Abstract: It is the first time for ChangE-3 lander landing on an extraterrestrial celestial body in China. Guidance, navigation and control system is one of the most important systems. Guidance, navigation, hazard avoidance and attitude control are demanded strictly for safe landing during powered descent. Adaptive powered explicit guidance, multibeam fault-tolerant navigation and partition quaternion control are proposed for ChangE-3 mission. The results in orbit show that these techniques are reasonable. The landing mission is successful and the performances of landing precision, attitude and velocity are better than the corresponding requirements. This paper presents requirement, composing and technique of ChangE-3 GNC system and results in orbit.

Abstract: Federal Aviation Administration is initiating an Alternative Position, Navigation, and Timing (APNT) program to insure continuous services in the event of GNSS failure. One of the promising solutions is an Optimized Distance Measuring Equipment (DME) Network based on DME/DME navigation. In comparison to other proposed APNT architectures, such as DME pseudolite network and passive Wide-Area Multilateration, airline operators find DME/DME more attractive for backup, as this solution requires no change to avionics used by commercial aircraft. This paper presents the implementation of the DME/DME system on the low-cost, Software Defined Radio (SDR) Nutaq ZeptoSDR platform. The SDR technology was chosen for its flexibility and reconfiguration. In fact, the success of implementing the DME avionic in a SDR platform will provide opportunities to implement other technologies. With such a versatile platform many problems can be avoided in an aircraft like the excessive wiring. To enable DME/DME in a single radio SDR, a new concept: “Sequential DME/DME” is introduced. This paper describes the principle of operation of the system and its implementation. To evaluate the Sequential DME/DME in a laboratory environment, a test bench platform is developed using avionics certification equipment. In lab tests using this platform are conducted to evaluate the system performances and results are presented. The accuracy of the system is studied by examining distance and position measurement precision.

Abstract: Unmanned aerial vehicles (UAV) are successfully exploited in different applications for the last years. To perform successfully the specified tasks they have to rely on navigation and automatic flight control systems. Development of such systems is a complex task that requires comprehensive testing throughout the whole process. This paper presents some recommendations regarding UAV navigation system test validation and some results from the flight experiment approving integrated navigation system efficiency of functioning.

