A new Glonass-M navigation satellite is now aloft, preparing to join Russia’s GLONASS constellation.
The satellite launched Dec. 11 at 11:54 Moscow time aboard a Soyuz-2.1b launch vehicle from the Plesetsk cosmodrome, the Russian Ministry of Defense’s Information and Communications Department said.
The launch was initially scheduled for December 10, but was postponed for a day for technical reasons.
Glonass-M satellites form the basis of the orbital constellation of the GLONASS system. They provide navigation information and accurate time signals to land, sea, air and space consumers.
The Ministry of Defense noted that pre-launch operations and the launch of the rocket were normal. “Means of the ground-based automated spacecraft control complex of the Russian orbital group controlled the launch and flight of the rocket,” the military department said.
The Fregat booster unit was manufactured by NPO Lavochkin (part of Roscosmos State Corporation.) The Glonass-M navigation satellite was produced by ISS Reshetnev (Reshetnev Information Satellite Systems).
The application was developed with special interest paid to raw data recording and NTRIP service connection.
With the SXblue ToolBox iOS application, the user can analyze the position data provided by the SXblue receiver, as well as location metadata.
More important for SXblue clients, the application can record, save and transfer raw data from the GNSS receiver, thereby allowing post-processing activities. The application also acts as a NTRIP client, capable of connecting to a NTRIP server for real-time kinematic (RTK) corrections, and thus allows the receiver to issue very accurate location information.
Receiver configuration is easy through the application, with the ability to set up and save user-defined commands for subsequent use. The settings include constellation to be used, differential source, NTRIP login credentials list and more.
In addition, the iOS application includes a series of audible and visual alarms that are user-configurable to determine the thresholds of information provided by the SXblue GNSS receiver.
The main features of the iOS SXblue ToolBox application are:
Display of location information and quality of positioning data
Skyplot of all-in-view constellations: GPS, GLONASS, Galileo BeiDou, QZSS, SBAS
Recording of raw data and data transfer
NTRIP/DIP client to receive RTK corrections
Terminal to send commands and view the output data of the SXblue device
Audible and visual alarms
Activation of options and licenses via the application.
China’s National Reference Station Network. (Image: BeiDou)
A Russian law was approved July 26 that sets forth cooperation between Russia and China on using GLONASS and BeiDou for peaceful purposes.
According to the RosCosmos website, the law was approved at a meeting of the Council of Federation of the Federal Assembly of the Russian Federation. The law is officially named, “On ratification of the agreement between the Government of the Russian Federation and the Government of the People’s Republic of China on cooperation in the use of GLONASS and Beidou global navigation satellite systems for peaceful purposes.”
An intergovernmental agreement was signed on Nov. 7, 2018, in Beijing during the 23rd regular meeting of the heads of government of Russia and China. The agreement creates an institutional and legal framework for cooperation in the development and manufacture of civil navigation equipment using GLONASS and Beidou systems.
It also establishes cooperation in the development of Russian-Chinese standards for the application of navigation technologies using both systems — in particular, standards for the control and management of traffic flows across the Russian-Chinese border. The border is 4,200 kilometers (2,615.5 miles) long — world’s sixth-longest international border.
Under the agreement, the two countries plan to place in their own countries measuring stations for the other country’s GNSS, on a reciprocal basis.
New GLONASS-K2 satellites will improve the accuracy of Russia’s satellite navigation system from 3-5 meters to less than 1 meter, said Chief Designer Mikhail Korablyov of the Joint Stock Company GLONASS, operator of the ERA-GLONASS traffic accident emergency response system, at a transport conference in Moscow in late May.
Russia plans to launch the first K2 satellite in late 2019 or early 2020. By 2030 the GLONASS constellation will consist wholly of K2 space vehicles, 24 of them.
The improved accuracy will better determine vehicle location in analyzing a traffic accident, according to Korablyov. It will not, however, be sufficient for lane-keeping and other advanced driver assistance systems, nor for more stringent autonomous driving requirements, at least according to emerging Western standards.
“There are also tasks linked with the country’s defense, there are special precision weapons, the requirements for which already make up less than a meter,” Korablyov added.
