Portable automatic radar simulator

• US 5,133,663 A
• Filed: 02/27/1992
• Issued: 07/28/1992
• Est. Priority Date: 02/27/1992
• Status: Expired due to Fees

• Current Assignee: The Government Of The United States As Represented By The Secretary Of The Navy
• Original Assignee: the united states of america as represented by the secretary of the navy
• Inventors: Willingham, Joseph A., Hedin, Robert A.
• Primary Examiner(s): Sotomayor, John B.
• Application Number:
  US07/824,959
• Time in Patent Office: 152 Days
• Field of Search: 434/2, 342/169, 342/170, 342/171, 342/172, 342/13, 342/14
• US Class Current: 434/2
• CPC Class Codes: G01S 7/4052 by simulation of echoes
• CPC Class Codes: G01S 7/4082 using externally generated reference signals, e.g. via remote reflector or transponder
• CPC Class Codes: G09B 9/40 Simulation of airborne radar

Abstract

A portable radar simulator which when connected to a transmitting means s as a magnetron generated microwave threat transmitter simulates up to 2048 pre-programmed radar signatures. The portable radar simulator comprises a replaceable Erasable Programmable Read Only Memory (EPROM) which will hold up to 2048 pre-programmed radar signatures. Selection of a particular radar threat to be simulated is entered by an operator via thumbwheel switches located on the front panel of the simulator. The portable radar simulator simulates such radar parameters as jitter, stagger, frequency hop, simple and complex scans, pulse repetition intervals and frequency pulse widths.

Claims

1. A digital radar simulation system for simulating up to 2048 pre-programmed radar signatures, said digital radar simulation system comprising:

thumbwheel switching means for providing a plurality of digital logic signals, said digital logic signals being representative of 2048 pre-programmed radar signatures said digital radar simulation system simulates, said thumbwheel switching means upon being set to one of the 2048 radar signatures to be simulated providing the most significant bits of the digital address indicative of said radar signature;

sequencing means for providing the least significant bits of said digital address indicative of said radar signature being simulated;

memory means for storing said 2048 radar signatures therein, said memory means in response to the address supplied by said thumbwheel switching means and said sequencing means providing an eight bit control word, a pair of pulse repetition interval data words, a plurality of lobe data words and a plurality of scan data words for the radar signature being simulated;

control register means for receiving said eight bit control word and storing said control therein while said radar signature is being simulated;

the first and second bits of said control word representing a pulse width for the radar signature being simulated;

pulse repetition interval generating means for

receiving a pair of eight bit data words from said memory means, said first eight bit data word being the least significant bits of said pulse repetition interval and said second eight bit data word being the most significant bits of said pulse repetition interval;

said pulse repetition interval generating means, responsive to said first and second data words generating a pulse repetition interval for the radar signature being simulated;

jitter generating means for receiving the third, fourth and fifth bits of said control word and in response to the third, fourth and fifth bits of said control word providing either a sixty four microsecond shortened time period for ever other pulse repetition interval generated by said pulse repetition generating means or a one hundred twenty eight microsecond shortened time period for every other pulse repetition interval generated by said pulse repetition generating means;

beamwidth and scan generating means for generating a beamwidth and side lobes for the radar signature being simulated in response to the lobe data words supplied thereto by said memory means, said lobe data words being indicative of the beamwidth and side lobes of the radar signature being simulated;

said beamwidth and scan generating means generating a scan and scan period for the radar signature being simulated in response to the scan data words supplied thereto by said memory means;

frequency hop generating means for generating a frequency hop within the radar signature being simulated by said digital radar simulation system, said frequency hop being generated by said frequency hop generating means in response to the sixth bit of said control word; and

output circuit means for receiving the seventh and eight bits of said control word, for providing in response to the seventh bit of said control word a direct scan radar signature and for providing in response to the eight bit of said control word a pulse group within the radar signature being simulated and for gating the pulse repetition interval, the frequency hop, the beamwidth, side lobes, scan and scan period into the radar signature being simulated by said digital radar simulation system.

