Showing papers on "Required navigation performance published in 2014"

Next Generation Flight Management System for Real-Time Trajectory Based Operations

Abstract: This paper presents the concept of operations, architecture and trajectory optimisation algorithms of a Next Generation Flight Management System (NG-FMS). The NG-FMS is developed for Four Dimensional (4D) Intent Based Operations (IBO) in the next generation Communications, Navigation, Surveillance and Air Traffic Management system (CNS+A) context. The NG-FMS, primarily responsible for the aircraft navigation and guidance task, acts as a key enabler for achieving higher level of operational efficiency and mitigating environmental impacts both in manned and unmanned aircraft applications. The NG-FMS is interoperable with the future ground based 4DT Planning, Negotiation and Validation (4-PNV) systems, enabling automated Trajectory/Intent Based Operations (TBO/IBO). After the NG-FMS architecture is presented, the key mathematical models describing the trajectory generation and optimisation modes are introduced. A detailed error analysis is performed and the uncertainties affecting the nominal trajectories are studied to obtain the total NG-FMS error budgets. These are compared with the Required Navigation Performance (RNP) values for the various operational flight tasks considered.

Navigation and Guidance System Architectures for Small Unmanned Aircraft Applications

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.

Avionics-Based GNSS Integrity Augmentation for Unmanned Aerial Systems Sense-and-Avoid

Abstract: This paper investigates the synergies between a GNSS Avionics Based Integrity Augmentation (ABIA) system and a novel Unmanned Aerial System (UAS) Sense-and-Avoid (SAA) architecture for cooperative and non-cooperative scenarios. The integration of ABIA with SAA has the potential to provide an integrity-augmented SAA solution that will allow the safe and unrestricted access of UAS to commercial airspace. The candidate SAA system uses Forward-Looking Sensors (FLS) for the non-cooperative case and Automatic Dependent Surveillance-Broadcast (ADS-B) for the cooperative case. In the non-cooperative scenario, the system employs navigation-based image stabilization with image morphology operations and a multi-branch Viterbi filter for obstacle detection, which allows heading estimation. The system utilizes a Track-to-Track (T3) algorithm for data fusion that allows combining data from different tracks obtained with FLS and/or ADS-B depending on the scenario. Successively, it utilizes an Interacting Multiple Model (IMM) algorithm to estimate the state vector allowing a prediction of the intruder trajectory over a specified time horizon. Both in the cooperative and non-cooperative cases, the risk of collision is evaluated by setting a threshold on the Probability Density Function (PDF) of a Near Mid-Air Collision (NMAC) event over the separation area. So, if the specified threshold is exceeded, an avoidance manoeuver is performed based on a heading-based Differential Geometry (DG) algorithm and optimized utilizing a cost function with minimum time constraints and fuel penalty criteria weighted as a function of separation distance. Additionally, the optimised avoidance trajectory considers the constraints imposed by the ABIA in terms of GNSS constellation satellite elevation angles, preventing degradation or losses of navigation data during the whole SAA loop. This integration scheme allows real-time trajectory corrections to re-establish the Required Navigation Performance (RNP) when actual GNSS accuracy degradations and/or data losses take place (e.g., due to aircraft-satellite relative geometry, GNSS receiver tracking, interference, jamming or other external factors). Various simulation case studies were accomplished to evaluate the performance of this Integrity-Augmented SAA (IAS) architecture. The selected host platform was the AEROSONDE Unmanned Aerial Vehicle (UAV) and the simulation cases addressed a variety of cooperative and non-cooperative scenarios in a representative cross-section of the AEROSONDE operational flight envelope. The simulation results show that the proposed IAS architecture is an excellent candidate to perform high-integrity Collision Detection and Resolution (CD&R) utilizing GNSS as the primary source of navigation data, providing solid foundation for future research and developments in this domain.

Application of the Shortest-Path Problem to Routing Terminal Airspace Air Traffic

Abstract: The flight navigation procedures envisioned under the Next Generation Transportation System will require a specification of the expected route of each flight. Once these specifications are provided, the flights must proceed along their routes with such speed profiles that every pair of aircraft complies with the minimal separation requirement imposed by the Federal Aviation Administration. The task of separation assurance is most challenging in terminal airspace, with many routes merging and crossing. This paper contributes a mathematical model and an algorithmic approach for routing flights strategically, with a foresight that potentially helps the subsequent computation of speed profiles compliant with the separation requirements and with each aircraft’s feasible speed range. The approach consists of reducing a general routing problem to the shortest-path problem.