Yury Urlichich, First Deputy Director General, Roscosmos. (Photo: Roscosmos)
Numbers. Writing in the December 2018 issue of GPS World, Yury Urlichich, First Deputy Director General, Roscosmos State Space Corporation, gave a somewhat more precise figure for the new accuracy to be achieved via the K2 generation. “The new signals will allow lowering the hardware-dependent SC-user ranging error by an order of magnitude, reducing the influence of signal reflections from buildings, constructions and landscape (multipath effect), thus enabling their effective use for high-precision navigation with real-time errors below 0.1 m.
“This SC will enable navigation not only using legacy FDMA signals available for users for more than 35 years, but simultaneously with a full row of CDMA signals in all GLONASS frequency bands: L1, L2 and L3.”
Later in the same piece, Urlichich wrote “Mission Definition Requirements for Glonass-K2 define user range error to be 0.3 m, qualitatively improving GLONASS user performance.”
The new K2 satellite will transmit nine navigation signals and will weigh about 1,800 kg, twice as much the latest GLONASS-K generation, known as K1. Of the 24 currently orbiting operational satellites, only two are K1 space vehicles. The other 22 are older GLONASS-M satellites.
A Shock to the System. A bolt of lightning struck the rocket launcher for the latest GLONASS-M satellite to rise, on May 27. It did not adversely affect the bird’s journey to space, and all systems were found to be functioning properly once the satellite was released into preliminary orbit, Russian space officials said.
Oregon Department of Transportation workers use DT Research’s GNSS rugged tablets. (Photo: DT Research).
The Oregon Department of Transportation (ODOT) has expanded its use of DT Research GNSS rugged tablets to all 15 of its construction management offices across the state, and also use the tablets for biology, geology, roadway and wetland projects.
DT Research worked closely with ODOT to design purpose-built rugged tablets that empower state workers to easily collect and transmit geospatial measurements in the field using GNSS real-time kinematic (RTK) technologies.
“DT Research’s GNSS rugged tablets have enabled us to bring high-accuracy geospatial measurements to workers across the Department of Transportation, which has literally changed the way we work,” said Chris Pucci, construction automation surveyor at ODOT. “The tablets have enabled us to save time, reduce costs and improve the accuracy of projects through ‘digital-as constructed’ measurements and real time data capture.”
The tablets have a dual-frequency GNSS module built in, which provides stand-alone sub-meter accuracy to centimeter-level accuracy with RTK from GPS, GLONASS and Galileo satellites.
The tablets are compatible with existing survey and GIS software for mapping applications and provide an advanced workflow for data capture, accurate positioning and data transmitting.
“We now have essentially created one-person survey crews because the DT Research tablets are so much easier to use than a tape measure and paper to accurately calculate and record measurements during complex construction projects,” Pucci said. “Using the tablets saves us an average of $2,000 for every survey-grade measurement job that does not require a full survey crew.”
“In addition, the tablets have provided us with a contract verification system by having highly accurate digital-as-constructed measurements that are delivered immediately and stored forever, which saves the state time and money by avoiding independent re-measurement checks due to billing discrepancies at the end of a project,” added Pucci.
The DT Research GNSS tablets can store up to 1 Terabyte of data for field data collecting. Users can avoid down time with a high-capacity hot-swappable battery pack, which delivers 60 or 90 watts for up to 15 hours of continuous mobile communications. The units include Long Range Class 1 Bluetooth, which powers wireless connectivity up to 1,000 feet and 4G mobile broadband.
“The simplicity of how the DT Research tablets work is amazing,” Pucci said. “Unlike complex professional survey equipment, the DT Research tablets are a Windows-based mobile device with a user interface that is familiar to workers. In just two hours, I can easily train state workers with diverse skill sets to measure quantity, linear features and volumes for a variety of projects — and they are ready to go.”
The tablets run on Microsoft Windows 7 Professional or Windows 10 IoT Enterprise and are high performance devices with an Intel 6th or 8th Generation Core i5 or i7 processor. The rugged tablet is designed for outdoor use with a brilliant LED-backlight, 800 nits sunlight-readable screen and capacitive touch.
