GPS World

Tag: GNSS simulator

  • BeiDou Numbering Presents Leap-Second Issue

    Leap-Second-O

    During preparation of playback scenarios for the upcoming leap-second event taking place in June, engineers at Racelogic identified a potential pitfall for GNSS engineers. The difficulty arises from the fact that BeiDou uses a different “day number” for the date to apply the leap second, compared with GPS and Galileo. GPS and Galileo use 1-7 as week day numbers, and BeiDou uses 0-6.

    If this fact has been missed during development, then the result is that the leap second may be implemented a day early on GNSS engines that are tracking the BeiDou constellation, said Mark Sampson, product manager for Racelogic.

    “We tested four different Beidou enabled receivers, from four leading GNSS companies, and none of them appeared to handle the Beidou leap second correctly. This included an engine which originates from China!” Sampson said. “We have since been in contact with two of these companies, who have confirmed that their hardware does have a bug in the leap-second code due to the numbering of the days.”

    The error presents itself when the receiver is running on the BeiDou constellation alone, and when the date is June 29 of this year. In some cases, the BeiDou leap second will be adjusted from 2 to 3 seconds from midnight on June 29, which should in fact occur on midnight of June 30. This will result in an error for the reported UTC time of 1 second for the period of this day. In other cases, the leap second was not implemented at all when running on BeiDou alone.

    “We have also checked the output of a BeiDou signal generator from a different simulator company, and this too uses the 1-7 range for the BeiDou leap-second date instead of the correct 0-6 range,” Sampson said. “This may explain why a number of commercial receivers appear to have been caught out by this issue.”

    Racelogic LabSat3 simulator.
    Racelogic LabSat3 simulator.

    In order to help companies test for this problem, Racelogic has generated simulated RF data for June 29 and 30, starting 15 minutes before midnight. “We have two sets of files. One set contains BeiDou only signals and the other contains a combination of BeiDou and GPS signals,” Sampson said. “Note that on some of the receivers we have tested, when GPS is being tracked as well, the GPS leap-second message overrides the one coming from BeiDou and applies the leap second correctly.”

    The scenarios are compatible with Racelogic’s LabSat3 triple constellation simulator, which is available on a free 15-day loan or can be purchased from Racelogic.

  • Successful Testing — and Why It Is More Important Than Ever

    By John Pottle and Neal Fedora

    John Pottle
    John Pottle

    Precision matters. While “accuracy” is somewhat one-dimensional, “precision” is multi-faceted. We submit to you that whatever area of GNSS-based location you are interested in, precision matters today and will matter more in the future. In this column, we’ll explain why this is.

    Traditional test approaches involve taking measurements to evaluate fundamental performance, for example, time-to-first-fix. As the number of critical applications that rely on positioning, navigation and timing (PNT) increases, the list of considerations for testing also grows.

    Critical applications typically require higher integrity. There are a myriad of techniques to achieve this, from adding constellations, additional frequencies, improved navigation message authentication approaches and everything in between. Examples of safety-related applications include rail, connected car and aviation. Commercially critical application examples are smartphone payment authentication and container port automation. Protecting the warfighter and ensuring mission success against growing interference and jamming are key initiatives for the military. All of these applications are becoming more sophisticated and complex, stressing the importance of precision in testing.

    Neal Fedora
    Neal Fedora

    Testing these critical applications requires:

    • Precise and clear test objectives
    • Precise definition of test approaches to explore both nominal and off-nominal conditions
    • Comprehensive test tools that include all required signal components precisely modeled and controlled
    • Test signal precision of at least an order of magnitude better than the device under test
    • Results analysis that can quickly and effectively highlight areas of interest or concern.

    Robustness against Cyber Attacks. The second area calling for more precision is the need for a more robust PNT systems in the face of increasing cyber attacks and interference. While well known in the IT world, the GNSS community is relatively unfamiliar with being targeted by hackers. Attacks on GNSS technologies are increasing in frequency and sophistication for both commercial and military users. The stakes are rising as the incidents increase from occasional (often accidental) interference to more structured and organized approaches to jamming and even spoofing.

    We’re predicting a game of cat and mouse where these cyber attacks and interference threats will continually evolve to try and stay one step ahead of the protections in place. In our view, this will call for increasingly clever and proactive threat-detection techniques in navigation systems, in addition to precise, reliable test solutions to verify them.

    Spirent’s test solutions address these growing demands by providing not only multi-GNSS signal simulators, but also inertial and interference simulators, anti-jamming test solutions, and record and replay of actual observed interference and even communications port vulnerability testing.

    In our view, the diversity of critical applications will increase, emphasizing the need for a precise approach to test planning, execution and analysis. Robust PNT is an achievable vision, and we are excited for the future.

