Conference Presentations by Mustafa AKKAMIŞ
International Conference on Energy Research (ENRES2018), 2018
Keskin M, M Akkamis, YE Sekerli. 2018. An Overview of GNSS and GPS based Velocity Measurement in... more Keskin M, M Akkamis, YE Sekerli. 2018. An Overview of GNSS and GPS based Velocity Measurement in Comparison to Other Techniques. International Conference on Energy Research (ENRES2018), 1-2 November 2018, Alanya, Turkey, Proceedings Book, pp.392-404. ......... .......... .............. ........... ............ ............ .......... ............ ............ ..........
Abstract: GNSS-based speed sensing have some advantages over other methods with no moving parts, not affected by tire properties, dust, ground ruggedness, tall vegetation, suitability for measuring human speed, etc. However, GNSS receiver manufacturers do not provide detailed data on the accuracy of their products in velocity measurement under different conditions. Hence, studies are conducted to assess the speed accuracy of the GNSS receivers. This paper overviewed studies on the accuracy of GNSS receivers for speed measurement and basic knowledge on other methods was also included. Studies revealed key findings: GNSS units determine the speed based on three methods (travel distance/time, Doppler shift and time-differenced carrier phase, TDCP) and the TDCP method can offer better accuracy than the other two methods. GNSS receivers with higher update frequencies give more accurate speed data as compared to the lower ones, especially in varying speed conditions (acceleration and deceleration). High correlation exists between GPS velocity error and acceleration and deceleration (R2>0.70) in variable speeds meaning that the error rises in higher acceleration and decelerations. GPS units underestimate the speed as compared to the actual speeds. The accuracy of speed with DGPS was improved as compared to non-differential GPS. Adding GLONASS to GPS does not improve the performance considerably. HDOP might be used as a quality indicator for speed data reliability. Also, caution should be exercised for GNSS speed measurement under challenging environments (overpass, forest, urban area, etc.). ............ ............ ............ ............ ............ .......... ........... ............ ............ ........... ........... .......... ............. .......... ............
Özet: GNSS esaslı hız ölçümü tekniği diğer yöntemlere göre bazı avantajlara sahiptir: hareketli parça bulunmaması, teker ve lastik özelliklerinden, tozlanmadan, zemin yüzeyinin düz olmamasından, zeminde yüksek boylu bitki örtüsü olmasından etkilenmemesi ve insan hızını ölçmeye uygun olması. Ancak, GNSS alıcısı üreten firmalar, ürünlerinin farklı koşullardaki hız ölçümü doğruluğu konusunda yeterli bilgi sunmamaktadır. Bu nedenle, GNSS alıcılarının hız ölçüm doğruluğunu değerlendirmek için çalışmalar yürütülmektedir. Bu makalede, GNSS alıcılarının ve kıyaslamalı olarak diğer yöntemlerin hız ölçümündeki doğruluğu konusunda yapılan çalışmalar özetlenmiştir. Bu konuda yapılan çalışmalar, önemli bulgular ortaya koymuştur: GNSS alıcıları hızı üç yöntemle belirleyebilmektedir (Alınan yol/zaman, Doppler frekans kayması ve TDCP). TDCP yöntemi hız ölçümünde diğer iki yöntemden daha iyi doğruluk sağlayabilmektedir. Yüksek veri güncelleme frekansına sahip GNSS alıcıları, özellikle değişen hız koşullarında (hızlanma ve yavaşlama), düşük frekanslı olanlara kıyasla daha doğru hız verisi sağlamaktadır. Değişken hızlarda GPS hız ölçümü hatası ile hızlanma ve yavaşlama ivmesi arasında yüksek korelasyon (R2>0.70) bulunmaktadır, bu, hata değerinin yüksek ivmeli hareket durumunda arttığı anlamına gelmektedir. GPS alıcıları, gerçek hızı az miktarda daha düşük değerlerde tahmin etmektedir. Diferansiyel GPS (DGPS) ile ölçülen hızın doğruluğu, diferansiyel olmayan GPS ile karşılaştırıldığında artmaktadır. GPS'e ek olarak GLONASS uydularının kullanımı performansı önemli ölçüde etkilememektedir. HDOP, hız ölçümünün güvenilirliği için kalite göstergesi olarak kullanılabilir. Ayrıca, olumsuz ortam koşullarında (üst geçit, orman, kentsel alan vb.) GNSS hız ölçümü doğruluğu konusunda dikkatli olunmalıdır.
