Global Positioning System Technology Research Articles

Analysis of GPS Technology in Surveying and Mapping Engineering Technology

With the rapid advancement of digital and information technology, global positioning system (GPS) technology has seen increasing utilization in surveying and mapping engineering, extending its application across land, ocean, and various other domains. By analyzing the technical means of GPS in surveying and mapping engineering, understanding the characteristics and key technologies in different application environments, and exploring the application process and key technical means, accurate control can be effectively realized. Based on this, this paper mainly analyzes the specific application of GPS technology in surveying and mapping engineering technology for reference.

Match-play running demands in a female soccer professional club: From academy to professional team

The objective of the study was to examine the match-running load of female soccer players competing at distinct age groups (U15, U18 and senior cohorts) belonging to the same professional club, over a competitive season. The external load variables of the official matches were monitored with Global Positioning System (GPS) technology: total distance (TD), at >18 km·h−1 (running), at >21 km·h−1 (high-speed running, HSR) and at >24 km·h−1 (sprint, SPR) distances, efforts at >85% of the maximal sprint speed (>85% MSS), acceleration load (aLoaD), accelerations (ACC2 and ACC3, >2 and >3 m·s−2) and decelerations (DEC2 and DEC3 <−2 and <−3 m·s−2). Overall, distances covered at running, HSR and sprinting were greater for senior players than their younger peers (U15 and U18; p < 0.05). Regarding HSR and sprints, no difference was found for sprints accumulated by central defender (CD) players in comparison to U18 and U15 ( p > 0.05). In addition, U18 and senior players engaged more often in ACC and DEC, >2 and >3 m·s−2, respectively, than U15 players ( p < 0.05). In conclusion, older female soccer players are exposed to higher match load than their younger peers. These findings could be useful for soccer coaches to design specific speed development programmes across the long-term athletic development pathway.

Navigating Event Landscapes: A Study of GPS-Based Event Discovery Systems

Abstract: This paper proposes a system for locating events that are around the user by using the Global Positioning System. Globally, GPS has transformed location-based services and navigation, radically changing our understanding of and use for geographic positioning. These days, GPS is everywhere. It's been incorporated into cars, wearable technology, cellphones, and a host of other products. To identify new trends of substantial correlations between geographic regions and events, the proposed system examines the correlation between user locations and event locations in our research. In our research, we aim to explore the evolving landscape of event discovery and participation by harnessing the ubiquitous presence of the Global Positioning System (GPS). With GPS technology seamlessly integrated into various devices and applications, including cars, wearable technology, and smartphones, users have come to rely on its accuracy and accessibility for navigating their surroundings and accessing location-based services. By leveraging the wealth of location data provided by GPS, our proposed system seeks to identify emerging trends and patterns of substantial correlations between user locations and event locations. Through in-depth analysis and correlation studies, we aim to uncover insights that can inform the development of more effective and personalized event discovery solutions, ultimately enhancing the user experience and engagement with local events and activities.

Development of Blind Campus Navigation System with Obstacle Detection Device

This study focuses on integrating Text-To-Speech software, Global Positioning System (GPS) and other technologies attached to existing white cane to create a robust navigation system that provides real-time feedback and assistance to Students with Visual Impairment (SVI) using Nigerian accent. It uses the design science research methodology for the development and validation of the GPS based mobility into object detection white cane for orientation and mobility of SVI. A speech-corpus database was created to serve as a dictionary for the Text-To-Speech and synthesized through machine learning and artificial intelligence to enable the object detection white cane to detect objects and identify common places at 30 meters in Federal College of Education (Special), Oyo campus, Oyo state, Nigeria. The developed object detection white cane was evaluated with 20 SVI selected for the study using the purposive sampling technique and data were collected through interviews and questionnaires. Two research questions were raised for the study. Data collected were analyzed both quantitatively and qualitatively, using Statistical Package for the Social Sciences (SPSS) and Atlas.ti. The results revealed that the mean response of the participants to all the items on the integration of Text-To-Speech software into object detection white cane is “1” an indication that Text-To-Speech software enhances the independent navigation of students with visual impairment. The study recommended that the components used were imported and expensive, hence the need for locally source components that can be used in producing the devices in large quantities and at reduced cost.

Acute Response to Training after Returning from the Off-Season in Elite Rugby League Athletes.

