TriDAR
Encyclopedia
TriDAR, or Triangulation and LIDAR Automated Rendezvous and Docking, is a relative navigation vision system developed by Neptec Design Group
and funded by the Canadian Space Agency and NASA
. It provides guidance information that can be used to guide an unmanned vehicle during rendezvous and docking operations in space. TriDAR does not rely on any reference markers positioned on the target spacecraft. Instead, TriDAR relies on a laser
based 3D sensor
and a thermal imager
. TriDAR’s proprietary software uses the geometric information contained in successive 3D images to match against the known shape of the target object and calculate its position and orientation.
TriDAR made its inaugural demonstration space flight onboard Space Shuttle Discovery
on the STS-128
mission, launched on August 28, 2009. On STS-128, TriDAR provided astronauts with real-time guidance information during rendezvous and docking with the International Space Station (ISS). It automatically acquired and tracked the ISS using only knowledge about its shape. This marked the first time a 3D sensor based “targetless” tracking vision system was used in space.
(SVS) used black on white or white on black dot targets. These targets were imaged with Space Shuttle
or International Space Station
(ISS) video cameras to compute the relative pose of ISS modules to be assembled.
The Trajectory Control System (TCS) is currently used on board the space shuttle to provide guidance information during rendezvous and docking with the International Space Station (ISS). This laser-based system tracks retro reflectors located on the ISS to provide bearing, range and closing rate information. While reliable, target based systems have operational limitations as targets must be installed on target payloads. This is not always practical or even possible.
For example, servicing existing satellites that don’t have reflectors installed would require a targetless tracking capability.
during the STS-128
mission to the ISS
. The objective of the test was to demonstrate the capability of the TriDAR system to track an object in space without using targets markers such as retro-reflectors. For this mission, TriDAR was located in the payload bay on the Orbiter Docking System (ODS) next to the Shuttle’s Trajectory Control System (TCS).
The system was activated during rendezvous when the Shuttle was approximately 75 km away from the ISS. Once in range of the 3D sensor, TriDAR automatically determined bearing and range to the ISS. During rendezvous, TriDAR entered shape based tracking which provided full 6 degree of freedom guidance and closing rate. Key system information was provided in real-time to the crew via enhanced docking displays on a laptop computer located on the shuttle’s crew compartment.
The system was designed to perform the entire mission autonomously. It self-monitored its tracking solution and automatically re-acquired the ISS if tracking had been lost. TriDAR was also tested during undocking and fly-around operations.
during the STS-131
mission to the International Space Station
. The TriDAR operated during shuttle rendezvous with the ISS, and acquired useful data up till the shuttle R-bar Pitch Maneuver. At that point, a cabling issue resulted in a loss of communications. Using a backup cable for undock and flyaround, the TriDAR operated "flawlessly", according to flight director Richard Jones.
during the STS-135
mission to the International Space Station.
This technology provides the ability to automatically rendezvous and dock with vehicles that were not designed for such operations.
The system includes a 3D active sensor, a thermal imager and Neptec’s model based tracking software. Using only knowledge about the target spacecraft’s geometry and 3D data acquired from the sensor, the system computes the 6 Degree Of Freedom (6DOF) relative pose directly. The computer vision algorithms developed by Neptec allow this process to happen in real-time on a flight computer while achieving the necessary robustness and reliability expected for mission critical operations. Fast data acquisition has been achieved by implementing a smart scanning strategy referred to as More Information Less Data (MILD) where only the necessary data to perform the pose estimation is acquired by the sensor. This strategy minimizes the requirements on acquisition time, data bandwidth, memory and processing power.
The laser triangulation subsystem is largely based on the Laser Camera System (LCS) used to inspect the Space Shuttle’s thermal protection system after each launch.
By multiplexing the two active subsystem’s optical paths, the TriDAR can provide the functionalities of two 3D scanners into a compact package. The subsystems also share the same control and processing electronics thus providing further savings compared to using two separate 3D sensors. A thermal imager is also included to extend the range of the system beyond the LIDAR operating range.
and enabled it to automatically navigate to its destination. Once the rover arrived at its destination, TriDAR was used to acquire high resolution 3D images of the surrounding area, searching for ideal drill sites to obtain lunar samples.
TriDAR applications are not limited to space. TriDAR technology is the basis of Neptec's OPAL product. OPAL provides vision to helicopter crews when their vision has been obscured by brownouts or whiteouts. TriDAR technology can also be applied to numerous terrestrial applications such as automated vehicles, hazard detection, radiotherapy patient positioning, assembly of large structure as well as human body tracking for motion capture or video game controls.
Neptec Design Group
Neptec Design Group is an Ottawa based, Canadian vision systems company, providing machine vision solutions for space, industrial, and military applications. Privately owned and founded in 1990, Neptec is a NASA prime contractor, supplying operational systems to both the Space Shuttle and...
and funded by the Canadian Space Agency and NASA
NASA
The National Aeronautics and Space Administration is the agency of the United States government that is responsible for the nation's civilian space program and for aeronautics and aerospace research...