Papers by Mustafa AKKAMIŞ
Mustafa Kemal Üniversitesi tarım bilimleri dergisi, Nov 7, 2023
Research Square (Research Square), Feb 16, 2023
Proper irrigation and fertilization are essential to achieve high tuber yield and quality in pota... more Proper irrigation and fertilization are essential to achieve high tuber yield and quality in potato production. Water and nitrogen (N) use e ciencies are required to be improved due to high costs of these agricultural inputs. This study aimed to optimize the use of water and N in potato to ensure high water and N use e ciencies as well as achieve optimum yield and tuber quality. Potato plants were subjected to three irrigation treatments, i.e., a water application of 100% (S100), 66% (S66) and 33% (S33) of eld capacity and six N levels, 0 (N0), 100 (N1), 200 (N2), 300 (N3), 400 (N4) and 500 (N5) kg N ha − 1. Yield, growth parameters and tuber quality were generally more sensitive to irrigation than nitrogen. The highest total tuber yield was obtained under full irrigation with an application of 300 kg N ha − 1. Plants indicated higher values for yield and growth parameters in full irrigation applications, and signi cantly lower values were obtained at low irrigations. On the contrary, the full irrigation (S100) application caused a decrease in quality characteristics compared to low irrigations (S66 and S33). The WUE was improved by N supply, when N level applied above 300 N ha − 1. In addition, N3-S66 was determined the most suitable application for tuber quality and WUE. These results indicated that potato can be produced with acceptable yields while saving irrigation water and certain nitrogen level.
Research Square (Research Square), Jun 26, 2023
Water and nitrogen are agricultural inputs that are widely used in potato production areas. Exces... more Water and nitrogen are agricultural inputs that are widely used in potato production areas. Excessive and inappropriate use of these two important inputs causes rapid consumption of water resources and results in inappropriate nitrogen leakage. In potato production, understanding the effects of water and nitrogen on the physiological properties will help to overcome these di culties. This study was therefore conducted to determine the effects of different nitrogen and irrigation levels on the physiological (photosynthesis rate, leaf area index, leaf chlorophyll content, leaf temperature) characteristic of potato. Field experiments were conducted during the 2021 and 2022 main potato cropping seasons to select the suitable combination of irrigation and fertilization levels for potato production in the Nigde Province of the Central Anatolia Region of Turkey. The study conducted in a factorial design with six nitrogen fertilization rates and three irrigation levels. The experiment included no nitrogen (control, N0), 100 kg N ha − 1 (N1), 200 kg N ha − 1 (N2), 300 kg N ha − 1 (N3), 400 kg N ha − 1 (N4) and 500 kg N ha − 1 (N5) and I1 = 100%, I2 = 66%, I3 = 33% of Field Capacity (FC). All the measurements were taken at ve different times (40, 50, 60, 70, 80 days) after emergence. The results revealed that nitrogen treatments improve the crop physiology traits by increasing the photosynthetic rate, chlorophyll content and leaf area index, except the leaf temperature, compared with the control (no-nitrogen treatments) while the full irrigation (I1) treatment recorded the highest photosynthesis and leaf area index values. I1N3 was the most e cient treatment for both photosynthesis and leaf area index. The increase in irrigation treatments resulted in a decrease in leaf chlorophyll and leaf temperature (Pt). Leaf chlorophyll content tended to increase with increasing nitrogen, but leaf temperature did not show a regular increase or decrease. The highest N and I interaction for leaf chlorophyll content and leaf temperature were obtained from I3N0 treatment. This study identi es the most appropriate nitrogen and irrigation application for optimum physiological yield of the potato for crop producers. The study used only one commercial potato cultivar (agria), so more research should be carried out on several cultivars in order to arrive at a more conclusive conclusion, since it may be that this result is unique to agria potato cultivars only. In addition, both biochemical and physiological assessments in comparison with tuber yield should be conducted using different nitrogen and irrigation levels to assess their correlations.