Abstract: The differences in performance of various manufacturers' Flight Management Systems (FMSs) and their associated Flight Management Computers (FMCs) have the potential for significant impact on the air traffic control system and as such need to be examined and reexamined. While Performance Based Navigation (PBN) Area Navigation (RNAV) and Required Navigation Performance (RNP) procedures and routes are designed according to criteria contained in Federal Aviation Administration (FAA) orders, FMC manufacturers build their systems in accordance with Minimum Aviation System Performance Standards (MASPS) and Minimum Operational Performance Standards (MOPS) for area navigation systems, Technical Standard Orders (TSOs) and Advisory Circulars (ACs). It has been shown in previous papers on this subject that the resulting performance of the aircraft FMC will generally meet the procedure design requirements identified in the FAA criteria. However, there are notable differences. A goal of this paper is to provide supporting data for the development of instrument procedures and associated criteria where aircraft operations meet expectations for repeatability and predictability to levels of performance sufficient to support PBN worldwide and specifically in the National Airspace System (NAS) and the Next Generation (NextGen) environment. Sometimes, due to the nearly independent development of procedure design criteria and aircraft performance standards, the paths of various aircraft on the same procedure do not overlap and do not closely match the intent of the procedure designer. This paper is an addition to eight annual studies which began in 2006, (all presented at previous Digital Avionics System Conferences) with the basic title of Analysis of Advanced Flight Management Systems (FMSs), Field Observations Trials. The hypothesis of these papers has been that the FMSs produced by the major avionics manufacturers and installed in various airframe platforms will perform differently and each paper has attempted to quantify those differences. This paper studies Performance Based Navigation to x Landing System (PBN to xLS), where xLS includes instrument (ILS) or Ground Based Augmentation System (GBAS) landing systems (also referred to as GLS), or Space Based Augmentation System (SBAS) landing systems (also referred to as LPV) through analysis of data collected from a series of trials where FMS bench testing devices and high fidelity simulators fly an RNP to ILS approach at selected temperatures. The paper analyzes differences between aircraft models (with specific avionics equipage) and how they transition from Lateral Navigation/Vertical Navigation (LNAV/VNAV) to the ILS Localizer/Glideslope (LOC/GS) given temperature deviations. In addition, MITRE will investigate differences and relationships between what is expected by procedure design and charting and the conditions under which they can be successfully executed by the FMSs and autopilot. The results support the validation of a Matrix Laboratory (MATLAB) [1] tool which has been developed to study the characteristics of such approach designs relative to current aircraft/avionics that might be used to fly them over a range of design and environmental conditions. The approach chosen for this exercise is the RNP to ILS approach, PAKT ILS Z RWY 11, at Ketchikan, Alaska. There are also EUROCONTROL, International Civil Aviation Organization (ICAO) and FAA PBN to xLS projects all over the world and there are reported to be over 200 RNP to ILS approaches published in China, but they are all special procedures coded for specific airlines. For MITRE's purposes, a public procedure that is already coded in Jeppesen, Lufthansa Systems (LIDO) and European Aeronautical Group (EAG) aircraft navigation databases is required and to date, the PAKT procedure is the only public RNP to ILS approach identified by Jeppesen and LIDO. Controlled field observations trials were made using fourteen FMS avionics test benches at seven major FMC manufacturers, and five high fidelity flight simulators at three major airlines. The focus on the subject presented follows The MITRE Corporation's previous analysis of manufacturers' FMSs. The intent of this report is to contribute data, analysis, conclusions and recommendations to industry and the FAA that may influence criteria development to enhance RNAV and RNP operations and to help the FAA establish criteria for PBN to xLS. Some conclusions in this paper propose that a continuously descending path definition for these procedures would be problematic operationally. For high International Standard Atmosphere (ISA) deviations, captures necessarily will be from above, which is behavior that flight crews deem unsatisfactory. It also can cause the systems to capture the GS before the LOC, which is another undesirable consequence. It was further observed that some systems automatically insert a shallower vertical path segment prior to the expected GS capture point which allows for deceleration. Relative to temperature variation in the barometric path however, this segment allows even hot day GS captures to be from below the GS, widening the temperature range over which capture can occur. This was unexpected but a very positive finding. Complete conclusions and recommendations are presented at the end of this paper.

Abstract: It is proposed a new structure of terrain-aided navigation system, developed the algorithms of terrain system and performing of software.

Abstract: This paper presents a proposal for new approach procedures for the most commonly used runways at Malta International Airport, runways 31 and 13, as a basis to facilitate the introduction of optimal descents in Maltese airspace. In addition, a standard arrival, one from the north from where the large majority of aircraft approach Malta, linking to runway 31 is proposed. The design, following ICAO recommendations, is described in detail. Current practice of aircraft inbound from the same entry point, observed using ADS-B recorded data, is also presented in a discussion leading to the identification of gains that could result from flying the proposed arrival and approach routes optimally.

Abstract: The BeiDou Navigation Satellite System, also named BDS for short, is China's second-generation satellite navigation system that will be capable of providing all-weather and seamless positioning, navigation and timing services to users on a continuous worldwide basis. As a GNSS constellation, BDS is being developed and operated by China and will be compatible with other navigation satellite systems worldwide once completed. However, to satisfy the rigorous requirement of civil aviation navigation, more augmentation methods are necessary to improve the performance of BDS. As a method of aircraft based augmented system (ABAS), Receiver Autonomous Integrity Monitoring (RAIM) is still the most prevalent use of satellite navigation system in aircraft today. Airborne GNSS RAIM can monitor the real-time navigation performance using redundant navigation information and it is the last vital key link related to life safety when applying in civil aviation. As the development and implement of BDS, we can use multi-constellation for advanced Receiver Autonomous Integrity Monitoring (ARAIM) on the basis of interoperability between BDS and GPS. Advanced RAIM with multi-constellation has greatly improved the number and geometry of satellites in view which will lead to an BDS.

