Short-range Navigation Research Articles

Biofuel–Electric Hybrid Aircraft Application—A Way to Reduce Carbon Emissions in Aviation

As global warming intensifies, the world is increasingly concerned about carbon emissions. As an important industry that affects carbon emissions, the air transportation industry takes on the important task of energy saving and emission reduction. For this reason, major airlines have designed or will design different kinds of new-energy aircraft; however, each aircraft has a different scope of application according to its energy source. Biofuels have an obvious carbon emission reduction effect in the whole life cycle, which can offset the drawback of the high pollutant emission of traditional fossil fuels in the preparation and combustion stages. At the same time, a battery has zero emissions in the operating condition, while the low energy density also makes it more applicable to short-range navigation in small aircraft. In this paper, the development direction of a biofuel–electric hybrid aircraft is proposed based on the current development of green aviation, combining the characteristics of biofuel and electric aircraft.

Ultrasound-Powered Wireless Underwater Acoustic Identification Tags for Backscatter Communication.

Autonomous underwater vehicle (AUV) operations are limited by currently achievable underwater localization and navigation solutions; hence, the development of low-cost and passive (i.e., operable without an active power supply) acoustic underwater markers (or tags) can provide accurate localization information to AUVs improving their situational awareness, especially when operating in small scales or confined missions. This work presents an acoustic identification (AID) tag that can be powered wirelessly with ultrasonic power transfer from a remote acoustic source (e.g., mounted on an interrogating AUV) and provide localization information using backscatter communication. The AID tag harvests energy from the acoustic signal generated from the AUV and communicates by modulating the reflected signals from an embedded piezoelectric transducer. A scaled broadband AID tag prototype that achieves concurrent acoustic energy harvesting (tuned around 1.3 MHz) and backscatter communication (in wider frequency band 600 and 800 kHz) using frequency-domain multiplexing is implemented using a custom broadband impedance matching-based transducer design approach. During concurrent power and data operation, this prototype AID tag achieves data rates up to 200 kb/s using amplitude- and frequency-based modulation communication. The use of broadband schemes to achieve robust communications in low SNR (tested here down to -6 dB) is also demonstrated using linear frequency-modulated data carriers. Finally, the extension to full-scale devices of this AID tag concept and potential applications for short-range AUV routing and navigation such as homing and docking are discussed.

Radio Beacon with the Function of Checking and Calibrating on Board Radio Receivers of the Instrument Landing System

A fundamentally new approach toverification and calibration of the on-board equipment of the radio beacon system for providing instrumental approach for an aircraft has been proposed, which consists of using directly radio beacons for these purposes that are in operation at existing airfields. Theoretically and experimentally, an original solution to the problem of checking and calibrating on-board equipment has been studied by generating landing radio signals with given values of the information parameter based on signals directly from the radio beacon and transmitting the generated signals through the surrounding space to the input of on-board receivers of the landing system. It is shown that commercially produced glide slope and localizer radio beacons of the decimeter wavelength range, supplemented by a signal combiner and a transmitting antenna with a radio frequency cable, will allow testing and calibration of on-board landing equipment with the accuracy that meets the requirements of GOST 15827–70. Monitoring the readings of the zero value of the information parameter on the indicator of the radio beacon system of the navigation and flight instrument by emitting signals from the glide slope radio beacon with a coefficient of inaudibility of signals equal to zero, has been experimentally confirmed when working with the short-range navigation radio system RSBN-2S and RSBN-PKV, which are part of AN aircraft –26Sh, TU-134Sh, TU-134UBL, located at the airfield in maintenance stops.

Method for improving the quality of service of request signals in information systems

The work notes that the request information systems are an important component of information support for air traffic control and airspace control systems. Interrogative information systems include: secondary radar systems, national identification radar systems and short-range navigation radio systems. It is shown that the characteristics of the process of servicing request signals in an aircraft transponder have a significant impact on the statistical properties of the response signal flow, which ultimately, as a consequence, affects the efficiency of the entire radar channel for transmitting response signals with an active response. It is pointed out that one of the important characteristics of the process of servicing request signals in an aircraft transponder is its correlation function, based on the analysis of which one can conclude the choice of the type of response signal flow and the structure of the aircraft transponder. This makes it possible to achieve: increasing the probability of service, increasing the probability of detecting an air object, reducing the root-mean-square error in estimating the azimuth of an air object and increasing the reliability of the transmission of flight information from the observed board of an air object. The article analyzes the possibility of improving the quality of request service by managing the flow of request signals in a network of request information systems. It has been shown that the correct choice of repetition periods of request signals in the area of joint operation of request information systems makes it possible to reduce the likelihood of interaction between individual request signals. Also, as a consequence, it makes it possible to increase the noise immunity of the interrogative information systems under consideration that are part of the specified information system.

