Search and Rescue Operations requirements in GNSS

Transcription

1 Search and Rescue Operations requirements in GNSS Abstract: Unquestionably, the achievement of search and rescue operations essentially depends on the time factor therefore, Search and Rescue SAR operations management developed to provide high reliability, redundancy, and efficiency as to reduce the response time. It planned using the art of technology in supporting Missions management, by integrated search plans with the Global navigation satellite system GNSS advantages of long-term stability and absolute accuracy. The GNSS is a highly promising technology with communication capabilities providing an enhanced Search-and-Rescue SAR-service in combination with the current Cospas-Sarsat system. The accuracy of distress position data is fundamental to SAR missions, and the precise GNSS navigation equipment can be supportive in covering a search area prudently. Moreover, GNSS allows small electronic receivers to determine their location within a few meters using time signals transmitted along a line-of-sight by radio from satellites. The past decade has perceived a fast improvement of several GNSSs. Some of them are already in service and GNSSs still under planning or at partial operational stage, besides others are struggled for many years until being back to full service lately. The paper illustrates the developed features of GNSS/SAR, which increase effectiveness of SAR operation with the contribution of advantages of GNSS by demonstrating between the contribution of SAR on GNSS/GPS GNSS/GLONASS and the recent SAR on GNSS/Galileo the future SAR constellation. Keywords: GNSS SAR- Galileo - Cospas-Sarsat Capt. Sameh K. Rashed Teaching staff member B.Nautical Dept Arab Academy for Science and Technology and Maritime Transport-AASTMT College of maritime transport and technology redmahi@aast.edu redmahi@hotmail.com rd June

2 Introduction Search and Rescue is the heart of civilization. Each year in the world s time, thousands of incidents occur resulting in the need for immense search and rescue efforts to be launched. A national or international Search and Rescue SAR conceder a safety response system that provides specialized lifesaving assistance by specialists in the event of a major disaster or emergency. Search and Rescue considered a multi-hazard system, as it needed for a diversity of emergencies or adversities counting earthquakes, hurricanes, typhoons, storms and maritime emergencies. SAR is an combined conventional services directed by a joint coordinating group responsible for all types of rescue operations sea, land and air. Moreover, SAR services achieves through a supportive efforts involving government interventions, voluntary administrations and private initiatives. Although present search and rescue efforts are wide-ranging and performed with devotion and attentiveness, current techniques employed are tolerable. There is no acknowledgement system available to users in distress. SAR needs presently signalled by secondary inputs. The advent of new technologies, such as GNSS decrease time and the costs of SAR operations and increase rescue rates by finding the lost individual in a quicker period. In addition to, acknowledgement technics art of technology. 1- Origin of the Search and Rescue: Modern search theory arises during World War II, from Allied military, research directed at developing ideal search approaches to detect enemy naval vessels, particularly submarines this effort can be traced back to the work of one man, a mathematician named Bernard Koopman, used possibility to predict and improve search results. However, in 1973 Dennis Kelly applied Koopman s research directly to land based search and rescue operations; Since this event, the search and rescue theory has grown-up and is widely adopted today by authorities the United States Coast Guards is an obvious example. (Zhang et al, 2003) Search theory is about maximizing the probability of success (POS) while minimizing the effort exerted in a search operation. It uses probability and information theory to quantize a search operation from movements to locations. Common search methodology referred to terms of probability of detection (POD), Probability of Success (POS), Probability of Area (POA), effort, sweep width, and coverage. (Nunn, 2003) 2-The core purpose search and rescue system: 2

