Honeywell International Inc.

Other

Benjamin J Winstead

Jason I Formo

Timothy J Reilly

Seth T Frick

James R Hager

Steven H Thomas

Lavell Jordan

Thomas W Heidemann

Adam Moya

Colin S Hanson

Apparatus and methods of determining altitude information with a radar receiver with quadrature detection is provided. A method includes generating baseband frames. An oscillator signal is created within each of the baseband frames. A return of the oscillator signal is coupled to a first input of a mixer. Moreover, the oscillator signal is coupled to a second input of the mixer. A phase of the oscillator signal is selectively changed between two or more distinct values. Timing of the change being based at least in part on a baseband frame timing of the generated baseband frames. Samples of an output of the mixer are selectively collected further based at least in part on the baseband frame timing. The collected samples are processed to compute altitude information.

Apparatus and method of quadrature detection using one mixer without oversampling in a receiver

Systems and methods of operating an interference prevention system in a radar altimeter are provided. A method includes generating integer values with at least one pseudorandom noise sequence generator. The generated integer values are used as indexes to select at least one of start frequencies and stop frequencies from at least one frequency table for frequency modulated continuous wave (FMCW) ramps for a generated radar signal. The selected at least one of the start frequencies and the stop frequencies is provided to a frequency synthesizer. The at least one of start frequencies and the stop frequencies are used in generating transmit frames of the radar signal with the frequency synthesizer.

Signal interference prevention system for a frequency-modulated continuous wave radar altimeter

A method and system for estimating velocity of an aircraft is provided. The method comprises transmitting a beam toward a surface from the aircraft using a Doppler beam sharpened radar altimeter, receiving a plurality of reflected signals that correspond to portions of the transmitted beam that are reflected by the surface, and forming a plurality of Doppler beams by filtering the received signals. A complex-valued array of range bin is computed with respect to frequency of the Doppler beams from at least one antenna aperture of the radar altimeter, and a range for each of the Doppler beams is estimated. A velocity vector magnitude for the aircraft is estimated by a curve fit of the range with respect to the frequency of the Doppler beams.

Velocity and attitude estimation using an interferometric radar altimeter

Systems and methods for measuring velocity with a radar altimeter are provided. In at least one embodiment a method for measuring velocity magnitude of a platform in relation to a surface comprises transmitting a radar beam, wherein the radar beam is aimed toward a surface; receiving a plurality of reflected signals, wherein the plurality of reflected signals correspond to portions of the transmitted radar beam that are reflected by a plurality of portions of the surface; and applying Doppler filtering to the plurality of signals to form at least one Doppler beam. The method also comprises identifying range measurements within each Doppler beam in the at least one Doppler beam; and calculating the velocity magnitude based on the range measurements of the at least one Doppler beam.

Systems and methods for measuring velocity with a radar altimeter

Systems and methods for using velocity measurements to adjust Doppler filter bandwidth are provided herein. In certain embodiments, a method for adjusting bandwidth for at least one Doppler filter in a Doppler beam sharpened radar altimeter comprises receiving a velocity measurement; adjusting the bandwidth of the at least one Doppler filter based on the velocity measurement; and transmitting a radar beam, wherein the radar beam is aimed toward a surface. The method further comprises receiving at least one reflected signal, wherein the at least one reflected signal is a reflection of the radar beam being reflected off of at least one portion of the surface; and filtering the at least one reflected signal with the at least one Doppler filter to form at least one Doppler beam.

Systems and methods for using velocity measurements to adjust doppler filter bandwidth

A method for distinguishing a signal of interest from one or more interference signals in a received analog signal comprises receiving an analog signal at a radio front end, and transmitting the received analog signal to an analog-to-digital converter to sample data in the received analog signal and output a digital signal. A sub-channel Fast Fourier Transform (FFT) is performed on the digital signal, and sub-channel FFT bin magnitudes are averaged over a set period of time to determine a shape of the received signal. The shape of the received signal is compared to one or more signal reference patterns by computing a metric for the shape of the received signal, and computing a metric for the one more signal reference patterns. The computed metrics are then compared to a predetermined threshold value to determine the presence, or lack thereof, of a signal of interest in the received signal.

