario Point-to-Point Advanced COMMS Transmitter Characteristics Receiver Characteristics Antenna Patterns Interference Losses Etc. May include in- band ACM control signals

6 STK Control of the Channel Simulator ACM Satellite Modem (or components) under test Ethernet TxRxTxRx STK Scenario Ethernet STK Spreadsheets - user created - from STK reports User Programs GUI

7 Role of the Channel Simulator  Create or perturb RF/IF signals to match a particular scenario.  Fully physics-compliant  Phase-continuous  Especially important for phase shift keying modulation (BPSK, QPSK, etc.)  Real-time  High-resolution interpolation (~18.7ns) Doppler Shift Delay Path Loss

8 Role of the Channel Simulator  Satellite passes are a fairly simple channel simulator task.  A missile flying on a test range, for example, is quite different.

9 Example: Testing the Test Range Amplifier Telemetry Tracking Site Equipment STK Scenario Telemetry Data Channel Simulator Amplifier Telemetry Tracking Site Equipment Channel Simulator Amplifier Telemetry Tracking Site Equipment Channel Simulator Amplifier Range Control Center BSS Displays  Space Launch Ranges  Missile & Weapons Test Ranges  Aircraft Test Ranges  Etc.

10 Example: Testing with On-orbit Assets On-orbit GEO Satellite To-be-launched LEO Satellite Simulated LEO-to- GEO signals Signal carrying response of GEO to simulated LEO signals  Inter-satellite links  Aircraft / Satellite links  Satellite / Ground links  Etc.

11 Other uses  Almost any situation where transmitters and receivers will be in motion Stimulus Signals Received Signals System Response Analysis tools, systems and processes to determine that Received Signals and/or System Response was appropriate based on the Stimulus Signals provided. RF or IF RF or IF Receiver System or Component Under Test Transmitter System or Component Under Test Flight Profile Channel Simulator

12 Role of the Channel Simulator  The Channel Simulator performs complex tasks, but must be very easy to use.  Keep users focused on the problems they are trying to solve, not how to make the instrument work.  STK Control  Spreadsheet Control  Can be fed by STK Reports  GUI Control  May contain STK elements in the future, via STK Engine  User-program Control  TCP/IP ASCII/Binary Commands  Synchronized to real-time events

13 Channel Simulator STK9 PlugIn Implementation Comms Systems, receivers, transmitters, sensors and antennas may be included.

14 Summary  STK is a advanced modeling, simulation and visualization package based on a solid physics engine foundation.  The Channel Simulator is a sophisticated RF instrument that adds high-accuracy, physics-compliant carrier and signal Doppler shift, delay, attenuation, noise and interference to test signals for a wide variety of applications.  Together, the combined solution is powerful, easy-to-use, flexible, cost-effective and unique.  For further information –Steve Williams, RT Logic, Colorado Springs, CO –