3 SAR Service is the action of distress surveillance, communication, coordination. This includes the facility of medical advice, initial medical assistance through the procedures of public and private assets, including support of airplane, ships and other installations. The Maritime SAR systems for any regional level recognised to give help and sustenance to people in distress instantly, and to ensure that persons in distress will support without respect to their localities, nationalities, or statuses. The Maritime Search and Rescue Act define the maritime SAR services as the search and rescue of persons in distress at sea, facilities of emergency medical services for them and conduct of radio communications related to an emergency phase. (IAMSAR) SAR system, like any other systems has individual components that must work together to offer the effective consequences. The essence of the maritime SAR system is of recognition, response and reporting, it can be viewed as the corners of the following triangle fig (1). Source: (Rashed, 2011) The response to a SAR occurrence usually proceeds through a sequence of five typical phases. These phases define the nature of SAR assistance provided at any particular time. A SAR episode may not necessarily include each phase, or the phases may overlap as following. (Rashed, 2011) Awareness SAR service becomes attentive of an actual or potential incident. 3

4 Initial Action This phase may include evaluation and classification of the information, alerting of SAR amenities, preliminary communication checks, and in urgent cases, immediate action from other phases. Planning Effective operations plan developed, including plans for search, rescue, and final provision. SAR plan is a general term often associated with three types of plans: a national, regional, or multinational SAR plan. Operations SAR operations are normally coordinated at the lowest practical level within the SAR organization. However, SAR facilities proceed to the scene, conduct searches, rescue survivors, support distressed unit, provide emergency care for survivors, and transport survivors to a suitable facility Conclusion Return SAR units to their regular position, and debriefed, refuelled, replenished, provided with a fresh crew, prepared for another mission and records of the SAR case, which is completed. (Goodrich, 2007) 2-1 Rescue Coordination Centre (RCC) The RCC is responsible for coordination of SAR operations within its assigned SAR Region. Moreover, receive a complete session, including past, existing, and predicting weather, from the relieved watch review all entries in the log pertaining to ongoing missions, failed missions closed during the past 24 hours, and other matters requiring action; stay informed about the mission-ready status of all SAR resources; and, test main lines of communication, as it apt. (IAMSAR) 2-2 Emergency alerting and Communications Persons in distress have a diversity of alerting ways, ranging from sophisticated electronic devices to waving a piece of cloth; SAR personnel should be familiar with emergency signals and devices. The Emergency Position Indicating Radio Beacon (EPIRB), Emergency Locator Transmitter (ELT), and Personal Locator Beacon (PLB) are devices specifically designed to transmit emergency signals to alert the SAR system and that can be located by satellites and by direction finding (DF) equipment. Each device is battery operated and engineered for a particular environment. EPIRBs are maritime devices and as such are required to be waterproof, corrosion resistant and able to float upright on their own (for those designed to float). ELTs built to survive the tremendous force of an aircraft crash. However, they carried inside the aircraft and are usually less waterproof and non-floating. PLBs designed to manually activate and operate on land. 4

5 3- GNSS Search and Rescue: 3-1 Background: Since 1970, the satellite-aided search and rescue commenced, when a plane carrying two U.S congressmen crashed in a remote region of Alaska, immense search and rescue efforts mounted, but to this day, no trace of them or their aircraft ever been found. At the mentioned time, search for missing aircraft conducted by search aircraft flying over thousands of square kilometres trying to find the lost aircraft. Because of this tragedy, Congress recognized this inefficient search method and issued an amendment to the Occupational Safety and Health Act of 1970 requiring most aircraft flying in the United States to carry emergency locator beacons (ELTs) to provide a local homing ability. Then suitable technology established by NASA to detect and find an ELT from ground stations using the beacon signal relayed by satellites to run more coverage that is global. (Ali, 2013) This circumstance generates a highly effective global search and rescue technique of COSPAS- SARSAT (COSPAS is an acronym for the Russian words Cosmicheskaya Sistema Poiska Avariynyh Sudov), which translates to Space System for the Search of Vessels in Distress that relies on SAR payloads on weather satellites in low-earth and geostationary orbits. In 1979 Canada, France, the United States, and the prior Soviet Union established SARSAT which an acronym for Search and Rescue Satellite-Aided Tracking). The system has 43 participating countries and has been involved in saving thousands lives worldwide. (COSPAS-SARSAT, 2014) 4-Types of Satellites Fig (2b) SAR Events Assisted by Cospas- Sarsat Fig (2a)-SAR Events and Persons Rescued with the Assistance of Cospas-Sarsat Alert Source: Cospas sarsat,

