Unmanned aircraft systems: A pathway to obtain a design verification report

This paper investigates the feasibility of operating future terrestrial air/ground control links for unmanned aircraft (UA) systems (UAS) in the 5030–5091 MHz band. Any new service proposed for this band must be compatible with the existing Microwave Landing System (MLS) and with the aeronautical-mobile satellite (route) service (AMS(R)S), which also has a spectral allocation in the band. No actual satellite communications (SATCOM) systems are currently using the AMS(R)S allocation, but one has been proposed to meet some of the future needs of satellite-based UAS control links. Our compatibility analysis demonstrates that it is feasible for terrestrial UAS control links to share the band with MLS and SATCOM UAS control links.

The application areas for Unmanned Aircraft (UA) Systems (UAS) are constantly expanding. Aside from providing an attractive alternative in applications that are risky for humans, smaller UAS become highly attractive for applications where use of larger aircraft is not practical. This paper presents the UAS Collaboration Wireless Network (UAS-CWN), a secure and reliable UAS communication mesh-network. This solution is proposed for the circumstances where a large number of UAS are deployed to cooperatively accomplish a mission such as surveillance in hostile environments. The proposed UAS-CWN system provides high fault-tolerance through use of information dispersal algorithm and meanwhile reduces the risk of information exposure to the adversaries via security-enhancing mechanisms. Our evaluation shows promising results. Especially, a UAS-CWN with high security-level settings can withstand losing 30% of the total number of unmaned aircrafts while steadily achieving above 96% data recovery rate.

The control links of small unmanned aircraft (UA) systems (UAS) typically operate in the 72-73, 902-928, and 2400-2483.5 MHz bands. They share those bands with many radio-frequency (RF) emitters that expose the links to the possibility of RF interference (RFI) and resultant control link interruptions. In this analysis we quantitatively assess the potential interference levels to which such links may be subjected. We characterize unlicensed emitters in the bands of interest, and estimate the resultant aggregate RFI levels to which small UAS uplink receivers may be exposed while operating at various altitudes above representative locales within the U.S. We also analyze the potential interference impacts of licensed RF transmitters, which are far less numerous but often individually much more powerful than the unlicensed emitters. We conclude that the possibility of RFI from the two classes of emitters may degrade the reliability of UAS control links operating in these bands, especially in populated areas. However, before any firm conclusions can be drawn from our findings, it will be necessary to validate our methodology by performing field measurements of ambient power densities and uplink performance at typical small-UA altitudes in a variety of locales within U.S. airspace.

The amount of radio spectrum available for command and control (C2) radio links of unmanned aircraft (UA) systems (UAS), and the effectiveness with which that spectrum is used, will strongly affect the eventual number of remotely piloted UAS that can safely operate within U.S. airspace. In this paper we analyze several possible methods for utilizing available UAS C2 spectrum as efficiently as possible. We assess the potential impact of various spectrum-management techniques, including synchronized time-division duplexing and two- and three-dimensional zonal frequency planning, that have been proposed for standalone terrestrial C2 links that will use licensed radio spectrum.

The planned introduction of unmanned aircraft (UA) systems (UAS) into non-segregated civil airspace will require highly reliable radio links to enable remote pilots to maintain operational control and ensure safe operation. The safety-critical functions of those control and non-payload communications (CNPC) links distinguishes them from “payload” links (e.g., area-surveillance data downlinks) that, although essential to UAS missions, are not needed for piloting. Enough spectrum must be allocated to meet the individual and aggregate bandwidth requirements of the CNPC links. Obtaining all the spectrum needed is a major challenge, since competing uses already exist for every usable frequency band of significant size. In this paper we describe our work in preparing for the 2012 World Radiocommunication Conference (WRC-12) to support the quest for protected UAS CNPC spectrum. We analyze the bandwidth requirements of the CNPC system, identify suitable frequency bands, describe a potential system architecture, and demonstrate that such a system can coexist with other radio systems using the same bands.

In order to facilitate the introduction of unmanned aircraft (UA) systems (UAS) into nonsegregated airspace, highly reliable radio control and nonpayload communications (CNPC) links will be required. The International Telecommunication Union Radiocommunication Sector (ITU-R) has estimated in report M.2171 [1] that in the year 2030 a total of 34 MHz of spectrum will be required for terrestrial communications and another 56 MHz will be necessary for satellite communications. This paper addresses only the terrestrial (that is, direct ground/air without satellites) links. Its purpose is to validate, via a concrete example, that all of the terrestrial link requirements can be met within a potential 34 MHz allocation in portions of the L-band (960–1164 MHz) and C-band (5030–5091 MHz). There are many potentially conflicting issues that have to be addressed to satisfy the requirements levied in [1]. All of these requirements are somewhat difficult to satisfy simultaneously; however, a system design that meets the known requirements has been devised. The proposed design should be considered as an “existence proof” that the terrestrial system requirements can indeed be met; it is not necessarily the final link design.