Device of tracking processing for indicator channel of short-range radio navigation systems

Features of the indicator channel of the short-range radio navigation systems (for example, the RSBN-4 system) are considered. It was revealed that a significant shortcoming of the indicator channel of the short-range radio navigation is the low accuracy of determining the navigation parameters (azimuth and inclined range of the aircraft) in comparison with on-board equipment. It is shown that one of the possible ways to increase the accuracy of measuring the coordinates of the aircraft in the indicator channel is the use of trajectory processing of radionavigation information whose purpose is to estimate the parameters of the motion of an aircraft in the short-range radio navigation observation zone on the basis of measurements of its instant position for determining the trajectory in the measurement interval and predicting his subsequent movement. The structure of the device for trajectory processing of the indicator channel RSBN can to a great extent repeat the structures of similar devices used in the processing of radar information, taking into account the features of the operation of the indicator channel. The structure of trajectory processing is developed and its features are noted on the example of the system RSBN-4. The performed mathematical modeling confirmed the possibility of a significant increase in the accuracy of the measurement of the coordinates of the aircraft in comparison with the existing indicator channel RSBN-4N.

DME test equipment receiving function metrological method and device design

The distance measuring equipment (DME) is a short-range radio navigation equipment stipulated by the International Civil Aviation Organization (ICAO). It is stipulated in the DME maintenance manual that ATC-1400A tester is used for its performance test. ATC-1400A may appear performance attenuation and index drift after long-term use, so it needs to be periodically metrological verification. At present, the metrological verification test of DME acceptance function adopts returning to factory for metrological test or using airborne DME component as calibration source for verification. However, returning to factory metrological test has the disadvantages of long test cycle and high test cost. The use of airborne DME component as calibration source also has the problem of mutual verification between the airborne DME component of the tested object and the test equipment ATC-1400A, so it is impossible to carry out quantitative traceability. To solve this problem, this paper built a calibration source device for DME receiving function test, so as to achieve the receiving function verification of ATC-1400A tester DME on the basis of ensuring that the calibration source system can carry out quantitative traceability.

Attitude sensors relative angular misalignment estimation in integrated navigation systems

When using modern navigation systems as part of an on-board system, the navigation task can be solved in several ways: using positional, velocity and angular corrections, and systems using measurements of various physical nature—radio, such as short-range and long-range navigation radio systems, GLONASS/GPS satellite global navigation systems, optical—celestial navigation systems—can operate as correctors. The best performance of INS and its sensors (gyroscopes and accelerometers) errors estimation can be obtained when all types of correction are implemented simultaneously. At the same time, it is particularly difficult to implement correction according to attitude parameters due to the fact that the measuring axes of the INS and correctors may not match on board of moving objects. Such a mismatch is commonly called relative angular misalignment. The paper considers a possible approach to the attitude sensors relative angular misalignment estimation in integrated navigation systems (NS), carried out in motion when the NS is in operating mode.

Short-range radio-technical navigation of small-class unmanned aerial vehicles using broadband linear frequency-modulated signals

Short-range radio-technical navigation of small-class unmanned aerial vehicles using broadband linear frequency-modulated signals

Simulation and Research of DME Signal Coverage

In civil aviation land-based navigation equipment, the DME(Distance Measuring Equipment) system is a widely used short-range navigation equipment. Through the research on the antenna of the DME equipment, the antenna signal of the DME equipment is modeled and simulated, and the electromagnetic signal three-dimensional pattern of the DME equipment and the corresponding pattern of the E plane are obtained. On the basis of mastering the antenna signal radiation characteristics of each navigation device, the DME coverage area is simulated and analyzed.

