The Global Positioning System Timothy S
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The Economic Impact of Bicycling in the Central Shenandoah Valley
THE ECONOMIC IMPACT OF BICYCLING IN THE CENTRAL SHENANDOAH VALLEY Bicycle tourism in the Central Shenandoah Valley region is estimated to have generated $8.6 million in sales activity in 2015. The total economic impact of bicycle tourism, including multiplier effects, is estimated to have been $13.6 million that supported 184 jobs in the region in 2015. August 12, 2016; Rev 1 THE ECONOMIC IMPACT OF BICYCLING IN THE CENTRAL SHENANDOAH VALLEY An estimate of the economic impact of bicycle-related tourism and business in the Central Shenandoah Valley Public-Private Sponsors of the Study City of Harrisonburg Rockingham County Shenandoah County Greater Augusta Regional Tourism (GART) representing Augusta County, City of Staunton, and City of Waynesboro Lexington & the Rockbridge Area Tourism representing Rockbridge County, City of Buena Vista, and City of Lexington Shenandoah Valley Bicycle Coalition (SVBC) Bryce Resort Massanutten Resort This report was prepared by the Central Shenandoah Planning District Commission with the assistance of the study sponsors and the Roanoke Valley-Alleghany Regional Commission. Bicycling in the Central Shenandoah Valley Economic Impact Analysis TABLE OF CONTENTS List of Figures ....................................................................................................................... 2 1 Executive Summary.......................................................................................................... 3 2 Background .................................................................................................................... -
GPS and GLONASS Vector Tracking for Navigation in Challenging Signal Environments
GPS and GLONASS Vector Tracking for Navigation in Challenging Signal Environments Tanner Watts, Scott Martin, and David Bevly GPS and Vehicle Dynamics Lab – Auburn University October 29, 2019 2 GPS Applications (GAVLAB) Truck Platooning Good GPS Signal Environment Autonomous Vehicles Precise Timing UAVs 3 Challenging Signal Environments • Navigation demand increasing in the following areas: • Cites/Urban Areas • Forests/Dense Canopies • Blockages (signal attenuation) • Reflections (multipath) 4 Contested Signal Environments • Signal environment may experience interference • Jamming . Transmits “noise” signals to receiver . Effectively blocks out GPS • Spoofing . Transmits fake GPS signals to receiver . Tricks or may control the receiver 5 Contested Signal Environments • These interference devices are becoming more accessible GPS Jammers GPS Simulators 6 Traditional GPS Receiver Signals processed individually: • Known as Scalar Tracking • Delay Lock Loop (DLL) for Code • Phase Lock Loop (PLL) for Carrier 7 Traditional GPS Receiver • Feedback loops fail in the presence of significant noise • Especially at high dynamics Attenuated or Distorted Satellite Signal 8 Vector Tracking Receiver • Process signals together through the navigation solution • Channels track each other’s signals together • 2-6 dB improvement • Requires scalar tracking initially 9 Vector Tracking Receiver Vector Delay Lock Loop (VDLL) • Code tracking coupled to position navigation • DLL discriminators inputted into estimator • Code frequencies commanded by predicted pseudoranges -
Comparing Four Methods of Correcting GPS Data: DGPS, WAAS, L-Band, and Postprocessing Dick Karsky, Project Leader
United States Department of Agriculture Engineering Forest Service Technology & Development Program July 2004 0471-2307–MTDC 2200/2300/2400/3400/5100/5300/5400/ 6700/7100 Comparing Four Methods of Correcting GPS Data: DGPS, WAAS, L-Band, and Postprocessing Dick Karsky, Project Leader he global positioning system (GPS) of satellites DGPS Beacon Corrections allows persons with standard GPS receivers to know where they are with an accuracy of 5 meters The U.S. Coast Guard has installed two control centers Tor so. When more precise locations are needed, and more than 60 beacon stations along the coastal errors (table 1) in GPS data must be corrected. A waterways and in the interior United States to transmit number of ways of correcting GPS data have been DGPS correction data that can improve GPS accuracy. developed. Some can correct the data in realtime The beacon stations use marine radio beacon fre- (differential GPS and the wide area augmentation quencies to transmit correction data to the remote GPS system). Others apply the corrections after the GPS receiver. The correction data typically provides 1- to data has been collected (postprocessing). 