2. The system of claim 1 wherein said memory means comprises an Erasable Programmable Read Only Memory.

3. The system of claim 1 further characterized by clock generating means for providing a 0.5 microsecond clock signal, a two microsecond clock pulse, an eight microsecond signal, a 1.024 millisecond clock signal, a 2.048 millisecond clock signal and a 131.072 millisecond signal, said 0.5 microsecond clock signal being provided to said pulse repetition interval generating means, said two microsecond clock signal being supplied to said sequencing means, said eight microsecond clock signal being supplied to said jitter generating means and said 1.024, 2.048 and 131.072 millisecond clock pulses being supplied to said beamwidth and scan generating means.

4. The system of claim 3 wherein said clock generating comprises:

oscillating means for generating a 0.5 microsecond clock signal;

first counter means for receiving said 0.5 microsecond clock pulse and for dividing said 0.5 microsecond clock signal and thereby provide said two and eight microsecond clock signals;

second counter means for receiving said eight microsecond clock signal and for dividing said eight microsecond clock signal and thereby provide said 1.024 and said 2.048 millisecond clock signals; and

third counter means for receiving said 2.048 millisecond clock signal and for dividing said 2.048 millisecond clock signal and thereby provide said 131.072 millisecond clock signal.

5. The system of claim 1 wherein the scan generated by said beamwidth and scan generating means may comprises a circular scan, a bi-directional scan, a conical scan, a circular palmer scan or a raster scan.

6. The system of claim 1 wherein said sequencing means comprises:

means for generating a two microsecond clock signal

a first AND gate having a first input for receiving said two microsecond clock signal, a second input and an output;

an OR gate having a first input connected to the output of said first AND gate, a second input electrically coupled to said beamwidth and scan generating means and an output;

a synchronous binary counter having a clock input connected to the output of said OR gate, a clear input and first, second, third and fourth outputs;

a four line to sixteen line decoder having first, second, third and fourth inputs respectively connected to the first, second, third and fourth outputs of said synchronous binary counter and sixteen outputs;

a first monostable multivibrator having an input connected to the first output of said four line to sixteen line decoder, and an output connected to the clear input of said synchronous binary counter;

a second monostable multivibrator having an input connected to the third output of said four line to sixteen line decoder, and an output electrically coupled to said pulse repetition interval means;

a third monostable multivibrator having an input connected to the fourth output of said four line to sixteen line decoder, and an output electrically coupled to said pulse repetition interval means;

a second AND gate having first, second, third, fourth, fifth and sixth inputs respectively connected to the fifth, seventh, ninth, eleventh, thirteenth and fifteenth outputs of said four line to sixteen line decoder and an output;

a third AND gate having first, second, third, fourth, fifth and sixth inputs respectively connected to one sixth, eighth, tenth, twelfth, fourteenth and sixteenth outputs of said four line to sixteen line decoder and an output;

a JK Flip-Flop having a preset input connected to the first output of said four line to sixteen line decoder, a clear input connected to the fourth output of said four line to sixteen line decoder and an output connected to the second input of said first AND gate;

a NAND gate having first and second inputs connected to the output of second AND gate and an output electrically coupled to said beamwidth and scan generating means; and

a fourth AND gate having first and second inputs connected to the output of second AND gate and an output electrically coupled to said beamwidth and scan generating means.