The New York Griffiss Unmanned Aircraft Systems (UAS) Test Site is a designated Federal Aviation Administration (FAA) national UAS test site. With an integrated UAS test facility and airspace covering around 7,000 square miles over central and northern New York State, the test site mission is to promote safe UAS integration into civil airspace through UAS test operations, together with collection and analysis of air traffic surveillance data.Following legislation passed by the U.S. Congress in 2012, the FAA selected New York in 2013 from among 25 applicants as a national UAS flight test site. The FAA noted that the New York planned "to work on developing test and evaluation as well as verification and validation processes under FAA safety oversight." The FAA role for New York was research on "sense and avoid capabilities for UAS and to aid in researching the complexities of integrating UAS into congested northeast airspace."This paper describes the test range data collection and instrumentation capability, employing multiple ground-based air traffic sensors to track both cooperative and noncooperative manned aircraft. Sensors include wide area multilateration (WAM or MLAT), ADS-B, and 3-D primary radars.The original test site concept was to support development of RTCA minimum operational performance standards (MOPS) for ground-based radar air traffic surveillance systems. RTCA standards in this area apply to ability of unmanned aircraft (UA) to remain well clear of and avoid collisions with manned aircraft. The test range would become a proof-of-concept for future ground-based detect and avoid (GBDAA) systems for UAS beyond visual line-of-sight (BVLOS) operations in the airport terminal area and in transition to enroute airspace.In 2015, the New York UAS test range started to support NASA UAS Traffic Management (UTM). This required adding an ability for UAS remote pilots to detect and remain well clear of, not only manned aircraft, but also small UAS operating below 400 ft. above ground level (AGL).A major step in 2016 was a $30 million New York State award to develop a 50-mile Rome to Syracuse New York UTM corridor. The grant, along with state financial support for unmanned and connected systems development, enabled investment in a five-year program for air traffic surveillance, data collection, cyberphysical security, safety risk management, and commercialization.Working with NASA and FAA through succeeding UTM Capability Level demonstrations from 2017 to 2019, New York prepared a foundation to go beyond demonstrations and build a versatile and long-life UTM systems integration and operational testbed covering a wide geographic area.The paper reports on New York UAS Test Site development and lists challenges into the mid-2020s for unmanned applications, focusing on UTM evolution and UTM’s contribution to safe UAS integration into the NAS.

: Recent proliferation of Unmanned Aircraft Systems (UAS) has significantly affected combat operations. Current operational theaters serve as proving grounds for both programmed and experimental UAS; many are successfully supporting the commanders situational awareness requirements. Wartime commanders are increasing their requests for UAS. The Department of Defense's (DOD) subsequent actions to fulfill these requirements attest to their growing relevance. Like many of the technical capabilities fielded as part of DOD transformation, UAS requires communications networking resources to operate in order to realize their maximum potential. However, fully integrating UAS within these operational theaters continues to challenge military leaders. DOD cannot progress on the path to implement its vision of Network Centric Warfare (NCW) without fully integrating UAS into the theater communications network. This paper examines UAS' role in NCW. It starts by providing brief background on NCW and UAS to establish their distinct relevance. Then it addresses three key considerations necessary to fully integrate these two elements: UAS' role in facilitating information dissemination, UAS' role as an aerial communications relay, and UAS' ability to operate within a constrained frequency spectrum environment. It then concludes with recommendations for establishing UAS as a valuable theater asset within the network-centric warfare environment.

