GPS Receiver Research Articles

Estimation and evaluation of hourly Meteorological Operational (MetOp) satellites' GPS receiver differential code biases (DCBs) with two different methods

Abstract. Differential code bias (DCB) is one of the Global Positioning System (GPS) errors, which typically affects the calculation of total electron content (TEC) and ionospheric modeling. In the past, DCB was normally estimated as a constant in 1 d, while DCB of a low Earth orbit (LEO) satellite GPS receiver may have large variations within 1 d due to complex space environments and highly dynamic orbit conditions. In this study, daily and hourly DCBs of Meteorological Operational (MetOp) satellites' GPS receivers are calculated and evaluated using the spherical harmonic function (SHF) and the local spherical symmetry (LSS) assumption. The results demonstrated that both approaches could obtain accurate and consistent DCB values. The estimated daily DCB standard deviation (SD) is within 0.1 ns in accordance with the LSS assumption, and it is numerically less than the standard deviation of the reference value provided by the Constellation Observing System for Meteorology Ionosphere and Climate (COSMIC) Data Analysis and Archive Center (CDAAC). The average error's absolute value is within 0.2 ns with respect to the provided DCB reference value. As for the SHF method, the DCB's standard deviation is within 0.1 ns, which is also less than the standard deviation of the CDAAC reference value. The average error of the absolute value is within 0.2 ns. The estimated hourly DCB with LSS assumptions suggested that calculated results of MetOpA, MetOpB, and MetOpC are, respectively, 0.5 to 3.1 ns, −1.1 to 1.5 ns, and −1.3 to 0.7 ns. The root mean square error (RMSE) is less than 1.2 ns, and the SD is under 0.6 ns. According to the SHF method, the results of MetOpA, MetOpB, and MetOpC are 1 to 2.7 ns, −1 to 1 ns, and −1.3 to 0.6 ns, respectively. The RMSE is under 1.3 ns and the SD is less than 0.5 ns. The SD for solar active days is less than 0.43, 0.49, and 0.44 ns, respectively, with the LSS assumption, and the appropriate fluctuation ranges are 2.0, 2.2, and 2.2 ns. The variation ranges for the SHF method are 1.5, 1.2, and 1.2 ns, respectively, while the SD is under 0.28, 0.35, and 0.29 ns.

Measurements for GPS meteorological applications

The Global Positioning System (GPS) is at present used for the location and the synchronization of the ground, marine and air meteorological measurements as well as for wind measurements. In the first part of the paper, are presented results of measurements of the positioning of a point known with the Algerian National Center of Space Techniques, CNTS [1] of Arzew and it is included of the national geodesic network and the world network Tyrgeonet : 305 site. The purpose is the study of the total electron content (TEC) using measurements of GPS signal code. For that, two methods are used: Dual-frequency and Klobuchar model method. To eliminate possible skews from the satellite and the receiver. For a GPS receiver alone, one can use the model of Klobuchar to determine the vertical time on the code transmitted by the signal L1. A comparison between the two models will be made to choose that which characterizes best the ionospheric effect. In the second part of this article, we describe the principle of a new technique which is the radio occultation allowing to sound the troposphere by using the GPS signal. Finally, the study of the ionosphere has for application the spatial telecommunications, whereas the study of the troposphere has for application the meteorological phenomena.

IoT-based compensation and control of power theft in weak distribution system

This paper presents a prototype model of real-time rampant power theft detection and compensating the required power current components through switching of distribution static compensator (DSTATCOM) using IoT (Internet of Things) based microcontroller via the GSM module. In this case study, an Internet of Things (IoT) application is used to wirelessly transmit data of the difference of smart meters through intelligent current sensors with ESP8266 module. Transmitted pulse sequences find out the derivatives of functions at discrete points through weight function. A weighting function includes power theft detection information in the pulse sequence series form. It computes the unknown sample of pulse in the line that identified the power theft and the quality of the power supply. The sequence error of the of energy meter units communicates microcontroller through the IoT. Microcontroller communicate to μ-PMU to addressed power quality error with a GPS receiver in the line. Based on weight function an algorithm has been developed for switching DSTATCOM for compensation of power quality. The reference and feedback quantities’ resultant errors are sampled within a time rate of the weight function. This control approach is applied with dynamic load to analyze the power quality issues. The results are implemented in MATLAB Simulink and validated experimentally for power theft detection and its compensation in low voltage distribution system.