Dorsal Landmark Navigation in a Neotropical Nocturnal Bee

Bees, ants and wasps are well known to visually navigate when traveling between their nests and foraging sites. When leaving their nest, landmarks in the vicinity are memorised and used upon return to locate the nest entrance 1-3 . The Neotropical nocturnal sweat bee Megalopta genalis navigates under the forest canopy at light intensities ten times dimmer than starlight. Despite these dim conditions, Megalopta is able to memorise visual landmarks around the nest entrance in the frontal visual field. Even though frontal landmarks can clearly be discerned by Megalopta, the visual feature of greatest contrast in the rainforest at night is actually the dark dorsal silhouette of the distant canopy against the brighter night sky. Several species of day-active ants, as well as a subsocial shield bug, use bright open gaps in the canopy as dorsal landmarks for short-range navigation while walking. Here we show that Megalopta is also able to distinguish dorsal landmarks, the first flying insect known with this capacity. Megalopta is able to discriminate between differently oriented dorsal black striped patterns, or an “artificial canopy” of black circles, and to use this information to locate its nest entrance. These results suggest that the local foliage patterns created by the canopy against the brighter sky could potentially provide the bee with reliable landmark information for navigation during foraging and homing at night.

A Fast Weakly-Coupled Double-Layer ESKF Attitude Estimation Algorithm and Application

Aimed at the problem of small unmanned aerial vehicle (UAV) attitude solution accuracy and real-time performance in short-range navigation flight, in this paper, we propose a fast weakly-coupled double-layer error-state Kalman filter (DL-ESKF) attitude estimation algorithm. Considering the application of short-range navigation, we designed an improved attitude error model for low-cost gyroscope/accelerometer/magnetometer devices. In addition, we reasonably simplified certain factors that affect the attitude solution to reduce the filtering calculation burden. For the data coupling phenomenon caused by the different sampling frequencies of the attitude sensor data in the filtering process, we designed a new attitude algorithm combined with the ESKF and hierarchical filter. The first layer of filters used an accelerometer and the second layer used a magnetometer to correct the attitude error. We also built an offline and real-time test platform to verify the performance of the proposed algorithm in a simulation and flight test environment compared with the classic attitude algorithms. The experimental results demonstrated that the proposed algorithm not only improved the attitude solution accuracy and stability but also reduced the filter running time.

Motion and Navigation Control System of a Mobile Robot as A Prototype of An Autonomous Vehicle

Autonomous vehicle is a vehicle that can automatically navigate both long-range and short-range navigation. In this paper, we designed a motion and navigation control system of an autonomous vehicle that is implemented on a mobile robot. The remote navigation process involves using the global positioning system (GPS) sensor as a reference to navigate, and for short-range navigation using the proximity and force sensor. The robot task is to reach several coordinate points that are determined and marked with a traffic-cone at each point. In the control of short-range navigation, the robot uses five ultrasonic and three switch sensors to read the environment as input to the description of the distance between the robot and the object. The micro-controller then compares it to the robot’s safe distance instructions in navigating with surrounding objects. GPS sensor is used to provide remote navigation path information. To compensate for the accuracy of the wide GPS sensor readings, several waypoints are designed to guide the robot to the specified traffic-cone. From the implementation, the robot movement can go along the navigation area and can avoid short-range objects in the robot trajectory and get to the traffic-cone point with the percentage of success reaching the final destination above 86% both in sunny and cloudy weather.

Human Detection and Avoidance Control Systems of an Autonomous Vehicle

A long-range and short-range navigation systems of an autonomous vehicle are the most important thing to develop because it is very complex and related to safety in the driving of an automatic vehicle. The purpose of this research is to develop a short-range navigation system for autonomous vehicles focused to detect and avoid humans which implemented on an autonomous vehicle prototype. Image Processing and deep learning algorithm used for human detection and ultrasonic sensor used for distance calculation. Decision making for human avoidance system using the Fuzzy algorithm based on the position of detected human and human distance. The implemented system has a success rate of 85.71% to avoid human which ideal distance more than 2 meters. The implemented prototype of an autonomous vehicle can be implemented in the real vehicle with some adjustments in the sensor and hardware system, however, the systems are expected to reduce traffic accidents caused by human error.

Research of accuracy characteristics of measurement of coordinates in the ground-based radionavigation system based on pseudosatellites

The issues of measurement accuracy of coordinates in the short-range navigation system based on pseudosatellites are considered in the article. The analysis of the errors components the of measurement of radio-navigation parameters is given, the values of the geometrical factor are calculated for various options of system constructing

Simulation of short-range navigation system based pseudolites and investigation of its accuracy characteristics

This papers considers a laboratory complex for studying the characteristics of short-range navigation system based pseudolites. The complex was built on the National Instruments hardware platform in the LabView programming environment. The complex is a real prototype of a navigation system based on pseudosatellites. It provides simulation of the navigation field, analysis of received signals, determination of signal characteristics and navigation parameters. The article presents the results of experimental studies of the complex with the aim of determining the error in pseudo-range measurements from the signals of navigational spacecraft and pseudosatellites.