Fuel burn and emissions evaluation for a missed approach procedure performed by a b737-400

Abstract: This paper presents the results of a study conducted at the Laboratoire de recherche en commande active, avionique et aeroservoelasticite, Ecole de technologie superieure, regarding the costs in fuel burn and pollutant emissions corresponding to a flight profile determined by a missed approach procedure. The evaluated missed approach flight profile starts at the point where the missed approach decision is made and ends at the same point, after the aircraft completes the missed approach procedure. This study uses the fuel burn and pollutant emissions data for a Boeing 737-400 aircraft (chosen at random for this study), published by the European Environment Agency, and the standard flying cycle model elaborated by Group 08 of the Task Force on Emissions Inventories and Projections a task force created by the United Nations Economic Commission for Europe (UN ECE) / the co-operative program for the monitoring and evaluation of the long-range transmission of air pollutants in the Europe (EMEP). The missed approach flight profile is based on the Area Navigation/Required Navigation Performance procedure for runway 13R of the King County International Airport/Boeing Field (BFI) in Seattle. Four study cases are considered for the missed approach flight evaluation. These cases correspond to four navigation profiles – a combination of two lateral navigation profiles, one with a 20 nautical miles holding pattern and the other without, and two vertical navigation profiles. The results obtained for the missed approach flight profiles, in terms of fuel burn and emissions, are compared with the fuel burn and emissions reference data corresponding to a standard approach procedure and complete flights (from taxi out to taxi in).

RPAS navigation and guidance systems based on GNSS and other low-cost sensors

Abstract: A new navigation system for small size Remotely Piloted Aircraft Systems (RPAS) is presented, which is based on Global Navigation Satellite System (GNSS), Micro-Electro-Mechanical System (MEMS) based Inertial Measurement Unit (IMU), Vision Based Navigation (VBN) and other low-cost avionics sensors. The objective of this research is to design a compact, lightweight and relatively inexpensive Navigation and Guidance System (NGS) capable of providing the required navigation performance in all phases of flight of a small RPAS, with a special focus on precision approach and landing, where VBN techniques can be fully exploited in a multisensory integrated architecture. Additionally, the potential of carrier-phase GNSS for Attitude Determination (GAD) is explored and a six-degree-of-freedom (6-DoF) Aircraft Dynamics Model (ADM) is adopted to compensate for the MEMS-IMU sensor shortcomings in high-dynamics attitude determination tasks. The NGS data fusion architectures investigated are based on Extended Kalman Filter (EKF) and Unscented Kalman Filter (UKF) approaches. After introducing the key hardware and software features of the NGS, the system performance is evaluated in a small RPAS integration scheme (i.e., AEROSONDE RPAS platform) by exploring a representative cross-section of this RPAS operational flight envelope, including a variety of high dynamics maneuvers and CAT-I to CAT-III precision approach tasks. The performance evaluation shows that the position and attitude accuracies of the proposed integrated navigation and guidance systems are compatible with the Required Navigation Performance (RNP) specified in the various RPAS flight phases, including precision approach down to CAT-II.

GNSS avionics-based Integrity augmentation for RPAS detect-and-avoid applications

Abstract: Taking the move from our recent research on GNSS Avionics Based Integrity Augmentation (ABIA), this article investigates the synergies of ABIA with a novel Detect-and-Avoid (DAA) architecture for Remotely Piloted Aircraft System (RPAS). Based on simulation and experimental data collected on a variety of manned and unmanned aircraft, it was observed that the integration of ABIA with DAA has the potential to provide an integrity-augmented DAA for both cooperative and non-cooperative applications. The candidate DAA system uses various Forward-Looking Sensors (FLS) for the non-cooperative case and Automatic Dependent Surveillance-Broadcast (ADS-B) in addition to TCAS/ASAS for the cooperative case. Both in the cooperative and non-cooperative cases, the risk of collision is evaluated by setting a threshold on the Probability Density Function (PDF) of a Near Mid-Air Collision (NMAC) event over the separation area. So, if the specified threshold is exceeded, an avoidance manoeuvre is performed based on a heading-based Differential Geometry (DG) algorithm and optimized utilizing a cost function with minimum time constraints and fuel penalty criteria weighted as a function of separation distance. Additionally, the optimised avoidance trajectory considers the constraints imposed by the ABIA in terms of RPAS platform dynamics and GNSS constellation satellite elevation angles, preventing degradation or losses of navigation data during the whole DAA loop. This integration scheme allows real-time trajectory corrections to re-establish the Required Navigation Performance (RNP) when actual GNSS accuracy degradations and/or data losses take place (e.g., due to aircraft-satellite relative geometry, GNSS receiver tracking, interference, jamming or other external factors). Cooperative and non-cooperative simulation case studies were accomplished to evaluate the performance of this Integrity-Augmented DAA (IAS) architecture. The selected host platform was the AEROSONDE RPAS and the simulation cases were performed in a representative cross-section of the RPAS operational flight envelope. The simulation results show that the proposed IAS architecture is capable of performing high-integrity conflict detection and resolution when GNSS is the primary source of navigation data.

