Critical government and industry sectors (such as law enforcement, transportation, communication, finance) are growing increasingly dependent on Global Navigation Satellite Systems (GNSS) for positioning, navigation, timing. At the same time, availability of low-cost GNSS jamming devices presenting a serious threat to increasing likelihood outages infrastructures relying GNSS. The attacks range from malicious parties intentionally signals within targeted geographical region uninformed users...

Sensors play important roles for autonomous driving. Localization is definitely a key one. Undoubtedly, global positioning system (GPS) sensor will provide absolute localization almost all the future land vehicles. In terms of driverless car, 1.5 m accuracy minimum requirement, since vehicle has to keep in driving lane that usually wider than 3 m. However, skyscrapers highly-urbanized cities, such as Tokyo and Hong Kong, dramatically deteriorate GPS performance, leading more 50 error....

Urban canyon is typical in megacities like Hong Kong and Tokyo. Accurate positioning urban canyons remains a challenging problem for the applications with navigation requirements, such as pedestrian, autonomous driving vehicles unmanned aerial vehicles. The GNSS can be significantly degraded canyons, due to signal blockage by tall buildings. visual LiDAR considerably affected numerous dynamic objects. To facilitate research development of robust, accurate precise using multiple sensors we...

Reliable continuing positioning is a critical requirement for intelligent transportation systems (ITS). An integrated system presented, where the global navigation satellite (GNSS) real‐time kinematic (RTK) method was mainly used. When RTK not available, maintained by using Doppler measurements or low‐cost inertial measurement unit (IMU) coupled with vehicle odometer measurements. A new integrity monitoring (IM) presented that addresses each mode of proposed system. Models protection levels...

With the official announcement of open service since end 2018, BeiDou navigation satellite system (BDS) has started to provide global positioning, and timing (PNT) services. Thus, it is worth assessing positioning new BDS satellites signals. In this paper, we comprehensively assess status performance regarding single point (SPP) real-time kinematic (RTK) performance. Results show that signal in space range error (SISRE) BDS-3 superior BDS-2 satellites, showing an overall accuracy 0.71 m...

The reduction of multipath errors is a significant challenge in the Global Navigation Satellite System (GNSS), especially when receiving non-line-of-sight (NLOS) signals. However, selecting line-of-sight (LOS) satellites correctly still difficult task dense urban areas, even with latest GNSS receivers. This study demonstrates new method utilization C/N0 to detect NLOS elevation-dependent threshold setting may be effective mitigating errors. fluctuation affected by signals quite large. If...

Real-Time Kinematic Global Navigation Satellite System (RTK-GNSS) is currently the premier technique for achieving centimeter-level accuracy quickly and easily. However, robustness of RTK-GNSS diminishes in challenging environments due to severe multipath effects a limited number available GNSS signals. This pressing issue, especially users navigation industry. paper proposes evaluates several methodologies designed overcome these issues by enhancing availability reliability solutions urban...

Inertial navigation systems (INSs) provide autonomous position estimation capabilities independent of global satellite (GNSSs). However, the high cost traditional sensors, such as fiber-optic gyroscopes (FOGs), limits their widespread adoption. In contrast, micro-electromechanical system (MEMS)-based inertial measurement units (IMUs) offer a low-cost alternative; however, lower accuracy and sensor bias issues, particularly in maritime environments, remain considerable obstacles. This study...

Continuous and trustworthy positioning is a critical capability for advanced driver assistance systems (ADAS). To achieve continuous positioning, methods such as global navigation satellite real-time kinematic (RTK), Doppler-based using low-cost inertial measurement unit (IMU) with car speedometer data are combined in this study. ensure reliable the system should have integrity monitoring above certain level, 99%. Achieving level when combining different types of measurements that...

Instantaneous real-time kinematic (RTK) techniques are one approach to achieving high-accuracy positioning. The object of this paper is show the advantage adding velocity information instantaneous RTK In paper, from Doppler frequency measurements used help resolve integer ambiguities in LAMBDA method. urban areas, pseudorange can suffer significant errors due strong multipath, despite use advanced multipath-mitigation techniques. However, do not deteriorate as much pseudoranges, because...

The current GPS satellite constellation provides limited availability and reliability for a country like Japan where mountainous terrain urban canyons do not allow clear skyline to the horizon. At present, Japanese Quasi-Zenith Satellite System (QZSS) is under investigation through government-private sector cooperation. QZSS considered multi-mission system, as it able provide communication, broadcasting positioning services mobile users in specified region with high elevation angle....

Precise point positioning (PPP) is a high-precision global navigation satellite system (GNSS) technology. The convergence time to obtain sufficient accuracy from the start of and after have been actively studied as research problems in PPP. However, most these studies used archived correction data, discussions on how data are obtained broadcasts actual environment lacking owing low availability low-cost GNSS receivers capable receiving new signals. In this study, we evaluate an using...

In Japan, the PPP-RTK method of CLAS has been officially in operation since 2018, and our laboratory continued fixed-point evaluation on roof laboratory. We have also conducted long-term MADOCA-PPP, not only Japan but at seven universities overseas, mainly Asia. The MADOCA-PPP results were generally stable, with horizontal RMS accuracy less than 10 cm all countries. stable a FIX rate almost over 99% from 2018 to 2021. However, showed slight degradation performance as solar activity increased...

The current global positioning system (GPS) provides limited availability and capability for a country like Japan where mountainous terrain urban canyons do not allow clear skyline to the horizon. At present, Japanese Quasi-Zenith Satellite System (QZSS) is under investigation through cooperative effort between government private sector. QZSS considered multi-function satellite system, as it able provide communication, broadcasting, services mobile users in specified region with high...