Position information of individual nodes is useful in implementing functions such as routing and querying in ad-hoc networks. Deriving position information by using the capability of the nodes to measure time of arrival (TOA), time difference of arrival (TDOA), angle of arrival (AOA) and signal strength have been used to localize nodes relative to a frame of reference. The nodes in an ad-hoc network can have multiple capabilities and exploiting one or more of the capabilities can improve the quality of positioning. In this paper, we show how AOA capability of the nodes can be used to derive position information. We propose a method for all nodes to determine their orientation and position in an ad-hoc network where only a fraction of the nodes have positioning capabilities, under the assumption that each node has the AOA capability.

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Ad hoc positioning system (APS) using AOA

The Global Positioning System (GPS) is a satellite-based navigation and time transfer system developed by the U.S. Department of Defense. It serves marine, airborne, and terrestrial users, both military and civilian. Specifically, GPS includes the Standard Positioning Service (SPS) which provides civilian users with 100 meter accuracy, and it serves military users with the Precise Positioning Service (PPS) which provides 20-m accuracy. Both of these services are available worldwide with no requirement for a local reference station. In contrast, differential operation of GPS provides 2- to 10-m accuracy to users within 1000 km of a fixed GPS reference receiver. Finally, carrier phase comparisons can be used to provide centimeter accuracy to users within 10 km and potentially within 100 km of a reference receiver. This advanced tutorial will describe the GPS signals, the various measurements made by the GPS receivers, and estimate the achievable accuracies. It will not dwell on those aspects of GPS which are well known to those skilled in the radio communications art, such as spread-spectrum or code division multiple access. Rather, it will focus on topics which are more unique to radio navigation or GPS. These include code-carrier divergence, codeless tracking, carrier aiding, and narrow correlator spacing.

Global Positioning System: Signals, Measurements, and Performance

We present a new approach to remote sensing of water vapor based on the global positioning system (GPS). Geodesists and geophysicists have devised methods for estimating the extent to which signals propagating from GPS satellites to ground-based GPS receivers are delayed by atmospheric water vapor. This delay is parameterized in terms of a time-varying zenith wet delay (ZWD) which is retrieved by stochastic filtering of the GPS data. Given surface temperature and pressure readings at the GPS receiver, the retrieved ZWD can be transformed with very little additional uncertainty into an estimate of the integrated water vapor (IWV) overlying that receiver. Networks of continuously operating GPS receivers are being constructed by geodesists, geophysicists, government and military agencies, and others in order to implement a wide range of positioning capabilities. These emerging GPS networks offer the possibility of observing the horizontal distribution of IWV or, equivalently, precipitable water with unprecedented coverage and a temporal resolution of the order of 10 min. These measurements could be utilized in operational weather forecasting and in fundamental research into atmospheric storm systems, the hydrologic cycle, atmospheric chemistry, and global climate change. Specially designed, dense GPS networks could be used to sense the vertical distribution of water vapor in their immediate vicinity. Data from ground-based GPS networks could be analyzed in concert with observations of GPS satellite occultations by GPS receivers in low Earth orbit to characterize the atmosphere at planetary scale.

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GPS Meteorology: Remote Sensing of Atmospheric Water Vapor Using the Global Positioning System

Many ad hoc network protocols and applications assume the knowledge of geographic location of nodes. The absolute location of each networked node is an assumed fact by most sensor networks which can then present the sensed information on a geographical map. Finding location without the aid of GPS in each node of an ad hoc network is important in cases where GPS is either not accessible, or not practical to use due to power, form factor or line of sight conditions. Location would also enable routing in sufficiently isotropic large networks, without the use of large routing tables. We are proposing APS - a distributed, hop by hop positioning algorithm, that works as an extension of both distance vector routing and GPS positioning in order to provide approximate location for all nodes in a network where only a limited fraction of nodes have self location capability.

/pdf/ad-hoc-positioning-system-aps-3roowtu3q3.pdf

Ad hoc positioning system (APS)

Many ad hoc network protocols and applications assume the knowledge of geographic location of nodes. The absolute position of each networked node is an assumed fact by most sensor networks which can then present the sensed information on a geographical map. Finding position without the aid of GPS in each node of an ad hoc network is important in cases where GPS is either not accessible, or not practical to use due to power, form factor or line of sight conditions. Position would also enable routing in sufficiently isotropic large networks, without the use of large routing tables. We are proposing APS --- a localized, distributed, hop by hop positioning algorithm, that works as an extension of both distance vector routing and GPS positioning in order to provide approximate position for all nodes in a network where only a limited fraction of nodes have self positioning capability.

