The European Terrestrial Reference System 1989 (ETRS89), introduced in Europe as a geodetic reference system, is implemented in Romania (by the ODG of the ANCPI No. 212/2009) for the creation of a modern National Spatial Geodetic Network (RGNS) and the realization of pan-European cartographic products.
ETRS89 is defined according to the international standard ISO 19111, as composed of the ETRS89 geodetic datum, based on the GRS80 (Geodetic Reference System 1980) ellipsoid and the elliptical geodetic coordinate system.
• In Romania, two reference systems are officially used:
• The 1942 coordinate system (internationally known as "S-42"), based on the 1940 Krasovski ellipsoid, with the fundamental point at Pulkovo (Russia), together with the 1970 Stereographic projection;
• Reference system based on the reference 1910 Hayford ellipsoid, oriented on the fundamental astronomical point located inside the Military astronomical observatory in Bucharest, together with the 1930 stereographic projection – Bucharest secant plane.

The coordinates transformations used in Romania can be classified into two categories:
• Local coordinate transformations without a model of Helmert data distortion with 7 parameters or 4 parameters (standard deviation is around ± 0.10 m or less, depending on the distance between the joint points);
• Coordinate transformations with a data distortion model for which the standard deviation of the transformed coordinates is around ± 0.10-0.15 m, provided the existence of a sufficient number of joint points spread evenly across the entire country territory.

Weather
The GPS reference stations located in Baia Mare, Brăila, Cluj, Deva, Sibiu, Suceava and Timişoara are equipped with high-performance meteorological sensors of MET 3A-type, which accurately record, every 1 minute, temperature, pressure and the humidity of the place where this station is located.
The MET 3A-type weather sensor, produced by the american company Paroscientific Inc., has the following performances and features:
Performance:
-Pressure Accuracy ±0.08 hPa from 620 to 1100 hPa
-Temperature Accuracy ±0.1 deg C from -50 to +60 C
-Relative Humidity Accuracy ±2 Percent from 0 to 100 %RH at 25 deg C.
-Rapid Humidity Recovery Time after Saturation.
Features:
-Weatherproof Enclosure
-Fan Aspirated Probe System
-High Performance Pressure Port (Wind Insensitive)
-Bi-Directional RS-232 Serial Bus
-User Selectable Parameters Including Resolution, Update Rate
-Engineering Units, Sampling Commands etc. with Supplied Software
-LED Status Indicators (Power, Transmit, Receive)
-3 Year Long-term Stability Warranty
-Interfaces with GPS Receivers, Data Loggers and Computers
-Free zero adjustment
Example of a weather data file:

Necessary equipment for the use of ROMPOS® services
ROMPOS® DGNSS – Single-frequency receiver and direct internet access for connection to the ROMPOS®-DGNSS service server (mobile internet via GSM/GPRS); data format provided RTCM 2. x, 3. x
ROMPOS® RTK – Receiver with two (one * *) frequencies and direct internet access for connection to the ROMPOS®-RTK service server (mobile internet via GSM/GPRS); data format provided RTCM 2. x, 3. x
ROMPOS® GEO – Single or dual-frequency receiver whose satellite measurements will be connected in post-processing mode to the National Network of Reference GNSS Stations; data format provided: (V) RINEX G (M) V. 2.1 (1)

* - provided the possibility of internet access;
** - with certain limitations related to the distance from the reference station, no. of contacted satellites, the status of ionosphere etc.

