Harbor radio navigation system
AssigneeRaytheon Company
InventorFritz A. Gross
Life of this patent
Estimating the term…
Abstract
A radio beacon navigation system wherein buoys placed at predetermined locations in a harbor or channel transmit identification signals. Every buoy is assigned a unique carrier frequency upon which is transmitted a signal capable of identifying the buoy. Each buoy is shown on harbor charts according to the unique properties of its signal. Radio receiving means carried aboard vessels navigating through the harbor or channel include means for determining the identity of the buoy from which signals are received and the direction from which the received signals emanate.
Claims10
A receiver for use in a radio navigation system comprising in combination:
- antenna means;
- means for mixing signals received by said antenna means with a local oscillator signal;
- a voltage controlled oscillator for producing said local oscillator signal;
- means for demodulating output signals from said mixing means;
- means for simultaneously detecting the presence of a plurality of modulation components in received signals at an output of said demodulating means, each of said modulation components being of a different frequency;
- a source of clock pulses;
- means for gating said clock pulses ON when the presence of said received signals has not been detected and OFF when the presence of said received signals has been detected;
- means for producing a cyclical binary count in response to the gated clock pulses;
- means for converting the count output of said binary counter to an analog signal, said analog signal forming a control voltage input to said voltage controlled oscillator;
- means for indicating the presence of said received signals;
- and
- means for determining the direction to the source of said received signals;
- said indicating means and said direction determining means operating independently of the phase of said received signals.
A receiver system for use in navigating a vessel such as through a harbor channel with buoys marking passage through the channel with each of the buoys emitting a radio frequency signal capable of identifying the buoy from which the signal is emitted comprising:
- a directional antenna;
- an omnidirectional antenna;
- a radio frequency signal amplifier;
- switch means for selectively coupling one of the directional antenna or omnidirectional antennas to the radio frequency signal amplifier;
- a signal mixer, the output of the radio frequency signal amplifier being coupled to an input of the mixer;
- an intermediate frequency filter coupled to the output of the mixer;
- a demodulator coupled to the output of the intermediate frequency filter;
- means for detecting the presence of predetermined modulation components for identifying the buoy from which the received signals were emitted;
- a digital counter;
- a source of clock signal for operating the digital counter, the clock signal being inhibited to the digital counter in response to the detecting means;
- a digital-to-analog converter coupled to the outputs of the digital counter;
- and
- a voltage controlled oscillator, the output of the voltage controlled oscillator being derived in accordance with the output of the digital-to-analog converter and coupled to an input of the mixer.
Dependencies are inferred from the claim text.