Real-time error calculating method of integrated system in RNP (Required Navigation Performance)

Abstract: The invention discloses a real-time error calculating method of an integrated system in an RNP (Required Navigation Performance) The real-time error calculating method specifically comprises the following steps: 1, figuring out a navigation error probable ellipse through using a navigation equation; 2, rotating the navigation error probable ellipse into a positive ellipse by using a coordinate system rotation algorithm; 3, solving an exterior tangent curve parameter of the positive ellipse, wherein a curve adopted by the invention adopts an exterior tangent straight line (a line tangent ellipse method) and an exterior tangent circle (a circle tangent ellipse method); 4, calculating a real-time TSE (Total System Error) by using the exterior tangent curve parameter; 5, comparing the real-time TSE with an RNP standard threshold to output an alarm result The real-time error calculating method of the integrated system in the RNP, provided by the invention, is relatively small in calculation cost and can be used for relatively accurately performing a TSE estimation, and is suitable for real-time TSE calculation in the RNP

Flight testing of noise abating required navigation performance procedures and steep approaches

Abstract: To test different types of noise abatement approach procedures the Institute of Flight Guidance and the Institute of Aerodynamics and Flow Technology performed flight tests on 6 September 2010 with a Boeing 737-700. In total, 13 approaches to the research airport in Brunswick, Germany (EDVE) were flown while the approach area of the airport was equipped with six noise measurement microphones. Brunswick airport is equipped with an experimental ground based augmentation system which allows the implementation of 49 instrument landing system (ILS) look-alike precision approach procedures with different approach angles simultaneously.

Method and device for automatically monitoring a flight path of an aircraft during an operation with required navigation performance

Abstract: A monitoring device including a memory containing a reference path, the memory being separate from a flight management system. The reference path corresponding to a path that is defined during a navigation data validation on ground for the flight management system. A monitoring unit is configured to monitor a current flight path that is determined by the flight management system, by monitoring if this current flight path is in conformity with the reference flight path that is recorded in the memory.

Algorithm and configuration availability tool for integrity monitoring test bed

Abstract: This paper describes an availability analysis tool that is developed to simulate a ground-based augmentation system (GBAS) prototype as an integrity monitoring test-bed (IMT) at an airport of interest. This simulation tool includes the IMT master station algorithm, reference station algorithm, reference station siting configurations, and IMT user algorithm. In addition, a user-friendly graphical user interface is developed to allow the user to modify the parameters of the algorithms, the IMT reference station network, user locations, and satellite constellations. The output of the tool is the Stanford Chart, which indicates the availability for the user protection level calculation versus various required navigation performance levels, such as Category I landing. The simulation tool is implemented in Qt (http://qt.digia.com/), an open-source cross-platform toolkit, allowing the tool to run on various devices. Several airports in different flight information regions are used as examples to demonstrate the utility of the proposed IMT algorithm and the configuration availability simulation tool by analyzing their GBAS service volumes. Cases with reduced error models are also simulated in this paper. This study develops a fast, accurate, and highly customizable GBAS availability simulation tool for GBAS algorithms and configuration planning at the airport of interest.