Abstract: European Air Traffic Management system requires continuous improvements as air traffic is increasingday by day. For this purpose it was developed by international organizations Free Route Airspace and PerformanceBased Navigation concepts that allow to offer a required level of safety, capacity, environmental performance alongwith cost-effectiveness. The aim of the article is to provide detailed analysis of Free Route Airspace and PerformanceBased Navigation implementation status within European region including Ukrainian air navigation system.

Abstract: An Alternative Positioning Navigation and Timing concept, called Diverse Ranging (DivR) is proposed for sustaining NextGen Performance Based Navigation and Automatic Dependent Surveillance - Broadcast during Global Navigation Satellite System outages. The system consists of a network of ground stations providing navigation signaling services to aircraft. The service is provided by using ground stations to selectively reply to the spontaneous broadcast messages of a small subset of aircraft. These new messages allow avionics to calculate positions in two modes – the Direct-Reply (DR) mode and Non-Reply (NR) mode. The DR mode is used by aircraft receiving addressed replies from the ground stations and is based on observed round-trip range measurements. The NR mode is used by aircraft receiving ground station replies that are addressed to other aircraft, and the processing is based on pseudorange and echoed pseudorange measurements. Timing signal broadcasts are also sent by the ground stations, which are synchronized using aircrafts’ position broadcasts. The following analyses were conducted in order to characterize the performance of DivR: (1) nominal error overbounding and a preliminary Fault Modes and Effects Analysis, (2) initial integrity and continuity risk allocations based on Targeted Level of Safety Fault Tree Analysis, (3) theoretical derivations of the Navigation System Error (NSE) and Horizontal Protection Level (HPL) performance bounds, and (4) a terminal case study based on Washington Dulles International Airport for which the NSE, nominal-condition HPL, and spectrum impact were analyzed. The results show that DivR meets the required navigation accuracy and integrity requirements under nominal conditions for terminal operations in both low and high interference environments, with 99% availability and a 1-sec update interval. Further analyses are required to evaluate the performance under faulted conditions and evaluate time to alert and continuity performance. Timing service synchronization accuracy is expected to be sub-microsecond.

Abstract: In this manuscript, we derive a concept for a four dimensional Required Navigation Performance by extending the existing lateral RNP into the vertical and along-track dimensions. Based on the target level of safety desired by ICAO and traffic on a given route, an along track requirement can be formulated for the traffic using the airway. In the vertical, accuracy requirements at the 99.5% level are already specified within the performance based navigation concept, however monitoring and alerting is not foreseen. Here, we suggest a monitoring technology based on satellite navigation that can also be used to ensure vertical separation in RVSM airspace.

Abstract: Unmanned aerial vehicles (UAV) are used for tasks solution which are early relied for aircrafts. But the solutions of these tasks with help of UAV are simpler and cheaper. For the solution this tasks it is necessary to supply the precise navigation of UAV under the condition of limitations for size, weight for navigation complex. It has been doing with help of MEMS-technology. But it doesn’t supply the high accuracy of the navigation parameters determination. The basic autonomous navigation systems for UAV are inertial navigation systems (INS), but they have a rising time error. These problems are solved by use of additional satellite navigation systems (SNS). Such navigation complex is known as integrated navigation complex (INC). This increases the accuracy of the navigation complex, but leads to a loss of autonomy and noise immunity. Thus, we have a typical conflict: methods that lead to improved accuracy of navigation, while leading to a loss of autonomy and system noise immunity. This contradiction is solved by additional

Abstract: Currently, GPS global positioning system has been in the areas of precise positioning, navigation, timing has been widely used. By GPS-OEM combined with computer and communications technologies, users are able to easily and independently developed to meet the specific needs of GPS systems. Design system based on GPS navigation navigation system requirements package, in-depth study of the main factors affecting the precision of navigation. Several factors made corresponding solutions, implements navigation navigation system the main functions of the software.

