The conference, sponsored by the Royal Institute of Navigation (RIN), is a premier forum for the presentation of research and advances in navigation. The theme of INC2018 is Navigation Challenges and Societal Benefits.”
According to RIN, INC2018 will offer a unique format of multiple keynotes throughout the three days. The sessions and themes will address key navigation topics, including cognition in navigation; human factors in navigation systems; connected autonomous vehicles; innovations in accuracy and indoor navigation, innovations in resilient positioning, navigation and timing; mapping, imaging and augmented reality; and progress in quantum.
This year’s INC will also feature a one-day symposium covering topics related to cognitive navigation. According to RIN, cognitive navigation is distinguished from other kinds of navigation methods/technology by the dependence on some type of representation of the to-be-navigated space. The goal of the symposium is to bring academics and industry experts together to facilitate the development of our understanding of and design for cognitive navigators, so that buildings and technology can work in a seamless way with human psychology.
The 2018 DACH Country Package for Maptitude includes 4th quarter 2017 map content for Germany, Austria, Switzerland and Liechtenstein. (Photo: Caliper)
Caliper has lunched a 2018 DACH Country Package for its Maptitude mapping software. According to the company, Maptitude country packages bring the power and flexibility of its Maptitude product suite to a global audience and enable its customers to make geolocation-based decisions internationally.
The 2018 DACH Country Package includes fourth quarter 2017 map content for Germany, Austria, Switzerland and Liechtenstein. The updated map includes refreshed streets and landmarks, as well as updated travel times and improved address matching.
According to the company, users can seamlessly switch between the countries purchased, and doing so will refresh the Maptitude interface with country-specific tools, such as those for territory and sales mapping, finding, pin mapping, routing, displaying demographics and Create-a-Map Wizard.
Caliper develops geographic information systems software, and its Maptitude software is designed to be a cost-effective, professional mapping software product. Maptitude also enables organizations to leverage their location-based data to improve decision making and planning, while minimizing expenditure through competitively priced solutions, the company added.
A roundup of recent products in the GNSS and inertial positioning industry from the November 2018 issue of GPS World magazine.
OEM
Simulator signals
GPS L5 and Galileo E5 added to simulator
Photo: Rohde & Schwarz
Rohde & Schwarz has added GPS L5 and Galileo E5 simulation capabilities to its R&S SMW200A GNSS simulator. The R&S SMW200A GNSS simulator is designed for efficient test and characterization of multi-constellation and multi-frequency GNSS receivers. It now enables generation of complex and highly realistic test scenarios with up to 144 channels in the GNSS frequency bands L1, L2 and L5. In addition to GPS (L1/L2/L5), GLONASS (L1/L2), Galileo (E1/E5) and BeiDou (L1/L2), the R&S SMW200A also supports signal generation for QZSS and SBAS on L1. Channels can be routed to up to four RF outputs, so that even multi-antenna systems can be tested. The R&S SMW200A can generate complex coexistence and interference scenarios with multiple interferers.
The BlueSky GNSS Firewall enables critical infrastructure providers to harden the security of their operations from GPS threats and deliver a more reliable and secure service. The security-hardened system provides protection against GPS threats such as jamming, spoofing and complete outage. It also supports a range of precision timing technologies, including atomic clocks, to enable continuous operation when GPS may be completely denied for extended periods. The TimePictra software management suite provides centralized control and visibility of GPS reception across regional, national and global geographic areas. It can incorporate an optional internal miniature atomic clock.
For reference deployments, CORS networks and monitoring
The VeraChoke GNSS antenna. (Photo: Tallysman)
The VeraChoke is a high-accuracy choke ring antenna with a choice in form factor for reference and monitoring applications. The VC6100, the first model variant of the VeraChoke, shares a common high-efficiency element design with its counterpart VeraPhase. With the choke-style form-factor, however, the rings have been optimized for all GNSS signals and are slightly pyramidal in shape to improve reception of low-elevation satellites. The VC6100 offers a tight phase center variation (PCV) of no more than ±1 mm for every frequency. It is capable of receiving all GNSS signals, and achieves a very low axial ratio. The antenna also supports large and small SCIGN radomes.
Duro Inertial is a ruggedized version of Swift Navigation’s Piksi Multi dual-frequency real-time kinematic (RTK) GNSS receiver combined with Carnegie Robotics’ SmoothPose sensor fusion algorithm, which fuses GNSS and inertial measurements into a combined solution. The blending of GNSS and inertial measurements provides a dead-reckoning capability that allows Duro Inertial to provide a highly accurate, continuous position solution during brief GNSS outages and to deliver a robust precision navigation solution in harsh GNSS environments.