The transfer of DGNSS/RTK differential corrections from the reference stations (network of reference stations) to the user can be done by various means, the most common being: transfer via radio waves, via GSM/GPRS mobile communication systems or via the internet. ROMPOS's DGNSS/RTK services are based on the transfer of data via the internet. This data is transmitted in a standardized RTCM (Radio Technical Commission for Maritime Services) format using the NTRIP (Networked Transport of RTCM via Internet Protocol) technology. NTRIP includes a standalone protocol based on HTTP – Hypertext Transfer Protocol and adapted to GNSS data transfer requirements. It allows the dissemination of differential corrections (in RTCM format) or other types of GNSS data, to stationary or moving users via the internet. NTRIP allows internet access via IP-based mobile networks (Internet Protocol), such as GSM, GPRS, EDGE or UMTS networks. The use of this technology is carried out by means of modules including: Ntrip Server (to transfer data from reference stations to central server), Ntrip Caster – for the administration and transfer of data from the central server (e.g. ROMPOS server) and Ntrip Client – to retrieve data (differential corrections) from the central server by users. The Ntrip Server and Ntrip Client modules are available free of charge from various software manufacturers, especially from the Federal Cartography and Geodesy Agency (BKG) in Germany (http://igs.bkg.bund.de), which was the promoter of this technology. These modules can be installed on various equipment such as: GNSS receivers, desktop computers, laptop, PDA, mobile phones, etc. The most practical variant is the one where the user has installed a Ntrip Client directly on the GNSS receiver, then, once this software is configured, using a GSM/GPRS modem, can connect and transfer data from the data server which runs a Ntrip Caster software to the GNSS receiver.

UPDATE 07.10.2019

Ca urmare a situației de forță majoră desfășurată în perioada 30 sep-3 oct 2019 abonamentele tuturor utilizatorilor au fost prelungite corespunzător cu 4 zile.

UPDATE 06.10.2019

Toate produsele RTK au revenit la soluții cu GLONASS, se poate folosi atât portul 2101 cât și 2105. 

04.10.2019

Descriere problemă.
S-a observat că roverele conectate la rețele de tip GNSS Spider nu obțin soluții fixe în descursul mai multor minute.
Problema se manifestă pentru orice produs de rețea și single-site RTK ce folosește NULLANTENNA și furnizează soluții GLONASS. Motivul pentru care roverul nu obține soluție fixă este că fluxul de date furnizat de GNSS Spider nu conține mesaje de observație după realizarea conexiunii. În cazul în care roverul stă conectat suficient, după câteva minute, GNSS Spider va începe să transmită mesajele cu observații și roverul va putea obține soluție fixă.
Fixarea ambiguităților în procesarea de rețea este conformă pentru toate constelațiile,
Cauze
Cauza acestei probleme se datorează faptului că, începând cu ziua de Sâmbătă, 29.09.2019, sateliții GLONASS transmit informații cu privire la almanah pentru satelitul R10, care nu sunt conforme cu documentația tehnică a constelației GLONASS (GLONASS ICD). Pentru satelitul GLONASS R10 este transmisă valoarea 7 pentru slot și publicată pe portalul de stare al constelației GLONASS (https://www.glonass-iac.ru/en/GLONASS/index.php) în timp ce ICD specifică valori între -7 și 6. Stațiile de referință GNSS Leica ce folosesc Measurement Engine (ME) v3 transmit această informație către GNSS Spider, unde nu sunt respinse în calculul NULLANTENA. Receptoarele care utilizează ME de generație nouă (ME4 sau OEM7) ex. Seriile GR/GM sau GRX1200+ și GRX1200+ GNSS, nu sunt afectate - firmware-ul deja filtrează informațiile greșite cu privire la almanah.
Soluții
1. Pe termen scurt au fost dezactivate observațiile GLONASS. Vă rugăm ca până la rezolvarea completă a problemei să utilizați doar portul 2101.
2. Pe termen mediu soluție este să nu se utilizeze efemeride de la receptoarele afectate. (Această soluție se va implementa de către administratorul ROMPOS în perioada 05-06.10.2019).
3. Pe termen lung se lucrează la un nou service pack pentru software.
Compensare caz de forță majoră
Având în vedere situația de forță majoră care a afectat furnizarea serviciilor ROMPOS, începând cu ziua de luni 7.10.2019 toate abonamentele active ale utilizatorilor de servicii ROMPOS vor fi prelungite corespunzător cu 4 zile.

The absolute differential positioning is a positioning technique that determines the position of a receiver, usually mobile, based on direct observations to satellites and some (differential) corrections transmitted (in real-time) from another fixed receiver called reference-receiver or base-receiver. A modern version allows the generation of these corrections based on a network of reference stations (receivers) such as the RN-GSP of the CNC. Pseudo-range (satellite-receiver distances) measured by the mobile receiver are corrected based on differential corrections obtained from the base-receiver, and then an absolute (punctual) positioning takes place. These differential corrections improve the accuracy of position determination.

