Query: Radio landing

title: Errors of UAV Autonomous Landing System for Different Radio Beacon Configurations
abstract: At the turn of the 20th and 21st centuries, development of microelectronics and microwave techniques allowed for minimization of electronic devices and systems, and the use of microwave frequency bands for modern radio communication systems. On the other hand, the global navigation satellite system (GNSS) have contributed to the popularization of radio navigation in civilian applications. These factors had a direct impact on the development and dissemination of unmanned aerial vehicles (UAVs) In the initial period, the UAVs were used mainly for the army needs. This results also from the legal aspects of the UAV use in the airspace. Currently, commercial UAVs for civilian applications, such as image recognition, monitoring, transport, etc. are presented increasingly. Generally, the GNSS system accuracy for the UAV positioning during a flight is enough. However, the GNSS use for automatic takeoff and landing may be insufficient. The extensive, ground based navigation support systems used at airports by manned aircraft testify to these. In the UAV case, such systems are not used due to their complexity and price. For this reason, the novel dedicated take off and landing systems are developed. The proposal of the autonomous landing system, which is based on the Doppler effect, was presented in 2017. In this case, the square based beacon configuration was analyzed. This paper shows the influence of various beacon configurations in the Doppler based landing system on the positioning error during the UAV landing approach. http:/www.transnav.eu the International Journal on Marine Navigation and Safety of Sea Transportation Volume 13

title: Unmanned Aerial System Inspection of Instrument Landing System Radio Signals
abstract: This study investigates the use of a unmanned aerial system (UAS) for instrument landing system (ILS) signal inspection. A model of expected equivalent isotropic receiver power was built. A 10 meter radio tower was constructed to be used as the test ILS source. Then, empirical channel power measurements were made with antennas and a spectrum analyzer mounted on the prototype vehicle in a simulated ILS environment. Channel power measurements were made by the prototype UAS at various altitudes 19.4 km (12.1 miles) from the base station. Comparisons are made between model and empirical data. The model reasonably predicted signal level and lobing patterns for two of the three ILS component signals. A method of channel power correction based on aircraft orientation was attempted but was ineffective due to UAS pitch data suspected to be inaccurate. This study finds that signal level inspection of ILS can be done by UAS with a reasonable level of repeatability and that measurement accuracies of 1.0 dB and 1.5 dB were achievable for localizer and glideslope respectively. Larger changes in signal levels can be observed on a day to day basis. This is likely due to changing atmospheric conditions and tear down and reassembly of the base station.

title: Radio technical Landing Systems
abstract: Landing is the most complicated stage of flight at the end of which an aircraft should be taken to the set point on the RW surface. Different technical aids which form the landing system are used in order to solve this task. Landing systems have strict requirements which are connected with the provisioning of predefined security level of this stage of flight. Radio technical landing systems satisfy these requirements the most.

title: Trajectory Measurements during Monitoring and Testing of Ground Based Radio Equipment and Airborne Equipment of Instrument Landing Systems
abstract: This report details the performance of trajectory measurements on the basis of GLONASS and GPS satellite navigation systems providing for testing of airborne equipment of landing systems and flight control of the information field for ground based equipment of instrument landing systems.

title: UAV Landing at an Unknown Location Marked by a Radio Beacon
abstract: We consider the problem of minimizing the time to approach and land near a target radio beacon at an unknown location with an Unmanned Aerial Vehicle (UAV) We show that a cone like region exists above the target inside of which bearing measurements of a directional antenna lose directionality: signal recordings in all directions yield similar signal strength. We present a geometric model of this region based on antenna simulations and data collected with a real system. Our main contribution is a strategy that takes advantage of a UAV's ability to change altitude and exploits a special structure occurring when approaching the target beacon from above to reduce the flight time required to land near the beacon. We analyze the performance of our strategy and demonstrate through simulations that by exploiting this structure we can achieve shorter flight times than our previous work.