GPS Receiver Simplification for Low cost Applications and Multipath Mitigation Analysis on SDR based Re configurable Software Receiver

Many modern position-based applications rely heavily on the Global Navigation Satellite System (GNSS). Most applications require precise position data obtained through sophisticated hardware with a high computational capacity in the receiver. Some cost-effective applications may not require precise position data and require less complex signal processing. The use of efficient hardware and signal processing techniques to reduce the overall cost of a GNSS receiver is an active research topic. This paper considers Global Positioning System (GPS) constellation and proposes two factors to reduce the receiver complexity: sampling frequency and the number of tracking channels. A Keysight GNSS signal generator to record GPS signals, a Software Defined Radio board and a software-based GPS receiver are used in the experimentation. The sampling frequencies are 40, 20, 10 and 5 MHz considered, and tracking channels are reduced from 12 to 6 and then 4. The increase of error in the receiver position with 6 and 4 satellites is considerably small, but the number of tracking channels and signal processing requirements are reduced considerably. The GPS signals are affected by many errors; one of the significant sources of error is multipath propagation. Three distinct GPS multipath scenarios are generated for four satellite signal combinations with the GNSS simulator for the receiver performance analysis. Three multipath mitigation techniques, namely Early Minus Late (EML), Narrow correlator (NC) and strobe correlator (SC) methods, are considered because of their simple structure and fewer signal processing requirements. The error reductions of three multipath scenarios are compared, and the SC method performs better in all three multipath scenarios.

Spatial and Temporal Variability of Vegetation Indices with Industrial Tomato Yield

Vegetation indices indicate crop development and help identify areas with potential productivity reduction in the desired crop. Thus, this study aimed to determine the spatial and temporal influence of vegetation indices on industrial tomato (Solanum lycopersicum L.) yield. The research was conducted at Barcelos Farm in Anápolis, GO, covering a 55-hectare area. A sampling grid of 61-point pairs, spaced at 90 x 90 meters, was established using a GPS receiver. Vegetation indices were characterized by measuring the Soil Plant Analysis Development (SPAD) index, foliar nitrogen content through the Kjeldahl method, and Normalized Difference Vegetation Index (NDVI) using both a spectroradiometer and satellite imagery. Industrial tomato yield was assessed during harvest. Through the results, it was observed that temporal variability between vegetation indices and actual foliar nitrogen content exhibited a significant and positive correlation with industrial tomato productivity, particularly during the flowering stage. However, temporal variability between vegetation indices and foliar nitrogen content displayed low correlation across the mapped areas over time. Determining foliar nitrogen content and vegetation indices during the flowering stage is recommended for the industrial tomato crop. The relationship between ground-based remote sensing NDVI and orbital NDVI displayed a 55% positive correlation during the flowering stage.

Performance Analysis of Relative GPS Positioning for Low-Cost Receiver-Equipped Agricultural Rovers.

Global navigation satellite systems (GNSSs) became an integral part of all aspects of our lives, whether for positioning, navigation, or timing services. These systems are central to a range of applications including road, aviation, maritime, and location-based services, agriculture, and surveying. The Global Positioning System (GPS) Standard Position Service (SPS) provides position accuracy up to 10 m. However, some modern-day applications, such as precision agriculture (PA), smart farms, and Agriculture 4.0, have demanded navigation technologies able to provide more accurate positioning at a low cost, especially for vehicle guidance and variable rate technology purposes. The Society of Automotive Engineers (SAE), for instance, through its standard J2945 defines a maximum of 1.5 m of horizontal positioning error at 68% probability (1σ), aiming at terrestrial vehicle-to-vehicle (V2V) applications. GPS position accuracy may be improved by addressing the common-mode errors contained in its observables, and relative GNSS (RGNSS) is a well-known technique for overcoming this issue. This paper builds upon previous research conducted by the authors and investigates the sensitivity of the position estimation accuracy of low-cost receiver-equipped agricultural rovers as a function of two degradation factors that RGNSS is susceptible to: communication failures and baseline distances between GPS receivers. The extended Kalman filter (EKF) approach is used for position estimation, based on which we show that it is possible to achieve 1.5 m horizontal accuracy at 68% probability (1σ) for communication failures up to 3000 s and baseline separation of around 1500 km. Experimental data from the Brazilian Network for Continuous Monitoring of GNSS (RBMC) and a moving agricultural rover equipped with a low-cost GPS receiver are used to validate the analysis.