Iğdır Üniversitesi Fen Bilimleri Enstitüsü Dergisi, Mar 1, 2023
DergiPark (Istanbul University), Dec 6, 2021
Water and nitrogen are the most important factors affecting yield and quality in potato managemen... more Water and nitrogen are the most important factors affecting yield and quality in potato management. Proper irrigation and nitrogen fertilizer management ensures water conservation and reduces nutrient loss. Nitrogen (N) is the most commonly deficient mineral nutrient in agricultural soils to increase potato production. Therefore, the split application of nitrogen fertilizers is important to prevent losses through leaching, evaporation, denitrification, weeding, erosion by running water, and precipitation. Determining the appropriate amounts of nitrogen and irrigation water to improve the efficiency of water and nitrogen use can minimize N losses, minimize costs and increase production profits. Potato is very sensitive to water stress due to its shallow root system and requirement to consume a plenty of water in all growing season. Therefore, regular irrigation of potato is important for obtaining the best tuber yield. This review has been made to identify and analyze in current research on N management practices and irrigation regimes to improve and maintain potato tuber yield. Variability of results from research studies show that determined precise results are not transferred from one place to another because potato varieties and cultivation conditions are not the same. In addition, it was determined that the responses of potato varieties to different nitrogen amounts varied from region to region. According to different irrigation regimes, it has been seen that the best result increasing yield in potato is obtained from applications when the plant is irrigated the most and field capacity is fully saturated. In addition, although the most appropriate nitrogen and irrigation interaction differ from region to region and depending on the variety, it has been determined that the most irrigation is applied and the nitrogen is obtained from application roughly 200 kg/ha.
DergiPark (Istanbul University), Jun 15, 2020
Bitkisel üretimde sürdürülebilirliğin sağlanması yenilikçi tarım uygulamalarının uygulanması ile ... more Bitkisel üretimde sürdürülebilirliğin sağlanması yenilikçi tarım uygulamalarının uygulanması ile mümkündür. Bu yeniliklerin üretim alanında uygulanmasıyla tarım arazileri birçok açıdan iyileşmekte ve üretim verimliliği artırılmaktadır. Bu uygulamalardan bir tanesi olan hassas tarım son yıllarda bütün dünyada bilinen ve arazilerde giderek artan düzeyde uygulanmaya başlayan teknolojik değişimin öncüsü olmuştur. Hassas tarım uygulamalarından biri olan uzaktan algılama ise tarım arazilerinin özelliklerinin belirlenmesinde uydu ve uçak teknolojilerini kullanarak daha etkin tarımsal yönetim modeli oluşturmada üreticilere yardımcı olmaktadır. Bununla birlikte son yıllarda uzaktan algılamada kullanılan uydu ve uçak sistemlerinin yerine daha yüksek çözünürlüklü görüntüler elde ederek diğer sistemlere göre hem hızlı hem daha ekonomik olan insansız hava araçları kullanılmaya başlanmıştır. Bu araçlar bitki durumu inceleme, hastalık ve zararlı tespiti, bitkisel stres, verim tahmini, yabancı ot tespiti gibi işlemlerde geleneksel olarak yapılan yöntemlere göre daha hızlı, ekonomik ve daha verimli şekilde elde edilmektedir. Bu makalede insansız hava araçlarının genel yapısı ve tarımda kullanım alanları açıklanmış ayrıca bitkisel üretim amacıyla yapılan çalışmalar eklenerek insansız hava araçlarının bu çalışmalarda nasıl kullanıldığı açıklanmıştır.
