1. Conformal Array for Radar Missile Seeker Chungbuk National University
B.-C. Ahn
Chungbuk National University

2. Contents 1. Missile Seeker Types 2. 발표자료 작성시 유의 사항 3. 글자 크기 4. 줄 간격
5. 그림 6.

3. 1. Missile Guidance
• Missile Guidance Operational Sequence

4. 1. Missile Guidance
• Missile Guidance Sensor

5. 1. Missile Guidance • Accurate guidance & control • Seeker calibration
• Error modeling & simulation
• Target angle estimation: fast moving air vehicle trajectory

6. 1. Missile Guidance • Signal processing • LOS reconstruction
• Guidance computer
• Missile control & final miss distance

7. 2. Semi-active Radar Homing
• Concept
- A separate target radar illuminates the target.
- A passive radar receiver detects the signal reflected from the target.
- Most common "all weather" guidance solution for anti-aircraft missile.
- Monopulse tracking
Sum beam
Azimuth difference beam
Elevation difference beam
- Example
Hughes AIM-4 Falcon

8. 2. Semi-active Radar Homing
• AIM-4 Falcon Semi-Active Radar Homing Head
- X-band, 40cm diameter, dual-polarized
- V-pol. : microstrip-fed slotted waveguide array
- H-pol. : microstrip dipole array
- Monopulse feed network

9. 2. Semi-active Radar Homing
• AIM-4 Falcon Semi-Active Radar Homing Head

10. 2. Semi-active Radar Seeker
• AIM-4 Falcon Semi-Active Radar Homing Head
- Specifications
Frequency GHz
CW & pulsed, 0.76μs, kHz
Receiver bandwidth: narrow band 4kHz/10kHz, wideband 56kHz,
very wideband 923kHz
Coherent processing interval: for data collection 50ms, for auto-track ms
Channel-to-channel tracking accuracy: gain 0.5dB(1σ), phase 3.0º rms
Absolute amplitude error: < ±1.0dB
Gimbal limits: ±50º pitch, ±40º yaw
Angle accuracy: < 1.0mrad (0.057º)

11. 2. Semi-Active Radar Seeker
• Avtomatika L-112E anti-radiation seeker
- Gimballed multiple baseline interferometer
- Seven wideband hemispherical spiral antennas
- 36cm diameter, 107cm length

12. 3. Active Radar Seeker • Platforms • Capabilities
- Missile diameter: mm
- Missile Types: air-to-air, air-to-surface, surface-to-surface
• Capabilities
- Target detection
- Lock on: at ranges up to 70 km
- Automatic tracking
- LOS rate measurement for missile guidance
- Anti-jamming

13. 3. Active Radar Seeker • Technology Components
- Stabilization by a gimbal
- Radome
- Antenna & mechanical scanner
- Transmitter & receiver
- Power supply
- Signal processor
- Computer
- Interface

14. 3. Active Radar Seeker
• Active radar seeker: block diagram

15. 3. Active Radar Seeker
• Active radar seeker: signal processing and computing

16. 3. Active Radar Seeker • Example
- Moscow Agat Research Institute, 9B-1103M
- Thin flat-plate slotted waveguide antenna, 350mm diameter

17. 3. Active Radar Seeker
• Russian active radar seeker

18. 3. Active Radar Seeker • Russian active radar seeker
- Left: 9B-1101K dual-plane monopulse semi-active
- Middle: 9B-1384E active radar seeker
- Right: 9B-1103K active radar seeker

19. 3. Active Radar Seeker • Phazotron PSM-E Ka-band active radar seeker
- Missile: km range, maximum missile speed 920m/s,
- Tank detection range: 4km
- Range accuracy: 8-10m
- Scan angle: ±30º AZ, ±20º EL
- Target velocity measurement accuracy: 0.5m/s
- Weight: 16kg

20. 4. Radome Induced Boresight Errors
- Non-uniform refraction through a nose cone radome
- Boresight error and boresight error slope
- Guidance computer
- Missile control & final miss distance

21. 5. PESA Radar
• PESA (Passive Electronically Scanned Array) Concept

22. 5. PESA Radar • Scan blindness
- Caused by mutual coupling between elements
- Can be avoided by careful design: element shape, size, spacing

23. 5. PESA Radar • PESA Components - Antenna
Phase shifter: digital control
Attenuator: digital control
Beam-steering computer
- Transmitter
Klystron: high voltage power source,
single point of failure
- T/R isolation
Circulator, duplexer, switch
- Exciter: waveform generator
- Receiver: one receiver
High dynamic range requrirements
Single point of failure
- Digital signal processor
- System computer