“We have found the DT Research tablets to be incredibility easy to manage and highly durable — we just turn them on and they work,” said Pucci. “In the three years that we have used the tablets, we have had very few technical support questions and they hold up well in different weather conditions. There isn’t a comparable product on the market at the price point.”
The DT Research tablets are military-grade durable devices, yet lightweight, offering the versatility to be used in field-to-office settings. For use in harsh environments, the tablet is fully ruggedized to meet the highest durability standards with an IP65 rating, MIL-STD-810G for vibration and shock resistance and MIL-STD-461F for EMI and EMC tolerance.
For use in a variety of environments, the tablets are complemented by many accessories including: external antennas, pole mount cradles, detachable keyboards, battery charging kits and digital pens.
By Juan Vázquez, Elisabet Lacarra, Jorge Morán and Miguel A. Sánchez, ESSP SAS, and Julian Rioja and Jimmy Bruzual, Topcon Agriculture
The European Geostationary Navigation Overlay Service (EGNOS), a satellite-based augmentation system (SBAS), provides corrections and integrity information to GPS signals over Europe and is fully interoperable with other SBAS such as North America’s WAAS. Among its services is the internet-based EGNOS Data Access Service (EDAS).
EDAS gathers raw data from GPS, GLONASS and EGNOS GEO satellites collected by receivers at approximately 40 EGNOS ground stations distributed over Europe and North Africa. EDAS reformats and disseminates GNSS data in real time and through an FTP archive to EDAS users and service providers.
Additionally, EDAS provides differential GNSS corrections to the GPS and GLONASS satellites in view by the EGNOS system network through its Ntrip service.
The tests summarized in this article focused on the EDAS Ntrip Service, which can be used for differential positioning. An earlier test near Seville, Spain, concluded that these corrections could support pass-to-pass accuracies in the order of 20 centimeters in a consistent manner and with a high degree of repeatability.
To assess EDAS performance validity for agriculture applications, two additional tests were done in Lisbon, Portugal, and York, UK. These locations provide diversity with respect to the Seville test, especially in terms of distance from the farm to the selected EGNOS reference station (≈320 km in York and 40 km in Lisbon, versus the 110 km baseline of the test in Seville) and also geographically. In all tests, a real-time kinematic solution operated in parallel to the EDAS DGPS solution to provide the required reference for the post-processing of the recorded data. Nine different runs with a total of 78 passes were performed in these two campaigns.
Considering the results from the three tests, the pass-to-pass accuracy supported by EDAS DGPS corrections was below 10 cm for more than 60% of passes and below 20 cm for more than 85 percent of the passes. These figures exceed the earlier results and confirm that EDAS DGPS corrections can deliver pass-to-pass accuracies in the order of 10 to 20 cm in a consistent manner.
Cumulative distribution of P2P accuracy, in centimeters. (Chart: Topcon)
The stability of the results and the very good pass-to-pass accuracy levels observed in the York scenario, where baselines larger than 300 km were tested, deserve highlighting. For grain and dry soil cultivation, at least 1 meter (95th percentile) of absolute horizontal accuracy is required. It can be assumed that, within the area where EDAS DGPS supports sub-meter horizontal accuracies (up to 260 km from the selected EGNOS station, according to previous studies), EDAS DGPS corrections can also support pass-to-pass accuracies in the order of 10-20 cm.
Such performance levels are considered to be appropriate for most grain farm operations. In particular, the observed performance is sufficient to support the following precision agriculture applications:
Mountainous areas present special problems for surveyors, overcome by the expanded availability of multi-GNSS. (Photo: Trimble)
Today’s GNSS satellites transmit on three or more carrier frequencies. The quality of the data in these signals from GPS, BeiDou, Galileo, GLONASS and QZSS reveals the expected measurement precisions. This article explores the noise of the range residual and ionospheric residual to indicate the oncoming capabilities.
