Apparatus and method for instantly automatic detecting clutter blocks and interference source and for dynamically establishing clutter map

• US 20070139258A1
• Filed: 12/19/2005
• Published: 06/21/2007
• Est. Priority Date: 12/19/2005
• Status: Active Grant

• Current Assignee: National Chung-Shan Institute of Science and Technology
• Original Assignee: Chung-Shan Institute of Science & Technology Armaments Bureau MND (Government of The Republic of China)
• Inventors: Tsai, Ming-Fa, Chang, Zheng-Cheng, Chen, Ming-Wey
• Granted Patent: US 7,298,316 B2
• Time in Patent Office: Days
• US Class Current: 342/159
• CPC Class Codes: G01S 7/2922 by using a controlled threshold
• CPC Class Codes: G01S 7/414 Discriminating targets with respect to background clutter

Abstract

An apparatus for detecting clutter blocks and an interference source for dynamically establishing a clutter map includes a clutter block detecting module accumulates a plurality of range cell data of each detecting area, and compares the accumulated value with a clutter block level to define the position of a clutter block; a interference source detecting module accumulates all range cell data in each radar beam area, and compares the accumulated value with an interference source reference level to detect whether any interference source exists; and a clutter map establishing module saves the clutter maps on different beam areas in three memory blocks. When one clutter map cell is extracted, the clutter map cells on different beam areas neighboring with the beam area saving extracted clutter map cell are also extracted. The largest value among the extracted clutter map cells is being a clutter threshold value of a detected target.

Claims

1. An apparatus for instantly automatic detecting clutter blocks and an interference source and for dynamically establishing a clutter map used for a radar system, comprising:

a clutter block detecting module, receiving a plurality of range cell data, wherein each of the range cell data represents an echo intensity at a different distance of a radar beam area with an elevation and an azimuth in the detection space of the radar system respectively;

the radar beam areas are divided into a plurality of detecting areas according to a predetermined range and when an accumulated value of a range cell data in a detecting area is larger than a clutter block level, the detecting area is defined as a clutter block;

an interference source detecting module, receiving a plurality of range cell data, used for accumulating the range cell data of each radar beam area, followed by comparing the accumulated value with an interference source reference level to detect whether an interference source exists; and

a clutter map establishing module, generates a plurality of the clutter map cell according to the range cells and the clutter map cells on different beam area store in three memory blocks sequentially, when one of the clutter map cells is extracted, two clutter map cells on adjacent beam area are also extracted, the largest value among the three clutter map cells regards as a clutter map threshold value to detect the target.

2. The apparatus for instantly automatic detecting clutter blocks and an interference source and for dynamically establishing a clutter map as recited in claim 1, wherein the clutter block detecting module comprises:

a first accumulated unit, receiving the input of the clutter block detecting module and used for accumulating the range cell data of each detecting area;

a first comparator, used for comparing the output from the first accumulated unit with the clutter block level, wherein if the output from the first accumulated unit is larger than the clutter block level, the first comparator produces a logic-1 output;

otherwise, the first comparator produces a logic-0 output;

a first memory device, coupled to the comparator and used for storing the output from the first comparator; and

a counter, coupled to the comparator and used for counting the number of logic-1 signals produced by the comparator.

3. The apparatus for instantly automatic detecting clutter blocks and an interference source and for dynamically establishing a clutter map as recited in claim 2, wherein the first accumulated unit comprises:

a first AND gate circuit, receiving the outputs from the first accumulated unit and a clearance signal;

a first adder, used for adding the input of the clutter block detecting module to the output from the first AND gate circuit; and

a first register, used for accumulating the output from the first adder, followed by sending the value to the first comparator.

4. The apparatus for instantly automatic detecting clutter blocks and an interference source and for dynamically establishing a clutter map as recited in claim 2, wherein the first memory device comprises a memory.