24. 5. PESA Radar
• T/R Module, Block Diagram

25. 5. PESA Radar • PESA Pros and Cons
- Electronically scanned beam: e-scan
- Short range: all solid-state transmitter
- Long range: high-power vacuum tube transmitter
- Better than mechanical scan: longer life, more reliable
- Pulse type, frequency agile, frequency hopping
- Narrow band mode, wide band mode
- Can be configured for ECM, passive scanning
- Multiple beam forming possible with digital processing!
- Compared to AESA
Lower cost
Lower power consumption
Lower internal heating
Less reliable: catastrophic single point failure
Less capability

26. 5. PESA Radar • N011M PESA Radar for Su-27
- X-band, 96cm diameter, slotted planar array
- Scan range: ±70º AZ, ±45º EL

27. 5. PESA Radar • SPAS (Strapdown Phased Array Seeker)
- No stabilization: antenna fixed on the missile body
- Measures look angle only
- Requires 3-axis rate gyros and an estimation algorithm
to produce LOS rate
- Mostly for air-to-air missile
- Installed on a stabilized platform
• Development programs
- US Air Force: Endo LEAP interception missile project
- US DoD: Dual-range missile
- MBDA (Europe): Air defense phased array seeker

28. 5. PESA Radar • ENDO-LEAP: Endoatmospheric Light Projectile
- Ballistic missile defense research program in 1990s

29. 5. PESA Radar • MBDA Meteor BVRAAM
- Beyond Visual Range Air-to-Air Missile
- 18cm diameter
- Advanced active radar seeker: detection, tracking and classification of targets

30. 5. AESA Radar
• AESA system with data link and multiple sensors

31. 5. AESA Radar
• Mechanical scanning versus AESA

32. 5. AESA Radar
• Multi-Function Radar

33. 5. AESA Radar
• AESA Concept

34. 5. AESA Radar • Digital Array Radar (DAR)
- Enabled by high levels of integration and Moore's law
- Flexibility: software-defined
- Real-time signal modification to task and condition
- Multiple frequencies simultaneously
- Different functions on different sub-arrays
- Different signals on different parts of the array: co-located MIMO

35. 5. AESA Radar
• OFDM DAR

36. 5. AESA Radar • AESA Pros and Cons
- Electronically scanned beam: e-scan
- Multiple beams and multiple frequencies at a time
- Fast scan rate
- Multiple target tracking
- Multiple tasks at the same time
- Robust against radar jamming
- All solid-state transmitter
- Pulse type, frequency agile, frequency hopping
- Narrow band mode, wide band mode
- Can be configured for ECM, passive scanning.
- Compared to PESA
More expensive
Far greater Internal heating
More reliable: graceful degradation

37. 5. AESA Radar • AESA Components - Antenna Radiating elements
T/R module
Beam-former
Beam-steering computer
- Exciter: waveform generator
- Receiver: RF signal digital conversion
- Signal processor: target detection
- Radar controller: synchronize, control and schedule radar operation

38. 5. AESA Radar • AESA Technical Issues
- Advanced active array architecture
Digital phased array radar system
- Polarimetric phased array
Dual-polarized phased array
- Multi-mission phased array
DBF: simultaneous multi-beams
Multi-frequencies
- System cost
- Maintenance considerations

39. 5. AESA Radar • Clutter Attenuation in AESA Radar
- Limited by hardware instability errors
Pulse-to-pulse phase/amplitude errors
Intra-pulse noise
- Major contributors to the clutter attenuation performance limit
ADC
1st LO
HPA
LNA
Exciter
- Active antenna improves system clutter attenuation
Errors are de-correlated across distributed HPA/LNA
Active antenna clutter attenuation: 57dB
Passive antenna clutter attenuation: 47dB

40. 5. AESA Radar • AESA vs PESA - Passive: high-peak power, low duty
1000 elements
1MW Tx power
1% Tx duty
10kW average power
20kW prime power at 50% PAE
- Active: low-peak power, high duty
5W T/R module
10% Tx duty
500W average power
2kW prime power at 25% PAE

41. 5. AESA Radar
• Digital Beam-forming (DBF) in AESA

42. 5. AESA Radar • Digital Beam-forming (DBF) in AESA
- Signal digitation at the radiating element / sub-array level
- Number of beams: limited by computation latency and data throutput
- DBF advantages
Increased instantaneous dynamic range (IDR): 60 dB → 77 dB
Improved clutter attenuation

43. 5. AESA Radar • Digital Beamforming in AESA
- Active digital beamforming
- FFT beamforming

44. 5. AESA Radar • Pulse Compression
- Matched filtering on receive: auto-correlation
- Use FIR filter

45. 5. AESA Radar • Doppler Processing
- Coherent processing interval (CPI)
- Processing demands: very low latency → fast memory and parallel
processing