Today, four GNSSs transmit various codes on various carrier frequencies: the USA’s GPS, Russia’s GLONASS, Europe’s Galileo and China’s BeiDou. Most of the carrier phase and pseudorange data are available using civilian GNSS receivers. Improvements in signal quality as well as reliability of the satellites are foreseen through the generations, as well as the introduction of new signals, such as L1C, L2C, L5 carrier and codes, and M-codes, on top of the existing L1-C/A code and the P(Y) code on both L1 and L2. Improvements are also seen in boosting the transmitting power.
This article investigates the use of two approaches to analyze the relative noise in the various carrier phase and pseudorange observable for GPS, BeiDou, Galileo, GLONASS and Japan’s Quasi-Zenith Satellite System (QZSS) augmentation. Two approaches analyze the relative noise in the observables: the range residual and the ionospheric residual. Both techniques can also be used to detect cycle slips.
Range Residual
UAV survey operations benefit from multi-GNSS receivers. (Photo: Septentrio)
The range residual is simply the change from one epoch to the next in the difference in the range calculated using the pseudorange and the range calculated by the carrier phase on a specific frequency. The pseudorange values are scaled using the wavelength to an equivalent range in units of the carrier’s cycles rather than meters. Equation 1 illustrates the range residual between the pseudorange ρ on a specific carrier frequency and the carrier phase observable φ, using the wavelength λ of the carrier to scale the pseudorange. The values of these observables are compared between adjacent epochs.
RR = (p/λ) – φ (1)
Two adjacent epochs are used, as then the integer ambiguity value, as well as the ionospheric and tropospheric errors, and satellite and receiver clock errors are the same, or negligibly different at such small (<1 s) epoch intervals. Therefore, these are all canceled out, and the resulting value is the measurement receiver and observable noise. The pseudorange observable will be significantly noisier than the carrier phase observable, therefore this method is a good way to calculate the measurement noise for the pseudoranges.
Ionospheric Residual
Surveyors work the Berezitovy mine in the North Amur region of Russia. (Photo: Javad GNSS)
If the carrier waves traveled only through a vacuum, then a phase observation from a specific satellite to a specific GNSS receiver could be scaled and converted to an equivalent phase measurement on another frequency using the frequencies of the carrier waves. However, as the signal passes through the ionosphere, systematic errors that are frequency dependent are introduced, so it is not possible to directly convert from one carrier phase value to another for a specific range measurement. The error is known as the ionospheric residual, and this will change slowly over time as the satellite passes overhead and the ionosphere being passed through changes, and also as the ionosphere slowly changes its characteristics over time, mainly due to the sun’s activities.
Equation 2 shows the calculation, using L1 and L2 carrier phase readings and corresponding frequencies, used to calculate the ionospheric residual. Again, the difference in the ionospheric residual values between adjacent epochs is used, as in the same way as the range residual values, external noise sources are eliminated.
(2)
Results
The results presented here are a subset of a much larger set. Figure 1 illustrates the range residuals for L1 and L2 as well as the L1L2 ionospheric residual for PRN32 (Block IIA satellite).
Figure 1. L1 range residual (left) L2 range residual (center) and L1L2 ionospheric residual (right) for GPS PRN32 (Block IIA) satellite. (Charts: Authors)
Figure 2 illustrates the L1 and L5 range residuals and the L2 (C-code) L5 ionospheric residual for PRN01 (Block IIF satellite).Both figures’ data are for the complete passing of the satellites from horizon over and back down again.The data for PRN32 is all that exists in the datafile, as this satellite only transmits L1 CA code and P(Y) code, as well as L2 P(Y) code, and corresponding carrier values.
Figure 2. L1 range residual (left) L5 range residual (center) and L2 (C code) L5 ionospheric residual (right) for GPS PRN01 (Block IIF) satellite. (Charts: Authors)
PRN01 is a block IIF satellite, and data for L1 CA code, L2 P(Y) code as well as L2 C-code, L5 code, and corresponding carrier phase values are recorded in the datafile.The block IIF satellites can result in four range residual values and five ionospheric residual combinations.Figure 2 only illustrates three of these combinations.The data were obtained from the Curtin University GNSS repository on Sept. 1, 2015, gathered at a 1-Hz epoch interval; 29,908 epoch of data were gathered for PRN32, and 26,073 epochs for PRN01.
