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In emergency situations, first responders must possess the means to communicate vital information, such as the number of patients requiring immediate medical attention, -and their precise locations, as quickly and efficiently as possible, to fire and rescue-, and police departments, as well as city officials. For these situations, we developed a mobile terminal incorporating a GPS, as well as an RFID...
In order to solve the problem of cooperative issue in single frequency network (SFN) positioning system, in this paper, a cooperative positioning scheme using the fundamental characteristic of SFN is proposed. Some different signal levels are described for cooperative signal selection. According to the difference between the cooperative signal levels, the proper signal can be selected for cooperative...
This paper studies the wireless positioning method using digital TV (DTV) signals with orthogonal frequency division multiplex (OFDM) modulation. A novel pseudo range estimation method is proposed, which utilizes the synchronization modules in the data demodulation as the signal acquisition for the coarse time delay estimation and introduces a data-directed delay tracking mechanism for the fine time...
The novel pulses, which not only meet the power spectral mask of the Federal Communications Commission(FCC) and IEEE 802.15.4a standard constraint but also preserve the orthogonality at the receiver, have been proposed by Kim et. al. for practical usage of Ultra-wideband (UWB) system. This paper analyzes the performance of proposed pulses with regards important conditions in UWB system, such as the...
In this paper, we analyze the performance of time delay estimation with regards to different pulse shape in UWB indoor navigation. For the performance of time delay estimation, the Cramer-Rao Lower Bound (CRLB) criterion is used and the performance is analyzed under various criteria of pulse shape, such as pulse period, order of differentiation, and the effective pulse width. Moreover, the reasonability...
The Finnish Geodetic Institute (FGI) is building a new multi-satellite GNSS network in Finland. The renewal of the old GPS-only network FinnRef is funded by the Ministry of Agriculture and Forestry. The new network will consist of 19 stations collecting data from GPS, Glonass, Galileo and later also from Compass satellites. The network stations will be build on stable bedrock sites, equipped with...
An algorithm to convert a GNSS satellite track segment into the generalised Kepler parameter format used in GPS ephemerides messages is presented. A track segment is a sequence of 3D positions in Cartesian coordinates, such as is produced by orbit prediction software for self-assistance, where the format conversion is an essential post-processing step to reduce storage and for compatibility with GPS...
A novel approach for monitoring the accuracy of the Bayesian estimate of linear Gaussian state-space model is introduced, based on the monitoring of the propagation of the errors in the Kalman filter algorithm. The effect of the sensor errors on the Kalman filter estimate is explicitly computed and compensated. A marginalized particle filter is used to compute the posterior distribution of the sensor...
In DVB-T Single Frequency Networks (SFN) different emitters simultaneously transmit the same signal on the same frequency. These signals can be used for positioning, or to integrate GNSS in hostile environments, but SFN characteristics may induce a path ambiguity problem. This paper demonstrates two solutions for solving this problem: pseudorange comparison and Doppler aiding decision. Both methods...
Laser scanners are widely used with mobile robots for simultaneous localization and mapping. The laser data can be used to build a dense map or a feature based map, where the features are extracted from laser scanner (LIDAR) data. On the other hand, diverse approaches exist, which use one or several cameras to extract features from the environment. In this paper, an approach to combine these sensors...
The University of Nottingham has purchased a set of more than 20 Ultra Wideband (UWB) sensors from Thales (UK) to enhance its ubiquitous positioning and navigation capacity. A scalable indoor testing facility has been set up recently and one of these testing scenarios consists of 8 fixed base stations and a few rover units onboard the moving objects, to simulate different applications. Two tests that...
Errors in gyroscope measurements due to linear accelerations are often overlooked in foot mounted navigation systems. Accelerations of foot mounted IMUs can reach 5 g while walking and 10 g while running, but vary depending on the sensors location and mounting. These accelerations are often very short and can induce large biases in the gyro which can produce attitude errors when the measurements are...
A severe drawback of using RF (Radio Frequency) Fingerprinting for indoor localization is the laborious effort to calibrate the radio map. Especially in case of environmental changes recalibration becomes necessary. The approach of our research project WIPoS (Wireless Indoor Positioning System) is to solve this problem by appropriate RF engineering and optimized methods. In former publications it...
An increasing number of WiFi and Bluetooth terminals, tags, and other mobile devices drives a growing demand for integration and coexistence of these two technologies. This paper gives the preliminary results of WiFi positioning in a WiFi and Bluetooth coexistence environment. The received signal strength indication is introduced as an observation applied to our WiFi positioning. Then, we present...
Positioning systems have gained importance in situations where various location-based services have been installed. Although the combination of Wi-Fi positioning with inertial navigation is considered to be accurate for indoor use, it is important to avoid increasing the error when using estimated positions for location-based services. In this paper, we propose a positioning system that combines several...
We design and simulate an improved wideband chaotic Colpitts oscillator based on micro-strip technology. The numerical and circuit simulation results are presented in order to verify the performance of the developed oscillator. In addition, we propose the synchronization model between two identical improved chaotic Colpitts oscillators coupled by a resistor. The chaotic synchronization, one of the...
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