The corrections submitted by the base-receiver can be Pseudo-Range-Corrections (PRC) and Rate of Range Corrections (RRC). These corrections can be determined using the pseudo-range defined on the basis of the codes transmitted by the satellites (DGNSS method -Differential GNSS) or on the basis of measurements performed using the carrier wave (RTK method - Real Time Kinematic). In addition, a specialized service based on a network of GNSS stations, can transmit further corrections, especially those due to the propagation of satellite signals through ionosphere and troposphere.

The Romanian Position Determination System - ROMPOS® is a project of the National Agency for Cadastre and Land Registration providing precise positioning in the european reference and coordinate system ETRS89 based on the national network of GNSS reference stations.

ROMPOS® is based on Global Navigation Satellite Systems – GNSS, including GPS, GLONASS and GALILEO (in the future), providing complementary data necessary to improve the accuracy of determining the position within several millimeters.

Covering the entire territory of Romania with a total of 74 GNSS reference stations, ROMPOS® is available at any time and for any location in Romania, provided the data signal coverage (internet) is present.

By using ROMPOS®, modern GNSS receivers work more efficiently, increasing labor productivity, reducing the costs.

With a single GNSS receiver and internet access via GSM/GPRS connections, the user can benefit of ROMPOS® services.

By integrating the ROMPOS System® in the similar european EUPOS® system, it ensures its interconnection with similar european systems, allowing for a uniform positioning even at the crossing of the border with neighbouring countries. ANCPI signed cross-border data exchange agreements with similar systems in Hungary, the Republic of Moldova and Ukraine. A significant number of users (geodesic and cadastre companies, authorized individuals in the geodetics domain, equipment manufacturers, etc.) utilize the real-time ROMPOS® services (DGNSS/RTK).

Real-time ROMPOS services can be easily accessed by following these 5 steps:

1. ANCPI user account and accessing the ROMPOS administration platform
2. Payment of services
3. Defining the rovers on the ROMPOS administration platform
4. Activating a ROMPOS service subscription
5. Rover configuration

Support Service
For the optimum and correct use of ROMPOS® services, CNC through the Support service, provides you with information and support regarding the services offered. The service is available via Live Chat and email.

The determination of the position refers to the acquirement of satellite observations (measurements) carried out in points of interest, coordinates (absolute or relative) of these points in a well-specified reference system. Satellite observations consist of various types of measurements performed between the satellite receiver located on the ground or near it and one or more satellites evolving on circumterrestrial orbits. The position determining methods are based on observations made using satellite signals broadcasted in the microwaves field. The emission flow of the satellite signal is usually continuous or can be pulses at regular intervals. The reception of these signals is done similarly.

Satellites play an active role by broadcasting signals that are received by specialized devices (receivers) that decode this signal. After decoding the signal from it, the information needed to determine the position of the receiver is extracted.
Global Navigation Satellite Systems (GNSS) are systems that allow high precision determination of position in a geocentric reference system at any point located on the earth surface, near or outside, using Earth's artificial satellites.
Currently the most well-known GNSS systems are NAVSTAR-GPS (USA) and GLONASS (Russia). There are no significant differences between the two GNSS systems in terms of operating principles and technology used. Each system includes three segments: the spatial segment (satellites), the control segment (Monitoring and control stations) and the user segment. GNSS satellites transmit time information, navigational information, and system status messages to users. The control segment is responsible for maintaining the satellite constellation, the attached time system and the determination of satellite orbit. Currently there are other countries intending to create GNSS systems (complementary).

NAVigation Satellites with Time and Ranging – Global Positioning System (NAVSTAR – GPS)

The GPS space segment comprises a number of 31 satellites positioned on 6 orbital planes angled at 55° at an altitude of 20230 km. The satellite revolution period is 11 hours and 56 minutes. An identical satellite constellation can be observed after a sidereal day 4 minutes earlier. The GPS constellation is composed of the GPS Block IIR-Replacement satellites (replacing the GPS Block II/IIA satellites from 1997), GPS Block IIR-M (modernized-introducing a new military signal-code M, on both carrier waves and C/A code on the second carrier wave called L2C), GPS Block IIF-Fallow On (introducing a new signal on a third frequency, L5) and GPS Block III (a new civilian signal, C/A code on the L1 carrier wave). The positioning accuracy for the civilian segment has improved from about 100m to 13m by suspending ITS (Selective Availability) technique. Major progress is expected by modernizing the spatial segment (the third L5 carrier wave, C/A code on the L2 carrier wave, etc.). The reference system used is WGS84 (World Geodetic System 1984).