7. The system of claim 1 wherein said beamwidth and scan generating means comprises:

means for generating a 1.024 millisecond, a 2.048 millisecond and a 131.072 millisecond clock signal;

a first NAND gate having a first input for receiving said 1.024 millisecond clock signal, a second input electrically coupled to said sequencing means and an output;

a first OR gate having a first input electrically coupled to said sequencing means, a second input and an output;

a first AND gate having a first input connected to the output of said first NAND gate, a second input connected to the output of said first OR gate and an output;

an eight bit synchronous counter having eight inputs for receiving the scan data words and lobe data words provided by said memory means, a clock input connected to the output of said first AND gate, a load input and first and second outputs;

a first monostable multivibrator having an input electrically coupled to said sequencing means and an output;

a second monostable multivibrator having an input electrically coupled to said sequencing means and an output;

a third monostable multivibrator having an input connected to the first output of said eight bit synchronous counter and an output electrically coupled to said sequencing means;

a second OR gate having a first input connected to the output of said first monostable multivibrator, a second input connected to the output of said second monostable multivibrator and an output;

a second NAND gate having first and second inputs connected to the output of said second OR gate and an output connected to the load input of said eight bit synchronous counter;

a second AND gate having a first input for receiving said 2.048 millisecond clock signal, a second input connected to the second output of said eight bit synchronous counter and an output;

a third NAND gate having first and second inputs connected to the second output of said eight bit synchronous counter and an output;

a third AND gate having a first input for receiving said 131.072 millisecond clock signal, a second input connected to the second output of said third NAND gate and an output; and

a third OR gate having a first input connected to the output of said second AND gate, a second input connected to the output of said third AND gate and an output connected to the second input of said first OR gate.

8. The system of claim 1 wherein said control register means comprises a first and second presettable binary latches, said first and second latches each having four data inputs, a load input and four data outputs.

9. The system of claim 1 wherein said thumbwheel switching means comprises three thumbwheel switches coded in hexadecimal.

10. A digital radar simulation system for simulating up to 2048 pre-programmed radar signatures, said digital radar simulation system comprising:

timing circuit means for providing a first clock signal, a second clock signal, a third clock signal, a fourth clock signal, a fifth clock signal and a sixth clock signal;

thumbwheel switching means for providing a plurality of digital logic signals, said digital logic signals being representative of 2048 pre-programmed radar signatures said digital radar simulation system simulates, said thumbwheel switching means upon being set to one of the 2048 radar signatures to be simulated providing the most significant bits of the digital address indicative of said radar signature;

sequencing means for providing the least significant bits of said digital address indicative of said radar signature being simulated;

memory means for storing said 2048 radar signatures therein, said memory means in response to the address supplied by said thumbwheel switching means and said sequencing means providing an eight bit control word, a pair of pulse repetition interval data words, a plurality of lobe data words and a plurality of scan data words for the radar signature being simulated;

said memory means not providing said lobe data words and said scan data words when the radar signature being simulated by said digital radar simulation system is a direct scan radar signature;

control register means for receiving said eight bit control word and storing said control word therein while said radar signature is being simulated;

said sequencing means receiving said first clock signal and responsive to said first clock signal providing sequentially a control word signal, a pulse repetition interval signal and alternatively a plurality of lobe word signals and a plurality of scan word signals;

said control word pulse latching the eight bit control word into said control register means;

the first and second bits of said control word representing a pulse width for the radar signature being simulated;

pulse repetition interval and jitter generating means for receiving a pair of eight bit data words from said memory means, said first eight bit data word being the least significant bits of said pulse repetition interval and said second eight bit data word being the most significant bits of said pulse repetition interval, said pulse repetition interval and jitter generating means, responsive to said first and second data words generating a pulse repetition interval for the radar signature being simulated;

said pulse repetition interval and jitter generating means receiving the third, fourth and fifth bits of said control word and in response to the third fourth and fifth bits of s id control word providing a sixty four microsecond shortened time period for every other pulse repetition interval generated by said pulse repetition generating means, a one hundred twenty eight microsecond shortened time period for every other pulse repetition interval generated by said pulse repetition generating means, or a complete pulse repetition interval for two cycles followed by a sixty four microsecond shortened time period pulse repetition interval for one cycle and a one hundred twenty eight microsecond shortened time period pulse repetition interval for the next cycle;

