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Roadway grades have a diverse effect on vehicle speeds, depending on vehicle and roadway characteristics. For example, passenger cars can generally negotiate grades of 5 percent or less without considerable reductions in vehicle speeds, while heavy-duty trucks are affected significantly by grades because of their inferior operating capability. Consequently, due to the potential significant speed differential between automobiles and heavy-duty trucks, these trucks can have a significant impact on the quality of flow, throughput, and safety of a traffic stream. Truck climbing lanes are typically constructed in an attempt to lessen this negative impact. Currently, the American Association of State Highway and Transportation Officials (AASHTO) and Highway Capacity Manual (HCM) represent the state-of-art and state-of-practice procedures for the design of truck climbing lanes. These procedures only consider the tangent vertical profile grades in the design of climbing lanes and do not capture the impact of vertical curvature on truck performance. The dissertation describes the TruckSIM framework for modeling vehicle motion along roadway sections by considering both the longitudinal and lateral forces acting on a vehicle. In doing so, the tool reflects the impact of horizontal and vertical alignment on a vehicle's longitudinal motion. The model is capable of reading Global Positioning System (GPS) (longitude, latitude, and altitude), roadway, and vehicle data. The dissertation demonstrates the validity of the software modeling procedures against field data and the HCM procedures. It is anticipated that by automating the design procedures and considering different vehicle and roadway characteristics on truck motion, the TruckSIM software will be of considerable assistance to traffic engineers in the design of roadways. The Global Positioning System (GPS) was originally built by the U.S. Department of Defense to provide the military with a super-precise form of worldwide positioning. With time, GPS units were introduced into the civilian domain and provided transportation professionals with an opportunity to capitalize on this unique instrumentation. With this GPS capability, this research investigates the feasibility of using inexpensive WAAS-capable units to estimate roadway vertical and horizontal profiles. The profiles that are generated by these inexpensive units (less than $500) are compared to the profiles generated by expensive carrier-phase DGPS units ($30,000 per unit including the base station). The results of this study demonstrate that the use of data smoothing and stacking techniques with the WAAS data provides grade estimates that are accurate within 10% of those generated by the carrier-phase DGPS units and thus offer a cost effective tool for providing input data to the TruckSIM software. Using the TruckSIM software, this research effort investigates truck performance reflective of various truck and road characteristics. These characteristics include vehicle engine power, weight-to-power ratio, pavement type, pavement condition, aerodynamic aid features, engine efficiency, tire type, and percentage mass on tractive axle. The study demonstrates that the vehicle weight-to-power ratio, vehicle engine power, pavement surface condition, tire type, aerodynamic aids, and engine efficiency are critical factors in the design of truck climbing lanes. / Ph. D.

A number of tests were conducted to determine the realizable accuracies of the Global Positioning System for natural resource conditions. The effects of terrain, forest canopy, number of consecutive position fixes, and PDOP on accuracy were evaluated. Position accuracies were determined for a total of 27 sites: three replicate sites selected for each of nine distinct conditions: three canopy (deciduous, coniferous, open) and three terrain (ridge, slope, valley) in all possible combinations. Each site was visited ten times over a span of eight months to collect position data, for ten replicates of 60, 100, 200, 300, and 500 position fixes. The mean differentially corrected positional accuracy for all sites was 4.35 meters with 95 percent of the positions estimated within 10.2 meters of the true value. The least accurate differential position data were observed at coniferous sites. Positional accuracy was higher for deciduous sites and the most accurate differential position data was collected at open sites. Accuracy increased with increasing number of position fixes. When the number of position fixes increased from 60 to 500, mean accuracy increased 46.7% at deciduous sites, 32.8% at coniferous sites, and 44.5% at open sites. The average time required by the GPS receiver to lock onto four satellites and begin collecting positions varied from one to two minutes. The most time was spent collecting position fixes at coniferous sites. No correlation was found between accuracy and the receiver's distance from the base-station. Nine replicates of 300 position fixes were averaged for six sites, which ranged from 43 kilometers to 247 kilometers from a Virginia Tech base-station. Mean accuracy ranged from 1.48 meters to 2.43 meters. GPS position data were evaluated for ease of conversion to GIS formats. Conversion was accomplished without problems. / Master of Science

This dissertation describes a novel method of providing position-location from geosynchronous communication satellites. The Global Positioning System (GPS) has become the standard for position-location and navigation in the world. It provides extremely accurate coordinates to military users and slightly less accurate coordinates to "non-authorized" users. Disadvantages of GPS are complexity and high cost. The U.S. Department of Defense (DoD) has spent billions of dollars in developing and fielding the system. Maintenance and GPS satellite replenishment costs will continue to climb. A simpler, lower cost alternative to the GPS system is explored. This study describes a position-location system using transponders on-board geosynchronous communication satellites. The system uses three geosynchronous communication satellites at a time to relay synchronized television signals. The signals provide a timing system to measure the ranges from the satellites to the receiver. The least squares method is used to calculate the location of the receiver. A software model is developed to demonstrate the ability of the system to "track" three geosynchronous satellites and calculate receiver position. A test is conducted to demonstrate the use of television signals to provide timing for the system. The basic model is further refined by adding perturbation forces which act on the satellites. The Intelsat Eleven-Parameter algorithm is incorporated into the systenl model and provided the most precise location of the satellites. The accuracy of the proposed system in determining the position-location of the receiver is estimated based on the results of the simulation and the test. Further research is proposed to build on the concepts discussed in this dissertation. / Ph. D.