/pdf/dv-based-positioning-in-ad-hoc-networks-12d026gqcv.pdf

DV Based Positioning in Ad Hoc Networks

Differential GPS and Integrity Monitoring Differential GPS Pseudolites Wide Area Differential GPS Wide Area Augmentation System Receiver Autonomous Integrity Monitoring Integrated Navigation Systems Integration of GPS and Loran-C GPS and Inertial Integration Receiver Autonomous Integrity Monitoring Availability for GPS Augmented with Barometric Altimeter Aiding and Clock Coasting GPS and Global Navigation Satellite System (GLONASS) GPS Navigation Applications Land Vehicle Navigation and Tracking Marine Applications Applications of the GPS to Air Traffic Control GPS Applications in General Aviation Aircraft Automatic Approach and Landing Using GPS Precision Landing of Aircraft Using Integrity Beacons Spacecraft Attitude Control Using GPS Carrier Phase Special Applications GPS for Precise Time and Time Interval Measurement Surveying with the Global Position System Attitude Determination Geodesy Orbit Determination Test Range Instrumentation.

Global positioning system : theory and applications

Volume I: GPS Fundamentals Introduction and Heritage and History of NAVSTAR, the Global Positioning System Overview of the GPS Operation and Design GPS Signal Structure and Theoretical Performance GPS Navigation Data Satellite Constellation and Geometric Dilution of Precision GPS Satellite and Payload Fundamentals of Signal Tracking Theory GPS Receivers GPS Navigation Algorithms GPS Operational Control Segment GPS Performance and Error Effects GPS Error Analysis Ionospheric Effects on GPS Tropospheric Effects on GPS Multipath Effects Foliage Attenuation for Land Mobile Users Ephermeris and Clock Navigation Message Accuracy Selective Availability Introduction to Relativistic Effects on the Global Position System Joint Program Office Test Results Interference Effects and Mitigation Techniques

Global Positioning System: Theory and Applications, Volume II

Details of the gps signal structure are discussed as relates to the signal generation and the performance of the navigation system. GPS performance objectives, orbit geometry, and propagation effects are summarized in order to gain better understanding of the signal and what characteristics it must provide. With these performance objectives as a preface, the details of the signal are described, showing the details of the dual frequency transmission and both the precision P and clear/acquisition C/A codes and their characteristics. Finally, the basic performance of simplified receivers operating on this received signal is discussed. It is shown that an rms position error of less than 10 meters is well within the achievable performance bounds of the system.

GPS Signal Structure and Performance Characteristics

A method, apparatus, and computer-readable media for determining the position of a user terminal comprises receiving at the user terminal a broadcast television signal from a television signal transmitter; determining a first pseudo-range between the user terminal and the television signal transmitter based on a known component of the broadcast television signal; receiving at the user terminal a mobile telephone signal from a mobile telephone base station; determining a second pseudo-range between the user terminal and the mobile telephone base station based on a known component of the mobile telephone signal; and determining a position of the user terminal based on the first and second pseudo-ranges, a location of the television signal transmitter, and a location of the mobile telephone base station; wherein the mobile telephone signal is selected from the group consisting of a EDGE (Enhanced Data Rates for Global System for Mobile Communications (GSM) Evolution) signal; a Code-Division Multiple Access 2000 (cdma2000) signal; and a Wideband Code-Division Multiple Access (WCDMA) signal.

Position location using broadcast television signals and mobile telephone signals

An apparatus and method for determining the position of a user terminal comprise an antenna subsystem which is able to receive signals of GPS and TV, a receiver front end which converts the frequency of the incident signals and filters out unwanted signals so that the desired signals can be sampled, a digital processing component which accommodates the imperfections of the front end and converts the measured signals into a position information The apparatus is capable of receiving at the user terminal, broadcast television signals from television signal transmitters; determining a first set of pseudo-ranges between the user terminal and the television signal transmitters based on a known component of the broadcast television signals; receiving at the user terminal global positioning signals from a global positioning satellites; determining a second set of pseudo-ranges between the user terminal and the global positioning satellites based on the global positioning signals; and determining a position of the user terminal based on the first and second sets of pseudo-ranges, locations of the television signal transmitters, and locations of the global positioning satellites

James J. Spilker

Papers

Global positioning system : theory and applications

Global Positioning System: Theory and Applications, Volume II

GPS Signal Structure and Performance Characteristics

Position location using broadcast television signals and mobile telephone signals

Radio frequency device for receiving TV signals and GPS satellite signals and performing positioning