The purposes of this study were to quantify the physiological response to the initial two-week preseason period in elite male rugby league (RL) athletes, and to determine if a repeated bout effect (RBE) occurs. Eighteen RL players were monitored for the initial two-week preseason period. Blood samples were collected on days (D)1, D2, D4, D5, D8, D9, D11 and D12 to measure creatine kinase (CK). Neuromuscular power was assessed on D1, D5, D8 and D12. During field-based sessions, the external training load was quantified using global positioning system technology, whilst the internal load was quantified using the training impulse and the session rating of perceived exertion. Resistance-based gym session volume was quantified by total repetitions x weight lifted. Perceived measures of fatigue and muscle soreness were assessed on all training days. Two-way (day x week) repeated measures analysis of variance and Bonferroni's corrected post-hoc tests identified significant changes. There were no significant changes in CK activity (649.2 ± 255.0 vs. 673.8 ± 299.1 µL; p = 0.63) or internal training load measures from week 1 to week 2. External training load measures including total distance (4138.1 ± 198.4 vs. 4525.0 ± 169.2 m; p < 0.001) and repeated high-intensity efforts (12.6 ± 1.8 vs. 17.5 ± 1.8 au; p < 0.001) significantly increased in week 2 compared to week 1. Internal training loads and CK activity did not change in response to an increase in external training loads during the initial preseason. The current results provide support for a 'real world' perspective of the RBE phenomenon that may be more applicable for team sport practitioners.

Comparison of Metabolic Power and Energy Cost of Submaximal and Sprint Running Efforts Using Different Methods in Elite Youth Soccer Players: A Novel Energetic Approach.

Sprinting is a decisive action in soccer that is considerably taxing from a neuromuscular and energetic perspective. This study compared different calculation methods for the metabolic power (MP) and energy cost (EC) of sprinting using global positioning system (GPS) metrics and electromyography (EMG), with the aim of identifying potential differences in performance markers. Sixteen elite U17 male soccer players (age: 16.4 ± 0.5 years; body mass: 64.6 ± 4.4 kg; and height: 177.4 ± 4.3 cm) participated in the study and completed four different submaximal constant running efforts followed by sprinting actions while using portable GPS-IMU units and surface EMG. GPS-derived MP was determined based on GPS velocity, and the EMG-MP and EC were calculated based on individual profiles plotting the MP of the GPS and all EMG signals acquired. The goodness of fit of the linear regressions was assessed by the coefficient of determination (R2), and a repeated measures ANOVA was used to detect changes. A linear trend was found in EMG activity during submaximal speed runs (R2 = 1), but when the sprint effort was considered, the trend became exponential (R2 = 0.89). The EMG/force ratio displayed two different trends: linear up to a 30 m sprint (R2 = 0.99) and polynomial up to a 50 m sprint (R2 = 0.96). Statistically significant differences between the GPS and EMG were observed for MP splits at 0-5 m, 5-10 m, 25-30 m, 30-35 m, and 35-40 m and for EC splits at 5-10 m, 25-30 m, 30-35 m, and 35-40 m (p ≤ 0.05). Therefore, the determination of the MP and EC based on GPS technology underestimated the neuromuscular and metabolic engagement during the sprinting efforts. Thus, the EMG-derived method seems to be more accurate for calculating the MP and EC in this type of action.

Practitioner Usage, Applications, and Understanding of Wearable GPS and Accelerometer Technology in Team Sports.

Dawson, L, McErlain-Naylor, SA, Devereux, G, and Beato, M. Practitioner usage, applications, and understanding of wearable GPS and accelerometer technology in team sports. J Strength Cond Res XX(X): 000-000, 2024-Monitoring training load is essential for optimizing the performance of athletes, allowing practitioners to assess training programs, monitor athlete progress, and minimize the risk of injury and overtraining. However, there is no universal method for training load monitoring, and the adoption of wearable global positioning system (GPS) and accelerometer technology in team sports has increased the volume of data and, therefore, the number of possible approaches. This survey investigated the usage, applications, and understanding of this technology by team sports practitioners. Seventy-two practitioners involved in team and athlete performance monitoring using GPS and accelerometer technology completed the survey. All respondents reported supporting the use of GPS technology in their sport, with 70.8% feeling that GPS technology is important for success. Results showed that 87.5% of respondents use data from wearable technology to inform training prescription, although only 50% use the data to influence decisions in competition. In addition, results showed that GPS metrics are used more than accelerometer-derived metrics; however, both are used regularly. Discrepancies in accelerometer usage highlighted concerns about practitioners' understanding of accelerometer-derived metrics. This survey gained insight into usage, application, understanding, practitioner needs, and concerns and criticisms surrounding the use of GPS and accelerometer metrics for athlete load monitoring. Such information can be used to improve the implementation of this technology in team sport monitoring and highlight gaps in the literature that will help to design future studies to support practitioner needs.