Abstract: Performance-Based Navigation (PBN) serves as a cornerstone for transforming the United States (US) National Airspace System (NAS) from a system that primarily relies on ground-based navigation and surveillance to a satellite-based system. The Federal Aviation Administration (FAA) has been leveraging PBN capabilities in the design of advanced arrival and departure procedures in terminal airspace surrounding major US airports. Implementations of PBN procedures have improved system efficiencies and provided operational benefits. Future progress in the design of terminal PBN procedures and further gains in operational efficiencies will increasingly rely on advancing applicable aircraft separation standards that safely capitalize on PBN-enabled improvements in navigation accuracy and precision. Safety assessments of such advances often rely in part on quantitative characterizations of actual navigation performance. The recent implementation and ongoing flight validations of Required Navigation Performance (RNP) and Area Navigation (RNAV) Visual Flight Procedures (RVFP) at The Hartsfield-Jackson Atlanta International Airport (ATL) now enable characterizations of actual navigation performance in terminal operations achieved along straight and curved segments of PBN procedures. This paper reviews key areas for advancing PBN-based terminal arrival and departure operations, describes the methodology developed to acquire and analyze surveillance data of RVFP operations, and presents quantitative characterizations of achieved navigation performance.

Abstract: Advances in aircraft navigation technology (i.e. Performance Based Navigation) have enabled the implementation of precise curved path approaches (i.e., RNP 0.3 w/ RF leg approach procedure) in the terminal airspace which improve flight efficiency and allows safe navigation near high terrain obstacles and airspace occupied by other flows of air traffic. However, the adoption of these technologies by airlines has been slow and haphazard due to uncertainties in the estimates of the benefits of these new approach procedures. This paper describes a methodology and results of an analysis of RNP approach for Runway 13C at MDW airport with the objective of quantifying its benefits from an airlines perspective. Surveillance track data for aircraft flying the approaches to MDW (including aircraft equipped to fly the RNP approach) was combined with meteorological data, operational data and an aircraft fuel burn performance model to estimate the total potential benefits of the RNP approach procedure. The results show the use of RNP approach on the MDW 13C has the potential of saving on average 17.6K gallons of fuel per year for arrivals at MDW by reducing the track distance while performing precise curved path RNP approaches when wind and ceiling/visibility conditions require using the ILS 13C. This corresponds to on average $98K savings in airline direct operation costs. The precise curved path RNP approaches also make the arrival operations to runway 13C at MDW independent from operations at ORD (neighboring airport). This has a potential for saving $38K for MDW arrivals from elimination of holding patterns. The implications of these results with respect to successful implementation of RNP approach at MDW have also been discussed.

Abstract: To complete the air operation,the small unmanned helicopter not only needs the exact navigation data for the flight control,but also needs installing other equipment to complete the work. This paper designed an algorithm of integrated navigation system based on GPS correction,and fused the multi sensors data by Kalman filtering.It maintained the autonomy of the strap- down inertial navigation system,eliminated the error accumulation,and improved the reliability of integrated navigation system. The system has been used in the flight control system of small unmanned helicopter,and the experimental results verify the effectiveness of the algorithm.

Abstract: The characteristics and influencing factors of flight technical error(FTE)in performance based navigation(PBN)were analyzed in terms of human factors,aircraft performances and environmental factors.The research and statistical analysis of FTE estimation based on flight experiments were discussed according to navigation schemes and certain operation configurations,and the limitations of the methods were discussed.The estimation models and methods of FTE variance based on moulding mechanism were researched,and the characteristicsand applied ranges of different methods were discussed.The limitations of current researches and expectation of further work were analyzed in terms of FTE estimation method and FTE application.Analysis result indicates that the effect of flying strategy on FTE is prominent when the manual mode is active.Furthermore,lateral FTE is inversely correlated with the sensitivity of course deviation indicator.The standard deviations of lateral FTE for certain general aviation aircrafts are as much as 759.32 and 481.52 m,and the main cause is lack of high-precision onboard navigation system.The FTE estimation method based on fitting flight experiment data has certain limitation because it can not cover all aircraft types,flight segments or weather conditions.The standard deviations of lateral and vertical FTE are 2.68 and 1.13 mrespectively because of using moulding mechanism.The method is proved to be effective through the comparison of both simulation result and test data.The onboard navigation equipment using a certain constant in substitute of real-time FTE estimation will endanger the aircraft.An important research direction in the future is to diminish the FTE in PBN with the consideration of multiple coupled factors.1tab,2figs,54 refs.