46. 5. AESA Radar • High-accuracy Ultra-high-speed Signal Processing
- Huge range of received signal levels: 100 dB
- Quantization noise level should be well below the receiver noise floor
- High precision and high dynamic range of the data path
- SNR of 30 dB for reliable detection
• Radar Signal Processing Engine
- GPUs
- Multicore CPUs: Analog Device Tigersharc, Freescale's PowerPC
- DSPs
- FPGAs
• Signal Processing Processor

47. 5. AESA Radar
• AESA Signal Processing Chain

48. 5. AESA Radar • Doppler Processing
- Coherent processing interval (CPI)
- Processing demands: very low latency → fast memory and parallel
processing

49. 5. AESA Radar • Dual-Polarization Configuration Modes
- Alternating transmit and simultaneous receive (ATSR) mode
- Simultaneous transmit and simultaneous receive (STSR) mode
- Alternating transmit and alternating receive (ATAR) mode
- Cost comparison parameters
RF switch cost
Transmit chain cost
Receive chain cost
Digital beamforming processing
Off array signal processor

50. 5. PESA Seeker • Commercial T/R modules
- API Technologies X-band quad T/R module
- Zhuk AE quad X-band T/R module

51. 5. AESA Radar
• LIG NEX1 AESA prototype (2010): X-band, 10W x 500, 32dB gain,
antenna diameter 590 mm

52. 5. AESA Radar
• LIG NEX1 AESA: system block diagram

53. 5. AESA Radar
• LIG NEX1 AESA: antenna and T/R module

54. 5. AESA Radar
• RAVEN ES-05 radar for GRIPEN E multi-role fighter

55. 5. AESA Radar
• Raytheon AN/APG-79 for F/A-18E/F

56. 5. AESA Radar • Canted antenna arrangement - Coverage improvement
- Reduction of the structural mode RCS

57. 5. AESA Radar • AESA seeker example
- Japan: AAM-4B missile with J/APG-2 AESA radar seeker
- Russian: Upgraded R-77 with AESA seeker
• Related information very scarce!

58. 6. Automotive Radar • Automotive Radar Frequencies
- 24GHz UWB: GHz , -41dBm/MHz EIRP, 30/80m range, 20cm resolution
- 24GHz ISN NB: GHz, +20dBm EIRP, 30/70m range, 75cm resolution
- 77GHz: 76-77GHz, +50dBm EIRP, 60/250m range, cm resolution
- 79GHz: 77-81GHz, -3dBm/MHz EIRP, 30/80m range, 4-8cm resolution
- 122GHz: GHz, +20dBm/MHz EIRP, 3m range, 1-10mm resolution

59. 6. Automotive Radar • Automotive Radar Market
- Intense international competition: price, quality, reliability, performance
- Huge market, huge production quantities: $12 billion by 2025
- Emerging applications: smart car, self-driving vehicle
- Leader-ruled market
Sensor MMIC chips: Infineon, STM, NXP
Long range radar: Bosch (Germany), HELLA KGaA (Germany), Continental (Germany),
Denso (Japan), Delphi (UK), Autoliv (Sweden), Valeo (France), Conti-Temic, TRW, Hitachi
Fujitsu Ten, Mitsubishi Electric
Short range radar: Bosch, Tyco (M/A-Com), TDK, s.m.s GmbH, Siemens-VDO, Hella InnoSent
Valeo, MTS GmbH, Hitachi

60. 6. Automotive Radar
• Bosch 3G Long Range Radar (LRR), 77GHz SiGe MMIC

61. 6. Automotive Radar

62. 6. Automotive Radar

63. 6. Automotive Radar
• Bosch 3G Mid Range Radar (MRR)

64. 6. Automotive Radar
• APAR (Automotive Phased Array Radar) in Development
- A radar system on a chip: a single SiGe RFIC package, 77-81GHz, 100m range,
±50º scan, 16-element phased array receiver chip 5.5 × 5.5mm2
- Beamforming phased array: high resolution, high dynamic range, pedestrian detection
- R&D Magazine 2014 R&D 100 Award
- Toyota Technical Center, Ann Arbor
- UC San Diego (Prof. Gabriel Rebeiz): RFIC receiver chip
- Fujitsu-Ten
- Michigan Technological Research Institute

65. 7. Missile Defense/Guidance Radar
• AN/TPY-2
- X-band AESA, air-transportable, mobile
- Fire control radar for land-based ballistic missile defense (THAAD)
- High-resolution phased array radar
- Upgrade program: Raytheon, hardware and software upgrade, GaAs replaced with GaN
- Units 1: Phased array antenna, 2: Electronic equipment, 3: 1.1MW prime power unit
(diesel generator), 4: Cooling equipment, 5: Operator control unit