Implementation on Location-Based Services Using Geofencing

Geo-fencing (geofencing) is an innovative technology that utilizes the Global Positioning System (GPS) to create virtual boundaries, enabling various applications such as electronic toll collection, contextual advertising, and tourist information systems. This system aims to explore the effectiveness of spatial data in enhancing advertising performance. By leveraging tracking systems and monitoring based on satellite navigation services, including the geofencing function, businesses can accurately pinpoint their locations, boost sales, and improve overall efficiency. Geofencing facilitates remote monitoring of defined geographic areas through virtual fences, allowing for automatic detections when tracked mobile objects enter or exit these areas. This paper introduces the fundamental concepts of geofencing and explores its applications in the transportation and logistics sector. Key Words: Geofence boundaries, Shopping app, User preferences, Geofence triggers, GPS technology, User notifications, Marketing strategy, Mobile commerce, Location-aware technology, Mobile user engagement, Retail industry.

Vehicle Theft Detection and Tracking Based on GSM and GPS

Abstract: The increasing incidence of vehicle theft poses a significant challenge to vehicle owners and law enforcement agencies worldwide. This paper presents a comprehensive solution for addressing this issue through the integration of Global System for Mobile Communications (GSM) and Global Positioning System (GPS) technologies. The proposed system aims to enhance the security of vehicles by providing real-time theft detection and efficient tracking capabilities. The GSM module facilitates communication between the vehicle and a centralized monitoring system, allowing forseamless data transmission. The system leverages the widespread coverage and reliability of GSM networks to ensure that alerts are promptly delivered to relevant stakeholders, irrespective of the vehicle's location. Furthermore, the GPS technology enables real-time tracking of the stolen vehicle, assisting law enforcement agencies in swiftly responding to the incident. The system's tracking feature provides continuous updates on the vehicle's location, allowing for efficient recovery operations. Additionally, the integration of geofencing capabilities allows users to define virtual boundaries, triggering alerts if the vehicle deviates from the predefined geographical area. The proposed system offers a multi-layered security approach, combining GPS-based tracking with GSMenabled theft detection, making it a robust and effective solution for combating vehicle theft. The integration of these technologies not only enhances the chances of recovering stolen vehicles but also acts as a deterrent, discouraging potential thieves. In conclusion, the Vehicle Theft Detection and Tracking System presented in this paper showcases a technologically advanced and practical solution to mitigate the impact of vehicle theft. The integration of GSM and GPS technologies provides a comprehensive and reliable framework that addresses the security concerns associated with vehicle ownership in today's dynamic environment.

Development and implementation of real-time staff performance monitoring and evaluation system based on Global Positioning System (GPS)

This work presents the development and implementation of a Real-Time Staff Performance Monitoring and Evaluation System (RT-SPMES) using Global Positioning System (GPS) technology. In line with the dynamism of the workplace, due to rapid changes in technology, existing staff performance appraisal systems have fallen short of expectations due to their manual nature. Hence, the need arises for a more robust approach to monitoring and evaluating employee work performance. To achieve this, this work carried out an exhaustive review of existing performance evaluation methods within the academic and a conceptual architecture was developed. A real-time monitoring and evaluation system was developed, using PHP programming language, Hyper Text Markup Language and Cascading Styles Sheet. The system is hosted on Azure Cloud infrastructure. Through sufficient testing of the developed system developed in this work, it was asserted effectively monitors employee performance in real-time, paving the way for an objective appraisal process devoid of bias and manipulation.