    John Pottle is marketing director for Spirent Communications plc. Neal Fedora is director of engineering for Spirent Federal Systems Inc.

  • Multiple RF Output Simulation

    Spectracom-GSG-5-Series-WSpectracom GSG-Series GNSS Simulators have added capability to provide multiple RF outputs for advanced testing where multiple receivers or antennas are in use in a single system. Typical examples include controlled radiation pattern antennas (CRPA) or heading/attitude receivers and systems.

    The intuitive StudioView software allows easy reconfiguration of test cases to change the conditions seen by one or all receivers and antennas under test — for example, adding a jamming signal to one antenna input on a CRPA receiver. Both over-the-air testing or cabled capabilities are available.

    Because the simulator operates independently of PC control, the simulators can be precisely synchronized with a common clock and trigger pulse. There is no theoretical maximum to the number of RF outputs. This flexibility also allows testing multiple rovers reporting into a single control system, such as asset tracking or personnel location management systems.

    This advanced feature is offered in both the L1 band GSG-5 series simulator for commercial applications as well as multi-band GSG-6 series simulator for professional applications.

  • Software-Based GNSS Multi-System Simulation Environment

    TeleOrbit’s software-based GNSS multi-system performance simulation environment, GIPSIE, consists of a satellite constellation simulator and an intermediate frequency simulator. The digital signal simulator GIPSIE streams the software-generated signals or recorded live data exactly into the receiver’s baseband processing chain to support development, test, verification, validation, qualification and certification.

    Features include simulation of multi-system, multi-frequency scenarios GPS L1/L2/L5 and Galileo E1/E5/E6; simulation of jamming signals on top of the GNSS signals; simulation of Galileo PRS-like signals as well as the unencrypted GPS P-Code signals; record and replay of recorded and software generated data. GLONASS and BeiDou constellations and signals and simulation of micro-electro-mechanical sensors (MEMS) are coming soon.

  • Rohde & Schwarz Offers Simultaneous Time Domain and Spectrum Analysis

    Rohde & Schwarz has added the R&S RTM-K18 spectrum analysis and spectrogram option to its R&S RTM oscilloscope family, making the R&S RTM the only oscilloscope in its class that can analyze the time domain while simultaneously analyzing the spectrum, logic and serial protocol. Interactions such as those that occur in electronic devices with RF components are quickly analyzed in a single measurement.

    Time and spectrum analyses can be configured completely independently of one another. This means that users can simultaneously analyze signal details that differ in time and frequency, with the optimum settings for each. Separate implementation of the signal paths makes this possible. Like a spectrum analyzer, important parameters such as center frequency and resolution bandwidth can be specifically configured to match each measurement task. The hardware-implemented digital downconverter (DDC) reduces the spectrum to the components relevant for analysis. As a result, the R&S RTM offers a fast, reactive analysis of embedded designs.

    Additional displays for min. hold, max. hold and average, as well as markers for automatic peak value searches, support the user during spectrum analysis. Changes in the spectrum over time or sporadic unwanted signals are immediately visible in the spectrogram display. The amplitudes versus frequency and time are color coded.

    With the R&S RTM-K15 history and segmented memory option, users can load all acquisition components from the 460 MSa deep memory and analyze them with the R&S RTM measurement functions.

    The R&S RTM portfolio, which already consists of models with 200 MHz, 350 MHz and 500 MHz bandwidth, now includes two-channel and four-channel models with 1-GHz bandwidth. The new models exhibit the same analog characteristics, offering true 1mV/div at the full bandwidth and full ADC resolution with exceedingly low 270 µV noise.

  • MWC 2015: Anritsu to Showcase Cloud-Based Connected Car System for Fleets

    Photo: Anritsu
    Photo: Anritsu

    Anritsu plans to showcase a sophisticated, cloud-based connected car system for fleet tracking at Mobile World Congress 2015, which will be held in Barcelona March 2-5. The system was developed by the University of Hertfordshire in the UK with the help of network simulation technology from Anritsu.

    The system will be demonstrated using a GNSS simulator from Spectracom to provide location information to the system being tested.

    The connected car demonstration will show a car’s diagnostics system connecting to the cloud via a simulated LTE network environment provided by Anritsu’s mobile network simulator, the MD8475A. An application in the cloud enables a fleet manager on any Internet-connected device to view the location and operating parameters of any vehicle in the fleet in real time.

    The MD8475A enables the university’s development team to test, from their Hertfordshire laboratory and with a single instrument, how the system’s in-car LTE modem would perform in mobile networks all across the world, and operating according to all major worldwide standards.

    The combination of the MD8475A and the Spectracom simulator provides a complete test environment, to simulate any global location, and any type of cellular connectivity, to ensure correct operation of the system. This test bed will showcase the effectiveness of a complete wireless test-bed solution, to enable cost-effective development testing, product validation, and customer experience evaluation within a single system.

