Reading Mission Control Data Out of Predator Drone Video Feeds

by Kingcope  (Original Article)


There have been recent reports of "insurgents" intercepting unencrypted U.S. Predator drone video feeds in Iraq and Afghanistan.  The Predator drone video feeds were sent - in some cases - from the drones without any encryption technology.  The insurgents were in a rather simple situation to intercept and monitor these video feeds, and also save them to share them among each other.

A Wall Street Journal article states that a software package called SkyGrabber was used to intercept the video feeds.  The original intention of this software is to decode images and video feeds "off the air" by using standard satellite receving hardware and antennas.

After doing some research on the issue, we found that within the Predator video feeds (aside from the image data) there is also mission control data carried inside the satellite signal which is sent to the ground control stations.  It is theoretically possible to read off this mission control data both in the real-time intercepted video feed or from a recorded video data feed.

Technology Used by the Drones

There is a command and control link to communicate from a control station to the Predator drone.  Further, there is also a data link that sends mission control data and video feeds back to the ground control station.  Here, one has to distinguish between line-of-sight communication paths and beyond line-of-sight communication paths.

The operation of the line-of-sight link is limited to approximately 81 to 138 miles.  This operating range can be extended, for example, by using mobile ground control stations which are locally deployed.  Line-of-sight links are critical for takeoffs and landings of the drone.  These links utilize a C-band (4.4 - 4.94 / 5.25 - 5.85 GHz) communication path.  Beyond line-of-sight communication links operate in the Ku-band (14.40 - 15.35 GHz) satellite frequency.  This allows the Predator to cover approximately 1,500 miles of communication range capability.

Figure: C-band & Ku-band Communication

This explains why the insurgents were able to intercept the Predator video feeds when they were sent unencrypted to the ground station.  The only hardware required is a standard C-band or Ku-band satellite receiving setup.  Transmitting traffic to a satellite is not needed in this case.

The drones normally use MPEG Transport Stream (MPEG-TS) to send video and data to the ground station.  MISB (Motions Imagery Standards Board) has developed several standards on how to embed the control data into MPEG streams.

Figure: Example of Metadata Sent with the MPEG Transport Stream

An important note is that our research shows that most, if not all, metadata within the MPEG video stream is not encrypted - if the MPEG stream itself is not encrypted.

How to Read the Control Data With Publicly Available Tools

During our research, we found a suitable tool to read the mission control data from the video feeds and also from any saved video feeds.  The tool is programmed by LEADTOOLS and is capable of reading KLV metadata out of MPEG-TS.  Inside the LEADTOOLS Multimedia SDK package, a programmer finds source code and binaries of the needed tool.

The following screenshot shows the tool in action.  The loaded file is a saved MPEG-TS Predator drove video feed with private metadata embedded:

Predator Receiving Station

Predator UAV C-Band Data Link Characteristics

The Predator data link system provides command and control information from the Ground Control Station (GCS) to the UAV using the Command Link (CL) and payload data and status information from the UAV to the GCS using the Return Link (RL).  The transmitter and receiver units can be software configured to perform CL or RL functions.  The Predator data link system utilizes two CLs and two RLs.  The data link system uses 16 bit messages.  The CL-configured terminals are capable of transferring data at 19.2 kilobytes per second (kbps) and 200 kbps using Frequency Shift Keyed (FSK) modulation.  The RL-configured terminals are capable of transferring either National Television System Committee (NTSC) formatted video with data subcarriers at 6.8 MHz and 7.5 MHz offset or 3.2 Mbps FSK data without the subcarriers.

The GCS contains computers, voice communications equipment, displays, and user interfaces, as well as accommodations for the pilot and payload operator.  The GCS is connected to the Ground Data Terminal (GDT), which consists of the antenna system, a diplexer, a custom-built Low-Noise Amplifier (LNA), transmitters, and receivers.  The antenna system contains three antennas: a 33 dBi parabolic dish, a 15 dBi horn, and a 6 dBi stacked dipole array.  The parabolic dish is used when the UAV is beyond approximately 48 km in range.  The horn is used when the UAV is within 48 km.  The stacked dipole array is typically not used.  The diplexer permits full-duplex operation.

The UAV data link system contains antennas, diplexer, computer, transmitters, and receivers.  The antennas utilized by the UAV are: a 15 dBi horn, a 3 dBi stacked-dipole array, and a 0.3 dBi stub antenna.  The horn is used by the primary data link.  The stacked-dipole array is used by the secondary data link.  The stub can be used with the primary data link, although it is typically not used.  The diplexer permits full-duplex operation.  The computer parity checks data, selects the optimum CL, and discards erroneous messages.

The final amplifier stage of the UAV and GDT data link transmitter can be software-controlled to switch between 1 mW and 10 watts output power.  The 1 mW low-power mode is used for ground testing.  The UAV transmitter will automatically revert to 10 watts if the link cannot be maintained at 1 mW.