Analysis of GNSS-ZTD retrieval using dual-frequency raw observations

The Global Navigation Satellite System (GNSS) is promising technology for zenith tropospheric delay (ZTD) retrieval. With the emergence of new multi-GNSS frequencies and maturity of precise point positioning ambiguity resolution (PPP-AR) technology, opportunities and challenges have arisen in high-precision GNSS-ZTD retrieval. However, certain strategies have usually been adopted, such as the traditional dual-frequency combination of American global positioning system (GPS) technology, for ZTD retrieval, but the influence of AR on ZTD retrieval has been ignored. To address this issue, in this study, the GNSS-ZTD retrieval performance of all existing dual-frequency combinations was first comprehensively evaluated by raw observations. Then, the influences of AR and system combinations were analysed with popular dual-frequency combinations. Finally, La Niña occurred during the GNSS data period considered in this article, and the effect on GNSS-ZTD retrieval was examined. The results of this study could not only provide a reference for GNSS-ZTD retrieval but also provide insight into the relationship between La Niña occurrence and GNSS-ZTD retrieval performance.

Effects of Caffeinated Coffee on Cross-Country Cycling Performance in Recreational Cyclists.

The ergogenic effects of acute caffeine intake on endurance cycling performance lasting ~1 h have been well documented in controlled laboratory studies. However, the potential benefits of caffeine supplementation in cycling disciplines such as cross-country/mountain biking have been rarely studied. In cross-country cycling, performance is dependent on endurance capacity, which may be enhanced by caffeine, but also on the technical ability of the cyclist to overcome the obstacles of the course. So, it is possible that the potential benefits of caffeine are not translated to cross-country cycling. The main objective of this study was to investigate the effects of acute caffeine intake, in the form of coffee, on endurance performance during a cross-country cycling time trial. Eleven recreational cross-country cyclists (mean ± SD: age: 22 ± 3 years; nine males and two females) participated in a single-blinded, randomised, counterbalanced and crossover experiment. After familiarisation with the cross-country course, participants completed two identical experimental trials after the ingestion of: (a) 3.00 mg/kg of caffeine in the form of soluble coffee or (b) 0.04 mg/kg of caffeine in the form of decaffeinated soluble coffee as a placebo. Drinks were ingested 60 min before performing a 13.90 km cross-country time trial over a course with eight sectors of varying technical difficulty. The time to complete the trial and the mean and the maximum speed were measured through Global Positioning System (GPS) technology. Heart rate was obtained through a heart rate monitor. At the end of the time trial, participants indicated their perceived level of fatigue using the traditional Borg scale. In comparison to the placebo, caffeine intake in the form of coffee significantly reduced the time to complete the trial by 4.93 ± 4.39% (43.20 ± 7.35 vs. 41.17 ± 6.18 min; p = 0.011; effect size [ES] = 0.300). Caffeine intake reduced the time to complete four out of eight sectors with different categories of technical difficulty (p ≤ 0.010; ES = 0.386 to 0.701). Mean heart rate was higher with caffeine (169 ± 6 vs. 162 ± 13 bpm; p = 0.046; ES = 0.788) but the rating of perceived exertion at the end of the trial was similar with caffeinated coffee than with the placebo (16 ± 1 vs. 16 ± 2 a.u.; p = 0.676; ES = 0.061). In conclusion, the intake of 3 mg/kg of caffeine delivered via soluble coffee reduced the time to complete a cross-country cycling trial in recreational cyclists. These results suggest that caffeine ingested as coffee may be an ergogenic substance for cross-country cycling.

Vehicle Theft Detection and Locking System using GSM and GPS

A vehicle tracking system is very useful for tracking the movement of a vehicle from any location at any time. An efficient vehicle tracking system is designed and implemented for tracking the movement of any equipped vehicle from any location at any time. The proposed system made good use of popular technology that combines a smartphone with an Arduino UNO. This easy to make and inexpensive compared to others. The designed in vehicle device works using Global Positioning System (GPS) and Global System for Mobile Communication(GSM) technology that is one of the most common ways for vehicle tracking. The device is embedded inside a vehicle those positions is to be determined and tracked in real time. A vehicle tracking system is an electronic device installed in a vehicle to enable the owner or a third party to track the vehicle's location. This paper proposed to design a vehicle tracking system that works using GPS and GSM technology, which would be the cheapest source of vehicle tracking and it would work as anti-theft system. It is an embedded system which is used for tracking and positioning of any vehicle by using Global Positioning System (GPS) and Global system for mobile communication (GSM). An Arduino UNO is used to control the GPS receiver and GSM module. The vehicle tracking system uses the GPS module to get geographic coordinates at regular time interval. The GSM module is used to transmit andupdate the vehicle location to a database. This paper gives minute by minute update about vehicle location by sending SMS through GSM modem. This SMS contain latitude and longitude of the location of vehicle. Arduino UNO gets the coordinates from GPS modem and then it sends this information to user in text SMS. GSM modem is used to send this information via SMS sent to the owner of the vehicle. Location is displayed on LCD. And then Google map displays location and name of the place on cell phone. Thus, user able to continuously monitor a moving vehicle on demand using smartphone and determine the estimated distance and time for the vehicle to arrive at a given destination

