Effect of Thai Ionospheric Maps (THIM) model on the performance of network based RTK GPS in Thailand

Charoenkalunyuta, T.; Satirapod, Chalermchon

doi:10.1179/1752270613y.0000000055

Cited by 10 publications

(6 citation statements)

References 3 publications

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“…In addition, several studies have shown that the ionospheric activity is more significant at low-latitude regions [7][8][9]. Furthermore, the effect of using a local ionospheric model was tested using one month of GPS observations [10]. The study confirmed that using such model increases NRTK performance.…”

Section: Introductionsupporting

confidence: 68%

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Feasibility of DOL-VRS Service for Establishing Survey Control Using Post-Processing Method

Chanutboonsin¹,

Andrei²,

Weerawong³

et al. 2016

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Abstract. The Department of Lands Virtual Reference Station (DOL-VRS) reduces several technical limitations of conventional RTK method and increases the productivity in a cost effective manner. This also opens the question how feasible DOL-VRS service may be for establishing survey control. This study investigates the feasibility from two points of view: the observation time and the influence of ionospheric conditions. In addition, the ambiguity fixing rate, rate of position jumps, and root mean squared error are defined as performance indicators. The numerical analyses reveal that the reliable survey control may be obtained when at least 180 epochs of observation at 5-sec interval are considered on good ionospheric conditions (i.e., low TEC). On the other hand, 720 epochs or more are needed when the ionospheric activity increases. In addition, the VRS based solutions compared to an average least square adjustment solution show an offset of about 0.7 cm. Furthermore, the errors in the vertical direction for 720-epoch solutions display peak-to-peak variations of 3.9 cm (low TEC) and 10.1 cm (high TEC), respectively. We can conclude that VRS based survey control may be established using DOL-VRS service precisely and accurately at 2-cm level especially in the low TEC scenario. The user is advised to use this approach with caution and take the average of multiple occupations on the same mark, separated in time to allow changes in the constellation geometry and ionospheric conditions. Such practice will enhance the reliability to establish high accuracy survey control.

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Section: Introductionsupporting

confidence: 68%

“…In the third step, we prepared the DPT9 observation files using TEQC toolkit. Each 24h RINEX file from DPT9 was split into short sessions of different lengths and number of epochs (10,30,60,120,180,360, and 720 epochs). Since the sampling rate for DPT9 was 5 sec, the 720-epoch case corresponds to 1 hour of data.…”

Section: Data Processingmentioning

confidence: 99%

Feasibility of DOL-VRS Service for Establishing Survey Control Using Post-Processing Method

Chanutboonsin¹,

Andrei²,

Weerawong³

et al. 2016

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“…Another example is the usage of real time kinematic (RTK) methods; in [ 11 ], the authors demonstrated the integration of local ionospheric and tropospheric corrections as constrain to the precise point positioning estimation. In [ 12 ], the introduction of the global ionospheric map in RTK positioning was investigated. Single frequency stand-alone devices need to mitigate the ionospheric error using a model.…”

Section: Introductionmentioning

confidence: 99%

Neustrelitz Total Electron Content Model for Galileo Performance: A Position Domain Analysis

Gioia¹,

Angrisano

Gaglione

2023

Sensors

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Ionospheric error is one of the largest errors affecting global navigation satellite system (GNSS) users in open-sky conditions. This error can be mitigated using different approaches including dual-frequency measurements and corrections from augmentation systems. Although the adoption of multi-frequency devices has increased in recent years, most GNSS devices are still single-frequency standalone receivers. For these devices, the most used approach to correct ionospheric delays is to rely on a model. Recently, the empirical model Neustrelitz Total Electron Content Model for Galileo (NTCM-G) has been proposed as an alternative to Klobuchar and NeQuick-G (currently adopted by GPS and Galileo, respectively). While the latter outperforms the Klobuchar model, it requires a significantly higher computational load, which can limit its exploitation in some market segments. NTCM-G has a performance close to that of NeQuick-G and it shares with Klobuchar the limited computation load; the adoption of this model is emerging as a trade-off between performance and complexity. The performance of the three algorithms is assessed in the position domain using data for different geomagnetic locations and different solar activities and their execution time is also analysed. From the test results, it has emerged that in low- and medium-solar-activity conditions, NTCM-G provides slightly better performance, while NeQuick-G has better performance with intense solar activity. The NTCM-G computational load is significantly lower with respect to that of NeQuick-G and is comparable with that of Klobuchar.

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“…The larger separation of distances between the reference and the rover, errors estimated at the reference site become de-correlated with those errors affected at the rover location due to the spatial difference between the error sources [1,11,12]. These logistical, economic and technical limitations have primarily contributed to the evolution of multi-reference (or network) DGPS techniques.…”

Section: Introductionmentioning

confidence: 99%

Performance Analysis of GPS Aided Geo Augmented Navigation (GAGAN) Over Sri Lanka

Dammalage¹,

Silva²,

Satirapod³

2017

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Abstract. Satellite-Based Augmentation Systems (SBAS) are being developed worldwide due to their unique advantage of wide area coverage. GPS Aided Geo Augmented Navigation (GAGAN) is an Indian implementation of SBAS, with three (03) geo stationary satellites in space covering a huge area even beyond Indian Territory. This study focused on analyzing the improvement in position solution with GAGAN corrections over Sri Lanka. In order to test its performances, several dual and single frequency GNSS receivers were used in this experiment, one receiver was configured as SBAS receiver and other two were kept as GPS stand-alone receivers. Observations were carried out over seven (07) known control stations of six (6) different districts to investigate its coverage over Sri Lanka. At each of the tested stations the GAGAN active L1 receiver has always shown a significant accuracy improvement over L1 uncorrected observations. Further, five out of the seven (7) observation locations the calculated average 3D positional errors were lower than 1m. Almost 79% of observations (out of 24 hours of observations) have shown acceptable 3D positional accuracy, of less than 1m, for many spatial data collection applications. However, the local DGPS correction has shown higher reliability than GAGAN corrections with almost 85% of observations with less than 1m, 3D positional error.

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Effect of Thai Ionospheric Maps (THIM) model on the performance of network based RTK GPS in Thailand

Cited by 10 publications

References 3 publications

Feasibility of DOL-VRS Service for Establishing Survey Control Using Post-Processing Method

Feasibility of DOL-VRS Service for Establishing Survey Control Using Post-Processing Method

Neustrelitz Total Electron Content Model for Galileo Performance: A Position Domain Analysis

Performance Analysis of GPS Aided Geo Augmented Navigation (GAGAN) Over Sri Lanka

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