6 - Figure (2a) illustrate the number of persons rescued per year from 1991to 2012 by the aids of using COSPAS-SARSAT. the figure illustrates the number of rescued person's effortlessly increased through the period. - Figure (2b) demonstrates the SAR events assisted by Cosapas Sarsat and it's clear that the maritime events have the majority by 43% of the total events. 4-1Low Earth Orbiting Search & Rescue (LEOSAR): - 6 satellites on Orbit - Polar orbiting and 101 to105 min. per orbit - Orbit is 850 km in altitude - Performs Doppler positioning function (primary means of positioning not GPS - Accomplishes Doppler locating occupation - Space segment altitude 850 km in Pole-Pole orbital pass - Stores & Forwards alerts continuously for 48 hours (Provides global coverage twice per day) MHz beacon recognitions can be stored on board the satellite and re-broadcast later. - Provides improved recognition possibility for obstructed beacons that can t be seen by GEOSAR Fig (3) LEOSAR Instantaneous Coverage Source: Cospas sarsat, 2014 Fig (4) - 57 LEOLUTs in 46 Locations Source: Cospas sarsat,

7 4-2 Geostationary Orbiting Search & Rescue (GEOSAR): - 5 satellites on Orbit - Performs instantaneous alerting service and no positioning ability unless beacon fitted out with GPS. No Doppler shift capability - Space segment altitude 36,000 km above the Earth s surface in fixed orbit - Continually monitors a large area of Earth s surface - Coverage from 70N 70S - GEOSAR system does not cover the polar areas. (Cospas SARsat, 2013) Fig (5) - 23 GEOLUTs in 20 Locations Source: Cospas sarsat, Search and Rescue on GPS SAR/GPS : The emergency beacons that uses by mariners and aviators and land users, detected by uses satellites after making the calculations at the control centre LUT. Since the year 1982, search and rescue satellite provides alerts to critical emergency distress and position information to the search units, and SAR services for over 30 years SARSAT provide lifesaving amenities in the rescue of peoples in distress situations. The current system of SARSAT which contains two satellites constellations working to support the global distress are LEO and GEO as it was mentioned before. The SAR global positioning satellite system is the new Generation of to the present SARSAT, which will use SAR payloads in GPS III satellites, it will operate in MEO- orbits. The constellation that equipped with Canadian supplied SAR repeater payloads, use frequency difference of arrival (FDOA) and Time difference of arrival (TDOA) algorithms in reverse triangular calculations to allow near instant global detection and beacon positioning. Overall act of the SAR operations will expand, and more accurate position will gained,(the position error will reduce to about 0.9 NM). 7