Systematic review of best practices for GPS data usage, processing, and linkage in health, exposure science and environmental context research

Global Positioning System (GPS) technology is increasingly used in health research to capture individual mobility and contextual and environmental exposures. However, the tools, techniques and decisions for using GPS data...

Modern methods of assess- ing the resources of honeylands

An information review of innovative methods for assessing the resources of honey-bearing lands is presented. The relevance and problems of their use are noted. Alternative strategies for determining the resource potential of honey-bearing lands are shown. Scientific methods of identifying honey plants are described: the study of vegetation, analysis of the chemical composition of honey and its properties, the use of drones to survey honey grounds, and the use of artificial intelligence to process large amounts of data about honey grounds. GPS (global positioning system) technologies, which allow accurate geospatial mapping of homelands, are currently the most widespread. The identification of honey plants to improve the food supply is carried out by various methods: floral analysis of vegetation, pollen analysis, informational analysis of vegetation, and observation of the behaviour of bees in hives. New techniques for determining the land’s honey reserves and the flowering intensity of honey plants are presented: collecting nectar samples and sugar content in nectar, which helps collect data on nectar productivity and nectar quality with greater accuracy and efficiency. RFID tags are widely used for producing and managing honey stocks, monitoring the condition of hives, and determining bee colonies’ productivity. Thanks to advances in technology and scientific research, many new approaches allow for more accurate and efficient selection of resource aspects of honey lands.

Pengembangan Aplikasi Jasa Cuci Sepatu Menggunakan Teknologi GPS Berbasis Android

The shoe cleaning service business provides professional services in shoe care and is a solution for the community. The development of the shoe industry is the cause of this business continuing to grow, making business actors have to create new innovations in promotional media and service processes to be able to compete. This research aims to develop an Android-based shoe washing service application using Android Studio with the Java programming language and Firebase as a database. This application applies Global Positioning System (GPS) technology to support shuttle services. The system development method used is the waterfall method with 5 stages, namely analysis, design, implementation, testing and maintenance. The results of this research are that the Android-based shoe washing service application can be used as expected, making it easier for business actors to manage orders and making it easier for customers to order by getting pick-up and drop-off services.

Real-time Soldier Health and Location Tracking System

To improve military personnel's overall health and operational efficiency, the Soldier's Health Monitoring and Position Tracking System integrates innovative technology in a comprehensive way. Military commanders are guaranteed complete situational awareness with this system's combination of real-time health monitoring and exact position tracking. Vital physiological indicators including heart rate, temperature, and blood oxygen levels are continuously collected and analysed as part of the health monitoring element. The measurements are sent wirelessly to a command centre, so any possible health problems may be identified quickly and responded to quickly. In order to keep meticulous records of each soldier's exact whereabouts in the field, the system simultaneously makes use of cutting-edge GPS and INS technology. The seamless integration of geo-spatial information with health data gives commanders a comprehensive picture of the troops' physical state and where they are. Military authorities may make educated judgements based on the collective health and positioning data using the system's user interface, which provides an intuitive dashboard for real-time monitoring. The data will be sent to the command centre via the Internet of Things. Components of the suggested system include gearbox modules, small wearable physiological equipment, and sensors. As a result, the suggested gear may be used to provide a cheap method of protecting the precious human life on the battlefield. Using global positioning system (GPS) and cellular service mobile phone (GSM) technology, this device can wirelessly monitor the soldier's vitals, including his or her heart rate and temperature.