It can be seen from these figures that the L1 range residuals are similar in characteristics for both PRN01 and PRN32.The values are noisy at the start and the end of the time series, indicating that the CA code is more prone to noise at low elevations.Comparing these to the L2 (PRN32) and L5 (PRN01) range residuals, we can see that both the L2 and L5 range residuals are not as prone to low elevation noise. Also, the two L2 and L5 range residuals are visually similar in characteristcs.By comparing the L1L2 and L2L5 ionospheric residuals (Figure 1, right, and Figure 2, right), we can see that the L1L2 combination is slightly noisier than the L2L5, in particular at low elevation angles.
If we compare BeiDou ionospheric residual results, we can see the comparison of noise on the three ionospheric residual combinations, B1B2, B1B3 and B2B3, as well as the results from the three types of satellite orbits, ie MEO, IGSO and GEO. Figure 3 illustrates the ionospheric residual results for PRN07 (IGSO) for the three frequency combinations, from data gathered on a static pillar located on top of the University of Nottingham Ningbo China’s Science and Engineering Building.
Figure 3. Ionospheric residual results for BeiDou PRN07 (IGSO) for combinations B1B2 (left), B1B3 (center), B2B3 (right). (Chart: Authors)
Figure 4 illustrates the ionospheric residual results for PRN01 (GEO) for the three frequency combinations.
Figure 4. Ionospheric residual results for BeiDou PRN01 (GEO) for combinations B1B2 (left), B1B3 (center), B2B3 (right). (Chart: Authors)
Figure 5 illustrates the ionospheric residual results for PRN12 (MEO) for the three frequency combinations. Here it can be seen that the B2B3 combination is generally less noisy than the B1B2 and B1B3. In addition to this, it can be seen that when the MEO and IGSO satellites are at lower elevation angles, the observables also become noisier. The GEO satellites have a constant elevation angle, and do not experience this phenomenon.
Figure 5. Ionospheric residual results for BeiDou PRN12 (MEO) for combinations B1B2 (left), B1B3 (center), B2B3 (right). (Charts: Authors)
Detailed Results
The data, gathered on a single GNSS receiver located at the University of Curtin’s GNSS research center, was downloaded in BINEX format and converted into RINEX 3.02 format using RTKLIB software. Software was developed by the authors in Matlab in order to interrogate the data files and implement the range residual and ionospheric residual algorithms. RINEX 3.02 format was chosen due to its compatibility with multi-GNSS and multi-frequencies.
Industrial UAV applications such as construction draw benefits from multi-GNSS receivers’ capabilities. (Photo: Skycatch, Swift Navigation)
Results are presented for both ionospheric residual and range residual results for various GNSS. These results have been calculated with varying elevation mask angles, ranging from 0° to 55° at 5° intervals. The RMS values of the resulting ionospheric residuals and range residuals were calculated and plotted against the respective elevation mask angle for each satellite and frequency combinations. This illustrates the influence of the elevation mask angle used on the results.
Typically, tens of thousands of epochs of data were used for every plotted point in the following figures. Further to this, not only are the results for the various frequencies and frequency combinations for the various GNSS illustrated, but also the various satellite types, MEO, GEO and IGSO, and various satellite Blocks for GNSS. GPS Block IIA (PRN04 and PRN32), Block IIR (PRN14), Block IIR-M (PRN31) and Block IIF (PRN01, PRN26, PRN25) data were all analyzed. Thus, the comparison of the various frequencies within each satellite system are illustrated, as well as the variations by comparing the various satellite constellation types and the various generations of GPS satellites.
Surveying accuracy is critical to roadway construction. (Photo: Leica Geosystems)
The BeiDou data illustrated are MEO (C12, C14, C11), IGSO (C09, C10, C07) and GEO (C01, C02). The data used were gathered on Sept. 1, 2015, in order to include GPS Block IIA satellites (PRN04 and PRN32). PRN32 was retired in June 2016, and PRN04 was taken out of active service in November 2015, but the satellite was reactivated in March 2018, this time broadcasting PRN18.