66. 7. Missile Defense/Guidance Radar
• AN/TPY-2

67. 7. Missile Defense/Guidance Radar
• AN/TPY-2 Technical Specifications
GHz, 1000km range, 9.2m2 aperture spanned by 72 subarrays
- Solid-state T/R module: 16W peak power, 3.2W average power, antenna elements
- Linear frequency-modulated intra-pulse modulation
- Scan angle: ±53º AZ & EL
- Distributed array processor connected to the radar control system via fiber-optic cable
- Radiating element: dielectric-loaded below cutoff waveguide fed by high dielectric
septum polarizer
- Rigid dielectric sandwich radome
- Multi-function:
Target search, acquisition, track, discrimination
Interceptor track
In-flight data uplink/downlink
Target classification/typing/identification
Intercept assessment
Forward-based mode: surveillance and detection of a ballistic missile
Terminal-based mode: part of THAAD integrated weapon system

68. 7. Missile Defense/Guidance Radar
• AN/SPY-6(V) AMDR (Air and Missile Defense Radar)
- S-band AESA, X-band AN/SPQ-9B for horizon search, radar controller suite
- GaN and GaAs MMIC
- Initial testing in 2016, combat system validation in 2017, IOC by 2023
- Adaptive digital beamforming, radar signal processing functionality
- Size-scalable aperture
Radar Modular Assemblies (RMA): 2'×2'×2', self-contained radar, time/phase-
synchronizable
RMAs are combined or stacked to form an aperture of varying sizes.
AN/SPY-6: 37 RMAs, 14'×14'
- Platform DDG-51 Flight III destroyer: four AN/SPY-6 panels for 360º coverage

69. 8. Conformal Array
• Commercial SOTM (Satcom -On-The-Move) system

70. 8. Conformal Array
• Conformal array geometry: seeker applications

71. 8. Conformal Array
• Alcatel: CAA for data transmission from LEO satellite
GHz, 3 simultaneously steered beams
- Semi-active array: azimuth 360º, elevation º
- 24 subarrays
- 24 power amplifiers drive the subarrays through a set of 8 3x3 Butler matrix
couplers (by CASA).
- Phase shifters at the inputs to the Butler matrices:
- RHCP
- 20dBi gain at EOC
- 377mm dia 173mm height

72. 8. Conformal Array
• ERAKO (Electronic Radar and Conformal Array Antenna) Demostration
- 30 subarray, microstrip patch elements, 10GHz
Knott(2012)
ERAKO(Electronic Radar with Conformal Array Antenna) demonstrator system
Conformal array: 9.4GHz, 15% bandwidth, scan range ±90º, outer 3 subarrays on both sides: matched terminated as dummies for reducing array edge effects. 24 subarrays active (fed by a conformal feed and calibration network), 330×200×165mm (minimum radius of curvature 83mm)
Ssubarray: gain 12dBi, inter-subarray mutual coupling < -20dB, 107×16×10mm

73. 8. Conformal Array • SI2 Technologies - Conformal phased array
- Wideband electronically (passive or active) steerable
- PCB-based antenna design

74. 8. Conformal Array
• ESA: Advanced antenna concept for aircraft in-flight entertainment
- Hemispherical phased array
- Tx/Rx, circular/linear dual polarization

75. 8. Conformal Array
• Patch Elements

76. 8. Conformal Array
• Tapered Slot Elements

77. 8. Conformal Array
• Waveguide Open End Elements

78. 8. Conformal Array
• Conformal Array on Missile Nosecone or Missile Body
- Element gain reduction in axial direction
- Mutual coupling: more difficult to model than planar array
- Array pattern synthesis
- Packaging and connection challenges
- Electronic scanning
- Low production cost
- Not mature technology
• Development Steps
- Conformal array and radiating element is a not limiting factor.
- Planar strapdown phased array seeker: passive
- Conformal phased array seeker: passive
- Planar phased array seeker: active
- Conformal phased array seeker: active

79. 9. Conformal Array
• Conformal Array on Missile Nosecone or Missile Body
- Element gain reduction in axial direction
- Mutual coupling: more difficult to model than planar array
- Array pattern synthesis
- Packaging and connection challenges
- Electronic scanning
- Low production cost
- Not mature technology
• Development Steps
- Conformal array and radiating element is a not limiting factor.
- Planar strapdown phased array seeker: passive
- Conformal phased array seeker: passive
- Planar phased array seeker: active
- Conformal phased array seeker: active

80. References D. A. James, Radar Homing Guidance for Tactical Missiles,
McMillan, 1986.
N. F. Palumbo, et al., "Principles of Homing Guidance", APL
Tech. Digest, 29(1), pp , 2010.