5. The apparatus for instantly automatic detecting clutter blocks and an interference source and for dynamically establishing a clutter map as recited in claim 1, wherein the interference source detecting module comprises:

a second accumulated unit, receiving the input of the interference source detecting module and used for accumulating the range cell data of each radar beam area;

a second comparator, used for comparing the output from the second accumulated unit with the interference source reference level, wherein if the output from the second accumulated unit is larger than the interference source reference level, the second comparator produces a logic-1 output;

otherwise, the second comparator produces a logic-0 output; and

a second memory device, coupled to the comparator and used for storing the output from the second comparator.

6. The apparatus for instantly automatic detecting clutter blocks and an interference source and for dynamically establishing a clutter map as recited in claim 5, wherein the second accumulated unit comprises:

a second AND gate circuit, receiving the outputs from the second accumulated unit and a clearance signal;

a second adder, used for adding the input of the interference source detecting module to the output from the second AND gate circuit; and

a second register, used for accumulating the output from the second adder, followed by sending the value to the second comparator.

7. The apparatus for instantly automatic detecting clutter blocks and an interference source and for dynamically establishing a clutter map as recited in claim 5, wherein the second memory device comprises a memory.

8. The apparatus for instantly automatic detecting clutter blocks and an interference source and for dynamically establishing a clutter map as recited in claim 1, wherein the clutter map establishing module comprises a third memory device with three memory blocks and each memory block comprises a plurality of memory regions for sequentially storing the data of clutter map cell of each radar beam area on every elevation layer, respectively, and the clutter map cells on different beam area store in three memory blocks sequentially, when one of the clutter map cells is extracted, two clutter map cells on adjacent beam area are also extracted, the largest value among the three clutter map cells is regarded as a clutter threshold value to detect the target.

9. The apparatus for instantly automatic detecting clutter blocks and an interference source and for dynamically establishing a clutter map as recited in claim 8, wherein each memory block in the third memory device comprises:

an third register, used for receiving the output from the dynamically updating circuit;

a memory, used for storing the output from the third register; and

a fourth register, used for receiving the output from the memory.

10. The apparatus for instantly automatic detecting clutter blocks and an interference source and for dynamically establishing a clutter map as recited in claim 8, wherein the third memory device comprises:

a first multiplexer, used for receiving the outputs from the memory blocks and selecting one of outputs from the memory blocks as the output of the first multiplexer according to a second selection signal; and

a fifth register, used for sending the output from the first multiplexer to the output end of the third memory device.

11. The apparatus for instantly automatic detecting clutter blocks and an interference source and for dynamically establishing a clutter map as recited in claim 8, wherein the memory blocks comprise a first memory block, a second memory block and a third memory block.

12. The apparatus for instantly automatic detecting clutter blocks and an interference source and for dynamically establishing a clutter map as recited in claim 8, wherein the clutter map establishing module further comprises a threshold value generating circuit comprises:

a third comparator, used for comparing the output from the first memory block with the output from the second memory block, wherein if the output from the first memory block is larger than the output from the second memory block, the third comparator generates a logic-1 output;

otherwise, a logic-0 output is generated;

a fourth comparator, used for comparing the output from the second memory block with the output from the third memory block, wherein if the output from the second memory block is larger than the output from the third memory block, the fourth comparator generates a logic-1 output;

otherwise, a logic-0 output is generated;

a second multiplexer, used for receiving the outputs from the first memory block and the second memory block and selecting one of the first memory block output and the second memory block output as an output of the second multiplexer according to the output from the third comparator;

a third multiplexer, used for receiving the outputs from the second memory block and the third memory block and selecting one of the second memory block output and the third memory block output as an output of the third multiplexer according to the output from the fourth comparator;

a sixth register, used for receiving the output from the second multiplexer;

an seventh register, used for receiving the output from the third multiplexer;

a fifth comparator, used for comparing the output from the sixth register with the output from the seventh register, wherein if the output from the sixth register is larger than the output from the seventh register, the fifth comparator generates a logic-1 output;

otherwise, a logic-0 output is generated;

a fourth multiplexer, used for receiving the outputs from the sixth register and the seventh register and selecting one of the sixth register output and the seventh register output as an output of the fourth multiplexer according to the output from the fifth comparator;

a eighth register, used for receiving the output from the fourth multiplexer;

a multiplier, used for multiplying the output from the eighth register by a predetermined multiple to generate the clutter threshold value; and

a ninth register, used for sending the output from the multiplier to the output end of the threshold value generating circuit.

