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The purpose of this paper is to provide a feasible method to solve the zenith pass problem that can occur when the inter‐satellite linkage antenna of the user satellite is tracing TDRS. The antenna uses the elevation‐over‐azimuth architecture.

The movement laws of the inter‐satellite linkage can be obtained based on the orbit predictions of the user satellite and TDRS. According to the movement laws, the zenith pass moments and blindness zones are found. The trajectory preprocessor is provided to design a command trajectory for driving the axis of the tilting mechanism.

In the worst situation, the blindness zone can appear once every half day. Three special orbit altitude values are obtained. When the user satellite picks one of them as its orbit altitude, the blindness zone may be avoided forever. The zenith pass tracing strategies based on the mechanical tilting method have been designed.

This method obtains the stable tracking during the zenith pass course by changing the hardware structure of the antenna. It is too expensive and can influence the pointing precision of the antenna.

The research can help the engineers analyze and solve the zenith pass problem of the antenna.

This paper studies the zenith pass problem that can occur when the inter‐satellite linkage antenna of the user satellite is tracing TDRS and provides a solving method.

In this paper, a coordinated attitude control law for a tracking and data relay satellite (TDRS) with mobile antennas is proposed. To track or point the target spacecraft with median/law orbit, the large mobile antennas have to move in a wide range, the movement of such mobile antennas disturbing the satellite attitude. Conventionally, the main body of the satellite and the mobile antennas are controlled independently. The proposed controller first estimates the TDRS's angular momentum which the mobile antennas will produce, based on the momentum conservation equation, then adds the estimated angular momentum as a feedforward signal to the conventional control law. The proposed controller is demonstrated using mathematical simulation, the results of which coincide well with analytical results.

Telemedicine is delivered to patient anywhere during emergency treatment care, and medical information is transferred from one site of patient to another site of specialist doctors by using mobile internet communication. Some rural areas have slow internet speed because of weak internet signal propagation from mobile towers. A good design of antenna is needed to improve mobile internet speed for big medial data transmission in telemedicine application. Hence, this paper aims to propose economically low-cost design of antenna.

Telemedicine recommended to design the satellite frequency modulation dish (SAT FMD) antenna ( where in FM radio antenna, dish antenna are combined ) to improve the internet speed at Telemedicine system and Hospitals for purpose of Telemedicine communication and information for emergency treatment.

In the proposed system, designed SAT FMD satellite-based antenna improved internet speed is achieved at 90.6% accuracy in this research method. Finding latitude and longitude angles to identify the patient location, nearest hospitals location and finding distance, shortest path routing between patient and hospital. Finding elevation, Azimuth, latitude, longitude, skew for alignment dish to focus satellite and mobile cell tower to improve internet speed at telemedicine area and hospitals and reduced transmission delay and nodal delay of big medical data.

The social awareness among people can be shared information of accident patient to communicate Hospital and Ambulance driver by internet mobile app tools and help find nearest hospitals to emergency treatment for accident people.

This paper presents SAT FMD antenna model based on satellite dish antenna consisting of FM radio receiver antenna and dish antenna for telemedicine communication.

The present work aims to analyze the performance of a newly designed graphene-based patch antenna by varying the chemical potential in graphene sheet, using the CST Microwave Studio ® software. This study mainly seeks to discuss and assess the advantage of using graphene, instead of copper, as the radiating patch. It should be noted that graphene is a new material that possesses unique properties. Its parameters are optimized for the purpose of introducing it in satellite technology.

The use of graphene as a radiating patch of space technology applications, where a polygonal graphene patch antenna element is designed by the CST Microwave Studio ® software with Taconic RF-41 substrate to resonate in the satellite bands.

Analysis of a graphene patch sheet by a variation in the chemical potential to ensure operation in a space environment.

The increase in the chemical potential for a graphene patch antenna has shown a prominent increase in the values of the gain. A new contribution, by the combination of the antenna performance improvement techniques and the use of graphene as a radiating patch of space technology applications.

On average, a medium-sized satellite consist of almost 500 sensors where powering these sensors in space in such an unreachable environment is critical. Backing this, a compact energy harvester for powering up distant sensors is discussed here is the purpose of this paper. This is in line with the geostationary satellite-powered using the available electromagnetic energy on the satellite panels in space.

The designed rectenna makes use of a compact wideband receiving antenna operating at the targeted frequency band from 8 to 18 GHz. It also consists of a simple dual diode rectifier topology with a matching circuit, bandpass filter and a resistive load to convert the received radio frequency energy into usable direct current (DC) voltage.

The rectenna measurement is performed using three different configuration setups. This shows that a maximum DC voltage of 1.8 V and 5-10 mV is harvested from rectifier and rectenna (includes antenna and rectifier) when 20 dBm power is transmitted from the transmitting antenna operating at X and Ku band. This makes the rectenna feasible to power wireless sensors in a structural health monitoring system.

The measurements are performed by considering a real-time environment in space in terms of the distance between the transmitting and receiving antenna, which depends on the far-field of the transmitting antenna in a satellite.

To make the single‐antenna attitude method more useful as a back‐up or fault diagnostic system than was targeted originally.