    Anritsu Corporation has been a communications provider solutions for more than 110 years, with test and measurement solutions including wireless, optical, microwave/RF and digital instruments, operations support systems and solutions that can be used during R&D, manufacturing, installation and maintenance.

  • GATE Facility Recertified as Galileo Test Bed

    The German Galileo test and development infrastructure GATE has been recertified to serve as a Galileo open‐air test laboratory, for receiver integrity testing (RAIM) for safety‐of‐life (SoL) applications, and for Galileo SIS ICD conformance of signal characteristics and signal quality.

    The GATE facility, in Berchtesgaden, is operated by IFEN GmbH. Certification was conducted by TÜV SÜD, an international service corporation focusing on consulting, testing, certification and training.

    GATE consists of eight transmitting stations that emit Galileo signals in the GATE test area in Berchtesgaden, as well as two monitoring stations that receive and process these signals.

    For application tests, it is essential for GATE to provide constant Galileo specifications for tests, including position accuracy, signal spectrum and navigation data. This is necessary for both test types: tests with the eight “GATE satellites” only and tests with simultaneously usage of the already-existing Galileo satellites in orbit.

    The compliance to the specification was verified by the company NavCert GmbH from Braunschweig, Germany, in a recertification of the GATE test bed. Compared to a full certification, taking place every three years, a recertification only verifies the compliance to the specification by the use of random inspections though tests in GATE.

    The recertification also includes an audit of the operation processes of the operating company IFEN GmbH. Here, the implementation and adherence to process procedures for GATE operation were verified. This includes questions such as whether a sufficiently technical skilled team is available for operating GATE, if the performed application tests are documented in a reproducible way, and how the GATE team handles non‐conformances to the specification and improvements to the system.

    With finalization of the recertification work, the GATE certificate was extended by TÜV SÜD to January 2016. Because of this, GATE customers can rely on the independent verification of the GATE test and development environment for upcoming testing activities, IFEN said.

    As an add‐on, customers of IFEN’s NavX‐NCS GNSS simulator benefit from the recertification by obtaining a confirmation from an independent organization (TÜV Süd), reassuring the functionality of GPS and Galileo signal characteristics and signal quality as per SIS ICD, IFEN said.

  • ION GNSS+ 2014: Spirent Communications

    John Pottle from Spirent Communications details the company’s GSS9000 RF constellation simulator at the 2014 ION GNSS+ Conference September 9-12 in Tampa, Florida. Spirent Federal’s GSS9000 RF constellation simulator has been reviewed and granted security approval by the Global Positioning Systems Directorate.

  • IFEN Officially Launches SX3 Software Receiver

    IFEN Officially Launches SX3 Software Receiver

    IFEN-SX3_with_chart-W Photo: IFEN
    Photo: IFEN

    IFEN has launched the SX3 receiver. The company’s previous scientific software receiver, the SX‐NSR, was subject to major upgrades, while the respective hardware front-end was completely redesigned. Together, they build the new SX3 GNSS software receiver.

    IFEN’s most important innovation of the year was introduced at the ION GNSS+ Conference September 9-12 in Tampa, Florida.

    One of the SX3’s key features is four RF frequency bands, which can be split into a maximum of eight sub-bands per unit. This enhances the bandwidth to a full 55 MHz per RF band, offering additional signal power, especially in E5 band. The new USB 3.0 port empowers a unrivaled data transfer rate that makes a maximal bit-quantization of up to 8-bit possible — for every single stream.

    The additional power is compressed into a significantly smaller and lighter hardware chassis than before. Among other options, a dual antenna-input feature can be ordered as well as an OXCO clock. (Standard equipment of the SX3 GNSS software receiver is a precise temperature-controlled oscillator.)

    The proofed difference correlator notably ruggedizes acquisition and tracking of any navigation satellite signals. Polyfit tracking reduces measurement noise through averaging (such as code/carrier measurements). (See “Innovation: Software GNSS Receiver.”) Accordingly, vector tracking improves the tracking of weak signals in degraded environments and the reacquisition of “lost” satellites.

    Just like its predecessor, it is also able to act as a framework for a customer’s own signal processing algorithms. “Customers can fully concentrate on their applications instead of dealing with potentially obscure code when using open source,” said Product Manager Bernhard Riedl. “Our professional support is specifically dedicated to scientific work as well as SX3’s capability for additional customizations. SX3 is far more than just a COTS product. This makes IFEN’s new SX3 scientific software receiver a mighty powerful tool for research and development.”

  • Spirent Simulator Granted Security Approval by GPS Directorate

    Spirent Simulator Granted Security Approval by GPS Directorate

    Spirent's GSS9000 constellation simulator.
    Spirent’s GSS9000 constellation simulator.

