Global navigation satellite system (GNSS) can provide autonomous geo-spatial positioning and time synchronization services for both civil and military uses. Satellite links in GNSS are used to transmit signal for constellation management and other applications. In this work, we focus on solving the satellite link scheduling problem over dynamic satellite network with the aim of minimizing the number of participant ground-based management stations and the cost of communication between satellites in the background of GNSS networking. Firstly, we assume the navigation constellation has finite states and cope the dynamic topology with Finite State Automation method. Secondly, a Fireworks algorithm (FWA) is designed according to the characteristic of the scheduling problem. Finally, the FWA is compared with ant colony optimization (ACO). The performance analysis of different scenarios is given. The study in this paper provides technical reference for the management of future large-scale satellite network.

Fireworks algorithm for the satellite link scheduling problem in the navigation constellation

The study was aimed to determine the coordinates of the points were measured by different ways and different instruments, the most precise way using the differential global positioning system (DGPS) that will be the reference measurements in comparison, less precise way using navigator GPS. Google earth (pro.), and the other applications of GPS mobile ( Samsung and I-phone). In this research (8 points) were chosen that are occasional in location. The comparison of the different observations can give us an idea of the extent to which the accuracy of the observations differs from the different devices used in the observing, as well as through the knowledge of the best device and the best way to measure coordinates accurately to serve the desired purpose. Keyword: navigation, precise way, remote sensing, errors. ةيقارعلا ةيعارزلا مولعلا ةلجم 2020 : 51 ) 4 :) 1149 1159 نورخآو دودولا دبع يملاعلا عقومتلا ماظن تاقيبطتو ةزهجا فلتخم نيب طاقنلا تايثادحا باسح يف ةقدلا ةنراقم GPS ىفطصم ميها ربإ مير ميها ربإ يلع رمع يداه حيبص ءاديغ دودولا دبع دوجو ىده سردم دعاسم ذاتسا دعاسم سردم ثحاب دادغب ةعماج/مولعلا ةيلك دادغب ةعماج/ةسدنهلا ةيلك دادغب ةعماج /مولعلا ةيلك دادغب ةعماج /مولعلا ةيلك صلختسملا لاا دصر ةقيرط يف فلاتخلاا ثيح نم تايثادحلاا سايق ةقد نيب ةنراقملا ىلا ةسا ردلا فدهت دنععتايثادح عضوملا باسح قلطملا ضرلأا زكرم رواحمو تايثادحإ ماظن ىلا ةبسن داعبلأا يثلاث هعقوم كرحتملا وأ تباثلا لبِقتسملا ددحي ، . سايق مت طب طاقنلا تايثادحإ ةفلتخم ةزهجا ةطساوب و ةفلتخم قر يملاعلا عقاوملا ديدحت ماظن لامعتساب ةقد رثكلأا ىلولاا ةقيرطلا ، يلضافتلا ) DGPS ( ا ثميس يذل ةنراقملا يف ةيعجرملا تاسايقلا ل دحت ماظن لامعتساب ةقد لقأ ةيناثلا ةقيرطلا ، عقاوملا دي يحلاملا لامعتسأب ةثلاثلا ةقيرطلا ، . Google earth pro تاقيبطتو ، GPS ومحملا فتاهلل ىرخلأا ل ( Samsung و I Phone ) ةركفب ةفلتخملا تاسايقلا نيب ةنراقملا اندوزت نأ نكمي جلأا نع جتانلاو تاسايقلا ةقد فلاتخا ىدم نع ةفلتخملا ةزه دصرلا يف ةمدختسملا ضرغلا بساني امب ةقدب تايثادحلإا سايقل ةقيرط لضفأو زاهج لضفأ ةفرعم للاخ نم كلذكو ، بولطملا . عناقتا , ءاطخا ,يئان سسحت ,ةحلام :ةيحاتفم تاملك *Received:15/8/2019, Accepted:26/11/2019 Iraqi Journal of Agricultural Sciences –2020:51(4):1149-1159 Abdulwadood & et al. 1150 INTRODUCTION Recently remote sensing utilization vanquish data accuracy troubles, any basin aspect may be acquired either direct form remotely sensing imageries or indirectly by using morphometrically analyses on the extracted topographically information form (2). Remote Sensing and GIS technologies, and their applications, have achieved in succeeded development (11). The Remote sensing progress has increased the achievement of accuracy for getting information sent from satellites to solve many subjects related to land and environmental conditions (1) .GIS, GPS and RS technologies are utilized in collection for agriculture utilization (20). Typically, Spatial technologies are well appropriate for applications of most resource management tasks (3). Remote sensing is a modern method, it can be utilized for studying natural resources and then develop plans for exploitation (12). The rapid developments of spatial technologies like GIS, GPS, and Remote Sensing, have constructed many new tools for extension profe (8). The physically basis of Remote Sensing is the electromagnetic radiation whether its sources natural or artificial (14). Some of remotely sensed imagery bands spectral reflectance may be used for visually interpretation with rates of potential error (9). Surveying by using the Global Navigation Satellite Systems (GNSS) receiver can give users a perfect location of points as a three dimensional position with respect to the origin of an Earth Center Earth Fixed Coordinate System ; a prerequisite for any survey project. Currently, two (GNSS)1 provide GPS navigation, positioning and timing services for all users of GPS receivers: GPS, GPS and GLONASS was operated by the Ministry of Defense of the Russian Federation (17). The advancing of the GPS technology is diversifying the approaches in the way that let it be integrated with RS and GIS (16). This study was aimed to investigate the differences in the accuracy between the correctable and uncorrectable data that was received from satellites to compute the coordinates of the points. MATERIALS AND METHODS The survey of the region was University of Baghdad, was done by using Differential Global Position System (DGPS), type Topcon GR5, Navigator GPS (type Garmen) and GPS application by mobile (Samsung and I-phone). The coordinate system of the observed data set was adopted as a geographic and projection coordinate system by : (WGS84/UTM-ZONE 38). DGPS: Is based on the principle that all receivers in the same vicinity simultaneously experience common errors (18). In this research Static method was used to observe the coordinates of the points. P.P.Static 1-This method was used to observed the coordinates of ground control points by receiving the signals from the available satellite in the region by the Base and the Rover receivers in the same time. The time of observing was four hours to get a high accuracy data. 2-Correct the base point by sending its file to the on-line positioning user service (opus) to submit it directly to NGS (national geodetic survey) for automatic processing. 3-Insert all the file points to the processing program (Topcon tools) and correct the control points according to the new base coordinates, so that they have the same rate of the correction. Navigator GPS and GPS mobile application In this way the signal is received directly from the available satellites at that time so in this way the data includes errors that will not be corrected as that which observed in DGPS. Google Earth Pro Initially, Google Earth Pro was the update of Google Earth (10).Recently, the Pro represents the standard version of the Google Earth Desktop Application as of version 7.3(6).To determine coordinates for a location: 1-Activate Google Earth program. 2-With mouse movement over different locations, coordinates will be appeared in the lower right corner (7). RESULTS AND DISCUSSION Correcting the DGPS data using Topcon tools as shown in the Figure 1 according to the base point that was corrected in (OPUS) Iraqi Journal of Agricultural Sciences –2020:51(4):1149-1159 Abdulwadood & et al. 1151 Figure 1. Correcting part of a set of study points with Topcon tools depending on the base point Converting the units of the data from Geographic System WGS 84 Longitude Latitude, degree, minute, second as shown in the Table 1 to X,Y, Elevation in meters by projection system using (UTM-ZONE 38 N), as shown in the Table 2 I r a q i J o u r n a l o f A g r i c u l t u r a l S c i e n c e s –2020: 5 1 ( 4 ) : 1 1 4 9 1 1 5 9 A b d u l w a d o o d & e t a l . 1152 Table 1.The Coordinates of the study points by geographic system WGS 84