Insect-inspired vision for autonomous vehicles.

Flying insects are being studied these days as if they were agile micro air vehicles fitted with smart sensors, requiring very few brain resources. The findings obtained on these natural fliers have proved to be extremely valuable when it comes to designing compact low-weight artificial optical sensors capable of performing visual processing tasks robustly under various environmental conditions (light, clouds, contrast). Here, we review some outstanding bio-inspired visual sensors, which can be used for either detecting motion in the visible spectrum or controlling celestial navigation in the ultraviolet spectrum and for attitude stabilisation purposes. Biologically inspired visual sensors do not have to comprise a very large number of pixels: they are able to perform both short and long range navigation tasks surprisingly well with just a few pixels and a weak resolution.

METHOD OF DIFFERENTIAL CORRECTION OF THE NAVIGATIONAL FIELD OF SHORT-RANGE NAVIGATION AND LANDING SYSTEMS WITH USE GLONASS

The effective requirements of the International Civil Aviation Organization (ICAO) for accuracy and reliability of aircraft (AC) positioning, especially in case of flights in the airfield area, make it particularly relevant to harmonize the accuracy characteristics of various radio systems so that any of them can be utilized during the flight. AC positioning accuracy amounts to several metres for standard GNSS modes or several centimetres for differential modes. At the same time, positioning errors for traditional short-range navigation and landing systems (VOR/DME, SHORAN or ILS), especially away from land-based radio beacons, are much higher than GNSS errors and may reach dozens, even hundreds of metres. The inferior accuracy of traditional navigation and landing systems is commonly associated with radio signal reflections from stationary land-based objects and with changes in terrain characteristics along the radio wave path. The paper presents a technique for improving radio navigation field accuracy for short-range navigation and landing on the basis of philosophy of differential correction and GLONASS technologies. The offered method of shaping of matrix of errors of navigational field of systems for short-range navigation and landing is illustrated on example of correction the abnormal error of the instrumental landing system (ILS).

Functional Diagnosis of Digital State Automation Networks

The problem of functional diagnosis of digital devices forming a network of state automata is considered. This task for the network components is supposed to be solved, and the corresponding diagnostic devices for them are provided. The possibility of their population transformation into the tools for the entire network diagnostics is shown. The result of the transformation with the restrictions on the number of components with errors is simplified in compare with the original population. A procedure is proposed allowing to find analytical expressions defining an auxiliary control and an error discriminator for the most probable case of error localization (all errors are concentrated in a certain component of the network). The first part of the article provides a solution of the functional diagnosis problem for the case when the parity functions of all components are scalar, and the class of detectable errors is given by unit multiplicity. Next, the result generalizes for the case of vector functions, where multiple errors can occur. The procedure minimizes the sought for functional diagnosis devices with respect to the order when preserving the initial detecting ability within any network component. The obtained results are illustrated by an example of construction of functional diagnosis equipment for ranging signal processing device in broadband short-range radio engineering navigation system.

Imaging Marine Fauna with a Tritech Gemini 720i Sonar

Multibeam sonar systems are increasingly used to detect, quantify and monitor behaviour of marine fauna. Over ranges of tens to hundreds of metres, animals can be detected as targets. However, at shorter ranges (typically \({ }1 \, \hbox {kHz}\)) sonar systems can provide high-quality images earning the term ‘acoustic cameras’ and have become particularly advantageous for discriminating and counting fish. However, limitations of power and the significant increase in attenuation with frequency limit the achievable range of such acoustic cameras. Systems that operate at frequencies between those of mapping and fisheries sonar (typically \({<}400\, \hbox {kHz}\)) and acoustic cameras (\({\approx }1 \, \hbox {MHz}\)) are often used for short-range navigation and to evaluate underwater structures. While these systems produce images at reduced resolution compared to acoustic cameras, they may also be capable of distinguishing features of marine fauna and do so at greater ranges. This study utilised a Tritech Gemini 720i imaging sonar to produce images from 14 species of fauna at close range. It assessed some simple morphological parameters, such as length and breadth, and highlighted the possibilities of using these to categorise targets. It also provided a coarse description of issues associated with using such a system for monitoring marine animals.

Long and short-range air navigation on spherical Earth

Long and short-range air navigation on spherical Earth