Research Square (Research Square), Mar 6, 2023
Proper irrigation and fertilization are essential to achieve high tuber yield and quality in pota... more Proper irrigation and fertilization are essential to achieve high tuber yield and quality in potato production. Water and nitrogen are required to be improved due to high costs of these agricultural inputs. This study aimed to optimize the use of water and nitrogen in potato to ensure high water use e ciencies as well as achieve optimum yield and tuber quality. Potato plants were subjected to three irrigation treatments, 100% (S100), 66% (S66) and 33% (S33) of eld capacity and six N levels, 0 (N0), 100 (N1), 200 (N2), 300 (N3), 400 (N4) and 500 (N5) kg N ha − 1. Yield, growth parameters and tuber quality were generally more sensitive to irrigation than nitrogen. The highest total tuber yield was obtained under full irrigation with an application of 300 kg N ha − 1. Plants indicated higher values for yield and growth parameters in full irrigation applications, and signi cantly lower values were obtained at low irrigations. On the contrary, the full irrigation (S100) application caused a decrease in quality characteristics compared to low irrigations (S66 and S33). Water levels treatments indicated that S66 had the highest mean value of WUE in both years. These results indicated that potato can be produced with acceptable yields while saving irrigation water and certain nitrogen level.
Water and nitrogen are agricultural inputs that are widely used in potato production areas. Exces... more Water and nitrogen are agricultural inputs that are widely used in potato production areas. Excessive and inappropriate use of these two important inputs causes rapid consumption of water resources and results in inappropriate nitrogen leakage. In potato production, understanding the effects of water and nitrogen on the physiological properties will help to overcome these difficulties. This study was therefore conducted to determine the effects of different nitrogen and irrigation levels on the physiological (photosynthesis rate, leaf area index, leaf chlorophyll content, leaf temperature) characteristic of potato. Field experiments were conducted during the 2021 and 2022 main potato cropping seasons to select the suitable combination of irrigation and fertilization levels for potato production in the Nigde Province of the Central Anatolia Region of Turkey. The study conducted in a factorial design with six nitrogen fertilization rates and three irrigation levels. The experiment inc...
Iğdır üniversitesi fen bilimleri enstitüsü dergisi, Mar 1, 2023
Turkish Journal Of Field Crops, 2021
The purpose of this study was to determine the effects of different doses of gibberellic acid (GA... more The purpose of this study was to determine the effects of different doses of gibberellic acid (GA3) on growth, tuber yield and some tuber quality traits of potato. The experiment was arranged in a split-plot design with three replicates, cultivars Marabel, Alegria and Agria were arranged in the main plots, and GA3 doses (0, 25, 50 and 100 mg GA3 L) in the sub-plots. Gibberellic acid was applied to leaves by spraying on the 50 day after planting (during flowering). The effects of GA3 applications on tuber yield of potato cultivars were varied. GA3 applications resulted in significant decrease on chlorophyll content (SPAD), tuber dry matter and chips quality of potato. But it caused significant increase on number of tubers and tuber yield plant. In 2019 and 2020 years, the highest tuber yield was obtained from Alegria cultivar (62.78 and 50.55 t ha respectively). Total tuber yield values increased from 52.08 t/ha to 65.14 t ha in 2019 and from 42.12 t ha to 53.94 t ha in 2020 with inc...
