US3797017A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Digital mti radar system
Assignee: Westinghouse Electric Corp
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Filing: 1972-10-05
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Granted: 1974-03-12
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Expires: 1992-10-05
Abstract
Abstract A radar system is disclosed utilizing digital techniques for implementing a moving target indicator (MTI) or pulse doppler type of radar. Significantly, the radar system of this invention has an inherent capability for far greater dynamic range than analog radar systems of the prior art, thereby enabling the detection of moving targets in a greater variety of operating environments. In a digital radar system, the achieved dynamic range is dependent upon the number of bits that the apparatus of the system is able to store and handle. In prior art digital radar systems, increased dynamic range was achieved by utilizing simple storage devices or handling devices capable of operating upon a greater number of bits. The obvious disadvantage of this approach, is the increasing cost of such equipment. In contrast to the prior art systems, this radar system incorporates apparatus for converting digital data into a logarithmic format, which converted data may then be handled and stored by apparatus of less complexity and cost.
Inventors
- 👤 J Taylor
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-23 07:11
CPC Classifications
G; G01; G01S; G01S13/00; G01S13/02; G01S13/50; G01S13/52; G01S13/522; G01S13/524; G01S13/526; G01S13/06; G01S13/42; G01S13/44; G01S13/449
Claims Analysis
Total Claims: 31
Claim 1
Independent Claim
161 words
In a moving target indicator radar system, a canceling circuit for suppressing echo signals from relatively slow-moving and/or stationary objects, said system comprising: a. analog-to-digital conversion means for converting a series of detected analog echo signals into corresponding natural digital words of n bits; b. logarithmic converting means for converting the series of natural digital words into logarithmic digital words having X bits indicative of its characteristic and Y bits indicative of its mantissa, where X + Y < n; c. storage means for storing a plurality of successive logarithmic digital words, said storage means having a storage capability of a number of bits; d. antilog converting means for converting the stored logarithmic digital words into natural digital words; and e. canceller means for combining the plurality of successive natural digital words derived from said storage means to suppress substantially those successive digital words of substantially equal amplitude corresponding to detected echo signals derived from the relatively slow-moving and/or stationary objects.
Claim 2
Dependent Claim
161 words
In a moving target indicator radar system, a canceling circuit for suppressing echo signals from relatively slow-moving and/or stationary objects, said system comprising: a. analog-to-digital conversion means for converting a series of detected analog echo signals into corresponding natural digital words of n bits; b. logarithmic converting means for converting the series of natural digital words into logarithmic digital words having X bits indicative of its characteristic and Y bits indicative of its mantissa, where X + Y < n; c. storage means for storing a plurality of successive logarithmic digital words, said storage means having a storage capability of a number of bits; d. antilog converting means for converting the stored logarithmic digital words into natural digital words; and e. canceller means for combining the plurality of successive natural digital words derived from said storage means to suppress substantially those successive digital words of substantially equal amplitude corresponding to detected echo signals derived from the relatively slow-moving and/or stationary objects.
Claim 3
Dependent Claim
28 words
A canceling circuit as claimed in claim 1, wherein said logarithmic converting means converts the series of natural digital words into logarithmic binary words of a base 2.
Claim 4
Dependent Claim
35 words
logarithmic converting means for converting the series of natural digital words into logarithmic digital words having X bits indicative of its characteristic and Y bits indicative of its mantissa, where X + Y < n;
Claim 5
Dependent Claim
35 words
logarithmic converting means for converting the series of natural digital words into logarithmic digital words having X bits indicative of its characteristic and Y bits indicative of its mantissa, where X + Y < n;
Claim 6
Dependent Claim
63 words
A canceling circuit as claimed in claim 1, wherein there is included scaling means for comparing the logarithmic digital words for determining the orders of magnitudes of the characteristics of the logarithmic digital words and for adjusting the positions of the mantissa bits of each of the smaller logarithmic digital words in accordance with their relative characteristics, to provide a normalized logarithmic word.