The durable Instinct has GNSS; three-axis compass; barometric altimeter; and wrist-based heart-rate sensor. The watch includes a built-in sports apps, smart connectivity and wellness data. It is built to endure challenging environments, and is constructed to military standards for thermal, shock and water resistance. The multi-GNSS feature helps users track their location in challenging environments, while the Garmin Explore app helps plan and track a trip.
The Navsight Land & Air Solution provides high-performance inertial navigation to make surveyors’ mobile data collection easier, whether for mobile mapping, GIS or road inspection. The solution consists of an inertial measurement unit (IMU), available at two different performance levels, connected to Navsight, a rugged processing unit embedding fusion intelligence and a GNSS receiver. It also has connections for external equipment such as lidar, cameras or computer. SBG’s fusion algorithms allow the company to get the best performance from inertial, odometer and GNSS technologies; exclude false GNSS fixes; and improve the trajectory in complicated areas such as urban canyons, forests and tunnels. The solution supports all GNSS constellations, and real-time kinematic (RTK) and precise point positioning services such as Omnistar and TerraStar.
iSTAR Pulsar is designed to capture 360-degree data while mounted on a vehicle, drone or on foot. An upcoming feature in cloud-based processing software VR.WORLD uses artificial intelligence and image recognition to analyze the images captured by iSTAR Pulsar so that objects like cars, trucks, traffic lights, road signs, pedestrians and cyclists can be automatically identified in images. Handheld 3D mobile mapping company GeoSLAM and mobile mapping software company Orbit GT have introduced integration with iSTAR Pulsar.
The SMART7 family features NovAtel’s GNSS + inertial navigation system (INS) SPAN technology; future-ready GNSS; Wi-Fi and internet protocol connectivity; superior tracking performance; and TerraStar-C PRO corrections. It is designed to increase GNSS availability, accuracy and reliability for major precision-agriculture equipment manufacturers. The SMART7-S includes SPAN technology, the SMART7-W includes Wi-Fi and an integrated NTRIP client, and the SMART7-I model also incorporates Ethernet. All SMART7 models provide exceptional positioning availability using signals from all constellations and frequencies to deliver assured positioning anywhere.
The DT301X rugged military-grade tablet is purpose-built to enhance the precision of 3D surveying, crime and crash scene reconstruction, and bridge and other construction inspections. An option is a dual-frequency GNSS module for real-time mapping and positioning. The tablet integrates the Intel RealSense depth camera, which provides real-time 3D imaging providing accurate measurements for CAD, engineering, design, utility management and crime-scene forensics. A high brightness 10.1-inch touchscreen offers flexible viewing in a wide range of lighting, and an Intel eighth-generation Core i5 or i7 processor offers high-performance while still being energy efficient. With high-capacity 60- or 90-watt hot-swappable batteries, the DT301X keeps working continuously, complemented with a variety of battery chargers so fully charged batteries are always available.
The Cedar CP3 rugged smartphone is capable of data collection and communication. It has a high-visibility 5.5-inch AMOLED display; 14- to 16-hour battery life operating at full brightness and running GPS; 16-megapixel user-facing camera and dual 12-megapixel rear camera; and 6 gigabytes of RAM with 64 gigabytes of internal storage.
Parachute rescue system DRS-5 is designed for multicopters up to 8 kg; the DRS-10 for multicopters weighing 5–20 kg. The system consists of a carbon cage in which the parachute is stored as well as associated electronics. The electronics, including the sensors, monitor the flight status of a drone independent of the flight controller. A sophisticated algorithm merges this sensor data, enabling automatic crash detection and parachute ejection. All flight data and movements are recorded in a black box.
PrecisionPass assesses UAV data collected in the field. The toolkit lets pilots quickly determine if a data-collection job meets the required criteria or if it needs to be collected again. PrecisionPass assesses coverage, assesses image resolution and quality, reviews required metadata, speeds upload and processing times, and packages data for processing. The immediate feedback reduces the risk of failures during the analysis stage, all but eliminating the need to re-fly a mission, so customer needs are met in a timely and cost-efficient manner.
The Skyfish computing platform fully automates crucial infrastructure inspection and measurement tasks. It supports DJI and PixHawk flight controllers and other drone architectures, as well as 3D modeling software from companies such as Bentley Systems. Its easy-to-use interface enables anyone to fly, inspect and model complex infrastructure. The platform also pre-processes the collected infrastructure data and metadata to help create impeccable 3D models.