Figure 6 illustrates RMS of the range residual results for GPS (a), BeiDou (b), Galileo (c), GLONASS (d) and QZSS (e) respectively. These figures have been drawn so that the y-axis ranges are the same for each, hence illustrating the relative values.
Figure 6A illustrates the range residual results for GPS. It can be seen that the L1 CA code results are the noisiest, with PRN14 being the noisiest, followed by PRN31, PRN26, PRN01, PRN04, PRN25 and PRN32. It can also be seen with these results that lower elevation angle mask increases the noise level. Both the L2 and L5 code results are less noisy.
Figure 6A. RMS range residual results for GPS. (Chart: Authors)
Looking at the detail, the L5 code results is less noisy than the L2 and affected less than the L1 results by the changes in elevation mask angles used. Interestingly enough, the data file includes both the L2 P(Y) code and L2C code results. L2C only exists on the Block IIR-M and Block IIF satellites. The L2C code results are generally noisier than the L2 P(Y) code.
Figure 6B illustrates the results for the range residuals for the BeiDou satellites. Here it can be seen that the B1 code is affected more by low elevation mask angles than B2 and B3. It can also be seen that both the geostationary satellites’ B1 results stand out, with satellite C02 being noisier than C01. The B2 and B3 values for both these GEO satellites are bunched up with the majority of the other results towards the middle of the figure. The pairs of B2 and B3 results for the GEO satellites are close to each other in values, and the pairs of B2 and B3 results for the other satellites are also close to each other.
Figure 6B. RMS range residual results for BeiDou. (Chart: Authors)
It can also be seen that the range residual results for BeiDou are generally less noisy than than GPS, in units of cycles.
Similarly, for Galileo, Figure 6C, the E1 results are worst, and affected more by low elevation masks. Again, generally the Galileo results are seen to be improved over GPS. The GLONASS results, Figure 6D, illustrate that the L1C results are generally noisier, and then the L1P, followed by L2C and L2P. PRN09 is also consistently generally noisier than PRN10. Finally, Figure 6E illustrates the results for QZSS. Again, L1C is the noisiest and affected most by low elevation mask angles.
Figure 6C. RMS range residual results for Galileo. (Chart: Authors)Figure 6D. RMS range residual results for GLONASS. (Chart: Authors)Figure 6E. RMS range residual results for QZSS. (Chart: Authors)
Figure 7 illustrates the ionspheric residual results for the same satellites as Figure 6. This time, however, the resulting ionospheric residual values are calculated using pairs of data from the same satellite on different carrier frequencies. The range residual results compare the code and carrier from specific satellites and frequencies.
Figure 7(a) shows that the ionospheric residual results are affected by low elevation masks, and that the L1L2CW (L1 CA code and L2 P(Y) code available on all the satellites) combinations are the noisiest, followed by L2L5WX (L2 P(Y) code and L5 code available on Block IIF satellites, PRN 26, PRN01, PRN25), followed by L1L2CX (L1 CA code and L2 C code available on Block IIF and Block IIR-M satellites, PRN31, PRN26, PRN01 and PRN25), followed by L1L5CX (L1 CA code and L5 code, Block IIF satellites, PRN01, PRN25, PRN26) and finally the least noisy were the L2L5XX results (L2 C code and L5 code available on Block IIF satellites, PRN26, PRN25 and PRN01).
Figure 7A. Ionospheric residual results for GPS. (Chart: Authors)
Figure 7(b) illustrates the BeiDou ionospheric residual plots, illustrating that satellite C14 is much noisier for all three combinations of B1B3, BB1B2 and B2B3 in that order. The B1B2 combinations for the satellites are generally the noisiest, and then the B1B3 and B2B3 combinations are intertwined. The Galileo results again illustrate that the E1 combinations are generally noisier, and again we see the effect of low elevation angle masks, Figure 7(c). Generally, however, the Galileo results are less noisy than GPS, as are the BeiDou results.