Claim 7
Dependent Claim
24 words
storage means for storing the logarithmic digital words, said storage means having a storage capability of a number of bits not greater than n;
Claim 8
Dependent Claim
24 words
storage means for storing the logarithmic digital words, said storage means having a storage capability of a number of bits not greater than n;
Claim 9
Dependent Claim
14 words
antilog converting means for converting the stored logarithimic digital words into natural digital words;
Claim 10
Dependent Claim
14 words
antilog converting means for converting the stored logarithimic digital words into natural digital words;
Claim 11
Dependent Claim
50 words
A canceling circuit as claimed in claim 3, wherein said scaling means includes digital comparator means for determining which of the logarithmic digital words has the largest characteristic, and subtraction means for determining the difference between a smaller characteristic and the largest characteristic as derived from said digital comparator means.
Claim 12
Dependent Claim
65 words
A canceling circuit as claimed in claim 4, wherein said antilog menas is responsive to the difference determined by said subtraction means for shifting the bits of the mantissas of the smaller logarithmic digital words in accordance with the difference in the characteristics to provide an indication of the relative magnitudes of the smaller logarithmic binary words with respect to the largest logarithmic binary word.
Claim 13
Dependent Claim
55 words
canceller means for combining a number of successive natural digital words derived from said antilog converting means to suppress substantially those successive digital words of substantially equal amplitude corresponding to echo signals derived from the relatively slow-moving and/or stationary objects and to provide an output signal indicative of echo signals corresponding to relatively fast-moving objects;
Claim 14
Dependent Claim
55 words
canceller means for combining a number of successive natural digital words derived from said antilog converting means to suppress substantially those successive digital words of substantially equal amplitude corresponding to echo signals derived from the relatively slow-moving and/or stationary objects and to provide an output signal indicative of echo signals corresponding to relatively fast-moving objects;
Claim 15
Dependent Claim
25 words
second logarithmic means for converting the natural digital words derived from said canceller means into logarithmic digital words normalized with respect to the largest characteristic;
Claim 16
Dependent Claim
25 words
second logarithmic means for converting the natural digital words derived from said canceller means into logarithmic digital words normalized with respect to the largest characteristic;
Claim 17
Dependent Claim
52 words
A canceling circuit as claimed in claim 4, wherein said digital comparator means provides a scaling factor indicative of the largest charactistic, and adder means responsive to the scaling factor and the bits indicative of the normalized logarithmic digital word for providing a logarithmic digital word whose absolute magnitude has been restored.
Claim 18
Dependent Claim
56 words
A canceling circuit as claimed in claim 2, wherein there is included scaling means for comparing the logarithmic binary words for determining the order of magnitudes of the characteristics of the logarithmic binary words and for adjusting the positions of the mantiSsa bits of each of the logarithmic binary words in accordance with their relative characteristics.
Claim 19
Dependent Claim
3 words
adder means; and
Claim 20
Dependent Claim
3 words
adder means; and
Claim 21
Dependent Claim
97 words
scaling means for deriving a scaling factor in accordance with the largest characteristic of the series of logarithmic digital words and for applying the scaling factor to said adder means whereby the largest characteristic is added to the normalized logarithmic digital word to provide a corrected logarithmic word of absolute magnitude; and c. subtraction means for subtracting the corrected logarithmic digital word derived from said first channel from the corrected logarithmic digital word derived from said second channel, to provide a signal indicative of the angle of the target from the boresight of said radar antenna means.
Claim 22
Dependent Claim
97 words
scaling means for deriving a scaling factor in accordance with the largest characteristic of the series of logarithmic digital words and for applying the scaling factor to said adder means whereby the largest characteristic is added to the normalized logarithmic digital word to provide a corrected logarithmic word of absolute magnitude; and c. subtraction means for subtracting the corrected logarithmic digital word derived from said first channel from the corrected logarithmic digital word derived from said second channel, to provide a signal indicative of the angle of the target from the boresight of said radar antenna means.