OpenIMU is a professionally supported, open-source GPS/GNSS-aided inertial navigation software stack for low-cost precise navigation applications. Integrating an inertial measurement unit (IMU)-based sensor network improves navigation and self-location capabilities. It is aimed at developing autonomously guided vehicles for industrial applications, autonomous cars, industrial robots and drones. OpenIMU enables advanced localization and navigation algorithm solutions; its extensible software infrastructure provides the code needed for algorithm development. A hardware development kit includes JTAG-pod, precision mount fixture, EVB and an OpenIMU300 module that features Aceinna’s 5 deg/hr, 9-Axis gyro, accelerometer and magnetometer sensor suite with an onboard 180-MHz ARM Coretex floating-point CPU.
The Teseo-LIV3F module incorporates the Teseo III receiver. It speeds application development and adds up to 16 MB of Flash memory for firmware updating or data logging without a backup battery. Used by automotive and industrial sectors, the Teseo III multi-constellation receiver combines high accuracy with fast response time and low power consumption. The Teseo-LIV3F module enables makers and small engineering teams to leverage the Teseo III advantages in creating new products in the industrial and consumer market segments such as vehicle trackers, drones, anti-theft devices and pet locators, and systems for services such as fleet-management, tolling, vehicle sharing or public transportation.
Audi’s latest e-tron electric car will launch in Europe with a digital rear-view system. Developed by Ficosa, the camera monitoring system is made up of cameras and displays that replace traditional external side mirrors to increase safety and comfort. The vision system is comprised of two cameras, integrated into the sides of the car’s chassis, and two tactile displays inside the doors.
Imagination Technologies has introduced a comprehensive GNSS IP offering. The Ensigma Location GNSS IP core supports GPS, GLONASS, Galileo and BeiDou as well as several satellite-based augmentation systems (SBAS) including WAAS and EGNOS.
With Ensigma Location GNSS IP, companies can integrate position, navigation and timing (PNT) services while keeping power consumption to a minimum, the company said.
The Ensigma GNSS IP is designed to be used with a wide range of GNSS receivers.
The IP is optimized for battery-powered remote internet of things (IoT) sensors and edge devices, wearables, health monitors, consumer mobile products, automotive after-sales products such as insurance boxes and road tolling equipment, and asset tracking devices.
A growing number of battery-operated products must support PNT services. Consumers want to track their devices, but don’t want to recharge batteries frequently. In industrial and agricultural environments, users need to track mobile assets to improve efficiency and reduce operational costs, but it isn’t possible to frequently change batteries across numerous devices in disparate locations.
In addition, new regulatory requirements mandate the use of location services in some products, for example, to address spectrum sharing requirements in IoT devices and base stations.
Key features of the Ensigma GNSS IP include:
Ultra-low power operation
Ability to share location information with external wireless technologies such as LTE or Wi-Fi
Options to share peripherals such as memory and system clock to enable reduced total system cost
High sensitivity for indoor location
Support for assistance information using external sources such as LTE and Wi-Fi to improve time to first fix
Radio Frequency Interference (RFI) detection and mitigation
With Ensigma GNSS IP, customers can choose a configuration, from standalone to highly integrated, that works best for their specific system implementation, the company said. The IP can be configured for lowest power or highest integration, and is designed to fit into any existing solution with the optimum level of design and resource reuse.
The Ensigma GNSS IP builds on the Ensigma connectivity engine, which incorporates an ultra-low power CPU core. Imagination employed many innovative GNSS techniques to build on the efficiency of this platform to ensure low-power consumption.
The GNSS IP includes dedicated hardware blocks which enable much lower power compared to a software only solution. In addition, the GNSS IP not only supports continuous fix techniques, but it also supports power-efficient “capture and process” for devices that only require periodic location updates, the company added. This feature further conserves battery life by capturing data, such as fitness information from a wearable device, and storing it for later processing.
The initial solution is optimized for use with SaberTek’s ultra-low power GNSS receiver.
A GPS/inertial trajectory data simulation podium can generate simulation data sets for all levels of GPS/INS integration. Here it verifies the operation and performance of a new ultra-tight GPS/INS integrated system, adaptable for both software and conventional hardware receivers.
Navigation systems for land vehicles, embedded in passenger cars, ambulances, police cars, fire trucks and others, provide reasonable accuracy in open-sky environments, but under conditions such as underpasses and tunnels GPS satellite signals cannot be readily tracked since they are not consistently available or have low signal power. One major factor that directly impacts the effectiveness of receivers in terms of complexity and speed is receiver architecture.
Scalar (conventional) signal tracking architectures process each satellite signal individually: pseudoranges and pseudorange rate measurements are produced separately and only combined in the navigation filter to generate the required solution. Hence, no information exchange happens between the different tracking channels.