13. A method for instantly detecting clutter blocks, suitable for a radar system, comprising the following steps:

receiving a plurality of range cell data, wherein each of the range cell data represents an echo intensity at a different distance of a radar beam area with an elevation and an azimuth in the detection space of the radar system, respectively;

dividing each of the radar beam areas into a plurality of detecting areas, wherein each detecting area comprises a preset number of range cell data;

accumulating all the range cell data of each detecting area to obtain corresponding accumulated values;

extracting the accumulated values of each detecting area;

comparing the accumulated value of each detecting area with a clutter block level to get a comparison result; and

deciding whether each of the detecting areas is a clutter block according to the comparison results.

14. The method for instantly detecting clutter blocks as recited in claim 13, wherein the steps for deciding whether a detecting area is a clutter block comprise:

defining a detecting area as a clutter block if the value of a detecting area is larger than the clutter block level and outputting logic-1 signal, and storing in a memory device; and

defining a detecting area as a non-clutter block if the value of a detecting area is less than the clutter block level, and outputting logic-0 signal, and storing in a memory device.

15. The method for instantly detecting clutter blocks as recited in claim 14, further comprising counting the number of the detecting areas with a value larger than the clutter block level.

16. A method for instantly detecting an interference source, suitable for a radar system, comprising the following steps:

receiving a plurality of range cell data, wherein each of the range cell data represents an echo intensity at a different distance of a radar beam area with an elevation and an azimuth in the detection space of the radar system, respectively;

accumulating all the range cell data of each radar beam area to obtain corresponding accumulated values;

extracting the accumulated value of each radar beam area to obtain a value;

comparing the value of each radar beam area with an interference source reference level to get a comparison result; and

deciding whether an interference source exists at each of the radar beam area direction according to the comparison results.

17. The method for instantly detecting an interference source as recited in claim 16, wherein the steps for deciding whether an interference source exists comprise:

determining whether there is an interference source at a radar beam area if corresponding accumulated value is larger than the interference source reference level and outputting logic-1 signal storing in a memory device; and

determining whether there is no interference source at a radar beam area if corresponding accumulated value is less than the interference source reference level and outputting logic-0 signal storing in the memory device.

18. A method for establishing a clutter map, suitable for a radar system, comprising the following steps:

receiving a plurality of range cell data, wherein each of the range cell data represents an echo intensity at a different distance of a radar beam area with an elevation and an azimuth in the detection space of the radar system respectively;

collapsing all range cells of each radar beam area into a plurality of range collapsing cells and each range collapsing cell comprises a predetermined number of range cells;

dynamically processing each range collapsing cell and original clutter map cell at the same position, and obtaining a new clutter map cell;

storing all clutter map cells on the selected elevation layer in three memory blocks respectively; and

when one of the clutter map cells is extracted, two clutter map cells on adjacent beam area are also extracted, the largest value among the three clutter map cells is regarded as a clutter threshold value to detect the target.

19. The method for establishing a clutter map as recited in claim 18, wherein the steps of storing each clutter map cell comprise:

Dividing each number of radar beam area by 3 and obtaining a remainder;

storing a corresponding clutter map cell to a first memory block of the memory blocks when the remainder is equal to zero;

storing a corresponding clutter map cell to a second memory block of the memory blocks when the remainder is equal to one; and

storing a corresponding clutter map cell to a third memory block of the memory blocks when the remainder is equal to two.

20. The method for establishing a clutter map, suitable for a radar system as recited in claim 18, wherein the steps for generating the clutter threshold value further comprise multiplying the largest value among each clutter map cell of a selected radar beam area and the clutter map cells with the corresponding position at the radar beam areas adjacent to the selected radar beam area by a predetermined multiple.