5-meter accuracy in real time. In theory, all methods of correction should yield similar In principle, this process is quite simple. A GPS receiver results. However, because of the location of different normally calculates its position by measuring the time it reference stations, and the equipment used at those takes for a signal from a satellite to reach its position. stations, the different methods do produce different Because the GPS receiver knows exactly where results. -
The Global Positioning System the Global Positioning System
The Global Positioning System The Global Positioning System 1. System Overview 2. Biases and Errors 3. Signal Structure and Observables 4. Absolute v. Relative Positioning 5. GPS Field Procedures 6. Ellipsoids, Datums and Coordinate Systems 7. Mission Planning I. System Overview ! GPS is a passive navigation and positioning system available worldwide 24 hours a day in all weather conditions developed and maintained by the Department of Defense ! The Global Positioning System consists of three segments: ! Space Segment ! Control Segment ! User Segment Space Segment Space Segment ! The current GPS constellation consists of 29 Block II/IIA/IIR/IIR-M satellites. The first Block II satellite was launched in February 1989. Control Segment User Segment How it Works II. Biases and Errors Biases GPS Error Sources • Satellite Dependent ? – Orbit representation ? Satellite Orbit Error Satellite Clock Error including 12 biases ? 9 3 Selective Availability 6 – Satellite clock model biases Ionospheric refraction • Station Dependent L2 L1 – Receiver clock biases – Station Coordinates Tropospheric Delay • Observation Multi- pathing Dependent – Ionospheric delay 12 9 3 – Tropospheric delay Receiver Clock Error 6 1000 – Carrier phase ambiguity Satellite Biases ! The satellite is not where the GPS broadcast message says it is. ! The satellite clocks are not perfectly synchronized with GPS time. Station Biases ! Receiver clock time differs from satellite clock time. ! Uncertainties in the coordinates of the station. ! Time transfer and orbital tracking. Observation Dependent Biases ! Those associated with signal propagation Errors ! Residual Biases ! Cycle Slips ! Multipath ! Antenna Phase Center Movement ! Random Observation Error Errors ! In addition to biases factors effecting position and/or time determined by GPS is dependant upon: ! The geometric strength of the satellite configuration being observed (DOP). -
GLONASS & GPS HW Designs
GLONASS & GPS HW designs Recommendations with u-blox 6 GPS receivers Application Note Abstract This document provides design recommendations for GLONASS & GPS HW designs with u-blox 6 module or chip designs. u-blox AG Zürcherstrasse 68 8800 Thalwil Switzerland www.u-blox.com Phone +41 44 722 7444 Fax +41 44 722 7447 [email protected] GLONASS & GPS HW designs - Application Note Document Information Title GLONASS & GPS HW designs Subtitle Recommendations with u-blox 6 GPS receivers Document type Application Note Document number GPS.G6-CS-10005 Document status Preliminary This document and the use of any information contained therein, is subject to the acceptance of the u-blox terms and conditions. They can be downloaded from www.u-blox.com. u-blox makes no warranties based on the accuracy or completeness of the contents of this document and reserves the right to make changes to specifications and product descriptions at any time without notice. u-blox reserves all rights to this document and the information contained herein. Reproduction, use or disclosure to third parties without express permission is strictly prohibited. Copyright © 2011, u-blox AG. ® u-blox is a registered trademark of u-blox Holding AG in the EU and other countries. GPS.G6-CS-10005 Page 2 of 16 GLONASS & GPS HW designs - Application Note Contents Contents .............................................................................................................................. 3 1 Introduction ................................................................................................................. -