Precise orbit determination of Spire nano satellites

Spire Global, Inc. operates a growing fleet of currently more than 100 CubeSats in different low Earth orbits for commercial Earth observation. These satellites are equipped with dual-frequency GPS receivers and an attitude determination and control system, allowing for precise orbit determination. For three different satellites and a time span of six months we analyze the performance and quality of the on-board collected GPS and attitude data and employ it for precise orbit determination using the Bernese GNSS Software and Napeos, two independent state-of-the-art GNSS processing software packages. We describe technical details crucial for POD and present and compare the in-flight calibrated phase center variation maps. Reduced-dynamic and kinematic orbits are then inter-compared between the two software packages as well as to the orbit solutions produced by Spire Global. We report pseudo-range and carrier phase residuals at the level of 3–4 m and 8–9 mm RMS and a good agreement between the reduced-dynamic and kinematic orbits of around 5 cm 3D RMS. The reduced-dynamic orbit positions and velocities produced with the two employed software packages agree in average on the level of 6–7 cm and 0.05–0.07 mm/s 3D RMS, while the comparison to the orbits produced by Spire Global is markedly worse with 27–30 cm and 0.32–0.36 mm/s 3D RMS. The presented results are an encouraging first step towards using GPS data from the Spire constellation for geodetic, geophysical and ionospheric applications.

Boat Tracking, Weather Monitoring and Ocean Cleaning System Based on IoT

Sea cleaning is challenging these days, so humans invented a method to organically clean the sea or any other bodies of water utilising smart technology with the aid of hub MCU and Internet of Things (IoT) stage. This paper suggests developing a system that uses both a tracking unit and a monitoring unit independently to clear ocean garbage easily, monitor the weather, and detect border crossings. An Arduino Uno (microcontroller) with an ATmega328p chip is used to collect and change sensor data. The IR sensor and DHY11 sensor are the sensors used in the microcontroller. A NEO-6M GPS receiver module and Bluetooth module are used to locate the boat. The Global Positioning System (GPS) location is collected and uploaded to the IoT cloud via a wifi module. The system’s microprocessor instructs the buzzer to sound. In order to communicate with the base station, which keeps tabs on the boats at sea, it also uses a message transmitter. The suggested system alerts both the coast guards and fishermen.

Analysis of differential code biases for GPS receivers over the Indian region

Abstract The GPS Aided Geo Augmented Navigation (GAGAN) system provides the navigational services for single-frequency GNSS user via broadcasting the differential corrections with GEO stationary satellites. The significant differential correction contribution comes from ionospheric time delays and is necessary to be determined precisely. Dual-frequency GPS receivers measure the ionospheric time delays using GPS code and carrier phase measurements. The determination of absolute ionospheric Total Electron Content (TEC) requires the calibration of GPS satellites and receiver hardware biases due to different frequency-dependent signals (L1 and L2) due to environmental changes (Temperature and Humidity). In this paper, A receiver-based Differential Code Biases (DCB) algorithm is implemented to derive a joint estimation of TEC and RDCB parameters using the weighted Least Square (WLS) method. The daily averaged DCBs data for 26 GPS receivers are obtained for 3 years (2014–2016) from 26 GPS reeivers over Indian region. The receiver DCB algorithmis validated with the Fitted Receiver Biases (FRB) method. The correlation (R) between VTEC and RDCB is conducted to investigate the RDCB stability. The results would be useful for the accurate determination of ionospheric differential corrections to GAGAN users.

AugerPrime surface detector electronics

Operating since 2004, the Pierre Auger Observatory has led to major advances in our understanding of the ultra-high-energy cosmic rays. The latest findings have revealed new insights that led to the upgrade of the Observatory, with the primary goal of obtaining information on the primary mass of the most energetic cosmic rays on a shower-by-shower basis. In the framework of the upgrade, called AugerPrime, the 1660 water-Cherenkov detectors of the surface array are equipped with plastic scintillators and radio antennas, allowing us to enhance the composition sensitivity. To accommodate new detectors and to increase experimental capabilities, the electronics is also upgraded. This includes better timing with up-to-date GPS receivers, higher sampling frequency, increased dynamic range, and more powerful local processing of the data. In this paper, the design characteristics of the new electronics and the enhanced dynamic range will be described. The manufacturing and test processes will be outlined and the test results will be discussed. The calibration of the SD detector and various performance parameters obtained from the analysis of the first commissioning data will also be presented.