beamwidth and scan generating means for generating a beamwidth and side lobes for the radar signature being simulated in response to the lobe data words supplied thereto by said memory means, said lobe data words being indicative of the beamwidth and side lobes of the radar signature being simulated;

said beamwidth and scan generating means generating a scan and scan period for the radar signature being simulated in response to the scan data words supplied thereto by said memory means;

frequency hop generating means for generating a frequency hop within the radar signature being simulated by said digital radar simulation system, said frequency hop being generated by said frequency hop generating means in response to the sixth bit of said control word; and

output circuit means for receiving the seventh and eight bits of said control word, for providing in response to the seventh bit of said control word a direct scan radar signature and for providing in response to the eight bit of said control word a pulse group within the radar signature being simulated and for gating the pulse repetition interval, the frequency hop, the beamwidth, side lobes, scan and scan period into the radar signature being simulated by said digital radar simulation system.

11. The system of claim 10 wherein said memory means comprises an Erasable Programmable Read Only Memory.

12. The system of claim 10 wherein said pulse repetition interval and jitter generating means comprises:

first and second storage registers each having eight data inputs, a clock input, a load input and eight data outputs, the data inputs of said first storage register receiving the first of said pair of pulse repetition interval data words, the data inputs of said second register receiving the second of said pair of pulse repetition interval data words and the load input of said first and second storage registers receiving the pulse repetition interval signal generated by said sequencing means;

first and second counters having eight data inputs, a clock input, a load input and eight data outputs, each data input of said first counter being connected to one of the data outputs of said first storage register, each data input of said second counter being connected to one of the data outputs of said second storage register, the clock input of said first counter receiving the second clock signal from said timing circuit means, and the clock input of said second counter being connected to the eight data output of said first counter, said first and second counters being configured as a presettable binary counter;

a first AND gate having a first input connected to the eight data output of said first counter, a second input for receiving the third bit of said control word and an output;

a second AND gate having first, second, third and fourth inputs respectively connected to the first, second, third and fourth outputs of said second counter and an output;

a third AND gate having first, second, third and fourth inputs respectively connected to the fifth, sixth, seventh and eight outputs of said second counter and an output;

a first OR gate having a first input connected to the output of said first AND gate, a second input for receiving the fourth bit of said control word and an output;

a second OR gate having a first input for receiving the seventh bit of said control word, a second input for receiving said plurality of scan word signals and an output electrically to said output circuit means;

a fourth AND gate having a first input connected to the output of said second AND gate, a second input connected to the output of said third AND gate and an output;

a fifth AND gate having a first input connected to the output of said second AND gate, a second input connected to the output of said third AND gate, a third input connected to the output of said first OR gate, a fourth input and an output;

a sixth AND gate having a first input connected to the output of said fourth AND gate, a second input connected to the output of said first OR gate, a third input connected to the output of said first AND gate, a fourth input and an output;

a third OR gate having a first input connected to the output of said fifth AND gate, a second input connected to the output of said sixth AND gate and an output;

a NAND gate having a pair of inputs connected to the output of said third OR gate;

a seventh AND gate having a first input connected to the output of said NAND gate, a second input connected to the eighth output of said second counter and an output;

a first monostable multivibrator having an input connected to the output of said eighth AND gate, a Q output electrically coupled to said output circuit means and a not Q output;

a second monostable multivibrator having an input connected to the output of said first monostable multivibrator and a not Q output connected to the load inputs of said first and second counters;

a first JK Flip-Flop having a clock input connected to the Q output of said first monostable multivibrator, a Q output and a not Q output;

a second JK Flip-Flop having a clock input connected to the Q output of said first JK Flip-Flop, a clear input electrically coupled to said control register means, a Q output connected to the fourth input of said sixth NAND gate and a not Q output;

an eight AND gate having a first input connected to the not Q output of said first JK Flip-Flop, a second input connected to the not Q output of said second JK Flip-Flop and an output connected to the fourth input of said sixth AND gate; and

a ninth AND gate having a first input for receiving said third clock signal, a second input for receiving the fifth bit of said control word and an output connected to the clock input of said first storage register.