Abstract: We describes an operational concept in this paper, it enables increased airspace and airport capacity by using the Flight Management System (FMS), Required Navigation Performance capabilities (RNP) and air traffic management automation tools. This concept can be applied to en route and terminal operation. It realizes ground to air communication by using of voice and data chain. This paper analyzes several key performance parameters which affect arrival management process. This concept models the arrivals by using the performance modeling approach. The results of the modeling proves several factors that influence the delivery accuracy and delay in the arrival process ,these factors include the path and speed discretization, wind, trajectory prediction and navigation performance.

Abstract: The global positioning system (GPS) is the core element of the next-generation communication, navigation, surveillance, and air traffic management (CNS/ATM) system. However, GPS signals are vulnerable to radio-frequency interference (RFI), which can significantly impact the normal operation of the CNS/ATM system. In order to maintain CNS/ATM system operation during GPS outages and to meet safety requirements, an alternative positioning, navigation and timing (APNT) based on a radio link of the automatic dependent surveillance-broadcast (ADS-B) can be used. This study first evaluates two navigation algorithms for an ADS-B radio link, and the real aircraft ADS-B data collected at the civil aviation authorized ground stations are used to evaluate the positioning performance of the proposed backup aviation navigation and surveillance system. In addition, the main factor affecting the positioning performance of the radio navigation system is the geometric distribution of ground stations. Therefore, the geometric distribution of the actual ADS-B ground stations in the CNS/ATM system is evaluated using horizontal dilution of precision for a specific flight information region. Overall, the results of the actual flight data show that it is highly feasible to apply the ADS-B radio link as an APNT solution.

Abstract: An aircraft navigation system and method of navigating an aircraft are proposed. The system (1) comprises a civil-certified GPS-receiver (3) for determining first position information based on C/A-GPS-signals and a military-type GPS-receiver (5) for determining a second position information based on P(Y)-GPS-signals. The system (1) is adapted to issue aircraft navigation signals based on the first position information when the aircraft is flying under normal navigation conditions in civil airspace. A monitoring unit (7) detects a first abnormal navigation condition upon occurrence of jamming conditions within the C/A-GPS-signals. Furthermore, it compares the first position information with the second position information and detects a second abnormal navigation condition upon occurrence of a difference between these position information being larger than a threshold value for more than a threshold duration. Upon detection of an abnormal navigation condition, an alert procedure such as transmitting a warning signal to a pilot is initiated. In a particular application in remotely piloted aircraft, Command & Control link-loss is additionally monitored and in case of link-loss, a transponder code is automatically set to issuing a signal indicating communication failure. Furthermore, when in such situation an abnormal navigation condition is additionally detected, a transponder code is set for issuing a signal indicating airborne emergency and, subsequently, the aircraft navigation system (1) is switched to navigating based on position information from the military-type GPS-receiver (5).

Abstract: Based on GPS/INS integrated navigation algorithm, The simulation of integrated navigation process is designed, comparing the accuracy advantages in contrast to pure inertial navigation; Based on the search model of terminal guidance radar, the hit probability calculation module of anti-ship missile is designed. The two modules form the GPS/INS integrated navigation simulation software, which can be used as a visualization platform for study of inertial navigation algorithm, integrated navigation algorithm and hit probability calculation, and also provide a powerful tool for the missile design.

Abstract: Summary The article analyses new trends in aircraft control under instrument flight rules. It describes the possibilities of using conventional area navigation methods with GNSS devices in approach phase. The authors describe the actual possibilities of using GNSS, especially GPS system, during navigation. In the next part, arrival and departure RNAV routes that are actually in use are described. The article also discusses briefing and preparation for RNAV approaches and describes requirements for the aircrew.