GPS (Global Position System) RNP (Required Navigation Performance) flight program checking method

Abstract: The invention discloses a GPS (Global Position System) RNP (Required Navigation Performance) flight program checking method, belonging to the field of flight check. The flight program checking method comprises the steps: firstly, confirming a flight plan according to a flight checking task; then, inputting a waypoint code in a flight program to be checked to a checking system or a flight management system, and checking whether navigation data used in the designed flight program, the calculated distance between waypoints and direction data are correct in a cross checking way; next, forecasting the checked flight period and the GPS RAIM availability condition on a route to execute a flight mission by using a GPS RAIM (Receiver Autonomous Integrity Monitoring) availability forecasting tool; and finally, flying according to the design of the flight program, wherein the flight height is executed according to the minimum value designed by the flight program. The flight checking is finished according to the concrete checking items, and a checking report is generated. The method is designed according to the international civil aviation organization standard, meets relevant requirements and provides a reference method for checking the GPS RNP flight program.

Extending Required Navigation Performance to IncludeTime based operations and the vertical dimension

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.

Comparison of Required Task Load in Simulated Autonomous and Controlled Airspace

Abstract: This paper presents a first-order analysis of the control cost associated with a novel concept of operation for future air traffic. The concept of operation divides the airspace into autonomous flows and actively controlled flows. The paper models the effects of autonomy ratio and traffic volume on controller task load. A Monte Carlo simulator framework is used that allocates directly controlled routes and autonomous self-deconflicting four-dimensional trajectory flows in the airspace. Several stochastic models of aircraft scheduling, navigation precision, and conflict detection and resolution are interconnected in the simulation. Results show that autonomy can provide a buffer, preventing rapidly increasing task load with high traffic volumes. The projected increase in traffic volume still maintains feasible averages, but it poses a risk due to the rapidly growing variance that signals unpredictability. A Poisson process model is proposed for task load.

Characterizations of navigation performance in terminal performance-based navigation operations

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.

On the compatibility of ACAS with the concept of segmented independent parallel approach

Abstract: Although air traffic's growth rate has slowed, airport capacity and environmental issues, especially noise mitigation, are identified as major challenges that face aviation. From the perspective of flight guidance, the development of segmented or curved approach procedures based on required navigation performance (RNP) allow for rerouting around congested areas and is thus a promising approach in coping with these issues. Considering airports with parallel runway systems, an increased airport capacity can be reached when runways are operated independently. This, however, requires straight precision approaches to be conducted according to current guidelines issued by the International Civil Aviation Organization (ICAO).

An Alternative Positioning Navigation and Timing concept based on Diverse Ranging

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.

Research on Collision Avoidance in Terminal Area Based on RNP and 3D Paths

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.

On the Compatibility of ACAS with the Concept of Independent Parallel Approach

Abstract: Although air traffic’s growth rate has slowed, airport capacity and environmental issues, especially noise mitigation, are identified as major challenges that face aviation. From the perspective of flight guidance, the development of segmented or curved approach procedures based on required navigation performance (RNP) allow for rerouting around congested areas and is thus a promising approach in coping with these issues. Considering airports with parallel runway systems, an increased airport capacity can be reached when runways are operated independently. This, however, requires straight precision approaches to be conducted according to current guidelines issued by the International Civil Aviation Organization (ICAO). To help pave the way for independent operations of segmented approaches at parallel runway systems, an elementary safety concept was developed in previous work that utilizes the ground-based system of precision runway monitoring. Within this concept, a generic airport scenario with two parallel runways was considered, at which a straight approach is proposed for one of the parallel runways and a segmented or curved approach is assumed for a second runway. Based on this, it was shown that a modified concept of precision runway monitoring is capable of achieving target levels of safety comparable to or even more stringent than those defined in the literature for independent parallel precision approaches. Although the Airborne Collision Avoidance System (ACAS) is by definition not part of this kind of safety assessment, an important question to answer is whether the current ACAS implementation can be characterized as compatible to the proposed approach geometry. Because classical approaches towards parallel runways are already critical with respect to generating nuisance ACAS alerts, this issue might even be exacerbated due to the segmented routing. To approach this issue, a method will be presented in this work that allows for calculating an approach geometry-dependent critical runway spacing that will not result in nuisance ACAS alerts. The obtained value can be compared to a given runway layout to determine whether ACAS may be used or should be deactivated for a given procedure.

Benefits analysis of RNP approach procedure to runway 13C at Midway airport

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.