A preliminary analysis was conducted of 1,317 U.S. Federal Aviation Administration (FAA) Unmanned Aircraft Systems (UAS) sighting reports collected from the period July 1, 2020 to March 31, 2021. This set is the three most recent calendar quarters of reports recorded by FAA between November 2014 and March 2021, and represents 11% of the total 11,694 reports available. The purpose of this study was to enhance basic knowledge concerning the nature and presence of drones in U.S. airspace; explore the possibility that UAP are recorded in the FAA data; and contribute towards enhanced aviation safety. The sighting reports, almost all originating from pilots, were screened for valid altitude information, confirmation that the recorded incident involved a UAS above ground level (AGL), and duplication. The 1,235 reports remaining were sorted and further reviewed for altitude ranges, instances of close approaches to aircraft, event time of day, UAS descriptions, and any noted characteristics. An unexpectedly large number of drones were found to be flying at surprisingly high altitudes across the U.S. In fact, 93% (1,144 of the 1,235) were flying higher than the FAA legal limit of 400 feet (ft) above ground level; 72% percent (889/1,235) were at or above 1,400 ft; 32% (398/1,235) were at or above 4,100 ft; and 13% (156/1,235) were at or above 8,200 ft. Most observations were made during the day, with 90% (1,109/1,235) reporting daylight viewing. Descriptions of UAS vary widely in size, shape and appearance. Just over half of the report descriptions included color (645/1,235), with some recording multiple colors. In the 645 cases, there were 831 separate notations of color; the colors reported most often were black, white, red, silver, and gray, together comprising more than 80% of the 831 notations. Relatively few reports 16% (197/1,235) had a physical description of the UAP beyond its color. Among these 197 reports, most described were quadcopter drones (165); the others were balloon (17), fixed-wing drone (12), and “object” (3). Size descriptions were found in 8% of the reports (96 of 1,235) and these ranged from “small” to “large,” although the terms are relative and not defined. Of the 60 “small” or “medium” UAS, 21 were observed at more than 4,000 feet AGL, where steady wind becomes a factor. Shapes were rarely reported (13 reports); round, spherical or oval shapes (7 reports) were the most common. These 13 reports of shape included such unusual descriptions as “elliptical, silver-colored drone,” “shiny chrome, oval shaped, UAS with a red stripe,” and “medium-sized, bubble-shaped UAS.” Other unusual descriptions included “UAS with two engines” and “gray, 4 meters long UAS.” Close approaches, one of the primary hazards of UAP, occurred in 20% (241/1,235) of the reports, where UAS flew within an estimated 500 feet of an aircraft in flight. A majority of these close approaches (160) occurred within 300 feet or less. Nine incidents required the reporting aircraft to take evasive maneuvers, and in six, Near-Miss Air Collisions (NMACs) were reported. The FAA is expecting that the number of drones in operation will increase greatly, and possibly double, over the next 1-2 years. Adjusting this study’s 9-month findings to one year and assuming a modest increase of 33% in the total number of drones flying in 2023, the data suggest that 2023 FAA UAS reports could include more than 2,000 drones flying above 400 ft and 1,500 above 4,000 ft; and more than 400 UAS close approaches to aircraft. However, attributing all UAS sightings to drones is problematic in view of the legal and technical difficulties of effective drone performance at high altitudes, such as steady winds, decreasing temperatures below freezing, and the difficulty of control at great distances. Whatever the nature of the reported UAS, potential risks to civil aviation are apparent.

Unmanned aircraft systems (UAS) represent a disruptive technology for aviation within the United States and worldwide. Efforts have been made to develop regulations, policies, and guidance materials to minimize their impact while maintaining an equivalent or sufficient level of safety. A key challenge is that there is no one-size fits all model for UAS. Moreover, there is a variety of UAS operations proposed and ongoing where the traditional file-and-fly model is insufficient. The classification and categorization of UAS and their operations plays a key role in their integration into the National Airspace System (NAS). Current approaches, e.g. the FAA’s Small UAS Aviation Rulemaking Committee, follow traditional schemes regarding size and weight of the aircraft, the airspace in which they fly, and line-of-sight (LOS) versus beyond LOS operations. An alternative approach must be considered. At Embry-Riddle Aeronautical University, a team of researchers is addressing this problem as part of NASA’s UAS NAS Integration program. A survey of literature regarding UAS systems, UAS operations, and NextGen technologies impacting UAS operations was performed. Key differentiating parameters were analyzed using Qualify Function Deployment’s House of Quality to determine the parameters having the greatest impact on safety and NAS integration. From the analysis, an expert system has been developed to map UAS system characteristics (e.g. weight, autonomy, redundancy, etc.) to operational requirements (e.g. airspace, LOS vs. BLOS, operator requirements, maximum distance to landing site, etc.). Likewise, the expert system can map a proposed UAS operation/mission description to UAS system requirements. This paper will present this research. Several straw-man test examples will be reviewed to highlight the performance of the system under realistic UAS system and operational configurations. Lessons learned and future work will be discussed to move toward a tool to assist regulators.