Abstract: As part of the Next Generation Air Transportation System (NextGen) initiative, a redevelopment of the high-altitude airspace is underway to realize the benefits of area navigation (RNAV) capabilities. Three nomenclatures were evaluated as possible alternatives to the current waypoint nomenclature used in the Navigation Reference System (NRS). A part-task study was conducted to assess if speed of NRS waypoint location on an en route chart, speed of flight management system (FMS) entry, number of FMS entry errors, and NRS waypoint reroute use were different among the nomenclatures tested. Overall preference was also assessed.

Abstract: The following work will be aiming to investigate the level of how the airspace is being operated under the current conditions and propose the most appealing way to be implemented in order to meet the requirements of capacity increase. Air Traffic Management operates a set of services aiming primary at ensuring safety of flights. The services in Europe are provided by various ATM systems, including controllers, control centers and airports, managing approximately of 30000 daily flights and providing aircraft separations, collision preventing and providing information. The assuring predictions made for the year 2030, is estimated for Air Traffic to double. If nothing will be done we are to be expected, flight cancellations, missed connections and negative impact on safety. Traffic growth cannot be sustained with the current divided air navigation services organization and some ageing ATM technologies. It must be recognized that the air transport must be grown in a sustainable manner, where the future of European ATM system will cope with expected growth in air Traffic. There is a need for one simplified European framework to cope safely with the increased demand. Hence a new Air Traffic Management System is required for the benefit of the European Sky. The possible solutions for the traffic management is provided by SESAR, the goal of which is to enable EU skies to handle 3 times more traffic, improving safety of flights and decreasing of ATM cost and cost per flight. The creating of change of change in European ATM will demonstrate the ability to deliver benefits to the Air Transport community. A performance-based approach will be used for the development of the future ATM system, with common objective: to handle up to three times more traffic than today and decrease in ATM cost per flight. (by 2020) The area navigation and navigation performance specifications have to be globally harmonized for a set of Performance Based Navigation, which defines the performance requirements for aircraft navigation within the Air Traffic Service route. By simulating the possible outcome for the future planning, we will look into how or which of the ways is more attractive to be applied in order to meet the requirements of increasing capacity, in the airspace field. For this we will use Nest desktop application, used by the EUROCONTROL, for airspace structure design and development, preparing scenario for fast and real time simulation. Nest is a scenario-based tool, where we can make changes to the original dataset scenario to model an unlimited number of different operation planning options, also to generate future traffic samples using traffic growth forecasts provided by STATFOR (Statistics and Forecasts). Data will be taken from the Demand Data Repository project, objective of which is to provide airspace users with the a potential accurate outcome of the past and future European air traffic demand, to meet their planning and monitoring needs.