Figure 7B. Ionospheric residual results for BeiDou. (Chart: Authors)Figure 7C. Ionospheric residual results for Galileo. (Chart: Authors)
The GLONASS results are again generally the noisiest, and again PRN09 is noisier than PRN10, with the L1P combinations being noisier, Figure 7(d). Figure 7(e) for QZSS shows that there are generally two groups of results. The upper set consists of L1L2ZX, L1L5ZX, L1L2XX, L1L5XX, L1L6ZX and L1L6XX from highest to lowest noise respectively. The lower, less noisy, group consists of L1L2CX, L1L5CX, L2L5XX, L2L6XX, L1L6CX and L5L6XX from highest to lowest noise respectively. Further details about the various codes and carrier values can be found in the RINEX 3.02 manual produced by the IGS.
Figure 7D. Ionospheric residual results for GLONASS. (Chart: Authors)Figure 7E. Ionospheric residual results for QZSS.(Chart: Authors)
Conclusions
A surveyor checks an urban construction project. (Photo: Topcon)
These preliminary results illustrate that there are differences in the noise values for various GNSS, frequencies as well as satellite generations and orbit types. It can be seen that generally L1, B1 and E1 have noisier results, and are affected moreso by low elevation mask data, and hence multipath. It can also be seen that newer generations of satellites do indeed produce better quality data.
Some specific satellites produce lower quality data such as GLONASS PRN09 and BeiDou C14. This could be due to multipath produced at the satellite.
Today roughly 100 GNSS transmit data, and typically users can gather data from 30 to 50 at any time. Positioning requires nowhere near this number of satellites, therefore decisions are needed as to which satellites and which data to use in a positioning solution. Our findings imply that our approach could be used in such decision-making in GNSS processing software, helping the software to choose the optimum satellites to draw from in a positioning solution.
Acknowledgments
This work described in this article was first presented at the FIG 2018 conference held in Istanbul, Turkey. The authors acknowledge the use of data supplied from the Curtin University GNSS Centre.
Manufacturers
The GNSS receiver used is a Trimble NET R9, and the antenna is a Trimble TRM 59800.00 SCIS choke ring antenna. A ComNav K508 GNSS receiver supplied some of the BeiDou results.
GETHIN WYN ROBERTS is an associate professor at Fróðskaparsetur, the University of the Faroe Islands. He is past Chairman of the FIG’s Commission 6, Engineering Surveys, and previously held posts at the University of Nottingham both in the UK and in China. He holds a Ph.D. in engineering surveying and geodesy from the University of Nottingham.
CRAIG M. HANCOCK is an associate professor in Geodesy and Surveying Engineering and the head of the Department of Civil Engineering at the University of Nottingham, Ningbo, China as well as the head of the Geospatial and Geohazards Research Group. He holds a PhD from the University of Newcastle Upon Tyne.
XU TANG is a research fellow at the University of Nottingham, Ningbo, China. He holds a PhD from Nanjing University.
The ground station will be built in Bengaluru, a city that is already home to the ISRO Telemetry, Tracking and Command Network (Istrac). Istrac will host the Russian ground station as well.
A memorandum of understanding was signed between the two nations in October 2016. In return, Roscosmos will host ground-measurement gathering stations in Russia for India’s NavIC, which will boost the operations of the IRNSS satellites.
The ZALA Arctic drones are capable of successfully solving both civilian and military tasks, according to maker Kalashnikov.
Russian small arms manufacturer Kalashnikov presented the ZALA Arctic unmanned aerial vehicle (UAV) adapted for work in Arctic latitudes at the eighth international forum, “The Arctic: the Present and the Future,” reports Russian state news agency TASS.
The drone has its own GIRSAM alternative navigation system developed specially for the navigation of both UAVs and the ground-and water-based users amid the suppression or the absence of GPS or GLONASS signals.
The ZALA 421-08M and ZALA 421-16E systems are suited for their operation at freezing temperatures, which makes it possible to carry out numerous surveillance operations and regularly monitor the ice. The ZALA Arctic’s capabilities facilitate oil and gas extraction planning in areas where accurate weather and ice situation forecasts are required, according to the Kalashnikov website.