On the contrary, vector tracking systems combine all the channels in one system along with the navigation filter to produce pseudoranges, pseudorange rates and the navigation solution all at the same time. Figure 1 shows the general architecture of a vector tracking system. Vector-tracking architectures have proven themselves able to provide better performance over scalar tracking systems in challenging environments where most satellite signals are received at low signal-to-noise ratios (SNR).
Figure 1. General view of the vector-based signal tracking system. (Image: Authors)
Any information available about the satellite constellation and user position and dynamics can be used to predict the received signals. Therefore, the best estimation we have for the receiver position and dynamics makes the vector tracking loops more robust. One approach to reduce or perhaps remove the receiver dynamic stress in the signal tracking loops is to provide external aiding information.
Several sensor types have been augmented with GPS to improve navigation system accuracy and reliability. The most common systems that have been widely augmented with GPS are inertial sensor systems (INS). Because an INS system can provide a continuous solution at a high data rate, it is virtually a twin to the GPS with respect to its widespread use in navigation applications.
Using the solution obtained from INS, one can estimate a line-of-sight acceleration that can be integrated to obtain a line-of-sight velocity. Car odometers also provide reasonably accurate measurements of the vehicle speed. Incorporating this velocity (from INS or other aiding sources) into tracking-loop computations helps the tracking loop to maintain tracking at a lower bandwidth even when high dynamics are experienced at the receiver. When the aiding source to the GPS signal tracking loops is an INS, the system is known as ultra-tight GPS/INS integration. Figure 2 shows a general block diagram of an ultra-tightly coupled GPS/INS integration system.
The ultra-tight GPS/INS integrated system enhances a GPS receiver’s tracking ability in challenging environments and consequently improves navigation availability.
Loose. The loosely coupled integration mode is easier to implement since the inertial and GPS navigation solutions are generated independently before being weighted together in a separate navigation filter. The advantages of this coupling strategy are that the INS errors are bounded by the GPS updates, the INS can be used to bridge GPS updates, and the GPS can be used to help calibrate the deterministic parts of the inertial errors instantly. The main drawback of this strategy, however, is that it requires at least four satellites in view which cannot always be guaranteed because of signal interruption due to many factors such as signal blockage by trees or tall buildings.
Tight. The tightly coupled integration mode combines both systems into a single navigation filter. The major limitation of visibility of at least four satellites is removed since this integration mode can provide a GPS update even if fewer than four satellites are visible. The tightly coupled architecture also overcomes the problem of correlated measurements that arises due to cascaded Kalman filtering in the loosely coupled approach. However, these advantages come with the penalty of increased system complexity.
Ultra-tight. In the ultra-tightly coupled integration approach, the raw measurements come from one step further towards the front end of a GPS receiver, in the form of I (in-phase) and Q ( quadrature ) signal samples. These I and Q measurements are integrated with the position, velocity and attitude of the INS in a complementary filter. The integration of INS-derived Doppler feedback to the carrier tracking loops provides a vital benefit to this system; the INS Doppler aiding removes the vehicle Doppler from the GPS signal. Hence, it results in a significant reduction in the carrier tracking loop bandwidth. In addition, due to lower bandwidths, the accuracy of the raw measurements is further increased.
The proposed method uses a variant of the Kalman filter as the core of the navigation processor coupled with the inertial sensor’s input in a reduced inertial sensor system (RISS) configuration and car speed odometer; see Figure 3. Additionally, the data sets used in this work are generated using a newly composed GPS/INS trajectory data simulation platform.
Figure 3. Reduced inertial sensor system (RISS). (Image: Authors)
Secondly, it demonstrates a novel GPS/INS trajectory data simulation podium. This combined simulation system can produce simulation data sets for all levels of GPS/INS integration and is used to verify the operation and performance of the ultra-tight GPS/INS integrated system.
SYSTEM ARCHITECTURE AND IMPLEMENTATION
The goal of signal tracking loops is to monitor changes in the main signal parameters, namely, code phase and carrier frequency, to keep the locally generated signal aligned with the received signal. Successful tracking of these variables will provide good estimations of the parameters that are required for the navigation filter to function correctly. Errors in the code phase and carrier frequency are usually represented as:
(1)
(2)
where and are the measured and estimated code phases, respectively. and are the measured and estimated carrier Doppler frequencies, respectively. These estimated errors at the signal tracking stage are directly linked to the errors in the states at the navigation filter.
Each tracking channel provides its own measurements based on a discriminator’s output. All the measurements are then processed together in the navigation filter and feedback is provided to each channel based on the obtained navigation solution results. The filter will process the error signals received from the discriminators in the form of code phase error and frequency error . Thus, the measurements of the filter will be pseudorange errors and pseudorange rate errors.
