Indian Regional Navigation Satellite System Receiver Research Articles

IRNSS Performance Evaluation of SPS Services on Military Aircraft

The essence of this paper is to study and characterise the performance of Indian Regional Navigation Satellite System (IRNSS), also known as NavIC (Navigation with Indian Constellation), in actual dynamic environment by conducting field trials on military aircraft. The dynamic accuracy of IRNSS receiver in terms of position, velocity and altitude has not yet been tested on any aircraft system i.e. commercial or military applications. These field trials and performance evaluation will help in on-field assessment of IRNSS receiver performance with availability of five, six and seven IRNSS satellites. During conduct of trials, IRNSS receiver and IRNSS antenna were placed inside the aircraft. Results analysis of 18 hours flying data depicts position availability of 99.872% with five satellites and 100% position availability with six and seven satellites.

Characteristics of Electron Content Between GPS and IRNSS Altitudes Studied Around the Northern Anomaly Crest Location Over Indian Longitude Sector

AbstractOne of the newly launched satellite navigation systems is the Indian Regional Navigation Satellite System (IRNSS) operating at L5 and S band and providing position determining with an accuracy of 10 m over the Indian subcontinent and 1,500 km beyond. Collocation of this constellation, containing three geostationary and four geosynchronous satellites, with GPS over a common ionospheric volume at certain times of the day provides a unique opportunity to estimate the highly sparse electron content existing between the GPS and geostationary/synchronous orbital altitudes. These values of electron contents, though an order of magnitude less than the diurnal maximum of TEC, could account for significant proportion of postmidnight TEC around the northern crest of Equatorial Ionization Anomaly in the Indian longitude sector. Such measurements are of importance when efforts are being made to achieve subcentimeter level position accuracies. Data recorded using a tri‐band IRNSS receiver and dual‐frequency GPS receiver from Calcutta during April–June 2019 have been analyzed to calculate electron contents along a specific look angle containing GPS as well as IRNSS satellite at different times of the day. Diurnal maximum values of 4–5 TECU are noted for electron contents bound within the altitudes of GPS and IRNSS. Spatial distribution of such electron content shows diurnal maximum around 14:00–15:00 LT over subionospheric swath of 20–22°N with 80–82.5°E and 87–90°E.

Performance analysis of IRNSS using compact microstrip patch antenna for S band application

The Indian Regional Navigation Satellite System (IRNSS) is a newly functional regional satellite navigation system around Indian subcontinent. It is also known as its functioning name of NaVIC, Navigation with Indian Constellation, working on L5 and S band. In this paper a compact and low cost circularly polarized microstrip patch antenna is proposed for IRNSS S band application, to provide single frequency navigation solution. Fabrication of proposed antenna is performed using substrate of RT Duroid 5880 with the dimensions of 0.66λ × 0.5λ. The performance of IRNSS is investigated by prototype antenna and Accord made triband antenna with IRNSS/GPS/SBAS receiver which is enable to receive L1, L5 and S band data. The comparison of proposed S band antenna, triband accord system antenna and GPS antenna is presented in terms of carrier to noise ratio and positioning error. Results show that proposed antenna is suitable for S band application of IRNSS receiver.

Analysing impact of major solar flares on ionospheric TEC with RTISM model using IRNSS receiver, at SVNIT, Surat, India

Indian regional navigation satellite system (IRNSS) is a navigation system developed by the Indian Space Research Organisation (ISRO), India. The IRNSS receiver granted by Space Application Centre (SAC), ISRO, Ahmedabad is installed at SVNIT, Surat, India. A solar flare is a natural event that occurs when an unpredicted flash of distended Sun's illumination is observed near its surface. The ionosphere is greatly ionised by solar radiations. Hence it is a current challenge to investigate effects of ionospheric scintillation on IRNSS signals. This study examines impact of major solar flare events like Class ‘C’ solar flare happened on 22 July 2016 and class ‘M’ solar flare occurred on 23 and 24 July 2016, on IRNSS signals with measurement of total electron content (TEC). Real-time ionospheric scintillation monitoring (RTISM) model based on empirical mode decomposition (EMD) and second-order Daubechies (db2) wavelet is used for comparing measured and denoised TEC. The RTISM model is also used for determining automatic threshold using Neyman–Pearson detector, probability of detection and probability of false alarm. It is proven with analysis that EMD is giving more sharp results as compared to db2 wavelet for determining fluctuations in TEC during the solar flare events.