Autonomous take-off and landing for unmanned aircraft system: Risk and safety analysis

Abstract: The aim of this paper is to conceive the possibility of applying the Required Navigation Performance (RNP) requirements where Global Navigation Satellite System (GNSS) augmentations are considered for the Automatic Take-Off and Landing (ATOL). An aircraft, belonging to the Medium Altitude Long Endurance (MALE) category of Unmanned Aerial System (UAS) has been considered as case-study. Once the avionic architecture has been designed, the Safety and risk analysis was carried out with a particular focus on Functional Hazard Analysis and Fault Tree Analysis techniques. The proposed methodology allows the researchers to evaluate the reliability of each avionic equipment and the safety level of the whole avionic system. Furthermore, the results pointed out the main criticalities of the architecture and some future in-depth studies are proposed.

New Trends of Using GNSS In the Area Navigation

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.

Autonomy in Satellite Navigation Systems: The Indian Programme

Abstract: India is developing an Indian Regional Navigation Satellite System (IRNSS) to provide itself and neighbouring countries with the Position Navigation and Timing (PNT) service This project is likely to become operational by 2015 Initially, the system will have seven satellites, and the number will later go up to 111 IRNSS will be an independent 7 satellite constellation, built and operated by India with indigenous capability: three in GSO and 4 in non-GSO (inclined 29 degrees with equatorial plane)2 India has already launched three satellites of their constellation and one thereafter, thus making the initial phase of this system operationalThe IRNSS will provide an absolute position accuracy of approximately 20 metres throughout India, and within a 2,000 km region around it3 The system is expected to provide two types of services: one for civilian use, and another as a restricted encrypted service for specific usersIndia has also developed the GPS-Aided Geo Augmented Navigation (GAGAN) system GAGAN is interoperable with GPS, and provides greater reliability than GPS alone GAGAN has been designed primarily for civil aviation purposes and, when it becomes fully operational, it will be useful in aircraft landing where accuracy of six meters is desirable4 The IRNSS is expected to cater for the presence of GAGAN It will be designed to maintain interoperability between GAGAN and other regional augmentations to the GPS for global navigation5 The first GAGAN navigation payload was launched on 21 May 2011 on board the GSAT-8 communications satellite With this satellite now in position, the process of certification has begun for India's Satellite-Based Augmentation System (SBAS)6 During January 2014, the Director General of Civil Aviation (DGCA) certified the GAGAN system to RNP01 (Required Navigation Performance 01 Nautical Mile) service level7BackgroundIt is an established fact that primitive tribes used the sky as a guide for path finding Medieval humans mostly used various star position based techniques for track detection and location identifications Broadly, such direction finding techniques are commonly known as navigational techniques In the modern world, navigation involves monitoring and controlling vehicles on land, in water, or in air/space Navigation can also be viewed as an instrument or mechanism to fix the position and direction of an object These techniques are based on trigonometry, and owe their origin to the science of astronomy which is probably the oldest of all the sciences to demonstrate the finding of location by using the positions of the stars in the sky Since then, the techniques for navigation have evolved significantly and, for some years now, satellite based navigation is in useThis essay analyses the politico-strategic significance of various existing and futuristic space navigation systems The essay has three major sections: the first section presents an account of global space navigation systems; the second discusses the socio-economic aspects of these systems; and the last section debates the strategic relevance of space navigationThe Navigation NarrativeThe initial investments in designing and developing satellite based navigational systems were made in the early 1960s by the then two superpowers The first such system came into being during the mid-1960s Transit, a naval navigation satellite system, was deployed by the US military in the 1960s, and was operational till 31 December 1996 This system was based on the principle of the frequency shift By monitoring the shift in frequency over a period of time, the system used to identify the location A minimum of four operational satellites were required for this purpose8Transit began operating in 1964, with five satellites that broadcast two different tones in a polar orbit The use of two tones allowed the system to compensate for variable signal delays that occurred in the ionosphere …

Required navigation performance (RNP) flight program check method based on double range finders

Abstract: The invention discloses a required navigation performance (RNP) flight program check method based on double range finders, and belongs to the technical field of the flight check. A way of combining real-time data collection and analysis, visual judgment of a checker and unit comprehensive evaluation is used for integrally evaluating the performance of a double-range-finder RNP flight program. The flight program comprises an airway section, a terminal airway section, a circumferential mobile area, a waiting air line, a standard departure procedure, a standard approach airway and a standard instrument approach program. Check subjects include the accuracy check of designed navigation data of the program, obstacle clearance design inspection, verification of designed safety of the mobile area, verification of airport signs and runway lights, verification of communication and radar coverage and verification of other performances of the program. The method is designed according to the international civil aviation organization standard, relevant requirements can be met, and a reference method can be provided for checking the double-range-finder RNP flight program.