    Spirent Federal Systems, a U.S. provider of positioning, navigation and timing test solutions to the government and its contractors, announces that its GSS9000 RF constellation simulator has been reviewed and granted security approval by the GPS Directorate.

    Higher dynamic simulations with more accuracy and fidelity are enabled by 1000-Hz (1 ms) System Iteration Rate — a four-fold increase over Spirent’s current GSS8000 product — zero inter-channel bias and a 0.3 mm RMS pseudorange accuracy. The GSS9000 also includes support for restricted and classified signals from the GPS and Galileo systems as well as advanced capabilities for ultra-high dynamics.

    According to Spirent, the GSS9000 is being rapidly adopted worldwide by key GNSS system and solution developers and providers because of its flexibility, performance and capability. The GSS9000 builds on the capability and performance of previous solutions from Spirent.

    The GSS9000 is highly flexible and can support the widest range of carriers, ranging codes and data streams for the GPS, GLONASS, Galileo and BeiDou as well as regional/augmentation systems. Its flexibility is key to supporting tailored and customizable solutions for specific and unique test needs. Multi-antenna/multi-vehicle simulation, for differential-GNSS and attitude determination, and interference/jamming and spoofing testing are also supported.

  • TEOCO’s AIRCOM Lab Strengthens Carrier Aggregation, LBS Testing

    TEOCO, a provider of assurance, analytics and optimization solutions to communications service providers, has expanded the testing capabilities of its AIRCOM Device Test Lab in Columbia, Maryland, with additional test systems from Rohde & Schwarz. Combined with Rohde & Schwarz’s conformance and carrier test case support, the R&S TS-LBS Location Based Services (LBS) and the R&S CMW-PQA Performance Test Systems enable TEOCO to support new industry and carrier testing requirements for next-generation wireless technologies including carrier aggregation, IMS, VoLTE, RCS, E911 over IMS, LTE A-GNSS, LTE OTDOA and LTE eCID.

    Release 10 and beyond, also referred to as LTE-Advanced, allows for a substantial uplift in the capacity and throughput of LTE, in addition to mobile device performance improvements. In LTE-Advanced, carrier aggregation (CA) is a key feature that allows the combination of multiple carriers to increase bandwidth and ultimately data rates in the network. To meet this need, the R&S CMW-PQA test system performs automated testing of a devices downlink, uplink and bidirectional data performance with or without carrier aggregation under simulated network conditions.

    LBS is already a key technology enabling a myriad of new applications that people depend on every day. LTE and additional satellite constellations are being leveraged to improve availability and performance of location technologies indoors and outdoors. Higher customer expectations are driving the need for more advanced testing methodologies, and the R&S TS-LBS test system supports field-to-lab testing where real-world conditions are captured with high performance 16-bit resolution, and replayed in the lab for more accurate simulation.

    “We are excited to expand our testing capability and capacity for LTE-Advanced and LBS-enabled devices,” said Hemant Minocha, Executive Vice President at TEOCO. “And given the increase in test complexity and costs, we are pleased to be working with a partner such as Rohde & Schwarz whose expertise in conformance and carrier acceptance testing and breadth of test cases helps future-proof our investment while delivering the quality and results our customers have come to expect.”

  • Averna Acquires Testing Company Cal-Bay Systems

    Averna, a developer of test solutions and services for communications and electronics device-makers worldwide, has acquired U.S.-based Cal-Bay Systems, a privately owned provider of test systems, test and measurement solutions, automated testing and vibration monitoring tools. This move is intended to strengthen Averna’s presence in the consumer electronics, medical device, and vibration monitoring markets, as well as providing the company with strategic positioning on the U.S. West Coast.

    Averna has acquired 100-percent share of Cal-Bay Systems for an undisclosed amount and will take on management of its U.S. and European offices. The current owners, Buck Smith and Patrick Kelly, will continue to participate in the day-to-day operations and expansion plans. Cal-Bay Systems, headquartered in San Rafael, California, brings to Averna 20 years of test expertise and customer relationships in comprehensive, automated test and measurement processes for mission-critical applications.

    “We are thrilled with the acquisition of Cal-Bay, as it is very synergistic with our portfolio of test engineering services and expertise, and constitutes another building block of our growth plan,” said Averna President and CEO André Gareau. “Cal-Bay’s customer base and strategic location on the U.S. West Coast are a great addition to our current operations. This is also a fantastic growth opportunity for Cal-Bay’s team and we welcome them into the Averna family.”

    Gareau continued, “These are exciting times for our company and shareholders. This acquisition brings a wealth of business opportunities for our company, and could not have been accomplished without the talented team that we have assembled.”