GLObalnaya NAvigatsionnaya Sputnikovaya Sistema - GLObal NAvigation Satellite System (GLONASS)

The GLONASS space segment comprises a number of 27 satellites positioned on 3 orbital planes angled at 64.8° at an altitude of 19100 km. The satellite revolution period is 11 hours and 16 minutes. From the 27 designed satellites a total of 22 are operational. Each satellite has an atomic clock that generates a frequency from which the two carrier waves are formed. The signals transmitted are similar to the GPS system, including the C/A code on the L2 carrier. The precision level of the Russian GLONASS system is comparable to that of the NAVSTAR-GPS system. In Romania, the GLONASS system can be used, complementing the constellation of the GPS system. The reference system used is PZ90.

Galileo

European Union (EU) and the European Space Agency have developed the GNSS European system, named Galileo. The constellation of the Galileo system will consist of a number of 30 satellites positioned on 3 orbital planes angled at 56° at the altitude of 23616km. The revolution period of a satellite will be about 14.4 hours. In terms of positioning accuracy, availability and integrity, Galileo will be superior to the other systems. GALILEO will be interoperable with NAVSTAR-GPS and GLONASS. The reference and coordinate system used will be ETRS type (European Terrestrial Reference System). For positioning ROMPOS® uses the NAVSTAR-GPS and GLONASS global systems. When commissioning the new European system Galileo, ROMPOS® will also implement the use of this new GNSS system.

For accessing real-time ROMPOS products via NTRIP protocol, the following products are available:

1. “Network” type products = network of GNSS Stations
(generated using the principles of calculating differential corrections based on the network of GNSS reference stations): VRS (Ritual Reference Station), FKP (Flachen Korrektur Parameter), MAX (Master Auxiliary Concept)

Network products are transmitted in standardized RTCM format (version 3.1), excluding products which include CMR + characters.
The user (if he has the possibility through the software he owns), will first download the product list ("Mount points" in column 1) and then choose from this list the type of product you want to be purchased in real time. Note that for these types of products (network type), the user will necessarily have to transmit the coordinates of the station point (by NMEA-GGA type message). If the user is not able to automatically download the product list, then you will need to MANUALLY enter in the GNSS receiver the point of connection to the desired product, by writing in that menu the characters retrieved from column "RT Product Name".

2. “Nearest” type products = a reference station
(Generated using the principles of calculating differential corrections based on a single GNSS reference station)

“Single station” products are transmitted in a standardized RTCM format (3.1); The user (if he has the possibility through the software he owns), will first download the product list ("Mount points" in column 7) and then choose from this list the type of product you want to be purchased in real time. Note that for these types of products (“single station” type), the user needs to transmit the coordinates of the station point (by NMEA-GGA type message). If the user is not able to automatically download the product list, then you will need to MANUALLY enter in the GNSS receiver the connection point to the desired product, by writing in that menu the characters retrieved from column "RT Product Name".

3. Test products

In the list of ROMPOS-RTK products, at some point there may be products that are available for testing. The name of this product includes the word "Test", as users are warned that such a product will only be used for the purpose of verifying the generation and testing of product performance/quality. Such a product is NOT guaranteed and therefore will not be used for real applications.

Realtime products for port 2101.

Realtime products for port 2105.

The Hour value is in GMT

Global RMS

Residual Ionosphere (RTK): The estimated residual ionospheric error for a single base RTK user using data from the nearest site.

Residual Ionosphere (Network RTK): The estimated residual ionospheric error for a network RTK user.

Residual Troposphere/Geometry (RTK): The estimated residual tropospheric and orbit error for a single base RTK user using data from the nearest site.

Residual Troposphere/Geometry (Network RTK): The estimated residual tropospheric and orbit error for a network RTK user.