Space Communications

In this introductory paper, a discussion of natural threats and recent history will show the global extent of disasters, and introduce some problems and issues. A set of temporal phases for describing a disaster scenario are prediction, detection, warning, location, and response/mitigation. Communications aspects of each phase are identified. Three clear roles for satellite systems are noted and relevant papers from this issue are listed by role. Communications interoperability, a major obstacle presenting both technical and institutional challenges, will be discussed. We will then illustrate an overall systems response to the problems, involving two way connectivity with a central disaster database, maintained by a disaster management center. High Data rate (wideband) communications in the disaster area as well as to a remote connection to the center and Internet are needed capabilities. These concepts and responsive systems are described or implied in the papers of this issue and the discussion in this paper places these papers in an overall context.

This paper describes an existing worldwide satellite system – Cospas‐Sarsat – that provides the valuable, humanitarian service of pinpointing the locations of disaster survivors. The system demonstrates international cooperation in space and is used in many applications. This system is unique in the way that it is funded and operated, while its use remains free of charge to the end‐user in distress.

Cospas‐Sarsat, an international satellite system for search and rescue, began operations in 1982, and has been credited with saving thousands of lives since then. Hundreds of thousands of aviators, mariners and land users worldwide are equipped with Cospas‐Sarsat distress beacons, which could help save their lives in emergency situations anywhere in the world.

This paper outlines system design and operation. Cospas‐Sarsat satellites provide global coverage searching for user distress signals. Tracking stations on six continents receive the satellite‐relayed distress signals, compute the locations of the distress events and initiate calls for help to the appropriate rescue authorities. The paper presents the evolution, current status and future plans of the system and describes some real distress cases where it helped save lives.

The Iridium low earth orbit satellite (LEOS) system is a powerful communications tool with applications for disaster relief and recovery efforts. It requires no local ground infrastructure, uses small, low power communications units with small antennas, and has both voice and data capabilities.

Coverage is truly global. While local conditions can impose a few limitations on connectivity, an Iridium user can connect from anywhere on the planet, providing only that his antenna (which can be outdoors, remote from the user's terminal) can get a clear view of the sky.

Iridium provides both voice and data modes. In data mode, users can connect from one Iridium unit to another Iridium unit, to the Internet, or to the public switched telephone network (PSTN). Similarly, in voice mode, a user can call another Iridium phone, or go via the ground station and the PSTN to any phone in the world. Iridium also provides pager service.

With its basic capabilities and special features, Iridium can provide individuals and groups involved in disaster relief or recovery with an efficient, low‐cost, reliable, and very portable system for communications.

A disaster monitoring, management and mitigation (DM3) system using satellite communications technologies has been developed through cooperation of the Communications Research Laboratory (CRL), the National Space Development Agency of Japan (NASDA) and the Asian Disaster Reduction Center (ADRC). The DM3 system includes an airborne video and still photo data acquisition, relay from the aircraft via Ka‐band satellite communications, and a model disaster management center which houses a computer data base accessible from the Internet. The DM3 SATCOM system can provide real‐time and bi‐directional communication capabilities for disaster monitoring using various mobile terminals, which can be installed on airplanes, helicopters and land vehicles. Internet delivery of disaster information from a disaster management center to public or professional organizations for disaster mitigation is available, and users can easily search images of particular disaster areas using commercially available Internet browsers. In this paper, we present the disaster monitoring system using a satellite terminal installed on an airplane, which can transmit and receive MPEG‐II moving pictures at data rates up to 8.5 Mbps using via existing Ka‐band (30/20 GHz) satellites. The terminal uses a 35 cm diameter Cassegrain antenna and a 100 W transmitter.

Emergency personnel responding to large‐scale disasters like those of 9/11/2001 require rapidly deployable integrated high‐capacity communications systems. This paper discusses the technical characteristics of such systems and describes one that the authors are developing under US government sponsorship. The system operates in the 28–30 GHz band, using radio technology originally developed for satellite links. We describe its important features and speculate about how it could be linked with a Ka‐band satellite network.

Survey activity identified more than one hundred needs for standards to facilitate communications among government and public service entities that respond to disasters and other emergency incidents. Message Sets for Incident Management was designated one of the seventeen most critical standards for Intelligent Transportation Systems.

Government agencies and professional societies established the IEEE Incident Management Working Group (IMWG) to develop message sets for incident management. IMWG has been tasked to develop a standard that is open, flexible, and interoperable, to enable common communications between all incident management agencies. This will be accomplished through the participation and representation of relevant associations and agencies – law enforcement, fire and rescue, medical, and hazardous materials (HAZMAT), industry, and the academic community.

The process for development and progress toward the standard IEEE1512 are outlined. Message standards including detailed definitions of terms to insure proper understanding are incorporated. Message sets are validated through table top exercises involving operational personnel. Major portions of the standard are complete and have been published. It is anticipated that this standard will greatly enhance disaster communications efficiency and effectiveness.

The role of telecommunications in general throughout an emergency management situation is outlined. No single telecommunications system can meet all emergency management needs. Consequently, interoperability among systems and protocols is a major issue. The increasing use of Internet Protocol based applications has alleviated some of those concerns. However, because space based technologies are in widespread use for management of most major events, and since Internet Protocol is intolerant of high latency, satellite‐specific techniques to mitigate latency should be adopted. The increasing use of the Global Positioning System for personnel and asset tracking is noted. The paper concludes by providing an overview of Canadian solutions to three differing disaster scenarios: a specific threat to a specific region; emergencies requiring communication with moving vehicles by satellite; and a system having a full feature set which can be transported to a major incident site. Created through three independent projects, these systems provide Canada with broad communications capabilities for meeting the needs imposed by disasters.