M. Tech. (Department of Information Technology, Faculty of Applied and Computer Sciences), Vaal University of Technology. / Tracking involves information gathering, manipulation and proving information on the location of a set item. Many single or hybrid technologies – Global Positioning System (GPS), Radio Frequency (RF), Bluetooth (BLT) or Wireless Fidelity (WiFi) – have been used to provide tracking information of an asset of interest. The use of hybrid technology in tracking assets has proven to be effective if the selection of the technologies used is done correctly. This study used a hybrid of GPS and Radio Frequency technologies to track assets of interest because of their characteristics for use inside and outside a building. In this study GPS geo-fencing was used and time interval was used to receive data from the technology. Heuristic methodology, which enabled us to divide a room into sections, was used, where testing was done in sections in a room with different types of material, such as bricks, wood or metal, and the RF signal degradation, called attenuation, was measured. A straight-line distance and a sum of distances at 30-minute intervals were calculated to determine how far the asset had travelled from the point of origin to the new position. A distance of less than 10 metres was ignored. Geofencing was used to trigger an event since it indicates that the asset has crossed the permitted boundary. An RF reader was placed at the door to identify when the asset left a building and triggered an event. A model was used for searching for a missing item in a room. The results showed that the system was able to produce two distances, one straight-line distance and the other the approximate sum distance travelled by the asset in 30-minute intervals. The RF model was able to find an asset in a room filled with different materials.

International Telemetering Conference Proceedings / October 20-23, 2003 / Riviera Hotel and Convention Center, Las Vegas, Nevada / This paper describes the development of a compact mobile telemetry system using commercial-off-the-shelf components. The personal computer-based systems support microwave pulse code modulation and serial spread-spectrum radio modem telemetry. The mobile ground station provides data display and archiving of test activities, air-ground communications between experimenters and the flight test crew, and acts as a flight test Differential Global Positioning System base station. The success of the systems indicates that functional telemetry capabilities can be established for small flight test programs at modest cost.

International Telemetering Conference Proceedings / October 20-23, 2003 / Riviera Hotel and Convention Center, Las Vegas, Nevada / Global Positioning System (GPS) was analyzed in terms of its repeatable accuracy, UTM projection for 2D plane coordinate system, satellite visibility performance and the horizontal dilution of positioning (HDOP). The principle of Dead Reckoning together with body coordinate system transformation was introduced. The complementary performance of GPS and DR, and GPS/DR integration using gyroscope and accelerometer were given. Test results were demonstrated that the repeatable accuracy of GPS alone is about 10 meters in open air, and DR can provide continuous positioning output within sufficient accuracy when GPS signal is outage.

ITC/USA 2007 Conference Proceedings / The Forty-Third Annual International Telemetering Conference and Technical Exhibition / October 22-25, 2007 / Riviera Hotel & Convention Center, Las Vegas, Nevada / This paper baselines the performance of common, single band telemetry blade antennas in two telemetry bands and compares that performance to two very differing multi-band antenna designs. A description of each antenna is presented followed by flight testing results and conclusions. Results are in the form of received signal strength versus geographic location, derived in-flight antenna patterns, link availability, and bit error analysis.

International Telemetering Conference Proceedings / October 26-29, 1998 / Town & Country Resort Hotel and Convention Center, San Diego, California / Communications support for the X-33 requires addressing several unique challenges to meet program and range safety requirements. As an avenue to minimize costs, the program has reduced requirements to the communications system, which lowered the cost of networking the extended range. Cost trade-offs showed that by lowering the telemetry data rate from 2 Megabits per second to 1.440 Megabits per second that significant cost avoidance could be realized. Also, by adopting standard telecommunications data rate for the uplink data stream, an efficient and integrated solution for the extended range communications could be supported. Meeting the program requirements as well as range safety requirements for this effort are critical to the success of the program. This paper describes some of the important requirements driving the design of the extended range communications support and the design of the system to meet those requirements.

International Telemetering Conference Proceedings / October 20-23, 2003 / Riviera Hotel and Convention Center, Las Vegas, Nevada / The intelligent vehicle navigation system is a multifunctional and complex integrated system that uses autonomous vehicle navigation, geography information, database system, computer technology, multimedia technology and wireless communication. In this paper, an autonomous navigation system based on embedded hardware and embedded operation system that is Linux is proposed. The system has advantages of low cost, small mass, multifunction and high stability, especially connecting with Internet.