(3)
(4)
Where fcode is the code frequency = 1.023 x 106 Hz, fcarrier is the nominal L1 frequency = 1575.42 MHz, and η represents the measurement noise vector.
The computations of the navigation solution start with a mechanization process where we first calculate pitch, roll and azimuth angles. Knowing the Azimuth and pitch angles, vehicle forward velocity can be projected into East, North and Up velocities. The East and North velocities are transformed into geodetic coordinates and then integrated over the sample interval to obtain positions in latitude and longitude. The vertical component of velocity is integrated to obtain altitude. At this stage, we run the Kalman navigation filter through its two-step known cycle, prediction and update, incorporating any available measurements to estimate the receivers’ new position and velocity. Then, the estimated pseudoranges and pseudorange rates are calculated. Finally, the computed code and carrier frequencies are fed back to control the code and carrier oscillator inputs to align the locally generated signal with the incoming signal.
COMBINED SIMULATION SYSTEM
In our work, we combined two existing INS and GNSS simulators to build a comprehensive simulation tool that can produce a limitless number of data sets of repeated trajectories under entirely controlled circumstances. Moreover, these data sets can be used for any level of GPS/INS integration system validation. The system is also used to verify the performance of the above proposed ultra-tight GPS/INS integration system architecture.
For the GPS data, a satellite navigation simulation signal generator was used to build and generate the desired trajectory. The selected model has the ability to provide dynamic capacity in Doppler and signal power levels as well as adequate channels to simulate line-of-sight and multipath satellite signals. The unit is driven by a software package that comes in different versions; the most powerful version is used in this research to drive the simulation hardware system to generate the output radio frequency (RF) signal.
A receiver front-end then generates the discretized data stream in the form of in-phase (I) and quadrature-phase (Q) signals. The unit is a rugged dual-frequency L1/L2 front-end intended mainly for software receiver and interference detection systems. The unit is capable of logging L1/L2 data at bandwidths of 2.5 MHz, 5.0 MHz, 10 MHz and 20 MHz with data quantization varying from 1 bit to 8 bits.
For the INS data sets, the INS simulator, developed by the Mobile Multi-sensor Group at the University of Calgary, is used for simulating inertial measurement unit (IMU) raw data. The INS simulator can virtually generate the raw data measurements of any grade of IMUs such as navigation, tactical and consumer-grade systems. A wide number of sensor errors can be simulated using this software such as bias instability, random walk, scale factor, errors due to thermal drift and g-sensitivity and so on. While the simulator can generate raw IMU measurements using user-defined vehicle motion and dynamics, such as static scenarios, straight line, constant velocities, accelerations, turns and bumpy roads, and it can also accept externally injected vehicle dynamics from real trajectory data.
Figure 4 shows a high-level diagram of the trajectory data flow from the two arms of the synthesized simulator. Several conversion code scripts were written to convert raw data into the implementation platform workspace format. Both data sets were then merged through the implemented algorithm to provide the navigation solution.
Figure 4. Data simulation tool flow diagram. (Image: Authors)
Step 1 of Simulation Process. The trajectory design, Figure 5, outlines the general aspects of the process. Among these are the type of platform to be simulated, for example. land vehicles, ships, aircraft and so on; the satellite constellation, typically GPS, Galileo or GLONASS; the environment, whether rural, suburban or urban; and error sources, including ionospheric and tropospheric effects. All of this is done using the simulator’s software.
Figure 5. Trajectory data flow Step 1. (Image: Authors)
Step 2. This incorporates the implementation of the data stream that is fed into the signal generator hardware, which transforms this into an RF signal (Figure 6). Concurrently, the reference trajectory data is logged on the same computer that hosts the simulation software. The I and Q branches are recorded, simultaneously with the reference trajectory, on a GNSS receiver front-end.
Figure 6. Trajectory data flow Step 2. (Image: Authors)
Step 3. Finally, the inertial data is simulated. First, the INS simulator is configured according to the desired simulation parameters. Among these are the sensor data rate, grade (or quality) of the selected sensor(s), and some initialization quantities that are obtained from the output of the GNSS signal simulator. Once the configuration process is complete, data extracted from the reference trajectory is converted into a format appropriate to the INS simulator, and the inertial data simulation is performed. At this stage, data from both the GNSS side and INS side can be converted into a format suitable for use by the integrated INS/GNSS system (see Figure 7).
