Target tracking
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- 2. Tracking radar systems are used to measure the targets range, azimuth angle, elevation angle, and velocity Predict the future values Target tracking is important to military and civilian purposes as missile guidance and airport traffic control 2
- 3. Targets are divided to two types: 1- Single target 2- Multiple targets 3
- 4. 1- Angle tracking A- Sequential lobing B- Conical scan C- Amplitude compression monopulse D- Phase compression monopulse 2- Range tracking 4
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- 8. Describes how much the target has deviated from the beam main axis Radar trying to produce a zero error signal Azimuth and elevation error 8
- 10. Sequential lobing is often referred to as lobe switching or sequential switching Accuracy depends on the pencil beam width It is very simple to implement 10
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- 12. Measuring the difference between the echo signals voltage levels 12
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- 25. This type is more accurate than sequential and conical scanning Feed generated four beams simultaneously with single pulse The four beams are inphase but have different amplitudes. 25
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- 32. To move the servosystem on the target we need to calculate Error signal output 32
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- 34. Azimuth and elevation error can be calculated by using Microwave comparator circuitry 34
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- 41. It’s the same as the last type but the amplitude here is equal for the four beams with different phases Phase comparison monopulse tracking radars use a minimum of a two-element array antenna 41
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- 44. It consist of two gates: 1-Early gate 2- Late gate The early gate produces positive voltage output but the late gate produces negative voltage output. Subtracting & integration Output is: zero, negative or positive 44
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- 47. Here the system is more difficult since: Tracking Scanning reporting 47
- 48. This type of radar is used for multiple targets It scans for new targets while its tracking old targets When TWS scan a new target it initiates a new track file 48
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- 50. Target detection Generation of tracking “Gates” Target track initiation and track file generation (if a new target) Correlation Track gate prediction, smoothing and positioning Display and future target calculations 50
- 51. This task is accomplished by two method : Circuit in receiver signal-processing equipment 51
- 52. Gate : small volume of space consist of many of cells Function : monitoring of each scan of the target information Gating has responsibility for knowing if new/exist target 52
- 53. Acquisition gate Tracking gate Turning gate 53
- 54. This gate is large to facilitate target motion cross one scan period 54
- 55. This gate is generated when the target is within the acquisition gate on the next scan It is very small gate It is moving to the new expected target position 55
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- 57. It is generated if the observation within the tracking gate doesn’t appear It has larger size than tracking gate Tracking gate included by it 57
- 58. tracking gate 58
- 59. All observations site on the boundary of tracking gate must be correlate with that track Each observation is compared with all track files Perhaps, observation is correlated with one track files ,several tracks or no tracks 59
- 60. If the observation correlates with more one track files, tracking ambiguity is appear. Two reasons cause this result: 1- several targets site in the same gate 2- several gates overlap on a single target 60
- 61. If the system designed so that an operator initiate the tracks, then solution by delete track But for the automatic systems , the solving by maintain software rules 61
- 62. The track file is initiated when acquisition gate is generated Track file store position and gate data Each track file occupies position in the digital computer's high-speed memory Cont. refreshed data 62
- 63. - Error Repositioning Smoothing - The system lagged the target - The system leading the target - smoothing is completed by comparing predicted parameters with observed parameters 63
- 64. Scanning radar detects a target Do parameters match those from previous scan NO Yes Does track ambiguity exist NO Yes Generate a new track file & store data Generate an acquisition gate Resolve ambiguity Target previously in track or acquisition Compute target tracking parameters Acquisition Track Generate Track Gate & indicator in file Update tracking parameters Reposition track gate centered on future position Ready for the next radar scan information Recompute track gate Scanning radar detects a target Do parameters match those from previous scan NO Yes Does track ambiguity exist NO Yes Generate a new track file & store data Generate an acquisition gate Resolve ambiguity Target previously in track or acquisition Compute target tracking parameters Acquisition Track Generate Track Gate & indicator in file Update tracking parameters Reposition track gate centered on future position Ready for the next radar scan information Recompute track gate 64
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