The Ionospheric Response to the 2013 SSW Event Over the Asian‐Australian Sector

AbstractThis study investigates the response of the Asian‐Australian low‐latitude ionosphere to the 2013 Sudden Stratospheric Warming (SSW) event. The equatorial ionization anomaly structures were built from the latitudinal distribution of Total Electron Content (TEC) measured from 10 Global Positioning System receivers along 115°E in the Asian‐Australian sector. A pair of magnetometers and NASA Thermosphere‐Ionosphere‐Mesosphere Energetics and Dynamics satellite airglow instrument were also employed to measure the equatorial electrojet strength (inferred E × B drift) and to unveil the changes in the neutral thermospheric O/N2 ratio during the SSW event, respectively. The relocation of the northern crests to higher latitudes during the SSW compared to the non‐SSW periods was mainly attributed to the combined effect of enhanced magnetometer‐inferred upward‐directed E × B drift and increasing solar flux. The local time shift in the thermospheric O/N2 ratio, a slight enhancement in the magnitude of the semi‐diurnal magnetometer‐inferred upward‐directed E × B drift, and changes in solar flux were primarily responsible for the hemispheric TEC enhancement during mid‐January compared to SSW onset. Additionally, the photo‐ionization effect due to increasing solar flux further enhances the TEC magnitude during the relaxing phase. On the other hand, the strong thermospheric equatorward wind played a crucial role in moving the plasma to lower latitudes during the zonal wind transition phases. A moderate geomagnetic storm of 17 January 2013 did not perturb the Asian‐Australian ionosphere. However, on 18 January 2013, the storm had a significant impact and greatly diminished the effect of the SSW.

Opportunities to reduce random error satellite geolocation due to averagement of data received by U-BLOX NEO-6M-0-001 gps receiver with external active antenna

Opportunities to reduce random error satellite geolocation due to averagement of data received by U-BLOX NEO-6M-0-001 gps receiver with external active antenna

Equinoctial asymmetry of plasma bubble occurrence and electric field at evening: GPS and ionosonde measurements in Southeast Asia

We have investigated equinoctial asymmetry of scintillation occurrence and zonal irregularity drift velocity observed with closely-spaced GPS receivers at Kototabang (0.20°S, 100.32°E; geomagnetic latitude 10.6°S), Indonesia during a period from 2003 to 2016, and found that the scintillation occurrence rate is higher in Mar. equinox than in Sep. equinox, and that the eastward drift velocity at post-sunset is higher in Mar. equinox than in Sep. equinox. This result is consistent with previous work done by Otsuka et al. (2006), who have analyzed scintillation and zonal drift velocity data obtained at Kototabang in 2003–2004, and suggests that the eastward drift velocity corresponding to the downward electric field at post-sunset may be related to the pre-reversal enhancement of eastward electric field, which could play an important role in generating plasma bubble. In this study, we have investigated vertical drift velocity by analyzing the ionosonde data obtained near magnetic equator (Chumphon, Bac Lieu, and Cebu) during a period from 2003 to 2016, and found that the upward drift velocity at post-sunset is larger in Mar. equinox than Sep. equinox. We also find that solar activity dependence of the zonal and vertical drift velocities is more clearly seen in Mar. equinox than in Sep. equinox. In order to consider the mechanism causing the equinoctial asymmetry of the drift velocities, foF2 obtained by the ionosondes is also analyzed. We find that foF2 also depends on solar activity more clearly in Mar. equinox than in Sep. equinox, and that foF2 during high solar activity conditions is higher in Mar. equinox than in Sep. equinox. These results suggest that in Mar. equinox, due to high electron density, intense electric field could be generated through the F-region dynamo so that plasma bubble likely occurs.

Estimation of route speed parameters designed for electric buses

The paper presents a method for the estimation of speed parameters on urban bus routes designed for the use of electric buses. The considered bus route is divided into stopping and running sections. The bus stops are the stopping sections. The running sections connect two neighbouring bus stops. A bus equipped with the GPS receiver moves along the urban bus route at a variable speed. The GPS receiver records at a constant frequency location data that include current bus position and the measurement time. The location data enable the estimation of the time of varying speeds for the running sections and the stop time for the stopping sections. The speed parameters for the sections involve the specification of time periods assigned to the defined speed ranges. Measurement data were recorded on the selected bus route in off-pick and pick hours. The results obtained allow estimation of speed parameters for individual sections and by aggregation for the entire bus route considered. The speed parameters of the bus route correspond to the energy consumption of electric buses and can be applied to determine the properties of the urban bus routes on which electric buses are introduced.