Methods and systems for distinguishing a signal of interest from interference signals

Methods and systems for reducing a leakage component of a received-signal are disclosed. A transmit antenna of a radar system transmits a transmit-signal including a transmit component. A receive antenna of the radar system receives a received-signal including a leakage component and a target component. The received-signal corresponds to the transmit-signal. An overlap determination is made to determine whether the target component overlaps the leakage component and/or is received during a time when the leakage component is expected to be received. If overlap exists, a reduction leakage component (e.g., a previously determined reduction leakage component) is subtracted from the received-signal so as to produce a modified received-signal, the modified received-signal including the target component and substantially excluding the leakage component. If overlap does not exist, an estimate of the leakage component is produced and a reduction leakage component, based at least in part on the leakage component, is produced.

Method and system for reducing a leakage component of a received radar signal

Systems and methods for Doppler beam sharpening in a radar altimeter are provided. In one embodiment, a method comprises receiving a return signal at a radar altimeter receiver and applying a first gate to the return signal to select at least a first component of the return signal. Spectral analysis is performed on the first component of the return signal to generate a plurality of frequency bins, wherein each frequency bin is centered around a different frequency across a Doppler shift frequency spectrum for the first component of the return signal. The method further comprises tracking the first component of the return signal, selecting a first frequency bin of the plurality of frequency bins based on the Doppler shift frequency of the first component of the return signal, and outputting a portion of the first component of the return signal falling within the first frequency bin for further processing.

Doppler beam-sharpened radar altimeter

A method for acquiring targets within a search area using an electronic device is disclosed. The method involves partitioning a first acquisition time period into a plurality of range gates, simultaneously positioning one or more of the range gates within the search area during a search mode, and transmitting an energy pulse train. Upon receipt of a reflection of the transmitted pulse train, the method records a signal level of the reflected energy pulse train within the first acquisition time period. Based on the recorded signal level, the method advances one or more of the range gates by a prescribed outbound movement increment until the signal level within at least one of the range gates is above a prescribed acquisition signal level threshold.

Methods for rapid target acquisitions in range measurement systems

A false lock filter circuit for a pulsed altimeter is provided. The circuit includes a low pass filter having a relatively low bandwidth (LBW LPF), a low pass filter having a relatively high bandwidth (HBW LPF) and a false lock controller. The LBW LPF has an input that is coupled to receive a detector output. The HBW LPF has an input that is coupled to receive the detector output. The false lock controller is coupled to receive outputs from the LBW LPF and HBW LPF. Moreover, the false lock controller is configured to sample an output of the HBW LPF and apply a statistical analysis on the samples to determine if a valid target has been detected.

False lock filter for pulsed radar altimeters

A method and apparatus for dealing with noise spikes in a radar system is provided. The method includes monitoring a noise channel in the radar system. Controlling gain with a control loop based at least in part on the monitored noise channel and ignoring noise spikes detected in the noise channel when controlling gain with the control loop.

Filtering NAGC response to noise spikes

A radar sensor is described that includes a radar transmitter, a radar receiver configured to receive reflected returns of signals output by the radar transmitter, and a signal processing unit configured to process signals received by the radar receiver. The signal processing unit includes a comparator, a first filter comprising an output coupled to a reference input of the comparator, and a second filter comprising an output coupled to a signal input of the comparator. The first and second filters are configured to receive a common input related to the reflected returns. The first filter is configured to have a time constant such that a rise time of the first filter output is faster than a rise time of the second filter output.

Methods and systems providing an adaptive threshold for a beam sharpened pulse radar

A method of obtaining in-phase and quadrature phase components for a narrowband signal is provided. The method includes digitally sampling a narrowband signal at a digital sampling rate to obtain a number of data points. The method subtracts a first portion of the data points corresponding to a first half of one period of the signal from a second portion of the data points corresponding to a second half of the one period of the signal to obtain a number of output data points which is less than the number of data points obtained from sampling the narrowband signal.

Method and system for obtaining in-phase and quadrature components of a signal

A method of detecting interference noise at a radar altimeter. The method comprises periodically emitting a pulse from the pulsed radar altimeter, periodically detecting a noise level in a noise gate, and determining if the noise level detected during each noise-level-detection period exceeds a noise threshold. The period of emitting the pulse is a pulse repetition interval and the noise gate is offset from other gates in the altimeter. If the noise level detected during a noise-level-detection period is greater than the noise threshold, a counter value is incremented by a selected incremental value for that noise-level-detection period and it is determined if the counter value is greater than a count threshold.

Method and system of interference detection for radar altimeters

A method for simulating a Doppler signal under stationary conditions is described. The method includes sampling a radar return signal at an integer multiple of the return signal frequency plus a fraction of the return signal period and generating a base band signal from the samples.

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Minneapolis, MN, United States of America

Benjamin J Winstead