ZALA drones are equipped with the AIS system capable of detecting and identifying vessels at a distance of up to 100 kilometers, which exceeds the operational range of ground-based equipment. The user of the ZALA Arctic system receives information about each vessel: its name, size, course and speed.
The operators can autonomously live in the Arctic in a specially developed all-weather living module based on a marine 200-feet container. It is also designed for maintenance of unmanned aerial vehicles at the place of their operation.
“ZALA Arctic drones are capable of successfully solving civilian and military tasks for carrying out research in the Arctic zone, providing for the safety of sea shipping and the round-the-clock protection of the perimeters, organizing the full-fledged system of tracking the Arctic coast and territorial waters,” Kalashnikov Group CEO Vladimir Dmitriyev was quoted as saying.
The forum, “The Arctic: the Present and the Future,” organized by the Association of Polar Explorers, took place Dec. 5-7 in St. Petersburg.
The Orientale Basin in a 4K NASA video of the lunar surface using observations from the Lunar Reconnaissance Orbiter. (Photo: NASA)
Russian positioning satellites could circle the Moon by 2040.
In a draft document describing Russia’s program for lunar exploration, plans include deployment of navigational and communications satellite groupings in lunar orbit.
The document, adopted at a Nov. 28 joint meeting of Roscosmos and Academy of Sciences officials, was obtained by Russian news agency Sputnik, which described it here.
According to the document, the tasks described for 2025-2030 include “the delivery to the Moon of a series of spacecraft for orbital research and the establishment of a global communications and positioning system.”
The concept envisions the deployment of a lunar satellite navigation constellation between 2036 and 2040.
Russia’s Earthly navigation constellation is GLONASS.
A Roscomos press release Nov. 28 says a moon base is the agency’s top priority. “The interest of mankind to the moon is associated primarily with the fact that unique regions with favorable conditions for the construction of lunar bases were discovered on the satellite. The implementation of the lunar program will be held in several stages until 2040.”
Russia will reportedly implement its new strategy in three phases: the launch of an orbital station, a manned mission to the surface, and the eventual construction of a permanent base.
The United Nations’ International Committee on GNSS (ICG) held its 13th meeting in Xi’an, China, Nov. 4-9. Attendees included the four major GNSS: GPS (United States), GLONASS (Russia), BeiDou (China) and Galileo (Europe). Also attending were representatives from Japan, India and delegates from 16 countries and regions.
Members called for further strengthening of the interoperability and transparency of GNSS to help more countries enjoy the developments in positioning, navigation and timing, according to China Global Television Network.
On Nov. 7, China and Russia signed a cooperation agreement for BeiDou and GLONASS, stressing that the two systems begin testing service aims for countries along China’s Belt and Road.
More than 400 delegates across the world also watched the demonstration of applications based on China’s BeiDou system, which includes drones and vehicle positioning technology that could be used by self-driving cars.
The positioning system was tested on a bus with accuracy reaching millimeters, as shown in a video on this page. This technology lays the foundation for the management of urban traffic.
Garmin is now offering a GPS, GLONASS and Galileo watch called Instinct. Instinct is a strong and durable watch with GNSS support, plus built-in 3-axis compass, barometric altimeter and wrist-based heart rate sensor.
The watch includes a built-in sports apps, smart connectivity and wellness data.
Photo: Garmin
“We are thrilled to add Instinct to our adventure watch lineup, an approachable smartwatch that is rugged and reliable,” said Dan Bartel, Garmin vice president of global consumer sales. “Instinct is perfect for those who spend their time outdoors and demand a device built tough to stand up in the elements.”
The Instinct is built to endure challenging environments, constructed to military standards (MIL-STD-810G) for thermal, shock and water resistance (rated to 100 meters) with a fiber reinforced polymer case. The chemically strengthened and scratch-resistant display is readable in direct sunlight, and the fully vented silicone bands include two independent, removable keeper loops to ensure a secure fit.
The multi-GNSS feature helps users track their location in challenging environments. The Garmin Explore app helps plan the trip in advance, and the TracBack feature can navigate the same route back to the starting point.
The built-in heart-rate sensor helps monitor heart rate, steps taken, distance traveled, calories burned and more.