title: Observation Trajectory Model for Radio Frequency Aviation Landing Systems
abstract: The aim of the paper is to create software operational control of the current precision and reliability of onboard angular coordinates measurements by applying optimal discrete filtering methods, provided that they help simplify the technical implementation of the optimal filter by the criterion: accuracy amount of computing resources. Applying of special methods of signal processing should not reduce the accuracy of measurements under nominal conditions, and when faults appear, it is advisable to use the principle of continuity and enhancement of the functionality of classical signal processing methods.

title: Radionavigation field monitoring in the landing area using software defined radio receiver
abstract: The growth of aviation and the urgent need to reduce fuel consumption and emissions demand increased airspace and airport capacity and a focus on providing the preferred trajectory to each aircraft. Aircraft operators also require efficiency gains via approaches with the lowest possible minima and the significant safety benefits of vertical guidance. GNSS based services can meet these goals and have already provided significant safety and efficiency benefits to many aircraft operators worldwide (USA, and EU members mainly) Following this trend, Ukraine started GNSS implementation in aviation as well.  addresses main aspects of Performance Based Navigation (PBN) implementation in Ukraine. According the requirements and methodology provided in the Manual on Testing of Radio Navigation Aids [2,3] GNSS monitoring and testing should be performed, to confirm the ability of GNSS signals to support flight procedures in accordance with Annex 10  The safe operation of an aircraft landing based on GNSS signals depends on the performance of navigation receiver and accuracy of its coordinates determination, which depends on the accuracy of atmospheric parameters estimation  and surrounding electromagnetic environment [4] Therefore, an important scientific and technical problem is monitoring and control of the radionavigation field and electromagnetic environment in the approach and landing area in order to increase the safety of aircrafts using GNSS technology [6 9] Currently, multichannel scanning receivers are used for radio monitoring. They perform constant automatic control and radio signals search at predetermined frequencies. It should be noted that the efficiency of radio monitoring depends not only on the availability of expensive equipment (frequency meters, field indicators, spectrum analyzers, broadband antennas, band filters, low noise antenna amplifiers, high frequency cables with small losses) proper installation, but also on the methods of data analysis, qualification and experience of radio operators. Radio broadcast monitoring is a constant and intense work of qualified specialists in identification, measurements of radio signals parameters, recording, storing and processing of the obtained information. Radio monitoring is able to solve the following main tasks for providing information security of the object: detection of unauthorized radiation devices and their localization (jamming devices)

title: Method for Estimation the Veracity of Diagnosis of the Aircraft Navigation and Landing Radio Electronic Systems
abstract: The method for estimation of veracity of the diagnostics of an aircraft landing and navigation radio electronic system dismantled units is given in this article. It considers the stimulating signals source instability and the object of diagnosis reliability. Settlement formulas are offered for an assessment of the veracity indicators. These formulas take into account specifics of the aircraft landing and navigation system diagnosis device.

title: GNSS based technique of error matrix construction for radio technical short range navigation and landing systems
abstract: The paper presents a technique for improving radio navigation field accuracy for short range navigation and landing systems. Based on the differential augmentation philosophy and GLONASS technologies, the proposed method of error matrix construction is illustrated with an example where it is applied to correct an anomalous field error of the instrumental landing system (ILS)

title: Automatic landing system using neural networks and radio technical subsystems
abstract: The paper focuses on the design of a new automatic landing system (ALS) in longitudinal plane; the new ALS controls the aircraft trajectory and longitudinal velocity. Aircraft control is achieved by means of a proportional integral (PI) controller and the instrumental landing system the first phase of landing (the glide slope) and a proportional integral derivative (PID) controller together with a radio altimeter the second phase of landing (the flare) both controllers modify the reference model associated with aircraft pitch angle. The control of the pitch angle and longitudinal velocity is performed by a neural network adaptive control system, based on the dynamic inversion concept, having the following as components: a linear dynamic compensator, a linear observer, reference models, and a Pseudo control hedging (PCH) block. The theoretical results are software implemented and validated by complex numerical simulations; compared with other ALSs having the same radio technical subsystems but with conventional or fuzzy controllers for the control of aircraft pitch angle and longitudinal velocity, the architecture designed in this paper is characterized by much smaller overshoots and stationary errors.