LORAN ASSIST DEVICE

• US 3,858,217 A
• Filed: 01/21/1974
• Issued: 12/31/1974
• Est. Priority Date: 01/21/1974
• Status: Expired due to Term

• Current Assignee: Charles R. Edwards, George D. Wagner, Robert C. Moore, Ronald G. Roll, Ronald K. Burek
• Original Assignee: Charles R. Edwards, George D. Wagner, Robert C. Moore, Ronald G. Roll, Ronald K. Burek
• Inventors: Roll, Ronald G., Edwards, Charles R., Moore, Robert C., Wagner, George D., Burek, Ronald K.
• Primary Examiner(s): Wilbur, Maynard R.
• Assistant Examiner(s): Berger, Richard E.
• Application Number:
  US05/435,080
• Time in Patent Office: 344 Days
• Field of Search: 343/13R,112C 235/150.272
• US Class Current: 342/389
• CPC Class Codes: G01S 5/10 Position of receiver fixed by co-ordinating a plurality of position lines defined by path-difference measurements , e.g. omega or decca systemsG01S5/12 takes precedence ; beacons and receivers cooperating therewith G01S1/306, G01S1/308

Abstract

Apparatus to permit Loran-C navigation using an available Loran receiver and a commercial programmable desk-top calculator. A navigator is provided with heading angle, relative position information, velocity information and a real-time plot of ship'"'"''"'"'s position on standard navigation charts. An interface unit adjusts signal levels for system compatability and stores incoming data in preparation for its use by the caluclator. Destination data may be inserted from remote units and navigational information may be displayed remotely, as well.

Claims

1. In a hyperbolic navigation system including a receiver, for receiving signals transmitted by master and slave stations and for producing therefrom unique tracking strobe signals, and a programmable calculator capable when supplied with filtered time difference measurements of said tracking strobe signals of manipulating said measurements in accordance with predetermined navigation equations to produce navigational data, the improvement comprising an interface means for operably connecting said receiver and said programmable calculator, said interface means comprising:

read-only memory means for storing and outputting data enabling signals according to a predetermined sequence, means responsive to the signals from said memory means and being connected to receive said unique tracking strobe signals from said receiver for producing therefrom a plurality of timing difference signals defining a measure of the time differences between said tracking strobe signals, binary adder means having a first plurality of inputs, a second plurality of inputs, and a plurality of outputs representing the sum of said first and second pluralities of inputs, single register means connected to receive said plurality of output signals from said adder means and producing a plurality of output signals therefrom, a first plurality of shift register means responsive to the signals stored in said memory means, each of said first plurality of shift register means having inputs connected to receive said output signals of said single register means and each having a plurality of outputs connected to said first plurality of inputs of said adder means, and a second plurality of shift register means responsive to the signals stored in said memory means, each of said second plurality of shift register means having imputs connected to receive said output signals of said single register means and each having a plurality of outputs connected to said second plurality of inputs of said adder means, said programmable calculator having data input terminals connected to said plurality of outputs of said adder means.

2. The apparatus of claim 1 wherein said receiver interface means comprises:

oscillator means for generating a pulsed output signal, means connected to receive said oscillator output signal and said unique tracking strobe signals for reproducing groups of pulses of said pulsed output signal upon occurrence of said tracking strobe signal corresponding to said master station and for blocking said pulsed output upon occurrence of one of said tracking strobe signals corresponding to said slave stations, and register means connected to receive said groups of pulses for counting the number of pulses in each successive group of pulses and for producing a coded binary signal representing the difference in number of pulses between each of said successive groups.

3. The apparatus of claim 2 wherein:

said oscillator means is a crystal controlled oscillator, said means connected to receive said oscillator output signal comprises a plurality of flip-flop multivibrators, and said binary adder means is a binary coded decimal full adder.

4. The apparatus of claim 3 wherein:

said predetermined sequence of said enabling signals of said read only memory means is in accordance with the equations;

FN+ 1 FN+ VN VN+ 1 0.96VN+ 0.0004 (TD - FN+

     1) where F represents a filtered time difference output signal from said adder means, V represents the time rate of change of said output signal from said register means, and TD represents said output signal from said register means.