Figure 7. Data flow, Step 3. (Image: Authors)
EXPERIMENTAL WORK
Using the complete simulation system, several simulation data sets are used to verify the performance of the proposed algorithm in semi real-life scenarios. Each time a chosen scenario is run on the Spirent GNSS simulator, the software data is applied to the Spirent hardware to generate the RF signal, which is then applied to the input of the front-end unit to provide the corresponding I and Q signal streams. Meanwhile, the trajectory data is logged from the simulator to be used as a reference and then fed to the INS simulator to generate the corresponding raw IMU data. Finally, the I and Q and raw IMU data are combined (when the ultra-tight solution is used) in a software receiver code to extract the ultimate positioning solution. For scalar and vector-based signal tracking, only GPS data is used. One sample trajectory that simulates a land vehicle driving at low speed is selected to show results of the proposed method.
Table 1 shows initialization of the key parameters during the simulation period. A GPS-only satellite constellation is used. We also limited the maximum number of simulated satellites to seven.
RESULTS
The reference solution used to evaluate the proposed method and combined simulation system is the pure data sets extracted from the Spirent GNSS simulator. The figures below show results of 80 seconds of data processing. At around seven seconds of the period, a 43-dB signal drop was applied for 8 seconds on channel number 1, which is assigned to track PRN number 06. A similar signal drop is partially overlapped with this, but was applied for only 5 seconds on channel number 3, which is dedicated to track PRN number 21. The following abbreviations are used in the figures: ST for scalar tracking, VT for vector tracking, and UT for ultra-tight GPS/INS integration system.
Figure 8 and Figure 9 show the carrier frequency for PRN 06 and PRN 21. Large frequency errors (greater than 100 Hz) are noticeable in the scalar tracking system. The vector tracking system, however, was much less affected, showing more resistance to the drop in signal-to-noise ratio. The ultra-tight GPS/INS integration system was nearly unaffected and maintained a very accurate carrier frequency estimation throughout the simulated trajectory.
Figure 8. Estimated carrier frequency for PRN #6. (Image: Authors)Figure 9. Estimated carrier frequency for PRN #21. (Image: Authors)
The trend of the position errors is plotted in Figures 10, 11 and 12. The maximum position error was around 15 meters in the case of vector tracking, whereas the maximum position error from the ultra-tight system was below 4 meters in the worst case.
Figure 10. Position X error. (Image: Authors)Figure 11. Position Y error. (Image: Authors)Figure 12. Position Z error. (Image: Authors)
Velocity errors are depicted in Figures 13, 14 and 15. Velocity errors for the vector tracking system reached about 2 meters per second during the low signal-to-noise ratio period. However, they were only small fractions of a meter per second for the ultra-tight GPS/INS integration system.
Figure 13. Velocity X error. (Image: Authors)Figure 14. Velocity Y error. (Image: Authors)Figure 15. Velocity Z error. (Image: Authors)
CONCLUSIONS
This article shows the performance of a newly proposed ultra-tight GPS/INS integrated system using an RISS that is intended to enhance GPS receivers’ tracking ability in challenging environments, thus improving navigation availability. Additionally, we present a freshly combined GPS/INS trajectory data simulator that can be used to generate simulation data sets for all levels of GPS/INS integration. The two components of the simulator are demonstrated to be perfectly linked. Performance of the algorithm was tested using several trajectories, and the algorithm demonstrated durability against harsh signal degradation. Acceptable position and velocity errors were achieved. Expected future improvements to the algorithm aim to employ longer integration time, and the performance of different grades of IMUs are to be simulated.
ACKNOWLEDGMENT
This work described in this article was first presented at the ION GNSS+ 2018 conference in Miami, Florida.
MANUFACTURERS
The Spirent GSS6700 Satellite Navigation Simulation Signal Generator was used in these tests, with SimGen software. The NovAtel FireHose front-end generated the discretized data stream.
MALEK KARAIM is a Ph.D. candidate at the Department of Electrical and Computer Engineering, Queen’s University, Canada. He is working within the Navigation and Instrumentation Research (NavINST) Group at Queens’ University/Royal Military College of Canada.
MOHAMED YOUSSEF received his Ph.D. degree from the Department of Geomatics Engineering and the Department of Electrical and Computer Engineering, University of Calgary, Alberta, Canada. He leads GNSS R&D activities at Sony North America.
ABOELMAGD NOURELDIN is a cross-appointment associate professor at the departments of electrical and computer engineering in Queen’s University and the Royal Military College (RMC) of Canada. He is the director of the Navigation and Instrumentation Research Laboratory at RMC.
Airbus Defense and Space’s edited WorldDEM database, along with the WorldDEM4Ortho dataset, are now available for streaming. WorldDEM is a single-source digital elevation model.
According to the company, access to the WorldDEM and WorldDEM4Ortho of the entire Earth’s landmass facilitates a wide range of applications, such as line-of-sight analysis, hydrological modeling, satellite imagery orthorectification and more.