Field trial of IRNSS receiver

AbstractIRNSS is an independent regional navigation system being developed by Indian Space Research Organization, India. Ionospheric scintillations are very important to satellite‐based radio communication and navigation. Ionospheric variations are responsible for most of the range error which yields in inaccurate position coordinates and degradation in signal power (carrier to noise power ratio).This article represents a comparative analysis of position error and Ionospheric delay among IRNSS (Indian Regional Navigation Satellite System) and GPS (Global Positioning System) considering the ionospheric correction algorithms being used in both satellite constellations. Grid based ionospheric correction, dual frequency delay correction, and coefficient based have been considered for comparison of both IRNSS and GPS navigation system.

Comparison of TEC Estimation Techniques using S1 and L5 Signals of IRNSS

Indian Regional Navigation Satellite System (IRNSS) is a satellite based navigation system developed by Indian Space Research Organization (ISRO). The positional accuracy of IRNSS is limited by several errors including ionospheric delay. Ionospheric delay can be estimated with precise calculation of total electron content (TEC). However, TEC is biased by multipath and thermal noise. Therefore, multipath and thermal noise free relative TEC measurements are made and compared with two other methods, namely, code TEC and IRNSS Receiver Software (IRS) techniques. In this investigation L5 (1176.45 MHz) and S1 (2492.028 MHz) signals from IRNSS 1A to 1G satellites are considered. The results indicate that relative TEC estimation technique removes the multipath and thermal noise from the TEC measurements. Further, the TEC for signals coming from various IRNSS satellites are evaluated by calculating the standard deviation (SD). In the analysis the data is divided into segments with duration of 1 h each. The results indicate that SDs for the relative TEC estimation (2.5 TECU in case of IRNSS 1B) are lesser than the other two techniques indicating the relative TEC can be used in the receiver for the estimation of ionospheric delay. Further, the high ratio of the operating frequencies indicates a better TEC estimation.

Predicting and Analyzing TEC Variations Using Wavelet and Hilbert Huang Decomposition for IRNSS Signals at Low Latitude Location, Surat, India

Indian Regional Navigation Satellite System (IRNSS) is designed for various navigational and timing services in India. IRNSS receiver has been installed at SVNIT, Surat which is a low latitude station. In this paper, one of the major error in satellite communication which is Ionospheric effects on satellite signals while propagating in various layers of atmosphere known as Ionospheric Scintillation and its measuring parameters are discussed. IRNSS receiver is utilized to estimate Total Electron Content (TEC), Vertical total electron content (VTEC), Elevation angle and Carrier to noise (C/N) ratio. Daubechies wavelet decomposition and Hilbert Huang decomposition (HHT) of TEC is presented.

A Software Multi-GNSS Receiver Implementation for the Indian Regional Navigation Satellite System

ABSTRACTThe Indian Regional Navigation Satellite System (IRNSS) is currently under development with four out of the total planned seven satellites deployed in space. The Department of Navigation and Positioning of the Finnish Geospatial Research Institute (FGI) has been an early adopter of this system in Europe through the development of its software-based multi-frequency multi-GNSS receiver, called FGI-GSRx. This paper presents the results of the first comprehensive IRNSS receiver implementation in Finland, if not in Europe, using the FGI-GSRx receiver. Following a brief description of the IRNSS system, the paper presents the receiver architecture, including the acquisition and tracking stages, and position computation. The results show that IRNSS satellites when used in multi-GNSS positioning can be beneficial in augmenting other satellite systems over north and east Europe. These benefits are expected to grow as more IRNSS satellites are deployed in space in the future. Therefore, the impact of these results is interesting to the positioning, navigation, and timing community even outside the intended service area of IRNSS.