8 It will reduce the search time and saving lives by its quicker alerting and the significantly reduce the time needed to detect the beacon in distress (3 minutes, and calculate the estimating beacon position in 5 minutes from the time of activation). Furthermore, the beacon in distress will detect from continually changing angle resulting in reducing land masking, the beacon to satellite link is continuously changing so it provides flexibility against the link between beacon and satellite obstruction what s make it resilience to interference. (U.S. Government, 2014) 6- Search and Rescue on Galileo SAR/Galileo : The role of Europe to the international cooperative efforts on the Search and Rescue programme represented by SAR/Galileo, it provides, backward compatible SAR service through the application of transparent SAR transponders on board Galileo satellites and dissemination of SAR Return Link Messages in the Galileo navigation signal. In addition, it will reduce the false alert rate, which is one of the major shortcomings of the current system and support the three types of 406 MHz SAR Beacons: First- generation beacons: it transmits, after activation, a plain SAR signal. Second-generation beacons: it transmits, after activation, a signal containing its position information. Third- generation beacons: it transmits, after activation, a signal containing its position and have the ability to receive Return Link Messages. The first and second generation beacons defined before by COSPAS-SARSAT system, while the 3 rd generation beacons represent the new, MEOSAR Beacons. 6-1 New supported services: The system will provide two services, the Forward Link Service, that provides message from the SAR beacon to a MEO Local User Terminal of the International SAR Satellite Service and localisation of the beacon by the MEOLUT, and the second service is the Return Link Service that provides message from the SAR ground segment to a 3 rd generation beacon. (Hahn et al, 2002) Forward Link Service (FLS): It is a connection from the SAR beacon to the International SAR Satellite Service MEOLUTs via the Galileo s satellites, through second and third generation; beacons can transmit their position with probability of detection and recovers higher than 99.8%. Moreover, the Forward Link Service is the localisation of first generation beacons by measuring the Times of Arrival (TOA) and the Frequencies of Arrival (FOA) of the SAR signal as relayed by various Galileo SAR Payloads at one time. The position acquired by the processing of the collective TOA&FOA measurements will be better than 5 km within 10 minutes (98% of the time). ( Molina, 2011) 8

9 6-1-2 Return Link Service (RLS): RLS relays return Messages from the Return Link Service Provider (RLSP) to third generation beacons via the Galileo s Navigation Signal. The RLS provides Technical Acknowledgments, after successful detection of third generation beacon, and operational acknowledgements, this service will provides basic data dialogue between the persons in distress and the SAR operators thereby attains many possibilities as it will be better fit the distress situation requirements, improve the psychological state of the persons in distress, and reduce the false alert rate. Satellites SAR Payload Galileo Satellites 1 st Generation - MEO-LUT - MCC Mission uplink 2 nd Generation 3 rd Generation International SAR sat service Ground Seg RLS R Galileo Ground Segment Fig (6) - SAR/GALILIO Component Source: the author 7- The Future enhancements of SAR/SAT: The new SAR constellation will consists of new GPS satellites operated by the United States, navigation satellites of Russia (GLONASS), and European GALILEO navigation satellites, this component of Cospas-Sarsat is known as Medium-altitude Earth Orbit Search and Rescue system- MEOSAR, the combined system once fully started it will drastically improve both the speed and positioning-accuracy for locating beacons in distress. (Aguilera, 2013) As MEOSAR complete operational, it will offer LEOSAR and GEOSAR systems advantages without their current limitations. It will offer transmission of the distress message, and independent location of the beacon, with a near real time global coverage. Moreover, the large number of MEOSAR satellites that will be in orbit when the system is completed, it will allow each distress message to relay at 9

10 the same time by several satellites to several ground antennas, improving the possibility of detection and increase the accuracy of the beacons positioning determination and track it during its movement.(curtis et al, 2004) Fig (7) - The MEOSAR System Concept MEOSAR system aiming to be reliable and accurate, so Cospas-Sarsat enter a Demonstration and Evaluation (D&E) phase for the MEOSAR system at the beginning of 2013, to begin in 2014 and D&E phase is planned to end in 2015 and will be followed by the MEOSAR Initial Operational Capability (IOC) phase. (ICAO, 2014) Conclusion: SAR operations are precious, as it aiming to save lives and help people in distress. The current technique is adequate for the recent time but future require more technologies to increase the efficiency and reliability of the SAR operations. The paper describes, furthermore, the current system and future improved system to ensure backward compatibility with existing COSPAS-SARSAT Beacons, and the Main missions and concept of the MEO Search and Rescue system, and the two provided new services the Forward and the Return Link Service. Moreover, the three MEOSAR satellite constellations will use transparent repeater instruments to relay 406 MHz beacon signals, without on board processing, data storage, or demodulation, which achieves near instantaneous global coverage with accurate independent location capability. 10

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