Mustafa Kemal Üniversitesi Tarım Bilimleri Dergisi, 2021
This study aimed to determine the effect of different growth media on germination performance wit... more This study aimed to determine the effect of different growth media on germination performance with seedling quality of Sage (Salvia officinalis L.) seeds. Methods and Results: The study was conducted in 2020 at Greenhouse of Plant Production and Technologies, Faculty of Agricultural Sciences and Technologies, Nigde Omer Halisdemir University. The greenhouse experiment was laid out in the randomized complete block design with three replications and eight different growth media were used for experiment such as peat (%100), soil (%100), perlite (%100), sand (%100), peat + soil (1:1), peat + perlite (1:1), peat + sand (1:1), peat + soil + sand + perlite (1:1:1:1). Healthy seedlings were not obtained from soil (%100), perlite (%100) and sand (%100) used as growth media. The highest germination percentage (88.83%) and shortest day required for germination (26.60 day) was achieved in peat media. Besides, the highest seedlings heights (20.37 cm), leaf chlorophyll content (36.63), dry and fresh weight of seedlings (3.48 g ve 0.57 g) and dry and fresh weight of roots (3.48 g ve 0.84 g) were obtained in peat media. Conclusions: It was determined that peat gave the best result for sage plant used as growth media in terms of germination and healthy seedlings in comparison to other growth media. Significance and Impact of the Study: Different growth media were determined to an have influence on seed germination and development of seedlings and roots according to the results obtained in this study. Therefore, it is important to know the necessity for appropriate growth media to produce healthy and quality seedlings of sage. The most appropriate growth media was found peat according to the results obtained from the present study. As conclusion, the production of healthy and quality seedlings is essential for sage productivity. Determination of growth media will contribute to the producer and sustainability of agriculture activities in terms of sage production.
AgriEngineering, 2021
Low-cost GPS (Global Positioning System) speed sensors have been available to quantify vehicle sp... more Low-cost GPS (Global Positioning System) speed sensors have been available to quantify vehicle speed on different platforms including agricultural tractors in precision agriculture applications such as yield monitoring, variable rate fertilizer and pesticide applications. One of the advances in low-cost GPS receivers is the higher data update frequencies. However, we found no studies on the accuracy of low-cost GPS speed sensors with different update frequencies, especially under variable speed conditions. Thus, this work investigated the effect of the update frequency on the accuracy of low-cost GPS speed sensors under both constant and varying speed conditions. Three GPS speed sensors with update frequencies of 1 Hz, 5 Hz and 7 Hz (GPS1Hz, GPS5Hz and GPS7Hz) were simultaneously tested under the same conditions. A total of 144 tests were conducted on three different days and at three different times of each day with four speed levels and four repetitions. The percent errors were fo...
Bitkisel uretimde surdurulebilirligin saglanmasi yenilikci tarim uygulamalarinin uygulanmasi ile ... more Bitkisel uretimde surdurulebilirligin saglanmasi yenilikci tarim uygulamalarinin uygulanmasi ile mumkundur. Bu yeniliklerin uretim alaninda uygulanmasiyla tarim arazileri bircok acidan iyilesmekte ve uretim verimliligi artirilmaktadir. Bu uygulamalardan bir tanesi olan hassas tarim son yillarda butun dunyada bilinen ve arazilerde giderek artan duzeyde uygulanmaya baslayan teknolojik degisimin oncusu olmustur. Hassas tarim uygulamalarindan biri olan uzaktan algilama ise tarim arazilerinin ozelliklerinin belirlenmesinde uydu ve ucak teknolojilerini kullanarak daha etkin tarimsal yonetim modeli olusturmada ureticilere yardimci olmaktadir. Bununla birlikte son yillarda uzaktan algilamada kullanilan uydu ve ucak sistemlerinin yerine daha yuksek cozunurluklu goruntuler elde ederek diger sistemlere gore hem hizli hem daha ekonomik olan insansiz hava araclari kullanilmaya baslanmistir. Bu araclar bitki durumu inceleme, hastalik ve zararli tespiti, bitkisel stres, verim tahmini, yabanci ot t...
