For pt.I see ibid., vol.80, no.4, p.520-38 (1992). The concept of instantaneous frequency (IF) is extended to discrete-time signals. The specific problem explored is that of estimating the IF of frequency-modulated (FM) discrete-time signals embedded in Gaussian noise. Well-established methods for estimating the IF include differentiation of the phase and smoothing thereof, adaptive frequency estimation techniques such as the phase locked loop (PLL), and extraction of the peak from time-varying spectral representations. More recently, methods based on a modeling of the signal phase as a polynomial have been introduced. These methods are reviewed, and their performance compared on both simulated and real data. Guidelines are given as to which estimation method should be used for a given signal class and signal-to-noise ratio (SNR). >

Estimating and Interpreting The Instantaneous Frequency of a Signal

A location reporting paging communication system comprising space satellites, ground stations and a remote receiving unit adapted to resolve a global position from signals transmitted from a communication transmitter. The subscriber in possession of the remote receiving unit updates the paging network with global positioning information. A caller paging a subscriber in possession of the remote receiving unit may request the global location of the remote receiving unit. The paging network could divulge or block such information from a caller depending on the requirements of the subscriber.

Location reporting satellite paging system with optional blocking of location reporting

A system for communicating with a medical device (10) implanted in an ambulatory patient and for locating the patient in order to selectively monitor device function, alter device operating parameters and modes and provide emergency assistance to and communications with a patient (10). The implanted device (10) includes a telemetry transceiver for communicating data and operating instructions between the implanted device and an external patient communications control device (20) that is either worn by or located in proximity of the patient within the implanted device transceiving range. The control device preferably includes a communication link with a remote medical support network (50), a global positioning satellite (80) receiver for receiving positioning data identifying the global position of the control device, and a patient activated link for permitting patient initiated personal communication with the medical support network (50). A system controller (24) in the control device (20) controls data and voice communications for selectively transmitting patient initiated personal communications and global positioning data to the medical support network (50), and for receiving and initiating re-programming of the implanted device operating modes and parameters in response to instructions received from the medical support network (50). The communications link between the medical support network and the patient communications control device may comprise a worldwide satellite network, hard-wired telephone network, a cellular telephone network (82) or other personal communications system.

Worldwide patient location and data telemetry system for implantable medical devices

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Estimating and interpreting the instantaneous frequency of a signal. II. Algorithms and applications

A location system for commercial wireless telecommunication infrastructures (CMRRs). The system is an end-to-end solution having one or more location systems ( 42 ) for outputting requested locations of commercially available hand sets or mobile stations (not shown) based on, e.g. AMPS, NAMPS, CDMA or TDMA communication standards, for processing both local mobile station location requests and more global mobile station location requests via, e.g., Internet communication between a distributed network of location systems. The system uses a plurality of mobile station locating technologies including those based on: two-way TOA and TDOA; home base stations and distributed antenna provisioning. Further, the system can be modularly configured for use in location signaling environments ranging from urban, dense urban, suburban, rural, mountain to low traffic or isolated roadways. Accordingly, the system is useful for 911 emergency calls, tracking, routing, people and animal location including applications for confinement to and from certain areas.

Location of a mobile station using a plurality of commercial wireless infrastructures

The discrete polynomial-phase transform (DPT) is a new tool for analyzing constant-amplitude polynomial-phase signals. The main properties of the DPT are its ability to identify the degree of the phase polynomial and to estimate its coefficients. The transform is robust to deviations from the ideal signal model, such as slowly-varying amplitude, additive noise and nonpolynomial phase. The authors define the DPT, derive its basic properties, and use it to develop computationally efficient estimation and detection algorithms. A statistical accuracy analysis of the estimated parameters is also presented. >

The discrete polynomial-phase transform

The measurement of the parameters of complex signals with constant amplitude and polynomial phase, measured in additive noise, is considered. A novel new integral transform that is adapted for signals of this type is introduced. This transform is used to derive estimation and classification algorithms that are simple to implement and that exhibit good performance. The algorithms are extended to constant amplitude and continuous nonpolynomial phase signals. >

Estimation and classification of polynomial-phase signals

The authors derive the Cramer-Rao lower bound (CRLB) for complex signals with constant amplitude and polynomial phase, measured in additive Gaussian white noise. The exact bound requires numerical inversion of an ill-conditioned matrix, while its O(N/sup -1/) approximation is free of matrix inversion. The approximation is tested for several typical parameter values and is found to be excellent in most cases. The formulas derived are of practical value in several radar applications, such as electronic intelligence systems (ELINT) for special pulse-compression radars, and motion estimation from Doppler measurements. Consequently, it is of interest to analyze the best possible performance of potential estimators of the phase coefficients, as a function of signal parameters, the signal-to-noise ratio, the sampling rate, and the number of measurements. This analysis is carried out. >

The Cramer-Rao lower bound for signals with constant amplitude and polynomial phase

The authors consider the problem of estimating the parameters of a complex linear FM signal from a finite number of noisy discrete-time observations An estimation algorithm is proposed, and its asymptotic (large sample) performance is analyzed The algorithm is computationally simple, consisting of two fast Fourier transforms (FFTs) accompanied by one-dimensional searches for maxima The variance of the estimates is shown to be close to the Cramer-Rao lower bound when the signal-to-noise ratio is 0 dB and above The authors applied the algorithm to the problem of estimating the kinematic parameters of an accelerating target by pulse-Doppler radar A representative test case was used to exhibit the usefulness of the algorithm for this problem, and to verify the analytical results by Monte Carlo simulations >

Linear FM signal parameter estimation from discrete-time observations

A special mobile radio mobile, vehicle or personal location system is described where the system operates to locate any one of a the transmitters in an SMR system. The present invention operates by identifying the received signals, removing the modulation information to reconstruct a demodulated carrier and analyzing the carrier signals for multipath distortion. The multipath disruptions are removed to calculate the true incident angle of the transmitted signal at a base station. A plurality of base stations are used to simultaneously calculate the incident angle of the transmitted SMR signal and a central location calculates the most probable location of the transmitter based upon triangulation. The incident angle of the transmitted SMR signal at each base station is performed by calculating the phase differences of the incoming voice signal with phase ambiguity minimized by using a plurality of dipole antennas spaced at an irregular distance to eliminate phase ambiguity error.

S. Peleg

Papers

The discrete polynomial-phase transform

Estimation and classification of polynomial-phase signals

The Cramer-Rao lower bound for signals with constant amplitude and polynomial phase

Linear FM signal parameter estimation from discrete-time observations

Direction finding and mobile location system for trunked mobile radio systems