The WorldDEM dataset corresponds to a hydro-enforced digital surface model with water surfaces of lakes and reservoirs set to a single elevation. Rivers and canals are flattened with monotonic flow, oceans are set to zero and coastal infrastructure features are removed.
WorldDEM4Ortho, which is based no the global WorldDEM dataset, is tailored to orthorectification of high and very high- resolution optical and radar satellite data. According to Airbus, it enables corrections of all distortions induced by the topographical variations of the Earth’s surface and the satellite orientation when acquiring the image.
Airbus Defence and Space is a division of Airbus responsible for defence and aerospace products and services.
In Halle, Germany, Microdrones worked with construction company Strabag to fly the mdMapper1000DG above Highway A33 to create a point cloud and orthophoto of a 12-kilometer stretch of the Autobahn.
The drone was equipped with special transponders to make it visible to German Air Traffic Control, enabling beyond-visual-line-of-sight (BVLOS) flight. BVLOS allows for longer flights that cover more area and capture more data.
Using the drone for corridor mapping of the Autobahn enables closer inspection and visualization of the highway to find pavement imperfections, road wear and tear, and other potential safety hazards, Microdrones said.
DJI has unveiled its Mavic 2 Enterprise, a portable drone designed to improve everyday work for businesses, governments, educators and other professionals.
According to the company, the Mavic 2 Enterprise features an ultra-compact and foldable design with an array of advanced controls and accessories that extend users’ capabilities during critical operations like firefighting, emergency response, law enforcement and infrastructure inspections.
The drone carries a high-resolution, 12-megapixel camera that’s stabilized by a three-axis gimbal for smooth and stable videos and images. The camera also features a two-time optical and three-time digital zoom capability, the company said.
The Mavic 2 Enterprise can be used for inspections and other everyday tasks. (Photos: DJI)
The Mavic 2 Enterprise comes equipped with a number of accessories, including the M2E Spotlight, M2E Speaker and M2E Beacon. The M2E Spotlight, which has a brightness of 2,400 lumens, is ideal for search-and-rescue operations, as well as inspection applications, the company said. The M2E Speaker allows pilots to play up to 10 custom voice recordings on demand. Finally, the M2E Beacon features a bright flashing strobe that’s visible up to three miles away, DJI added.
According to DJI, the drone also includes a GPS timestamping feature that encodes the time, date, and location of every recorded image, aiding in pilot accountability and ensuring that data captured by the drone can be trusted and used in situations from reviewing critical infrastructure inspections to potential legal proceedings.
It also comes equipped with DJI’s AirSense technology to help improve pilots’ situational awareness and enhance airspace safety. According to DJI, AirSense uses an integrated receiver to automatically alert drone pilots of ADS-B signals from nearby airplanes and helicopters, providing real-time positioning alerts through the DJI Pilot mobile app.
Finally, the Mavic 2 Enterprise features DJI’s latest video and data transmission system, Ocusync 2.0, which helps provide a more stable connection between the drone and its remote controller.
“With the Mavic 2 Enterprise, DJI has created a drone that makes powerful technology accessible to every enterprise and revolutionizes how they do their work,” said DJI President Roger Luo. “DJI’s hardware and software set the standard for aerial innovation around the globe, and Mavic 2 Enterprise is the most compact, powerful, reliable and safe tool to help professionals integrate drones into their operations.”
Eos Positioning Systems has donated an Arrow Gold GNSS receiver to Haiti Outreach, a 21-year-old nonprofit organization dedicated to helping Haiti become a developed country.
Haiti Outreach collaborates with individual Haitian communities to create and maintain access to potable water through community outreach, well digging and distribution-network development.
The Arrow Gold GNSS receiver helps Haiti Outreach build and improve potable water distribution networks by providing accurate subfoot elevations required for hydraulic modeling simulations, the company said. It uses Atlas satellite-based corrections to provide real-time decimeter (three to five centimeters) location throughout the country.
“Water is life, and making this basic necessity available to every person is at the foundation of Haiti Outreach’s work,” said Eos Positioning Systems CTO Jean-Yves Lauture. “I believe strongly in Haiti Outreach’s long-term vision to empower Haitian communities through development, education and cooperation.”
Haiti Outreach first began in 1997, with a mission to bring clean water to more people in Haiti and encourage them to take on the responsibility of maintenance and sustainability. In 2005, the organization shifted its focus toward greater community outreach and support, developing a program much more effective at producing the desired long-term outcome. Its community-led initiatives are heavily planned and prioritized, thanks to comprehensive field data collection and advanced geospatial analysis, Eos said.