A compliance assessment of GNSS station networks in Serbia

Since the early 21st century, Global Positioning System (GPS) technology has dominated geodetic reference networks. Almost all countries established a permanent Global Navigation Satellite System (GNSS) station network to augment all available GNSS systems. By the end of 2005, Serbia completed the Active Geodetic Reference Network as a particular project of Serbia's Republic Geodetic Authority (RGA). Besides RGA, two private companies, Vekom and Geotaur, have established permanent station networks. This paper assesses the compliance of all the three networks, and network results are evaluated against the spatial distance determined by classical geodetic methods. When all available GNSS constellations are utilized, NAVSTAR, GLONASS, BEIDOU, and GALILEO, in the processing procedure, the established networks in Serbia align within a margin of about 3 mm across all coordinate axes. The results obtained within the research indicate that by using GNSS networks, it is possible to provide the coordinates of the points for the establishment of the national spatial reference system of Serbia, the reference system in almost all engineering fields, reference systems for the maintenance works of the real estate cadastre, and it is also possible to provide coordinates of points that can be used to define local, national, and world reference heights surfaces.

Health and environmental effects to wildlife from radio telemetry and tracking devices-state of the science and best management practices.

This paper discusses the potential health risks and benefits to tagged wildlife from the use of radio tracking, radio telemetry, and related microchip and data-logger technologies used to study, monitor and track mostly wildlife in their native habitats. Domestic pets, especially canids, are briefly discussed as radio-tagging devices are also used on/in them. Radio tracking uses very high frequency (VHF), ultra-high frequency (UHF), and global positioning system (GPS) technologies, including via satellites where platform terminal transmitters (PTTs) are used, as well as geo-locating capabilities using satellites, radio-frequency identification (RFID) chips, and passive integrated responder (PIT) tags, among others. Such tracking technologies have resulted in cutting-edge findings worldwide that have served to protect and better understand the behaviors of myriad wildlife species. As a result, scientists, field researchers, technicians, fish and wildlife biologists and managers, plus wildlife and other veterinarian specialists, frequently opt for its use without fully understanding the ramifications to target species and their behaviors. These include negative physiological effects from electromagnetic fields (EMF) to which many nonhuman species are exquisitely sensitive, as well as direct placement/use-attachment impacts from radio collars, transmitters, and implants themselves. This paper provides pertinent studies, suggests best management practices, and compares technologies currently available to those considering and/or using such technologies. The primary focus is on the health and environmental risk/benefit decisions that should come into play, including ethical considerations, along with recommendations for more caution in the wildlife and veterinarian communities before such technologies are used in the first place.

Validity of Global Positioning System Technology to Measure Maximum Velocity Sprinting in Elite Sprinters.

Thome, M, Thorpe, RT, Jordan, MJ, and Nimphius, S. Validity of global positioning system (GPS) technology to measure maximum velocity sprinting in elite sprinters. J Strength Cond Res 37(12): 2438-2442, 2023-The objective of this study was to assess the concurrent validity of 10-Hz wearable Global Positioning System (GPS) technology to measure maximum velocity sprinting (Vmax) relative to Doppler radar in elite sprinters. Data were collected from a single training session performed by elite 100 and 200 m sprinters (males: n = 5; 100 m best times: 10.02 ± 0.07 seconds, range: 9.94-10.10 seconds; 200 m best times: 20.29 ± 0.42 seconds, range: 19.85-20.80 seconds; females: n = 2; age: 28.0 ± 4.2 years; body mass: 65.8 ± 4.6 kg; 100 m best times: 11.18 ± 0.34 seconds; 200 m best times: 22.53 ± 0.04 seconds). Velocity and time data from 16 maximal, 60-m sprint efforts were recorded simultaneously with 10 Hz GPS and 47 Hz radar. Validity was assessed using Bland-Altman 95% limits of agreement (LOA) and intraclass correlation coefficient (ICC), each with respective 95% confidence intervals (CI). Vmax measured with 10 Hz GPS demonstrated a LOA of -0.11 m·s-1 (-0.17, -0.05) and an ICC of 0.99 (0.98, 1.0) relative to the radar device.10 Hz GPS overestimated Vmax by 0.11 m·s-1 relative to the radar but could still be considered a suitable tool for monitoring external load in elite sprinters. However, the much smaller average annual improvement in this population (∼0.1-0.2%) in comparison with the ∼1% overestimation reduces the utility of 10 Hz GPS to detect meaningful performance changes in maximum velocity.