AgriEngineering, 2021
Akkamis, M.; Keskin, M.; Sekerli, Y.E. Comparative appraisal of three low-cost GPS speed sensors ... more Akkamis, M.; Keskin, M.; Sekerli, Y.E. Comparative appraisal of three low-cost GPS speed sensors with different data update frequencies. AgriEngineering, 2021, 3, 423–437. doi.org/10.3390/agriengineering3020028 ..... ...... ..... ..... ..... ...... ..... ..... ..... ..... ..... ..... ..... ...... ...... ...... ...... ..... Abstract: Low-cost GPS (Global Positioning System) speed sensors have been available to quantify vehicle speed on different platforms including agricultural tractors in precision agriculture applications such as yield monitoring, variable rate fertilizer and pesticide applications. One of the advances in low-cost GPS receivers is the higher data update frequencies. However, we found no studies on the accuracy of low-cost GPS speed sensors with different update frequencies, especially under variable speed conditions. Thus, this work investigated the effect of the update frequency on the accuracy of low-cost GPS speed sensors under both constant and varying speed conditions. Three GPS speed sensors with update frequencies of 1 Hz, 5 Hz and 7 Hz (GPS1Hz, GPS5Hz and GPS7Hz) were simultaneously tested under the same conditions. A total of 144 tests were conducted on three different days and at three different times of each day with four speed levels and four repetitions. The percent errors were found to be up to 2.3%, 1.8% and 1.4% at constant speeds; up to 47%, 16% and 12% at the increasing speeds and 24%, 6% and 5% at the decreasing speeds, depending on the acceleration and deceleration levels, for GPS1Hz, GPS5Hz and GPS7Hz, respectively. The differences among the error values of the GPS speed sensors were found to be statistically significant (p < 0.05). The GPS speed sensors with higher update frequencies (5 and 7 Hz) provided higher accuracy compared to the one with lower frequency (1 Hz), particularly in the case of higher acceleration conditions. In sum, low-cost GPS speed sensors with higher update frequencies should be used for better accuracy, especially in variable speed conditions. ..... ...... ..... ..... ..... ...... ..... ..... ..... ..... ..... ..... ..... ...... ...... ...... ...... ..... Özet: Düşük maliyetli GPS (Küresel Konumlandırma Sistemi) hız sensörleri verim görüntüleme ve haritalama, değişken düzeyli gübreleme ve pestisit uygulamaları gibi Hassas Tarım uygulamalarında tarım traktörleri dahil olmak üzere farklı platformlarda araç hızını ölçmek için kullanılmaktadır. Düşük maliyetli GPS alıcılarındaki gelişmelerden biri, daha yüksek (˃1Hz) veri güncelleme frekansıdır. Ancak, özellikle değişken hız koşullarında yüksek güncelleme frekanslarına sahip düşük maliyetli GPS hız sensörlerinin doğruluğu ile ilgili herhangi bir çalışmaya rastlanmamıştır. Bu nedenle, bu çalışmada, güncelleme frekansının hem sabit hem de değişken (artan ve azalan) hız koşullarında düşük maliyetli GPS hız sensörlerinin doğruluğu üzerindeki etkisi araştırılmıştır. 1 Hz, 5 Hz ve 7 Hz (GPS1Hz, GPS5Hz ve GPS7Hz) güncelleme frekansına sahip üç GPS hız sensörü aynı koşullar altında aynı anda test edilmiştir. Üç farklı günde, her günün üç farklı saatinde, dört hız kademesi ve dört tekrar ile toplam 144 test yapılmıştır. Oransal hata değerleri hız ve ivme durumuna bağlı olarak; GPS1Hz, GPS5Hz ve GPS7Hz için sırasıyla sabit hızlarda; %2.3, %1.8 ve %1.4; hızlanma durumunda -%47, -%16 ve -%12 ve yavaşlama durumunda %24, %6 ve %5’e kadar değerlerde belirlenmiştir. GPS hız sensörlerinin hata değerleri arasındaki farklar istatistiksel olarak önemli bulunmuştur (p<0.05). Yüksek güncelleme frekansına sahip GPS hız sensörleri (5 ve 7 Hz), özellikle hızlanma ve yavaşlama koşullarında, düşük frekanslı (1 Hz) sensör ile karşılaştırıldığında yüksek doğruluk değerleri sağlamıştır. Özetle, özellikle değişken hız koşullarında daha iyi doğruluk için yüksek güncelleme frekansına sahip düşük maliyetli GPS hız sensörlerinin kullanımı önerilmektedir.