The New York Unmanned Aircraft Systems (UAS) Test Site is developing a next-generation capability for supporting extended UAS beyond line-of-sight (BLOS) operations in airport terminal areas and in transition airspace. The Test Site has set up an instrumented test range to provide air traffic surveillance. This test range currently extends from the Griffiss International Airport, in Rome, New York, and its Class D airspace to about 40 NM to the north. To safely integrate UAS into civil airspace, a robust detect and avoid (DAA) capability is required. RTCA Special Committee (SC) 228 is incorporating ground-based detect and avoid (GBDAA) into minimum operating performance standards (MOPS) for UAS DAA in the current SC-228 Phase Two. SC-228 is also developing GB primary radar MOPS for detecting noncooperating air traffic. SC-228 Phase Two MOPS development scope supports civil UAS equipped to operate under IFR rules in extended UAS operations in Class D, E, and G, airspace, down to but not including ground operations. The guiding RTCA SC-228 Terms of Reference (TORs) focus on both airborne DAA systems (with sensors onboard the unmanned aircraft) and GBDAA sensors. While the SC-228 DAA MOPS scope is limited to large UAS operating under IFR, this paper makes a case that SC-228 MOPS-compliant GBDAA systems can also support small UAS operations in Very Low Level (VLL) airspace. The New York UAS Test Site Griffiss test range system employs multi-sensor fusion, using a combination of primary radar, wide area multilateration, and ADS-B, to track both cooperative and noncooperative air traffic. The system operates in combination with other dedicated air traffic surveillance sensors, including airborne DAA sensors. The system incorporates data collection, storage, and analysis capabilities supporting UAS integration into terminal and transition airspace, with live, virtual and constructive (LVC) simulation capabilities. By repurposing and leveraging mature systems such as ASDE-X and ASSC, the New York UAS Test Site not only avoids development of completely new prototype systems but also secures the advantage of built-in system health and performance monitoring. This paper supports the argument that dedicated capabilities such as those under development at the New York UAS Test Site are necessary to support development of concepts of operation (ConOps) and performance standards for future certification of UAS DAA systems. An instrumented test range will assist in validation of DAA system performance standards. The paper concludes with an example of how multi-sensor fusion in a range instrumentation system can be employed to make the safety case for beyond line-of-sight (BLOS) UAS operation.

The widespread adoption of unmanned aircraft systems (UAS) has fundamentally altered modern combat, expanding beyond reconnaissance to include offensive strikes. Their affordability and accessibility have enabled both state and nonstate actors to integrate UAS into military operations. Despite their increasing use, the impact of UAS on military medical operations remains underrepresented in the literature. This review contextualizes current UAS capabilities and examines their implications for military medicine. The authors conducted a narrative review using PubMed, Google Scholar, and open-source materials to evaluate UAS applications in military medicine. Search terms included "drone," "unmanned aircraft system," "UAV," "UAS," "medical," "military," and "resuscitation." Resources published through December 2024 were screened for relevance. Given limited availability of peer-reviewed research involving the implications of UAS in combat, additional data were drawn from military leadership interviews, media reports, and third-party conflict analyses. This review identified 5 thematic areas: adversarial UAS impacts on force protection and medical evacuation; UAS use for medical resupply; UAS applications in casualty evacuation; integration challenges with airspace control systems; and risks of interference with medical systems from electronic warfare and counter-UAS measures. The rapid proliferation of UAS has created both challenges and opportunities across the military medical continuum. UAS have demonstrated effectiveness in delivering medical supplies, including blood products, critical medications, and portable medical equipment. Deployment of this technology onto the battlefield could significantly reduce logistical constraints in austere environments. Early casualty evacuation (CASEVAC) applications have shown promise, but there are numerous operational limitations including payload capacity, lack of onboard medical personnel, and the need for triage protocols tailored to autonomous evacuation. Additionally, adversarial UAS use presents significant risks to medical operations. Persistent aerial surveillance compromises force protection, while precision strikes and the coordinated use of large numbers of UAS threaten the ability to safely provide point-of-injury care, prolonged field care, CASEVAC, and medical evacuation. These emerging threats challenge long-held assumptions about air superiority and rapid evacuation capabilities. Counter-UAS technologies, electronic warfare, and emerging ethical considerations introduce further complexities to medical operations. As UAS continue to shape the battlefield, military healthcare systems must adapt to both the capabilities and threats they present. Ongoing research, operational testing, and regulatory developments will be critical in integrating UAS into military medicine while mitigating their risks to patient care and medical logistics.