Location Corrections Through Differential Networks (LOCD-IN)
Location Corrections through Differential Networks (LOCD-IN) A thesis presented to the faculty of the Russ College of Engineering and Technology of Ohio University In partial fulfillment of the requirements for the degree Master of Science Russell V. Gilabert December 2018 © 2018 Russell V. Gilabert. All Rights Reserved. 2 This thesis titled Location Corrections through Differential Networks (LOCD-IN) by RUSSELL V. GILABERT has been approved for the School of Electrical Engineering and Computer Science and the Russ College of Engineering and Technology by Maarten Uijt de Haag Edmund K. Cheng Professor of Electrical Engineering and Computer Science Dennis Irwin Dean, Russ College of Engineering and Technology 3 ABSTRACT GILABERT, RUSSELL V., M.S., December 2018, Electrical Engineering Location Corrections through Differential Networks (LOCD-IN) Director of Thesis: Maarten Uijt de Haag Many mobile devices (phones, tablets, smartwatches, etc.) have incorporated embedded GNSS receivers into their designs allowing for wide-spread on-demand positioning. These receivers are typically less capable than dedicated receivers and can have an error of 8-20m. However, future application, such as UAS package delivery, will require higher accuracy positioning. Recently, the raw GPS measurements from these receivers have been made accessible to developers on select mobile devices. This allows GPS augmentation techniques usually reserved for expensive precision-grade receivers to be applied to these low cost embedded receivers. This thesis will explore the effects of various GPS augmentation techniques on these receivers. 4 ACKNOWLEDGMENTS I would like to thank my academic advisor, Maarten Uijt de Haag, for providing guidance and opportunities in both my academic and professional careers. -
AEN-88: the Global Positioning System
AEN-88 The Global Positioning System Tim Stombaugh, Doug McLaren, and Ben Koostra Introduction cies. The civilian access (C/A) code is transmitted on L1 and is The Global Positioning System (GPS) is quickly becoming freely available to any user. The precise (P) code is transmitted part of the fabric of everyday life. Beyond recreational activities on L1 and L2. This code is scrambled and can be used only by such as boating and backpacking, GPS receivers are becoming a the U.S. military and other authorized users. very important tool to such industries as agriculture, transporta- tion, and surveying. Very soon, every cell phone will incorporate Using Triangulation GPS technology to aid fi rst responders in answering emergency To calculate a position, a GPS receiver uses a principle called calls. triangulation. Triangulation is a method for determining a posi- GPS is a satellite-based radio navigation system. Users any- tion based on the distance from other points or objects that have where on the surface of the earth (or in space around the earth) known locations. In the case of GPS, the location of each satellite with a GPS receiver can determine their geographic position is accurately known. A GPS receiver measures its distance from in latitude (north-south), longitude (east-west), and elevation. each satellite in view above the horizon. Latitude and longitude are usually given in units of degrees To illustrate the concept of triangulation, consider one satel- (sometimes delineated to degrees, minutes, and seconds); eleva- lite that is at a precisely known location (Figure 1). If a GPS tion is usually given in distance units above a reference such as receiver can determine its distance from that satellite, it will have mean sea level or the geoid, which is a model of the shape of the narrowed its location to somewhere on a sphere that distance earth. -
Travel Information Southwest Backpacking & Rock Climbing Outdoor Educator – 55 Days Course Number: CUQR-161 // 2.28.21 –