Claim 23
Dependent Claim
69 words
A canceling circuit as claimed in claim 2, wherein said logarithmic converting means inspects the T most significant bits of a natural binary word and provides its characteristic dependent upon the location of the most significant ''''one'''' of the T bits, said logarithmic converting means providing a mantissa of the logarithmic binary word from the next Y bits of the natural binary number from the most significant one thereof.
Claim 24
Dependent Claim
92 words
A canceling circuit as claimed in claim 1, wherein there is included second logarithmic converting means for converting the natural digital words derived from said canceller means into a logarithmic digital word normalized with respect to the largest characteristic, adder means, and means for deriving a scaling factor in accordance with the largest characteristic of the plurality of successive logarithmic digital words and applying the scaling factor to said adder means whereby the largest characteristic is added to the normalized logarithmic digital word to provide a corrected logarithmic word of absolute magnitude.
Claim 25
Dependent Claim
77 words
A moving target indicator radar system comprising: a. radar antenna means for receiving at least first and second radar beams and for providing at least first and second echo signals corresponding to the first and second radar beams, respectively; b. first and second channels for processing, respectively, the first and second echo signals, said channels being associated with at least one canceling circuit for suppressing echo signals from relatively slow-moving and/or stationary objects, said canceling circuit comprising:
Claim 26
Dependent Claim
77 words
A moving target indicator radar system comprising: a. radar antenna means for receiving at least first and second radar beams and for providing at least first and second echo signals corresponding to the first and second radar beams, respectively; b. first and second channels for processing, respectively, the first and second echo signals, said channels being associated with at least one canceling circuit for suppressing echo signals from relatively slow-moving and/or stationary objects, said canceling circuit comprising:
Claim 27
Dependent Claim
156 words
A moving target indicator radar system as claimed in claim 10, wherein each canceller circuit includes first and second synchronous detectors and a reference frequency source for generating a first reference frequency signal and a second reference frequency signal shifted 90* TO phase from the first reference signal, to be applied respectively to said first and second synchronous detectors and combined therein with the echo signal of that channel to provide in-phase (I) and quadrature (Q) signals, said analog-to-digital conversion means responsive to each of the I and Q signals to provide distinct natural digital words therefor, said storage means having the capability of storing the I and Q logarithmic digital words for each channel, and first and second vector combining means for respectively combining the I and Q signals of the first and second channels to provide a combined signal corresponding to the amplitude of the detected echo signals for the first and second channels.
Claim 28
Dependent Claim
42 words
A moving target indicator radar system as claimed in claim 11, wherein said analog-to-digital conversion means comprises first and second conversion means, each having a capability of converting analog echo signals into corresponding natural digital words of Z bits less than n.
Claim 29
Dependent Claim
122 words
A moving target indicator radar system as claimed in claim 12, wherein the detected echo signal is applied to said first conversion means, attenuation means for attenuating and applying said echo signal to said second conversion means, amplitude detecting means for detecting the magnitude of the detected echo signals and for determining whether the detected echo signal is above or below the predetermined level, and selector means responsive to said threshold detection means when a detected echo signal is below the predetermined level for deriving a first digital output from said first conversion means and responsive to said threshold detector means when the detected echo signal is above the predetermined level for deriving a second digital output from said second conversion means.
Claim 30
Dependent Claim
27 words
A moving target indicator radar system as claimed in claim 13, wherein the range of conversion of said first and second conversion means overlap with each other.
Claim 31
Dependent Claim
37 words
A moving target indicator radar system as claimed in claim 11, wherein there is further included commutation means for applying sequentially the I and Q signals of each channel to be processed by a single canceling circuit.
References Cited (Backward Citations)
No citation records indexed.
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1977-03-11 | 1977-09-10 | 1978-03-12 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1981-03-11 | 1981-09-10 | 1982-03-12 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1985-03-11 | 1985-09-10 | 1986-03-12 | $7700.00 | Window Closed / Lapsed |