國際民航組織（ICAO）作為聯(lián)合國的專門機(jī)構(gòu)，主要因應(yīng)AF447和MH370航班失蹤事件而建立了全球航空遇險(xiǎn)和安全系統(tǒng)（GADSS）。GADSS包含的標(biāo)準(zhǔn)和建議措施（SARP）規(guī)定了航空公司和飛機(jī)運(yùn)營商在正常情況下以及飛機(jī)遇險(xiǎn)時(shí)的飛機(jī)跟蹤要求。
GADSS起源和推進(jìn)情況自2014年3月8日馬航MH370航班發(fā)生失聯(lián)事件后，國際民航組織（ICAO）充分吸取事件本身所暴露出的安全隱患，即看似配置了多種類型高技術(shù)含量地空監(jiān)視手段的現(xiàn)代大型飛機(jī)，實(shí)際上缺乏一種自動(dòng)、自主、不受第三方影響的的地空實(shí)時(shí)險(xiǎn)情報(bào)告手段，導(dǎo)致飛機(jī)遇險(xiǎn)時(shí)地面不容易得到實(shí)時(shí)準(zhǔn)確的情況報(bào)告。此外，當(dāng)前地面對(duì)飛機(jī)的監(jiān)控主要依靠雷達(dá)，但雷達(dá)覆蓋范圍一般為從海岸向外延伸350公里左右。這意味著，當(dāng)飛機(jī)在跨海飛行或者在偏遠(yuǎn)地區(qū)飛行時(shí)，由于信號(hào)覆蓋不到而無法被地面控制中心掌控精確位置和實(shí)際運(yùn)行狀態(tài)。一旦發(fā)生意外情況，定位和搜救將十分困難
馬來西亞航空公司MH370客機(jī)失聯(lián)事件促使人們開始關(guān)注如何全程追蹤一架飛機(jī)，我們?cè)撊绾伪Ｕ弦患茱w機(jī)"看得見，聽得到，管得住"。為此，近年來，世界航空界大力開展自主的全球范圍內(nèi)航空器監(jiān)控工作，從而啟動(dòng)了全球飛機(jī)遇險(xiǎn)跟蹤系統(tǒng)（GADSS）的相關(guān)工作。
GADSS系統(tǒng)的基本理念是通過發(fā)送遇險(xiǎn)信號(hào)來應(yīng)對(duì)諸如通信系統(tǒng)被非法侵入的挑戰(zhàn)，該遇險(xiǎn)信號(hào)的發(fā)送獨(dú)立于其他機(jī)載系統(tǒng)，當(dāng)飛機(jī)飛行高度、速度等出現(xiàn)異常或動(dòng)力系統(tǒng)失靈等特殊情況時(shí)候，該系統(tǒng)基于特定的觸發(fā)規(guī)則就會(huì)自動(dòng)發(fā)送信號(hào)，從而實(shí)現(xiàn) “危險(xiǎn)自動(dòng)跟蹤”（ADT）信號(hào)的要求當(dāng)飛機(jī)進(jìn)入異常狀態(tài)時(shí)，由飛機(jī)上獨(dú)立的系統(tǒng)自動(dòng)的按照一定的時(shí)間間隔，周期性的報(bào)告飛機(jī)經(jīng)緯度等必要信息。ICAO 于2016年3月起正式實(shí)施這些改進(jìn)意見，并增加了新的標(biāo)準(zhǔn)和推薦措施（SARP）。
正常的飛機(jī)跟蹤SARP從2018年11月開始生效，其中規(guī)定，航空運(yùn)營人有責(zé)任在其整個(gè)運(yùn)行區(qū)域內(nèi)對(duì)其飛機(jī)進(jìn)行跟蹤。在無法通過空中交通服務(wù)進(jìn)行跟蹤時(shí)，運(yùn)營商應(yīng)至少每15分鐘收到一次飛機(jī)位置。與遇險(xiǎn)飛機(jī)位置有關(guān)的SARP將于2021年1月生效，其中要求對(duì)遇險(xiǎn)飛機(jī)進(jìn)行自動(dòng)跟蹤，并且每分鐘應(yīng)至少更新一次位置。
2017 年 7 月，中國民用航空局發(fā)布了《中國民航航空器追蹤監(jiān)控體系建設(shè)實(shí)施路線圖》。
飛機(jī)通信尋址與報(bào)告系統(tǒng)(ACARS)可以在航空器和地面用戶之間通過甚高頻、高頻或衛(wèi)星數(shù)據(jù)鏈傳輸報(bào)文，實(shí)時(shí)掌握飛機(jī)的空中情況。相比ACARS技術(shù)，廣播式自動(dòng)相關(guān)監(jiān)視(ADS-B)具有更強(qiáng)的實(shí)時(shí)數(shù)據(jù)傳輸能力。隨著航天技術(shù)的成熟與商業(yè)小衛(wèi)星的成本降低，采用星基手段開展空管應(yīng)用逐漸具備了可行性。未來，星基ADS-B衛(wèi)星系統(tǒng)將有效解決陸基地面站覆蓋能力不足的問題，成為空管系統(tǒng)的重要組成部分。
GADSS的關(guān)鍵組成部分如下圖：
AT:正常運(yùn)行期間的飛機(jī)跟蹤——飛機(jī)位置信息需要至少每15分鐘更新一次，并可用于空中交通服務(wù)（ATS）。
ADT:非正常操作期間的自主遇險(xiǎn)跟蹤（ADT）-當(dāng)飛機(jī)處于遇險(xiǎn)狀態(tài)時(shí)，飛機(jī)位置信息將至少每分鐘傳輸一次，無需機(jī)組人員采取行動(dòng)。
PFLR:飛行后的定位和數(shù)據(jù)恢復(fù)-向SAR服務(wù)提供準(zhǔn)確的飛機(jī)位置信息（1海里精度或更好）。
Concept
According to the ICAO Concept of Operations, the Global Aeronautical Distress and Safety System (GADSS) will address all phases of flight under all circumstances including distress. This GADSS will maintain an up‐to‐date record of the aircraft progress and, in case of a crash, forced landing or ditching, the location of survivors, the aircraft and recoverable flight data.