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Conference Presentations by Mustafa AKKAMIŞ
Abstract: GNSS-based speed sensing have some advantages over other methods with no moving parts, not affected by tire properties, dust, ground ruggedness, tall vegetation, suitability for measuring human speed, etc. However, GNSS receiver manufacturers do not provide detailed data on the accuracy of their products in velocity measurement under different conditions. Hence, studies are conducted to assess the speed accuracy of the GNSS receivers. This paper overviewed studies on the accuracy of GNSS receivers for speed measurement and basic knowledge on other methods was also included. Studies revealed key findings: GNSS units determine the speed based on three methods (travel distance/time, Doppler shift and time-differenced carrier phase, TDCP) and the TDCP method can offer better accuracy than the other two methods. GNSS receivers with higher update frequencies give more accurate speed data as compared to the lower ones, especially in varying speed conditions (acceleration and deceleration). High correlation exists between GPS velocity error and acceleration and deceleration (R2>0.70) in variable speeds meaning that the error rises in higher acceleration and decelerations. GPS units underestimate the speed as compared to the actual speeds. The accuracy of speed with DGPS was improved as compared to non-differential GPS. Adding GLONASS to GPS does not improve the performance considerably. HDOP might be used as a quality indicator for speed data reliability. Also, caution should be exercised for GNSS speed measurement under challenging environments (overpass, forest, urban area, etc.). ............ ............ ............ ............ ............ .......... ........... ............ ............ ........... ........... .......... ............. .......... ............
Özet: GNSS esaslı hız ölçümü tekniği diğer yöntemlere göre bazı avantajlara sahiptir: hareketli parça bulunmaması, teker ve lastik özelliklerinden, tozlanmadan, zemin yüzeyinin düz olmamasından, zeminde yüksek boylu bitki örtüsü olmasından etkilenmemesi ve insan hızını ölçmeye uygun olması. Ancak, GNSS alıcısı üreten firmalar, ürünlerinin farklı koşullardaki hız ölçümü doğruluğu konusunda yeterli bilgi sunmamaktadır. Bu nedenle, GNSS alıcılarının hız ölçüm doğruluğunu değerlendirmek için çalışmalar yürütülmektedir. Bu makalede, GNSS alıcılarının ve kıyaslamalı olarak diğer yöntemlerin hız ölçümündeki doğruluğu konusunda yapılan çalışmalar özetlenmiştir. Bu konuda yapılan çalışmalar, önemli bulgular ortaya koymuştur: GNSS alıcıları hızı üç yöntemle belirleyebilmektedir (Alınan yol/zaman, Doppler frekans kayması ve TDCP). TDCP yöntemi hız ölçümünde diğer iki yöntemden daha iyi doğruluk sağlayabilmektedir. Yüksek veri güncelleme frekansına sahip GNSS alıcıları, özellikle değişen hız koşullarında (hızlanma ve yavaşlama), düşük frekanslı olanlara kıyasla daha doğru hız verisi sağlamaktadır. Değişken hızlarda GPS hız ölçümü hatası ile hızlanma ve yavaşlama ivmesi arasında yüksek korelasyon (R2>0.70) bulunmaktadır, bu, hata değerinin yüksek ivmeli hareket durumunda arttığı anlamına gelmektedir. GPS alıcıları, gerçek hızı az miktarda daha düşük değerlerde tahmin etmektedir. Diferansiyel GPS (DGPS) ile ölçülen hızın doğruluğu, diferansiyel olmayan GPS ile karşılaştırıldığında artmaktadır. GPS'e ek olarak GLONASS uydularının kullanımı performansı önemli ölçüde etkilememektedir. HDOP, hız ölçümünün güvenilirliği için kalite göstergesi olarak kullanılabilir. Ayrıca, olumsuz ortam koşullarında (üst geçit, orman, kentsel alan vb.) GNSS hız ölçümü doğruluğu konusunda dikkatli olunmalıdır.
