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Azimuth ambiguity calculation method for airborne SAR with variable pulse repetition interval

A pulse repetition interval, azimuth ambiguity technology, applied in the direction of radio wave reflection/reradiation, instruments, measuring devices, etc.

Active Publication Date: 2019-03-22
BEIHANG UNIV
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

However, under the condition of variable pulse repetition interval, there may be a certain deviation between the transmitted pulse and the echo received pulse. Therefore, there will be a significant difference in the position of the fuzzy area on both sides of the target area, and it cannot be simply determined by the Doppler frequency and spatial angle. Efficient way to complete simple conversion

Method used

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  • Azimuth ambiguity calculation method for airborne SAR with variable pulse repetition interval
  • Azimuth ambiguity calculation method for airborne SAR with variable pulse repetition interval
  • Azimuth ambiguity calculation method for airborne SAR with variable pulse repetition interval

Examples

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Embodiment 1

[0105] For a typical airborne SAR, the azimuth ambiguity of the system is analyzed, and the specific calculation method is realized through the following steps:

[0106] Step 1: Input the radar system parameters and radar orbit parameters, and initialize the parameters.

[0107] (a) Input radar system parameters (including radar effective speed V is 250m / s, radar operating wavelength λ is 0.032m, azimuth antenna length L a is 1m, the angle of view γ under the antenna is 45 degrees, the Doppler bandwidth is 443Hz, the reference pulse repetition frequency prf is 600Hz and the variable pulse repetition interval sequence t p ) and orbit parameters (including radar height H is 10km);

[0108] (b) Calculate the antenna azimuth beamwidth β according to formula (18) a , according to formulas (19) to (20) to calculate the target position Its coordinates are T x ,T y ,T z and the shortest slope distance T r ;

[0109]

[0110]

[0111] T r =H / cosγ (20)

[0112] Then use...

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Abstract

The invention discloses a method for calculating the azimuth ambiguity of an airborne SAR with variable pulse repetition interval, which includes: determining the position of the radar at each pulse transmission time and the position of the target to be analyzed according to the pulse repetition interval; determining the echo intensity of the target pulse by pulse, Calculate the sum of the energy of the target; determine the echo intensity of the fuzzy area pulse by pulse, calculate the total fuzzy energy, calculate the ratio of the total fuzzy area energy to the total target energy, and obtain the azimuth ambiguity. The present invention provides a theoretical basis and implementation method for the system design of variable pulse repetition interval airborne SAR, and the traditional frequency domain analysis method cannot be applied to variable pulse repetition interval SAR system analysis; the present invention has no requirements for the antenna pointing at each moment, so it can It is suitable for SAR systems with any non-fixed pointing antenna.

Description

technical field [0001] The invention relates to the technical field of synthetic aperture radar (Synthetic Aperture Radar, SAR), in particular to an azimuth ambiguity calculation method for airborne SAR with variable pulse repetition interval. Background technique [0002] The azimuth ambiguity is caused by the pulse sampling working system of the synthetic aperture radar in the azimuth direction. The Doppler spectrum of the echo signal of the synthetic aperture radar is weighted by the antenna azimuth to the two-way pattern of sending and receiving, and is sampled by the system with the pulse repetition frequency, and the Doppler spectrum higher than the pulse repetition frequency is folded into the azimuth processing bandwidth , mixed with the main signal, so the signal spectrum of the side lobe after sampling will affect the signal in the Doppler bandwidth, resulting in azimuth ambiguity, so the azimuth ambiguity is caused by the working principle of SAR. The impact of a...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): G01S13/90G01S7/41
CPCG01S7/41G01S13/904G01S13/90
Inventor 孙兵李景文谭林姜予名
Owner BEIHANG UNIV