. It provides guidance information that can be used to guide an unmanned vehicle during rendezvous and docking operations in space. TriDAR does not rely on any reference markers positioned on the target spacecraft. Instead, TriDAR relies on a laser
Laser
A laser is a device that emits light through a process of optical amplification based on the stimulated emission of photons. The term "laser" originated as an acronym for Light Amplification by Stimulated Emission of Radiation...
based 3D sensor
3D scanner
A 3D scanner is a device that analyzes a real-world object or environment to collect data on its shape and possibly its appearance . The collected data can then be used to construct digital, three dimensional models....
and a thermal imager
Thermographic camera
A thermographic camera or infrared camera is a device that forms an image using infrared radiation, similar to a common camera that forms an image using visible light...
. TriDAR’s proprietary software uses the geometric information contained in successive 3D images to match against the known shape of the target object and calculate its position and orientation.
TriDAR made its inaugural demonstration space flight onboard Space Shuttle Discovery
Space Shuttle Discovery
Space Shuttle Discovery is one of the retired orbiters of the Space Shuttle program of NASA, the space agency of the United States, and was operational from its maiden flight, STS-41-D on August 30, 1984, until its final landing during STS-133 on March 9, 2011...
on the STS-128
STS-128
-Crew notes:Nicole Stott was originally scheduled to return aboard Soyuz TMA-15, but a change in the flight plan was made due to the possible flight delays in future shuttle missions, which may extend Canadian astronaut Robert Thirsk's mission beyond the six-month duration preferred for station...
mission, launched on August 28, 2009. On STS-128, TriDAR provided astronauts with real-time guidance information during rendezvous and docking with the International Space Station (ISS). It automatically acquired and tracked the ISS using only knowledge about its shape. This marked the first time a 3D sensor based “targetless” tracking vision system was used in space.
Background
To this date, most operational tracking solutions for pose estimation and tracking on-orbit have relied on cooperative markers placed on the target object(s). The Space Vision SystemAdvanced Space Vision System
The Advanced Space Vision System is a computer vision system designed primarily for International Space Station assembly...
(SVS) used black on white or white on black dot targets. These targets were imaged with Space Shuttle
Space Shuttle
The Space Shuttle was a manned orbital rocket and spacecraft system operated by NASA on 135 missions from 1981 to 2011. The system combined rocket launch, orbital spacecraft, and re-entry spaceplane with modular add-ons...
or International Space Station
International Space Station
The International Space Station is a habitable, artificial satellite in low Earth orbit. The ISS follows the Salyut, Almaz, Cosmos, Skylab, and Mir space stations, as the 11th space station launched, not including the Genesis I and II prototypes...
(ISS) video cameras to compute the relative pose of ISS modules to be assembled.
The Trajectory Control System (TCS) is currently used on board the space shuttle to provide guidance information during rendezvous and docking with the International Space Station (ISS). This laser-based system tracks retro reflectors located on the ISS to provide bearing, range and closing rate information. While reliable, target based systems have operational limitations as targets must be installed on target payloads. This is not always practical or even possible.
For example, servicing existing satellites that don’t have reflectors installed would require a targetless tracking capability.
STS-128
TriDAR was tested for the first time in Space on board Space Shuttle DiscoverySpace Shuttle Discovery
Space Shuttle Discovery is one of the retired orbiters of the Space Shuttle program of NASA, the space agency of the United States, and was operational from its maiden flight, STS-41-D on August 30, 1984, until its final landing during STS-133 on March 9, 2011...
during the STS-128
STS-128
-Crew notes:Nicole Stott was originally scheduled to return aboard Soyuz TMA-15, but a change in the flight plan was made due to the possible flight delays in future shuttle missions, which may extend Canadian astronaut Robert Thirsk's mission beyond the six-month duration preferred for station...
mission to the ISS
ISS
The ISS is the International Space Station.ISS may also refer to:* I See Stars, an American electronic rock band* ISS A/S, a Danish service company* Idea Star Singer, a Malayalam music reality show by Asianet TV...
. The objective of the test was to demonstrate the capability of the TriDAR system to track an object in space without using targets markers such as retro-reflectors. For this mission, TriDAR was located in the payload bay on the Orbiter Docking System (ODS) next to the Shuttle’s Trajectory Control System (TCS).
The system was activated during rendezvous when the Shuttle was approximately 75 km away from the ISS. Once in range of the 3D sensor, TriDAR automatically determined bearing and range to the ISS. During rendezvous, TriDAR entered shape based tracking which provided full 6 degree of freedom guidance and closing rate. Key system information was provided in real-time to the crew via enhanced docking displays on a laptop computer located on the shuttle’s crew compartment.