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Comparison the accuracy of computing point coordinats between different instruments and applications of gps

Protected satellite communications (SatComs) exhibit specific characteristics such as security, intelligence, anti-jamming, and nuclear disaster survivability. They constitute one of the key research topics in modern military communications and have become the basic means for implementing strategic and tactical command and control. Currently, the United States military is using the latest advanced extremely high-frequency (AEHF) system to provide protected communications. Other countries are also employing their own protected SatCom systems to meet future operational requirements. Furthermore, in the modern intelligent age, many intelligent-related technologies are introduced into the protected SatCom systems to provide more secure and efficient communication services. In this paper, a comprehensive overview of the protected SatCom systems is presented. More specifically, a system overview of the protected SatComs is illustrated. Our focus is placed on the critical technologies and practical applications, and finally discuss remaining challenges and look forward to the future research directions. It is undoubted that the protected SatCom is one of the most important systems in military communications, both now and in the future.

An overview of protected satellite communications in intelligent age

Sea-battlefield situation is a dynamic, nonlinear and multi-dimensional system where Artificial Intelligence (AI) system has a good role to play. Bayesian Network has a strong knowledge skills and reasoning ability to solve the problem of sea-battlefield situation assessment. After constructing the network, giving the probability, considering the time factor and then combining with Pattern Matching using a rule set, sea-battlefield situation assessment can be achieved. The knowledge representation will be discussed and how to complete reasoning through Bayesian Network and Pattern Matching will be researched. In the end, a simulation will illustrate the combining method has a good performance in sea-battle-field situation assessment.

Sea-battlefield situation assessment based on a new method combining dynamic Bayesian network with pattern matching

An optimized strategy for inter-satellite links assignments in GNSS

The Crosslink Ranging and Inter-satellite communication is the key technology of autonomous navigation for satellite, resulting in a constellation of satellites using a narrow beam antenna, due to the limit of the number of antennas on the satellite that bring a problem how effective allocation of limited antenna to establish inter-satellite links, to achieve inter-satellite ranging and inter-satellite communication. According to the satellite constellation cyclical and finite state, propose a new system which suit inter-satellite ranging and inter-satellite communication and a method which make the smallest satellite position dilution of precision(PDOP) and get the topological structure that have the minimum communication link cost. By means of simulation results show that the single satellite PDOP value is not more than 3, the navigation constellations average PDOP value is 2.2, which meet satellite autonomous orbit determination accuracy requirements, optimize network communication performance, and to reduce the delay of the satellite network communication.

Satellite network design method applicable to orbit determination and communication for GNSS

Considering the requirement to domain knowledge in event detection of situation assessment, a method based on rough-vague sets and D-S evidential theory was proposed for situation assessment. Rough sets and vague sets are used to conduct event detection, it establish event decision table by target historical data, and through the attribute reduction get reducted event decision table. An approach to getting vague sets of target event by the table is put forward, then according to the similarity measure between vague sets establish evaluation coefficient to determine the event rusult. Target events at different times are evidences, using the evidence combination rule determine situation assessment results. An example was shows that the process of event detection doesn't need to any domain knowledge and the method has a strongly focus ability to the uncertainty of the situation result.

Xiaoyou Yu

Papers

Satellite network design method applicable to orbit determination and communication for GNSS

Situation assessment method based on rough-vague sets and D-S evidence theory