A Mobile Health Application Using Geolocation for Behavioral Activity Tracking.

The increasing popularity of mHealth presents an opportunity for collecting rich datasets using mobile phone applications (apps). Our health-monitoring mobile application uses motion detection to track an individual's physical activity and location. The data collected are used to improve health outcomes, such as reducing the risk of chronic diseases and promoting healthier lifestyles through analyzing physical activity patterns. Using smartphone motion detection sensors and GPS receivers, we implemented an energy-efficient tracking algorithm that captures user locations whenever they are in motion. To ensure security and efficiency in data collection and storage, encryption algorithms are used with serverless and scalable cloud storage design. The database schema is designed around Mobile Advertising ID (MAID) as a unique identifier for each device, allowing for accurate tracking and high data quality. Our application uses Google's Activity Recognition Application Programming Interface (API) on Android OS or geofencing and motion sensors on iOS to track most smartphones available. In addition, our app leverages blockchain and traditional payments to streamline the compensations and has an intuitive user interface to encourage participation in research. The mobile tracking app was tested for 20 days on an iPhone 14 Pro Max, finding that it accurately captured location during movement and promptly resumed tracking after inactivity periods, while consuming a low percentage of battery life while running in the background.

Does the built environment influence location- and trip-based sedentary behaviors? Evidence from a GPS-based activity space approach of neighborhood effects on older adults

ObjectiveEvidence on the influence of built environments on sedentary behaviors remains unclear and is often contradictory. The main limitations encompass the use of self-reported proxies of sedentary time (ST), the scarce consideration of the plurality of sedentary behaviors, and environmental exposures limited to the residential neighborhood. We investigated the relationships between GPS-based activity space measures of environmental exposures and accelerometer-based ST measured in total, at the place of residence, at all locations, and during trips. MethodsThis study is part of the CURHA project, based on 471 older adults residing in Luxembourg, who wore a GPS receiver and a tri-axial accelerometer during 7 days. Daily ST was computed in total, at the residence, at all locations and during trips. Environmental exposures included exposure to green spaces, walking, biking, and motorized transportation infrastructures. Associations between environments and ST were examined using linear and negative binomial mixed models, adjusted for demographics, self-rated health, residential self-selection, weather conditions and wear time. ResultsParticipants accumulated, on average, 8 h and 14 min of ST per day excluding sleep time. ST spent at locations accounted for 83 % of the total ST. ST spent at the residence accounted for 87 % of the location-based ST and 71 % of the total ST. Trip-based ST represents 13 % of total ST, and 4 % remained unclassified. Higher street connectivity was negatively associated with total ST, while the density of parking areas correlated positively with total and location-based ST. Stronger associations were observed for sedentary bouts (uninterrupted ST over 20 and 30 min). ConclusionImproving street connectivity and controlling the construction of new parking, while avoiding the spatial segregation of populations with limited access to public transport, may contribute to limit ST. Such urban planning interventions may be especially efficient in limiting the harmful uninterrupted bouts of ST among older adults.

Prediction of ionospheric total electron content data using spatio-temporal residual network

Since the ionospheric total electron content (TEC) exhibits complex spatial and temporal behaviour including the seasonal and solar activity dependencies, resulting in large scale differences across different regions of the world, developing an effective deep-learning-based predictive model, capturing the complex behaviour of TEC is much needed. We present a novel deep learning-based model to predict the TEC using the spatio-temporal residual network (ST-ResNet). The TEC data used in the study were obtained from 185 GPS receiver locations, covering the latitude region from 10° N to 80° N and the longitude region from 110° W to 34° E. We considered TEC data of 154 days each corresponding to the solar maximum (2014) and the solar minimum (2020) years for training the network together with the exogeneous interplanetary magnetic field (IMF) data, including the magnetic field components By, Bz, plasma flow speed (Vp), and proton density (Np). A total of 44,352 maps (collected at the rate of 288 maps per day) were pre-processed by grouping them into closeness, period, and trend channels, which associate with the near-time, short-term, and long-term trends in the TEC data, respectively. After training, the model was tested for one day. The objectives of the study are: i) To develop and evaluate the performance of the ST-ResNet model, ii) to assess its performance on TEC data corresponding to mid-latitude region, under different solar conditions and iii) to compare the ST-ResNet model with other predicted models. For the entire study region, the root mean squared error (RMSE) was found to be 3.13 TECU for the solar maximum year and 1.23 TECU for the solar minimum year. Similar trends were observed in the mid-latitude region (30° N-60° N), with RMSE values of 2.31 TECU and 1.58 TECU for the solar maximum and solar minimum years, respectively. ST-ResNet model showed an improved accuracy over the long short-term memory (LSTM) deep learning network by about 23% and 31% for the entire study region and by 49% and 19% for only mid-latitude region, during the solar maximum and minimum years respectively, suggesting the superior performance of ST-ResNet over the LSTM network. A comparative observation of results of ST-ResNet model with those of back propagation and international reference ionosphere-2016 (IRI-2016) model also showed the superiority of the former. Results confirm the suitability of the ST-ResNet model for predicting the spatial and temporal behavior of TEC across different locations during various solar conditions.