The system was designed to perform the entire mission autonomously. It self-monitored its tracking solution and automatically re-acquired the ISS if tracking had been lost. TriDAR was also tested during undocking and fly-around operations.
STS-131
TriDAR was again carried onboard Space Shuttle DiscoverySpace Shuttle Discovery
Space Shuttle Discovery is one of the retired orbiters of the Space Shuttle program of NASA, the space agency of the United States, and was operational from its maiden flight, STS-41-D on August 30, 1984, until its final landing during STS-133 on March 9, 2011...
during the STS-131
STS-131
STS-131 was a NASA Space Shuttle mission to the International Space Station . launched on 5 April 2010 at 6:22 am from Kennedy Space Center's launch pad 39A, and landed at 9:08 am on 20 April 2010 on runway 33 at the Kennedy Space Center's Shuttle Landing Facility...
mission to the International Space Station
International Space Station
The International Space Station is a habitable, artificial satellite in low Earth orbit. The ISS follows the Salyut, Almaz, Cosmos, Skylab, and Mir space stations, as the 11th space station launched, not including the Genesis I and II prototypes...
. The TriDAR operated during shuttle rendezvous with the ISS, and acquired useful data up till the shuttle R-bar Pitch Maneuver. At that point, a cabling issue resulted in a loss of communications. Using a backup cable for undock and flyaround, the TriDAR operated "flawlessly", according to flight director Richard Jones.
STS-135
TriDAR will be carried onboard Space Shuttle AtlantisSpace Shuttle Atlantis
The Space Shuttle Atlantis is a retired Space Shuttle orbiter in the Space Shuttle fleet belonging to the National Aeronautics and Space Administration , the spaceflight and space exploration agency of the United States...
during the STS-135
STS-135
STS-135 was the final mission of the American Space Shuttle program. It used the orbiter Atlantis and hardware originally processed for the STS-335 contingency mission, which was not flown. STS-135 launched on 8 July and was originally scheduled to land on 20 July 2011, but the mission was...
mission to the International Space Station.
Capabilities
TriDAR builds on recent developments in 3D sensing technologies and computer vision achieving lighting immunity in space vision systems.This technology provides the ability to automatically rendezvous and dock with vehicles that were not designed for such operations.
The system includes a 3D active sensor, a thermal imager and Neptec’s model based tracking software. Using only knowledge about the target spacecraft’s geometry and 3D data acquired from the sensor, the system computes the 6 Degree Of Freedom (6DOF) relative pose directly. The computer vision algorithms developed by Neptec allow this process to happen in real-time on a flight computer while achieving the necessary robustness and reliability expected for mission critical operations. Fast data acquisition has been achieved by implementing a smart scanning strategy referred to as More Information Less Data (MILD) where only the necessary data to perform the pose estimation is acquired by the sensor. This strategy minimizes the requirements on acquisition time, data bandwidth, memory and processing power.
Hardware
The TriDAR sensor is a hybrid 3D camera that combines auto-synchronous laser triangulation technology with laser radar (LIDAR) in a single optical package. This configuration takes advantage of the complementary nature of these two imaging technologies to provide 3D data at both short and long range without compromising on performance.The laser triangulation subsystem is largely based on the Laser Camera System (LCS) used to inspect the Space Shuttle’s thermal protection system after each launch.
By multiplexing the two active subsystem’s optical paths, the TriDAR can provide the functionalities of two 3D scanners into a compact package. The subsystems also share the same control and processing electronics thus providing further savings compared to using two separate 3D sensors. A thermal imager is also included to extend the range of the system beyond the LIDAR operating range.
Applications
Because of its wide operating range, the TriDAR sensor can be used for several applications within the same mission. TriDAR can be used for rendezvous and docking, planetary landing, rover navigation, site and vehicle inspection. TriDAR's capabilities for planetary exploration have been demonstrated recently during field trials in Hawaii held by NASA and the Canadian Space Agency (CSA). For these tests, TriDAR was mounted on Carnegie Mellon University's Scarab lunar roverScarab (lunar rover)
Scarab is a new generation lunar rover designed to assist astronauts take rock and mineral samples and explore the lunar surface. It is being developed by the Robotics Institute of Carnegie Mellon University, supported by NASA.-See also:* LORAX...
and enabled it to automatically navigate to its destination. Once the rover arrived at its destination, TriDAR was used to acquire high resolution 3D images of the surrounding area, searching for ideal drill sites to obtain lunar samples.
TriDAR applications are not limited to space. TriDAR technology is the basis of Neptec's OPAL product. OPAL provides vision to helicopter crews when their vision has been obscured by brownouts or whiteouts. TriDAR technology can also be applied to numerous terrestrial applications such as automated vehicles, hazard detection, radiotherapy patient positioning, assembly of large structure as well as human body tracking for motion capture or video game controls.