“In most of these communities, there has only ever been a short-term vision, because the need has always been urgent,” Lauture said. “Haiti Outreach is changing that mentality. They are providing a development plan for now and the future. This is a slow process but is already proving successful. It is a true privilege to be able to support such noble efforts.”
TCarta, a global provider of geospatial products and services, was commissioned by the Environment Agency — Abu Dhabi (EAD) to carry out a landmark mangrove health assessment covering the entire Emirate of Abu Dhabi. The assessment contained mangrove condition information derived from high-resolution multispectral satellite imagery.
According to TCarta, the report showed 80 percent of the Emirate’s mangrove forests were healthy. The project also enabled EAD to designate conservation areas for immediate protection.
For the assessment, TCarta obtained high-resolution multispectral imagery acquired by the DigitalGlobe WorldView-2 and -3 satellites during from December through March. Computer algorithms were applied to the Coastal Blue, Visible Green, Visible Red and Near Infrared bands to differentiate mangroves from other vegetation across the Emirate.
The company then derived several vegetation indices from the spectral bands to rate the health of the mangrove forests, divided into small grids. From there, TCarta analysts obtained coarse-resolution Landsat imagery from 1987, 2001 and 2017 to chart mangrove coverage over three decades. According to TCarta, the combination of WorldView and Landsat data analysis clearly showed where mangrove loss had occurred over time. This data allowed the company to generate its disturbance index, which correlated health to external factors, such as urban development.
“The satellite-derived vegetation analysis process we developed for this project can be applied to large-area crop and forestry health mapping anywhere in the world,” said Chris Burnett, project manager at TCarta. “As part of the assessment, we created a disturbance index showing precisely where the most mangrove stress is occurring. EAD will use this to determine — and potentially mitigate — the external factors causing the mangrove conditions to decline.”
The company’s research proved that urban development near Abu Dhabi City was one of the primary threats to the Emirate’s mangrove forests. According to TCarta, EAD will use the report for remediation efforts, including the selection of more favorable areas to plant new mangroves to balance those that have already been lost.
Rohde & Schwarz’s Navigation and Guidance Solutions Learning Center offers brochures, articles, technical documents, videos and posters. (Image: Rohde & Schwarz)
Rohde & Schwarz has updated its Navigation and Guidance Solutions Learning Center with several features, including application notes, white papers, training videos and products for aerospace and defense applications.
Rohde & Schwarz provides accurate, flexible, high-performance test solutions to cover every need — from design, development, calibration and production to operational maintenance for ground based systems and advanced hybrid constellation simulations for GNSS systems, the company said.
The navigation learning center now includes the latest Rohde & Schwarz solutions for GNSS testing and avionics testing. It highlights the latest company products, including aeronautical radio navigation measurement solutions, vector signal generators and GNSS signal simulators. It also provides users with brochures, articles, technical documents, videos and posters.
The navigation center is organized under three main categories: radar and electronic warfare test, satellite communication systems, and navigation and guidance.
The company states that by using actual test call data to emulate active sensor compensation, its solution improved from 4.8- to 2.8-meter accuracy at the 80th percentile, which exceeds the commonly accepted definition of floor-level accuracy of under 3 meters.
The testing focus was to evaluate barometric-based solutions in advance of the Federal Communications Commission (FCC) establishing a vertical location accuracy metric for compliance by wireless carriers in the Top 50 markets, beginning in 2021.
Polaris Wireless was one of two technology vendors selected to participate and was the only solution tested in all buildings in all three cities: 48 buildings, 312 test locations and 55,592 test calls. The Polaris Wireless test included the widest variety of device and barometric sensor manufacturers.
Polaris Wireless achieved an official Stage Z vertical accuracy of 4.8 meters, 80th percentile, with a minimal one-time compensation of the barometric sensor outside of the test cities. However, this one-time compensation did not present a true test of Polaris Wireless vertical location accuracy.
Barometric sensor compensation is arguably the leading source of error in vertical location determination. During the test, Polaris Wireless did not enable active, in-market compensation of the baro sensor and instead relied solely on just a few test calls outside of the test market.
Polaris Wireless vertical accuracy from CTIA test data. (Chart: Polaris Wireless)
After learning that the other vendor included active, in-market compensation, Polaris Wireless submitted a comparable set of results using the same methodology to the CTIA for consideration in the report. This data was drawn exclusively from actual test calls, in the period before final results were published, to emulate the original performance as if active compensation had been activated.
These are referred to as “limited active compensation” results because sensor bias estimates were updated monthly instead of in real time. The figure shows the increase in Polaris accuracy when allowing for this active compensation.
Polaris Wireless says it continues to improve on its three-dimensional accuracy for both public safety and commercial applications, and is exploring additional forums for independent performance evaluation.