A significant impediment to the regular operations of Unmanned Aircraft Systems (UAS) in non-segregated civil airspace is the concern surrounding loss of the UAS command and control (C2) data link. While a UAS is typically preprogrammed to behave in a prescribed manner in a “lost link” situation, surrounding pilots and Air Traffic Control (ATC) may be unaware of the immediate flight intent of the UAS while it is flying autonomously without C2 link. This makes it difficult or impossible for controllers to predict where the UAS is going and to clear conflicting traffic along the UAS intended course in a timely fashion. This paper describes MITRE's current research investigating autonomous methods for maintaining automated situational awareness onboard the UAS and timely communication from the UAS to ATC, near-by pilots, and other operational personnel during a lost link situation. At MITRE, we have developed a prototype of an onboard UAS Intelligent Analyzer to monitor the state of the UAS during operations, detect link status changes and formulate an appropriate message regarding current flight status and future intent following standardized operational procedures. The message is then converted to a synthesized voice and is available for transmission over internationally recognized aircraft emergency frequencies. This voice message from the UAS without C2 link provides the needed situational awareness to ATC personnel and near-by pilots, and allows for safe and timely response. This prototype has been demonstrated and evaluated in a simulated environment. MITRE believes that an on-board capability to intelligently analyze flight status and develop and initiate appropriate communications in a timely fashion could provide an effective mechanism for ensuring safe UAS operations even in a lost link situation.

Unmanned Aircraft Systems (UAS) are a novel component in the aviation system, offering advancements which may open new and improved civil and military applications. In general employing UAS is considered useful in missions which are either too undemanding (i.e. steady border monitoring) or too dangerous (i.e. natural disaster reconnaissance, adverse terrain or weather) to employ manned aircraft. Unmanned aircraft systems are therefore becoming increasingly important even for non-military and civil applications. A main challenge however is the integration of UAS into the existing and future Air Traffic Management (ATM) system. Integration of UAS into non-segregated airspace remains a major goal to be solved for future acceptance of these systems. Currently, most civil and military UAS operations are taking place in segregated airspace so that collision avoidance and separation with other traffic is of no concern. To further enable the UAS operational scope, Unmanned Aircraft (UA) must be able to fly in airspace where other traffic is operating as well. In this paper, simulation trials are presented in which UAS are operating together with manned aircraft in non-segregated airspace. Different simulation scenarios were hereby investigated. The applied scenarios are based on the execution of two different mission types, a transfer and a surveillance flight. In the simulations the potential risk of collisions in different flight phases of the UA and the applicability of prevailing Air Traffic Control procedures for manned aircraft were examined. Flying UAS in non-segregated airspace may generate risks to other airspace users if they fail to follow the rules valid for this particular airspace. To investigate the potential risks, two exemplary failure scenarios of UAS were integrated into the simulation scenarios. In addition, air traffic controllers (ATCO) were surveyed with regard to workload and their evaluation of the maintenance of safety within the different scenarios.

HighlightsThe FAA has used two exemptions (17261 and 18009) as precedents for approval of numerous agricultural operations for unmanned aircraft systems (UAS).While many operators have received exemptions, a significant portion have not received an agricultural aircraft operator certificate (AAOC), despite the need for both to operate UAS in agricultural operations.Operators who have both an exemption and an AAOC tend to be clustered in geographic areas, with many states without a single such operator.Abstract. Unmanned aircraft systems (UAS) have seen rapid growth in many industries in the U.S. since the introduction of small UAS regulations (14 CFR § 107). However, adoption of UAS for agricultural aerial application has been limited. Two landmark regulatory exemptions by the Federal Aviation Administration (FAA) have laid the foundation for commercial agricultural aerial application with UAS. Since the initial introduction of these exemptions, the pace of new exemptions for agricultural aerial application with UAS has remained steady. By the end of 2019, 64 operators had received exemptions in which the FAA cited one of the two landmark exemptions as a precedent. This study analyzed these exemptions to determine geographic distribution, aircraft manufacturer, number of employees, and time to operator certification. Results indicate that less than half of operators who received an exemption from the FAA became certified for aerial application. Additionally, certified operators were not evenly distributed throughout the U.S. despite the broader distribution of exemption holders. Two UAS manufacturers dominated the market, with over 80% of exemptions requesting UAS from one or both manufacturers. While regulatory hurdles for agricultural aerial application with UAS have been substantially reduced through the introduction of standardized exemptions, this has not resulted in the anticipated influx of certified operators. There are additional impediments preventing operator certification, including technological limitations of currently available UAS, which need to be addressed to improve the rate of UAS integration into agricultural aerial application. Keywords: Chemical applications, Drone, Precision agriculture, UAS, UAV, Unmanned aerial vehicle, Unmanned aircraft systems.