13. The system of claim 10 wherein said control register means comprises:

a first and second control registers each having four data inputs, a load input and four data outputs, each input of said registers receiving one of the bits of said control word and the load inputs of said registers receiving the control word signal from said sequencing means; and

an AND gate having first and second inputs respectively connected to the first and second outputs of said control register.

14. The system of claim 10 wherein said sequencing means comprises:

a first AND gate having a first input for receiving said first clock signal, a second input and an output;

an OR gate having a first input connected to the output of said first AND gate, a second input electrically coupled to said beamwidth and scan generating means and an output;

a synchronous binary counter having a clock input connected to the output of said OR gate, a clear input and first, second, third and fourth outputs;

a four line to sixteen line decoder having first, second, third and fourth inputs respectively connected to the first, second, third and fourth outputs of said synchronous binary counter and sixteen outputs;

a first monostable multivibrator having an input connected to the first output of said four line to sixteen line decoder, and an output connected to the clear input of said synchronous binary counter;

the output of said first monostable multivibrator being electrically coupled to said output circuit means;

a second monostable multivibrator having an input connected to the third output of said four line to sixteen line decoder, and an output electrically coupled to said pulse repetition interval means;

a third monostable multivibrator having an input connected to the fourth output of said four line to sixteen line decoder, and an output electrically coupled to said pulse repetition interval means;

a second AND gate having first, second, third, fourth, fifth and sixth inputs respectively connected to the fifth, seventh, ninth, eleventh, thirteenth and fifteenth outputs of said four line to sixteen line decoder and an output;

a third AND gate having first, second, third, fourth, fifth and sixth inputs respectively connected to the sixth, eighth, tenth, twelfth, fourteenth and sixteenth outputs of said four line to sixteen line decoder and an output;

a JK Flip-Flop having a preset input connected to the first output of said four line to sixteen line decoder, a clear input connected to the fourth output of said four line to sixteen line decoder and an output connected to the second input of said first AND gate;

a NAND gate having first and second inputs connected to the output of second AND gate and an output electrically coupled to said beamwidth and scan generating means; and

a fourth AND gate having first and second inputs connected to the output of second AND gate and an output electrically coupled to said beamwidth and scan generating means.

15. The system of claim 10 wherein said beamwidth and scan generating means comprises:

a first NAND gate having a first input for receiving said fourth clock signal, a second input electrically coupled to said sequencing means and an output;

a first OR gate having a first input electrically

coupled to said sequencing means, a second input and an output;

a first AND gate having a first input connected to the output of said first NAND gate, a second input connected to the output of said first OR gate and an output;

an eight bit synchronous counter having eight inputs for receiving the scan data words and lobe data words provided by said memory means, a clock input connected to the output of said first AND gate, a load input and first and second outputs;

a first monostable multivibrator having an input electrically coupled to said sequencing means and an output;

a second monostable multivibrator having an input electrically coupled to said sequencing means and an output;

a third monostable multivibrator having an input connected to the first output of said eight bit synchronous counter and an output electrically coupled to said sequencing means;

a second OR gate having a first input connected to the output of said first monostable multivibrator, a second input connected to the output of said second monostable multivibrator and an output;

a second NAND gate having first and second inputs connected to the output of said second OR gate and an output connected to the load input of said eight bit synchronous counter;

a second AND gate having a first input for receiving said fifth clock signal, a second input connected to the second output of said eight bit synchronous counter and an output;

a third NAND gate having first and second inputs connected to the second output of said eight bit synchronous counter and an output;

a third AND gate having a first input for receiving said sixth clock signal, a second input connected to the second output of said third NAND gate and an output; and

a third OR gate having a first input connected to the output of said second AND gate, a second input connected to the output of said third AND gate and an output connected to the second input of said first OR gate.