The three main functions of the GDASS are:
Aircraft Tracking
The GDASS Aircraft Tracking function is planned to provide an automated 4 dimensional position (latitude, longitude, altitude and time) at a reporting interval of 15 minutes or less. This reporting interval will result in a reduction of the time necessary to resolve the status of an aircraft or, when necessary, help to locate an aircraft. If air traffic services obtain an aircraft position at 15 minute intervals or less, it will not be necessary for the operator to track the aircraft. However, should the aircraft be operating within an area where ATS obtains the aircraft position at intervals greater than 15 minutes, the operator will be required to ensure that the aircraft is tracked.
In general terms the aircraft tracking function:
Autonomous Distress Tracking
The Autonomous Distress Tracking (ADT) function will be used to identify the location of an aircraft in distress with the aim of establishing the location of an accident site within a 6 NM radius. An aircraft is considered to be in a distress condition when it is in a state that, if the aircraft event is left uncorrected, may result in an accident. Triggering criteria might include items such as unusual attitudes, altitudes or speeds, potential collision with terrain, total loss of thrust on all engines, Mode A squawk codes, and others as defined by the operator.
The ADT function will use on-board systems to broadcast either aircraft position (latitude and longitude), or a distinctive distress signal from which the aircraft position and time can be derived. Once the ADT has been triggered by a distress condition event, the aircraft position information will be transmitted at least once every minute.
Post Flight Localization and Recovery
In the event of an accident, the immediate priority is the rescue of any survivors. The ADT function will greatly reduce the potential search area and even more accurate aircraft position information will be provided through the Post Flight Localization function by means of Emergency Locator Transmitter (ELT) and/or homing signals to guide SAR services on site.
To facilitate the ability to locate the wreckage and recover the flight recorder data after an accident, the post flight localization and recovery function specifies a number of requirements for ELTs, Underwater Locator Beacon (ULB) and flight recorders which are being incorporated into the provisions of ICAO