Travel Information Southwest Backpacking & Rock Climbing Outdoor Educator – 55 Days Course Number: CUQR-161 // 2.28.21 – 4.23.21 WHAT TO EXPECT FOR COURSE START MEETING PLACE & TIME 11:00am – 1:00pm MDT COBS Leadville Mountain Center 1930 Hwy 300 Leadville, CO 80461 Your course begins at Colorado Outward Bound School’s basecamp in Leadville, Colorado. This document includes helpful driving directions from the town of Leadville and a map of the campus below. We are requiring all students and families to drive themselves to course start, rather than traveling via public transportation such as plane, bus, or train. When you arrive, our staff will greet you in the lower parking lot wearing Colorado Outward Bound School T-shirts so they can be easily identified. Students can be provided with a lunch at 12:00pm. Due to procedures related to COVID-19, we cannot offer lunch to those dropping students off. If you are a student driving yourself, you will have secure parking on our basecamp for the entirety of your course. Because the course begins promptly at 1:00pm, everyone will need to finish eating by 1:00pm. Please arrive by 1:00pm so that our group can begin course activities as scheduled. Also, please make sure that your enrollment has been approved by your Course Advisor; students whose approval is unconfirmed cannot participate on the course. When you arrive please wear your mask. Staff will be doing health / symptom checks at course start to make sure everyone is healthy. Please be prepared to report any symptoms or exposures to staff. -
Orienteering at Brighton Woods
ORIENTEERING AT BRIGHTON WOODS • There are eight numbered posts (controls) for the orienteering course at Brighton Woods. Each has a number that corresponds to the number on the Brighton Woods Orienteering Map, but they may be found in any order. • It is easier to go directly from control to control when there is less ground cover: late fall, winter, and early spring. Long pants are recommended because of the poison ivy and ticks. 1. NUMBERED CONTROL DESCRIPTIONS 1. Sports Field 2. Southwest End of Pipeline Clearing 3. Amphitheater 4. The Bridge 5. Head of Trail 6. Rock Outcropping 7. River 8. Northeast End of Pipeline Clearing 2. PLOTTING THE COURSE • Find control #1 on the map.(The Sports Field.) • On the map, line up one edge of the compass from where you are (Control #1: Sports Field) to where you want to go, (Control # 2: Southwest End of Pipeline Clearing) making sure the direction-of-travel arrow faces your destination point. (This is the first secret of orienteering.) • Rotate the housing of the compassso that the gridlines are parallel to the North - South gridlines on the orienteering map. The cardinal point N must be at the North side of your map. (This is the second secret to orienteering.) • Readyour bearing in degrees at the Bearing Index. (At the Direction-of- Travel line, or the "Read Bearing Here" mark.) The number of degrees is * • Do not rotate the housing again until you need a new bearing! 3. FINDING THE FIXED CONTROLS • Stand directly in front of the control #1 and hold your compass level and squarely in front of your body. -
And Dual-Frequency GPS and GLONASS Observations on Point Accuracy Under Forest Canopies
Effects of Differential Single- and Dual-Frequency GPS and GLONASS Observations on Point Accuracy under Forest Canopies Erlk Naesset Deckert and Bolstad (1996) and Sigrist et al. (1999) reported A 20-channel, dual-frequency receiver observing dual-fie- accuracies of approximately 3.1 to 4.4 m and 1.8 to 2.5 m for the quency pseudorange and carrier phase of both GPS and average position of 500 and 480 repeated measurements of indi- GLONASS was used to determine the positional accuracy of 29 vidual points under tree canopies, respectively, based on differ- points under tree canopies. The mean positional accuracy ential pseudorange. Nsesset (1999)found that, even under tree based on differential postprocessing of GPS+GLONASS single- canopies, carrier phase observations represent valuable addi- frequency observations ranged from 0.16 m to 1.I 6 m for 2.5 tional information as compared to traditional pseudorange min to 20 min of observation at points with basal area ranging acquisition. By using both single-frequency pseudorange and from <20 m2/ha to 230 m2/ha. The mean positional accuracy carrier phase observations in an adjustment with coordinates of differential postprocessing of dual-frequency GPS+GLONASS and carrier phase ambiguities as unknown parameters (float observations ranged from 0.08 m to 1.35 m. Using the dual- solution), an accuracy of 0.8 m was reported for two 12-chan- frequency carrier phase as main observable and fixing the nel receivers based on 30 min of observation. The correspond- initial integer phase ambiguities, i.e., a fixed solution, gave ing accuracy using pseudorange only was 1.2 to 1.9 m. -