Peak Ground Velocity (PGV) estimation of Mw 5.6 Cianjur earthquake November 11, 2022 using Global Positioning System (GPS)

The primary purpose of GPS is to be used for positioning, navigation, and timing (PNT). In the last decade, research on GPS for earthquake hazards has increased rapidly, such as for tectonic deformation, GPS seismology, modeling earthquake source parameters, estimation of magnitude, etc. In this study, following the Mw 5.6 Cianjur earthquake on November 11, 2022, we estimate the peak ground velocity from the CJUR GPS station, which is located about 15 km from the epicenter. We compute GPS velocity from the high-rate GPS receiver independent exchange (RINEX) data and broadcast ephemeris. Using a narrow line combination of L1 and L2 observations, we invert velocity epoch by epoch. The result shows the CJUR GPS station has a peak ground velocity of about 11.5 cm/s and equal to VI MMI scale. The peak ground velocity from the GPS station could be important for deriving the earthquake shakemap. By increasing the number of GPS stations in Indonesia, it is very important to support earthquake hazard monitoring.

NITIAL RESULTS OF COMPARATIVE ASSESSMENT OF SOIL EROSION INTENSITY USING THE WIntErO MODEL: A CASE STUDY OF POLIMLJE AND SHIRINDAREH DRAINAGE BASINS

This work aims to determine the current state of sediment production and propose land use measures that will affect the reducing the intensity of soil erosion for the areas of the Polimlje drainage basin on the territories of Montenegro and Serbia, and the small Shirindareh sub-basin of Iran. The approach is based on field and laboratory methods, which are processed by Web-based Intensity of Erosion and Outflow (WIntErO)model used to calculate erosion intensity. By using the computer-graphical method of the "WIntErO" software, in the study of erosion intensity, surface values (watershed surface, surface between isohypsies, etc.) and length, i.e. deviations from the map (length of the main watercourse, length of the watershed line, etc.) is processed very precisely, which was not the case before when using mechanical instruments, planimeters and curvimeters. The new WIntErO model is an integrated computer-graphic program package of the third-generation method based on the earlier generations of the modelling tools "River basins", and IntErO and calculates the amount of sediment, the intensity of soil erosion, as well as the maximum runoff from the basin, according to the EPM model of Gavrilović.During the procedure, an accuracy assessment is conducted with measurements of reservoir sediment deposition. These measurements were performed in April 2017 using professional hydrographic recording equipment, following the same methodology as in 2012. The measurement of point locations was conducted using a GPS receiver and a Trimble R6 base station. The reservoir's depth was measured using a single-frequency portable echo sounder, specifically the Odom Hydro Track. The initial assessment shows fairly acceptable results of the implemented WIntErO modelling for both study areas. Z coefficient values ranging from 0.01 to 1.00 for the observed period indicate that the river basins delineate areas with varying levels of susceptibility to water erosion processes—ranging from very low to moderate and high risk—within the studied drainage basins. Based on the analysis, we found that the average erosion intensity in Polimlje is 331.78 m³ km⁻² year⁻¹ per square kilometer. For the Shirindareh sub-basins, the average actual soil losses per square kilometer are 201 m³ year⁻¹ km⁻². Given these findings, it is evident that these basins require prompt implementation of soil conservation measures.

GPS 수신기 위치결정을 위한 다변량 Newton-Raphson 기법과 Bancroft 알고리즘 비교

GPS 수신기 위치결정을 위한 다변량 Newton-Raphson 기법과 Bancroft 알고리즘 비교