1. Analysis of the PAVE PAWS Radar (AN/FPS-115)
Nichole Hemmingsen
4/26/17

2. Outline Overview of PAVE PAWS RADAR Transmitter Characteristics
Antenna Characteristics
Deliverables
Maximum Detection Range Analysis

3. Overview PAVE PAWS Radar:
Precision Acquisition Vehicle Entry Phased Array Warning System
Developed in 1980 for use during the Cold War
An Air Force Space Command radar system
Uses:
Detect and characterize a sea-launched ballistic missile (SLBM) attack against the United States
Track satellite position and velocity information
Original Locations:
Cape Cod Air Force Station (Massachusetts) & Beale Air Force Base (California)
Robins Air Force Base (Georgia), Eldorado Air Force Station (Texas)
Aerial View of AN/FPS-115 PAVE PAWS phased array warning system radar site in Cape Cod [3]

4. Overview Cont’d Long range, ultra high frequency
105 foot tall transmitter building
Two faced, solid-state active aperture phased array radar
Each face covers 120 degrees (240 total degrees of azimuth)
Uses 1,792 active Tx/Rx modules per face (2,677 total)
Crossed dipoles used, creating vertical and horizontal polarization
Phased array design allows interweaving of tracking pulses with surveillance pulses
Ability to track multiple targets and keep up on surveillance
Faces are tilted back 20 degrees to allow for an elevation angles from three degrees to 85 degrees above horizontal
Crossed dipole antenna elements that make up the plane array [3]

5. Transmitter Characteristics
Peak Power: 600 kW (per face)
Average Power: 150 kW
Frequency Range: 420 – 450 MHz
Wavelength: 67 – 71 cm
Total PRF: 77 pps
Track Mode: Variable up to 25 pps
Search Mode: 40 pps
Duty Cycle: 25%
11% search
14% track
Waveform
Type: Chirp
Track Pulse Length: 0.25 to 16 ms (0.1 MHz chirp bandwidth)
Search Pulse Length: 0.3, 5, & 8 ms (1 MHz chirp bandwidth)
[5]
AN/FPS-115 Console [3]

6. Antenna Characteristics
Fixed-based solid state phased array
Gain
Mainbeam: 38 dBi
First sidelobe: 18 dBi
Polarization: Left and right circular
Beamwidth: 2.2º (azimuth and elevation)
Vertical Scan: 3º-85º
Horizontal Scan: ±60º
Maximum Range: 3,500 miles
[5]
AN/FPS-115 Transmitter Building [3]

7. PAVE PAWS (blue) and BMEWS (red) coverage [3]
1986 Cape Code PAVE PAWS computer room [3]

8. Deliverables
Maximum detection range of a 1 𝑚 2 RCS target with an SNR of 13 dB
Range accuracy of a 13 dBsm target at a range of 100 km
Radial velocity resolution
Maximum target speed for tracking

9. Maximum Detection Range
Minimum detectable signal (MDS) is the minimum received power that the radar receiver can sense
Maximum detection range can be calculated using the MDS
MDS is denoted as 𝑃 𝑟
Maximum detection range is denoted as 𝑅 𝑚𝑎𝑥

10. Maximum Detection Range
𝑅 𝑚𝑎𝑥 = 4 𝑃 𝑡 𝐺 2 𝜆 2 𝜎 𝑃 𝑟 (4𝜋) 3
𝑃 𝑟 is the minimum detectable signal [W]
𝑃 𝑡 is the transmitted power (600 kW)
G is the gain of the antenna (38 dBi)
λ corresponds to the wavelength (0.69 m)
σ is the radar cross section (1 𝑚 2 )

11. Minimum Detectable Signal
𝑆𝑁𝑅= 𝑃 𝑟 𝑃 𝑁
Signal to noise ratio is 13 dB
𝑃 𝑁 =𝑘 𝑇 𝑜 𝐵𝐹 [W]
k is Boltzmann’s constant (1.38 𝑥 10 −23 J 𝐾 −1 )
𝑇 𝑜 is the absolute temperature (290 K)
B is the receiver bandwidth (0.1 MHz for track, 1 MHz for search)
F is the receiver noise figure (4 dB)

12. Smith, John Q., David A (1991). Forty Years of Research and Development at Griffis Air Force Base: June 1951—June (Report). Rome Laboratory. Retrieved
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