Abstract: Current satellite navigation systems include global (GPS, GLONASS, Galileo), regional (SBAS, QZSS, Compass, IRNSS) and local systems (GBAS, hybrid systems combining GNSS and other sensors). The use of Global Navigation Systems for safety critical applications, and therefore for the implementation of the PBN (Performance Based Navigation) requires certain levels of confidence on the positioning obtained by the user equipment. This is possible by complementing the core GNSS signals with other systems or techniques to produce a solution with the needed level of integrity. Taking into account the current trends observed in the navigation community, it is expected that, for the coming years, the GNSS integrity solutions may rely on SBAS, GBAS, RAIM or new techniques including integration with other sensors. In this global GNSS picture, SBAS appears as a feasible solution to regionally augment the GNSS constellations to provide increased accuracy with integrity. WAAS, EGNOS, MSAS and GAGAN are operational SBAS systems. Additionally, there are other SBAS systems that are currently under development, such as SDCM in Russia, or under study as it is the case of SACCSA (Solucion de Aumentacion para el Caribe, Centro y Sudamerica / Augmentation Solution for the Caribbean, Centro and South America) program in Latin-America (ICAO Regional Project RLA/03/902). SBAS technology provides benefits not only to aviation users but also from a multimodal user perspective. Even if aviation community is clearly the motto of SBAS technology, most part of the users of SBAS systems are multimodal users (i.e. non-aviation community). At equatorial latitudes, the ionosphere can become a significant problem on GNSS and in particular on SBAS and GBAS technologies in comparison with other regions of the world. The ionosphere affects electromagnetic signals broadcast by GNSS satellites by delaying the propagation of the code and in some cases by losing the track of the satellite signal. The main problems associated to the equatorial region are: 1) the presence of the equatorial anomaly, that complicates the ionospheric modelling for systems like SBAS; 2) the presence of small scale electron density irregularities in the F region that cause scintillations on the received signals; and 3) the presence of ionospheric bubbles or depletions, which are strong reductions in the ionospheric F-region plasma density due to the appearance of a Rayleigh-Taylor instability in the post-sunset, producing severe radio signal disruptions when crossing them. During high solar activity GPS mono-frequency receivers provide degraded accuracy performances in equatorial regions. Using a SBAS solution would significantly improve the performances of GPS receivers (most mass-market receivers with SBAS capability) providing a high benefit for different user communities such as agriculture, farming, aviation (airports), maritime (including fluvial navigation), rail, oil and energy industry (including off-shore), road transport (AVL systems, dangerous goods transport) and LBS (Location Based Service). Additionally to the expected improvement in accuracy and availability, SBAS technology can provide reliability allowing the user the capability of computing Protection Levels that could be used as a guarantee of the SBAS positioning. It is also important to recall that most GNSS augmentation systems have been initially designed for mid-latitude ionospheric conditions and therefore a significant worsening at performance level is expected when applying the mid-latitude algorithms and configurations to equatorial regions. The main objective of this paper is to present a performance analysis using real data and the algorithms developed by GMV for low latitudes and for different equatorial regions in the World (South America, Africa, Middle-East and South Asia). Different ionospheric conditions (low – high solar activity) are to be taken into account, with the aim also of taking advantage of the current solar maximum conditions and the increasing number of stations available. The regions and ionospheric activity conditions considered will depend on the availability of data. The performance analysis has been done using a platform developed by GMV, magicSBAS, which is an SBAS Augmentation System demonstrator that collects multiconstellation GNSS data (measurements and ephemeris) from a regional network of reference stations where available, computes satellite orbits and clocks, ionospheric and integrity information in accordance with ICAO SARPS standards. Thanks to this powerful platform, important implementation advances have been achieved in equatorial regions. In order to analyse the performances achieved at user level in equatorial regions for different solar conditions, two different kinds of analysis have been performed, using as input the information generated by magicSBAS: • SBAS performance assessment in both pseudorange and position domains: Errors in pseudo-range and user domains will be estimated using GMV´s eclayr tool: SREW (Satellite Ranging Error at Worst user location), GIVDerror (Grid Ionospheric Vertical Delay Error) and Position Error (HPE and VPE). UDRE (User Differential Range Error), GIVE (Grid Ionospheric Vertical Error) and Protection Levels (HPL and VPL) will be also estimated and these boundaries will be compared with their corresponding errors and alarm limits to check integrity and availability. • Comparison of performances obtained in presence of high and low ionospheric activity and with/without the augmentation of the SBAS: in order to analyze the improvement in performances gained with a SBAS-like technology for multimodal users, GMV´s magicGEMINI tool will be used. The SBAS messages generated with magicSBAS and the corresponding GPS observation files will be used as input to magicGEMINI, which is a GNSS performance assessment and monitoring tool specifically designed to meet the needs of air navigation service providers and airspace users. Finally, the paper also compares the performance results achieved for the different regions analysed in this paper and provides a summary of the main limitations for SBAS technologies in equatorial regions.

Abstract: Two multisensor system architectures for navigation and guidance of small Unmanned Aircraft (UA) are presented and compared. The main objective of our research is to design a compact, light and relatively inexpensive system capable of providing the required navigation performance in all phases of flight of small UA, with a special focus on precision approach and landing, where Vision Based Navigation (VBN) techniques can be fully exploited in a multisensor integrated architecture. Various existing techniques for VBN are compared and the Appearance-Based Navigation (ABN) approach is selected for implementation. Feature extraction and optical flow techniques are employed to estimate flight parameters such as roll angle, pitch angle, deviation from the runway centreline and body rates.