The enhancement incorporates information from the GPS satellite constellation and aircraft dynamic model. The visibility of GPS satellites affects the accuracy of the aircraft's volocity that is the main source of single‐antenna attitude. In addition, to use the aircraft dynamic model is natural because single‐antenna attitude is for exclusive use of aircraft. These are considered and implemented as a covariance matrix or process model of Kalman filters. The enhanced performances are verified by an aircraft nonlinear simulation.

The proposed method estimates more accurate volocity and unpiased single‐antenna attitude by using satellite constellation information and the aircraft dynamics. Moreover, the implemented system has a structure that combines other navigation sensors easily.

It would be more desirable to perform further researches; sensor integration, stability against wind disturbance, and aircraft model uncertainty, etc.

A useful attitude sensor for a back‐up attitude system at low cost on manned aircraft or a main attitude system on unmanned aircraft that are sensitive to the mass or size of payload.

This paper has been the first to promote the potential of single‐antenna attitude and with only information that can be easily obtained.

With the continuous development of aerospace technology, space exploration missions have been increasing year by year, and higher requirements have been placed on the upper level rocket. The purpose of this paper is to improve the ability to identify and detect potential targets for upper level rocket.

Aiming at the upper-level recognition of space satellites and core components, this paper proposes a deep learning-based spatial multi-target recognition method, which can simultaneously recognize space satellites and core components. First, the implementation framework of spatial multi-target recognition is given. Second, by comparing and analyzing convolutional neural networks, a convolutional neural network model based on YOLOv3 is designed. Finally, seven satellite scale models are constructed based on systems tool kit (STK) and Solidworks. Multi targets, such as nozzle, star sensor, solar,etc., are selected as the recognition objects.

By labeling, training and testing the image data set, the accuracy of the proposed method for spatial multi-target recognition is 90.17%, which is improved compared with the recognition accuracy and rate based on the YOLOv1 model, thereby effectively verifying the correctness of the proposed method.

This paper only recognizes space multi-targets under ideal simulation conditions, but has not fully considered the space multi-target recognition under the more complex space lighting environment, nutation, precession, roll and other motion laws. In the later period, training and detection can be performed by simulating more realistic space lighting environment images or multi-target images taken by upper-level rocket to further verify the feasibility of multi-target recognition algorithms in complex space environments.

The research in this paper validates that the deep learning-based algorithm to recognize multiple targets in the space environment is feasible in terms of accuracy and rate.

The paper helps to set up an image data set containing six satellite models in STK and one digital satellite model that simulates spatial illumination changes and spins in Solidworks, and use the characteristics of spatial targets (such as rectangles, circles and lines) to provide prior values to the network convolutional layer.

To achieve right-hand circular polarization (RHCP), a 3-dB Wilkinson power divider with a λ/4 phase shifter is used. The crossed-dipoles are placed at almost λ/4 elevation on the ground plane and connected to two coaxial cables. Experiments show that the impedance bandwidth of 49.40% (913.7–1,513.1 MHz) and axial ratio bandwidth (ARBW) of 22.88% (1,145.8–1,441.8 MHz) are achieved.

In this study, a wideband crossed-dipole antenna with circularly polarized (CP) radiation for L-band satellite and radar applications is presented. The proposed CP antenna comprises two orthogonally placed printed dipoles, a quadrature coupler and a box-shaped ground plane.

Furthermore, by fixing the box-shaped ground plane under the radiators, 5.13 dBic RHCP peak gain at 1,300 MHz and maximum half-power beamwidth (HPBW) of 84.5° at 1,170 MHz are realized for the antenna.

Eight metallic walls are connected to four corners of the substrate to stabilize the radiation properties in this study. Results show that the ARBW and front-to-back ratio are improved and the maximum HPBW around 127° across the operating frequency band is achieved. The proposed CP antenna is a good candidate for Global Positioning System (GPS) L2 (1.227 GHz), GPS L5 (1.176 GHz) and air route surveillance radar system at 1,215–1,390 MHz frequency band.

The purpose of this paper is to design simple and high-performing screens capable to separate circularly polarized electromagnetic waves in Ku band from the ones in Ka band.

The proposed screen consists of an inductive double resonant element FSS, i.e. a regular array of circular holes in a metal thick plate, in order to grant the robustness to mechanical stress for antenna applications in extreme conditions.

The proposed design of a multi-band frequency selective surface (FSS) is able to separate circularly polarized electromagnetic waves in Ku band from the ones in Ka band.

The paper shows the capabilities of a novel FSS that combine the transmission properties of two simple FSSs which allows us to achieve an interesting behaviour in three typical bands of the satellite communications.

Before documentary information can be used, a complex series of operations have to take place: 1. information must be recorded in documents, 2. each document must be stored with others in some accessible place and its location known, 3. characteristic aspects of each document must be identified, to form a document profile, and this must be recorded with others in some file, 4. the potential user must formulate some query or express some interest in terms of characteristics recorded about documents, 5. this user profile must be compared with document profiles and the locations of matching documents identified, 6. the documents themselves must be located and presented to the user.