Automatic Dependent Surveillance-Broadcast (ADS-B) is an air traffic surveillance system in which aircraft broadcast GPS position, velocity and status on 1090 MHz at random intervals between 0.4 and 0.6 seconds. ADS-B...Automatic Dependent Surveillance-Broadcast (ADS-B) is an air traffic surveillance system in which aircraft broadcast GPS position, velocity and status on 1090 MHz at random intervals between 0.4 and 0.6 seconds. ADS-B networks for air traffic monitoring have been implemented worldwide, but ground stations cannot be installed in oceanic regions, leaving these areas uncovered. A solution for tracking aircraft over the ocean is through the monitoring of ADS-B signals by using spaceborne receivers. The Royal Military College of Canada has developed an ADS-B receiver that is scheduled to fly as a technology demonstrator on the Canadian Advanced Nanospace eXperiment-7 (CanX-7) nanosatellite. The payload will collect ADS-B data over the North Atlantic that will be compared to truth data provided by air traffic services. A potential issue for the CanX-7 payload is signal collisions. The extended footprint of the satellite coverage means that a large number of aircraft may be in view at any one time, leading to ADS-B messages that arrive simultaneously at the receiver not being decoded. A simulation of CanX-7 passage over the operations area was carried out to calculate the probability of signal collisions. Using the Aloha Protocol, it was determined that the loss of information as a result of signal collisions is well within the standards of ground based radars used by air traffic system agencies.展开更多
Devices participating in mobile ad hoc networks (MANET) are expected to strictly adhere to a uniform routing protocol to route data packets among themselves. Unfortunately, MANET devices, composed of untrustworthy sof...Devices participating in mobile ad hoc networks (MANET) are expected to strictly adhere to a uniform routing protocol to route data packets among themselves. Unfortunately, MANET devices, composed of untrustworthy software and hardware components, expose a large attack surface. This can be exploited by attackers to gain control over one or more devices, and wreak havoc on the MANET subnet. The approach presented in this paper to secure MANETs restricts the attack surface to a?single module?in MANET devices a trusted MANET module (TMM). TMMs are deliberately constrained to demand only modest memory and computational resources in the interest of further reducing the attack surface. The specific contribution of this paper is a precise characterization of simple TMM functionality suitable for any distance vector based routing protocol, to realize the broad assurance that “any node that fails to abide by the routing protocol will not be able to participate in the MANET”.展开更多
文摘Automatic Dependent Surveillance-Broadcast (ADS-B) is an air traffic surveillance system in which aircraft broadcast GPS position, velocity and status on 1090 MHz at random intervals between 0.4 and 0.6 seconds. ADS-B networks for air traffic monitoring have been implemented worldwide, but ground stations cannot be installed in oceanic regions, leaving these areas uncovered. A solution for tracking aircraft over the ocean is through the monitoring of ADS-B signals by using spaceborne receivers. The Royal Military College of Canada has developed an ADS-B receiver that is scheduled to fly as a technology demonstrator on the Canadian Advanced Nanospace eXperiment-7 (CanX-7) nanosatellite. The payload will collect ADS-B data over the North Atlantic that will be compared to truth data provided by air traffic services. A potential issue for the CanX-7 payload is signal collisions. The extended footprint of the satellite coverage means that a large number of aircraft may be in view at any one time, leading to ADS-B messages that arrive simultaneously at the receiver not being decoded. A simulation of CanX-7 passage over the operations area was carried out to calculate the probability of signal collisions. Using the Aloha Protocol, it was determined that the loss of information as a result of signal collisions is well within the standards of ground based radars used by air traffic system agencies.
文摘Devices participating in mobile ad hoc networks (MANET) are expected to strictly adhere to a uniform routing protocol to route data packets among themselves. Unfortunately, MANET devices, composed of untrustworthy software and hardware components, expose a large attack surface. This can be exploited by attackers to gain control over one or more devices, and wreak havoc on the MANET subnet. The approach presented in this paper to secure MANETs restricts the attack surface to a?single module?in MANET devices a trusted MANET module (TMM). TMMs are deliberately constrained to demand only modest memory and computational resources in the interest of further reducing the attack surface. The specific contribution of this paper is a precise characterization of simple TMM functionality suitable for any distance vector based routing protocol, to realize the broad assurance that “any node that fails to abide by the routing protocol will not be able to participate in the MANET”.