Papers by Mustafa AKKAMIŞ
Abstract: GNSS-based speed sensing have some advantages over other methods with no moving parts, not affected by tire properties, dust, ground ruggedness, tall vegetation, suitability for measuring human speed, etc. However, GNSS receiver manufacturers do not provide detailed data on the accuracy of their products in velocity measurement under different conditions. Hence, studies are conducted to assess the speed accuracy of the GNSS receivers. This paper overviewed studies on the accuracy of GNSS receivers for speed measurement and basic knowledge on other methods was also included. Studies revealed key findings: GNSS units determine the speed based on three methods (travel distance/time, Doppler shift and time-differenced carrier phase, TDCP) and the TDCP method can offer better accuracy than the other two methods. GNSS receivers with higher update frequencies give more accurate speed data as compared to the lower ones, especially in varying speed conditions (acceleration and deceleration). High correlation exists between GPS velocity error and acceleration and deceleration (R2>0.70) in variable speeds meaning that the error rises in higher acceleration and decelerations. GPS units underestimate the speed as compared to the actual speeds. The accuracy of speed with DGPS was improved as compared to non-differential GPS. Adding GLONASS to GPS does not improve the performance considerably. HDOP might be used as a quality indicator for speed data reliability. Also, caution should be exercised for GNSS speed measurement under challenging environments (overpass, forest, urban area, etc.). ............ ............ ............ ............ ............ .......... ........... ............ ............ ........... ........... .......... ............. .......... ............
Özet: GNSS esaslı hız ölçümü tekniği diğer yöntemlere göre bazı avantajlara sahiptir: hareketli parça bulunmaması, teker ve lastik özelliklerinden, tozlanmadan, zemin yüzeyinin düz olmamasından, zeminde yüksek boylu bitki örtüsü olmasından etkilenmemesi ve insan hızını ölçmeye uygun olması. Ancak, GNSS alıcısı üreten firmalar, ürünlerinin farklı koşullardaki hız ölçümü doğruluğu konusunda yeterli bilgi sunmamaktadır. Bu nedenle, GNSS alıcılarının hız ölçüm doğruluğunu değerlendirmek için çalışmalar yürütülmektedir. Bu makalede, GNSS alıcılarının ve kıyaslamalı olarak diğer yöntemlerin hız ölçümündeki doğruluğu konusunda yapılan çalışmalar özetlenmiştir. Bu konuda yapılan çalışmalar, önemli bulgular ortaya koymuştur: GNSS alıcıları hızı üç yöntemle belirleyebilmektedir (Alınan yol/zaman, Doppler frekans kayması ve TDCP). TDCP yöntemi hız ölçümünde diğer iki yöntemden daha iyi doğruluk sağlayabilmektedir. Yüksek veri güncelleme frekansına sahip GNSS alıcıları, özellikle değişen hız koşullarında (hızlanma ve yavaşlama), düşük frekanslı olanlara kıyasla daha doğru hız verisi sağlamaktadır. Değişken hızlarda GPS hız ölçümü hatası ile hızlanma ve yavaşlama ivmesi arasında yüksek korelasyon (R2>0.70) bulunmaktadır, bu, hata değerinin yüksek ivmeli hareket durumunda arttığı anlamına gelmektedir. GPS alıcıları, gerçek hızı az miktarda daha düşük değerlerde tahmin etmektedir. Diferansiyel GPS (DGPS) ile ölçülen hızın doğruluğu, diferansiyel olmayan GPS ile karşılaştırıldığında artmaktadır. GPS'e ek olarak GLONASS uydularının kullanımı performansı önemli ölçüde etkilememektedir. HDOP, hız ölçümünün güvenilirliği için kalite göstergesi olarak kullanılabilir. Ayrıca, olumsuz ortam koşullarında (üst geçit, orman, kentsel alan vb.) GNSS hız ölçümü doğruluğu konusunda dikkatli olunmalıdır.