         Transmitter Frequency: 4400 - 4940 MHz or 5250 - 5850 MHz, 1 MHz tuning steps
                Transmit Power: +40 dBm

                                LOS           DLOS          LOS          DLOS
	                        Command Link  Command Link  Return Link  Return Link
          Emission Designators: 560KF1D       88K3F1D       17M0F9F      4M72F1D
 Emission Bandwith (MHz) -3 dB: 0.34          0.063         8.5          2.8
                        -20 dB: 0.42          0.088         18.0         20.0 
		        -40 dB: -             0.219         -            - 
		        -60 dB: 1.2           0.671         46.2         66.0

            Receiver Frequency: 4400 - 4940 MHz or 5250 - 5850 MHz, 1 MHz tuning steps
          Receiver Sensitivity: -98 dBm (560KF1D/88K3F1D) or -84 dBm (17M0F9F/4M72F1D)
    RF Selectivity (MHz) -3 dB: 303
                        -20 dB: 375
                        -60 dB: 525
1st IF Selectivity (MHz) -3 dB: 35
                        -20 dB: 55
			-60 dB: 115
2nd IF Selectivity (MHz) -3 dB: 1 (CL)   20 (RL)
                        -20 dB: 3.2 (CL) 22.5 (RL)
			-60 dB: 4 (CL)   28 (RL)

   Diplexer Low-Band Frequency: 5250 - 5475 MHz
 Diplexer Cross-Over Frequency: 5475 - 5625 MHz
  Diplexer High-Band Frequency: 5625 - 5850 MHz

    GDT Parabolic Antenna Gain: 33 dBi, cosecant-squared illumination type, vertical polarization
   Azimuth/Elevation Beamwidth: 3/45 degrees

         UAV Horn Antenna Gain: 15 dBi, Technical Associates Model 11572, vertical polarization
   Azimuth/Elevation Beamwidth: 30/30 degrees

         UAV Stub Antenna Gain: 0.3 dBi, TECOM Associates Model 702-653-3, vertical polarization
   Azimuth/Elevation Beamwidth: 360/55 degrees

       UAV Dipole Antenna Gain: 3.0 dBi, TECOM Associates Model 702-653-1, vertical polarization
   Azimuth/Elevation Beamwidth: 360/25 degrees

References / Notes / Links

  1. Insurgents Hack U.S. Drones, Wall Street Journal (Mirror)
  2. MISB
  4. SkyGrabber v2.8.6.4  With crack.  (SkyGrabber Readme)  (16M ZIP)
  5. HDStar DVB-S2 TV Box  DVB-S2 HDStar is a digital satellite receiver box with USB2.0 interface, which allows you to access free-to-air high definition and standard definition digital satellite TV and digital radio in on your PC.
  6. Insurgents Intercept Drone Video in King-Size Security Breach
  7. Predator Drones Hacked in Iraq Operations
  8. Psycho Air Force Drone Operator Who Says He Participated in Missions Which Killed Over 1,600 People
  9. Electromagnetic Compatibility Analysis of the Predator UAV Line-of-Sight Data Link Terminal with the Communications-Electronics Environment at Indian Springs Air Force Auxiliary Field  JSC-PR-03-024  (643k PDF)
  10. Predator UAV C-Band Data Link EMC with 5 GHz CFR 47 Part 15 and Part 90 Devices  JSC-PR-03-026  (520k PDF)
  11. Predator UAV Line-of-Sight Data Link Terminal Radio Frequency Test Plan  JSC-CR-03-062  (136k PDF)
  12. Common Data Link EMC Analysis  JSC-PR-04-044  (307k PDF)
  13. Indian Springs C-Band Line-of-Sight Frequency Requirements Analysis  JSC-PR-04-049A  (534k PDF)
  14. C-Band and Ku-Band UAV Line-of-Sight Data Link EMC Analysis for Two Operational Scenarios  JSC-PR-04-054  (692k PDF)
  15. Predator UAV Line-of-Sight Datalink Terminal Radio Frequency Test Report  JSC-CR-04-066  (777k PDF)
  16. Predator UAV Basic Universal Metadata Set  (263k PDF)
  17. StrikeHawk Tactical Video Downlink Receiver  (712k PDF)
  18. FCC Frequency Data for General Atomics  Good way to look for test frequencies.  (48k PDF)
  19. L3 Communications Ku-band SATCOM Data Link Satellite  (183k PDF)  UAV Terminal: Forward (RX): 10.95-12.75 GHz / Reverse (TX): 14.0-14.5 GHz
  20. Northrop Grumman ZPY-1 STARLite Tactical Radar  (820k PDF)  16.4 GHz
  21. Raytheon AAS-52 Multi-Spectral Targeting System  (144k PDF)
  22. Tactical UAVs in a Proposed Joint Infrastructure to Counter Theather Ballistic Missiles  (1.8M PDF)
  23. Joint Unmanned Aircraft System Center of Excellence (JUAS-COE) Army Tactical Pocket Guide  Organic/Non-Organic Group 3/4/5 UAS Training Document  (4.9M PDF)
  24. Various Sensors Aboard UAVs  (3.8M PDF)
  25. Sensor Alternatives for Future Unmanned Tactical Aircraft  (1M PDF)
  26. Predator MTS Overlay  Symbol definitions.  (113k PDF)
  27. The Predator uses the C-band LOS link for landings and take-offs.  When over a remote target, it will most likely use the Ku-band SATCOM or TCDL link.  The LOS video streams are in the 5.25 - 5.475 GHz range.
  28. The NLOS Ku-band SATCOM communications is via the AN/TSQ-190 TROJAN SPIRIT II satellite communications system.  (C-band: 3.9 - 6.2 GHz [50 watts] / Ku-band: 12.4 - 18 GHz [16 watts])
  29. Standard Commercial Ku-band Receive Frequencies: 11.7-12.2 GHz / 10.95-11.45 GHz INTELSAT / 11.2-11.7 GHz INTELSAT / 12.25-12.75 GHz AUSSAT
  30. Other Related GBPPR Projects:

  31. GBPPR Interferometric Surveillance Device Experiments - Part 2
  32. GBPPR Homebrew Radar Experiments
  33. Battlefield Laser Warning Receiver
  34. Techniques for Countering Thermal Imaging Devices