Introduction to Backcountry Hiking
National Park Service U.S. Department of the Interior Grand Canyon National Park Grand Canyon, Arizona Hiking Into Grand Canyon Plan Ahead limits, and avoid spontaneity—Grand Canyon is an extreme Whether a day or overnight trip, hiking into Grand Canyon on environment and overexertion affects everybody at some point. the Bright Angel, North Kaibab, or South Kaibab trails gives an unparalleled experience that changes your perspective. Stay together, follow your plan, and know where you can call 911 with emergencies. Turning around may be your best decision. Knowledge, preparation, and a good plan are your keys to For information about Leave No Trace strategies, hiking tips, success. Be honest about your health and fitness, know your closures, roads, trails, and permits, visit go.nps.gov/grca- backcountry. Warning While Hiking BALANCE FOOD AND WATER Hiking to the river and back in one • Do not force fluids. Drink water when day is not recommended due to you are thirsty, and stop when you are long distance, extreme temperature quenched. Over-hydration may lead to a changes, and an approximately 5,000- life-threatening electrolyte disorder called foot (1,500 m) elevation change each hyponatremia. way. RESTORE YOUR ENERGY If you think you have the fitness and • Eat double your normal intake of expertise to attempt this extremely carbohydrates and salty foods. Calories strenuous hike, please seek the advice play an important role in regulating body of a park ranger at the Backcountry temperature, and hiking suppresses your Information Center. appetite. TAKE CARE OF YOUR BODY Know how to rescue yourself. -
The Global Positioning System II Field Experiments
The Global Positioning System II Field Experiments Geo327G/386G: GIS & GPS Applications in Earth Sciences Jackson School of Geosciences, University of Texas at Austin 10/8/2020 5-1 Mexico DGPS Field Campaign Cenotes in Tamaulipas, MX, near Aldama Geo327G/386G: GIS & GPS Applications in Earth Sciences 10/8/2020 Jackson School of Geosciences, University of Texas at Austin 5-2 Are Cenote Water Levels Related? Geo327G/386G: GIS & GPS Applications in Earth Sciences 10/8/2020 Jackson School of Geosciences, University of Texas at Austin 5-3 DGPS Static Survey of Cenote Water Levels Geo327G/386G: GIS & GPS Applications in Earth Sciences 10/8/2020 Jackson School of Geosciences, University of Texas at Austin 5-4 Determining Orthometric Heights ❑Ortho. Height = H.A.E. – Geoid Height Height above MSL (Orthometric height) H.A.E. Geoid height Earth Surface = H.A.E. Geoid Ellipsoid Geoid Height Geo327G/386G: GIS & GPS Applications in Earth Sciences 10/8/2020 Jackson School of Geosciences, University of Texas at Austin 5-5 Determining Orthometric Heights ❑Ortho. Height = (H.A.E. – Geoid Height) Need: 1) Ellipsoid model – GRS80 – NAVD88 ❑reference stations: HARN (+ 2 cm), CORS (+ ~2 cm) 2) Geoid model – GEOID99 ( + 5 cm for US) Procedure: Base receiver at reference station, rover at point of interest a) measure HAE, apply DGS corrections b) subtract local Geoid Height Geo327G/386G: GIS & GPS Applications in Earth Sciences 10/8/2020 Jackson School of Geosciences, University of Texas at Austin 5-6 Sources of Error ❑Geoid error – model less well constrained in areas of few gravity measurement ❑NAVD88 error – benchmark stability, measurement errors ❑GPS errors – need precise ephemeri, tropospheric delay model, equipment (antennae should be same for base and rover) Geo327G/386G: GIS & GPS Applications in Earth Sciences 10/8/2020 Jackson School of Geosciences, University of Texas at Austin 5-7 Static Carrier-phase solutions obtained by: ❑Commercial post-processing software ❑e.g.