1. MPAR Multifunction Phased Array Radar Multi-Purpose Airport Radar
Good morning. Our support for MPAR analysis comes from the FAA so my talk is going to be focussed on their interests to a significant extent. 1 1

2. ATC History Communication, Navigation and Surveillance Automation
Discrete Address Beacon System
Mode S
Surveillance and Communications
Microwave Landing System
Beacon Collision Avoidance System TCAS
UAS
Moving Target Detector
Communication,
Navigation and
Surveillance
Airport Surface Detection Equipment
ASR-9
Proc. Augmentation Card
SLEP
Parallel Runway Monitor
GPS Applications
Runway Status Lights
ADS-B
Mode S
Surface Comms
Airport Surface
Traffic Automation
GCNSS/SWIM
Automation
Terminal ATC Automation
NASA ATM Research
Storm Turbulence
I put this chart in just to indicate that our involvement with the U.S. Air Traffic Control System dates back almost 40 years now, and that a major component of our efforts have involved understanding and enhancing the nation’s aircraft and weather suveillance systems and the applications that ride on top of these.
Specifically: Mode-S, ASR-9, TCAS
TDWR, ASR-9 WSP, FAA Nexrrad applications
Point is that we understand surveillance requirements rather well!
Terminal Doppler Weather Radar
SLEP
ASR-9 Wind Shear Processor
NEXRAD Enhancements
Weather
Multi Function Phased Array Radar
Integrated Terminal Weather System
Aviation Weather Research
Wake Vortex
Corridor Integrated Weather System

3. ATC Real-Time Database
Collision avoidance
Radar
GPS
Flight plans update
Radar
Conflict resolution
Track data
Controller displays
Restriction avoidance
Real time database
Autovoice advisory
Terrain avoidance
Weather status
Pilot
Terminal conditions
Aircraft data

4. National Air Surveillance Infrastructure
Today
Future
ASR-9
ASR-11
ARSR-3
TDWR
ARSR-4
ASR-8
ARSR-1/2
NEXRAD
ADS-B
FAA transition to Automatic Dependent Surveillance Broadcast (ADS-B) dictates that the nation re-think its overall surveillance architecture. Needs:
Weather (national scale and at airports)
ADS-B integrity verification and backup
Airspace situational awareness for homeland security
MPAR
So from an FAA perspective, decision to implement ADS-B as primary a/c surveillance system is watershed event and requires rethinking of surveillance architecture. In the wake of ADS-B, the current national networks of primary and secondary aircraft surveillance radars are clearly sub-optimal.
What the next generation “non-cooperative” surveillance system needs to provide (and MPAR is part, but probably not the only part of that) is
Weather
ADS-B backup
Airspace Security

5. Today’s Operational Radar Capabilities
Function
Maximum Range for Detection of 1m2 Target
Required Coverage
Range Altitude
Angular Resol.
Az El
Waveform*
Scan Period
Terminal Area Aircraft Surveillance
(ASR-9/11)
60 nmi
60 nm
20,000'
1.4 5o
>18 pulses
PRI ~ sec
5 sec
En Route Aircraft Surveillance
(ARSR-4)
205 nmi
250 nm
60,000'
2.0
>10 pulses
12 sec
Airport Weather
(TDWR)
212 nmi 1
0.5
~50 pulses
180 sec
Nationwide Weather
(NEXRAD)
225 nmi
250 nmi
50,000'
>240 sec
Jeff Herd showed this chart yesterday so I can be brief
Key points in yellow box!
Weather surveillance drives requirements for radar power and aperture size
Aircraft surveillance functions can be provided “for free” if necessary airspace coverage and update rates can be achieved
Active array radar an obvious approach, but only if less expensive and/or more capable than “conventional” alternatives

6. Required Surveillance Performance (RSP) Methodology
Lincoln has been applying RSP methodology to understand whether alternative backup strategies, in particular MPAR, could provide the same level of service.
This chart summarizes the RSP analysis.
Basically involves a complete model of the surveillance chain including the sensor, date formats, and human display interface. Measured separation error PDFs associated with each of these stages are convolved to determine the end-to-end separation error distritubtion.
Reference system approach used to establish that system under test, in this case MPAR, has an end-to-end separation error PDF that is at least as compact as currently accepted surveillance systems.

7. RSP Derived from En Route Radar Capabilities*
Currently Acceptable
(sliding window SSR)
Latest Technology
(monopulse SSR)
Registration Errors
Location Bias
200’ uniform any direction
Azimuth Bias
 0.3 uniform
Range Errors
Radar Bias
 30’ uniform
Radar Jitter
 = 25’
Gaussian
Azimuth Error
Azimuth Jitter
 = 0.230
 = 0.068
Data Quant.
(CD2 format)
Range
760’ (1/8 NM)
Azimuth
0.088 (1 ACP)
Uncorrelated* Sensor Scan
Time Error
10-12 sec
Transponder Error
Range Error
(ATCRBS)
 250’ uniform
 = 144’
RSP Analysis
Location Error
 = 1.0 NM
  0.30 NM
Separation Errors
(at 200 NM
@ 600 kts)
 = 0.8 NM
 = 0.25 NM
90% <  1.4 NM
99% <  2.4 NM
99.9% <  3.3 NM
90% <  NM
99% <  NM
99.9% <  NM
Summarizes RSP analysis for currently accepted sensors providing 5 nmi separation capability in en route a/c. Critical measurement parameters are azimuth accuracy and refresh rate.
As you can see a separation error sigma of 0.8 nmi at full range is deemed acceptable for the currently defined ADS-B backup system.
*Only applies for multiple sensors
*Supports 5 nmi separation

8. RSP Derived from Terminal Radar Capabilities*
Currently Acceptable
(sliding window SSR)
Intermediate
(primary radar)
Latest Technology
(monopulse SSR)
Registration Errors
Location Bias
200’ uniform any direction
Azimuth Bias
 0.3 uniform
Range Errors
Radar Bias
 30’ uniform
Radar Jitter
 = 25’
Gaussian
 = 275’
Azimuth Error
Azimuth Jitter
 = 0.230
 = 0.160
 = 0.068
Data Quant.
(CD2 format)
Range
95’ (1/64 NM)
Azimuth
0.088 (1 ACP)
Uncorrelated* Sensor Scan
Time Error
4-5 sec
Transponder Error
Range Error
(ATCRBS)
 250’ uniform
 = 144’
N/A
RSP Analysis
Location Error
 = 0.20 NM
  0.15 NM
  0.10 NM
Separation Errors
(at specified 250 kts)
 = 0.16 NM
at 40 nm
 = 0.12 NM
 = 0.08 NM
at 60 nm
90% <  0.28 NM
99% <  0.49 NM
99.9% <  0.65 NM
90% <  0.20 NM
99% <  0.35 NM
99.9% <  0.46 NM
90% <  0.13 NM
99% <  0.23 NM
99.9% <  NM
Corresponding analysis for terminal airspace where 3 nmi separation criteria are enforced. In this case, separation error of 0.16 nmi is needed to establish RSP equivalent to today’s defined ADS-B backup system.
*Only applies for multiple sensors
*Supports 3 nmi separation

9. MPAR RSP Analysis
20:1 Monopulse
For MPAR, the most stressing RSP requirement in terms of system cost is azimuth accuracy, that is beamwidth, which of course relates to antenna size.
This chart just confirms my earlier point that an MPAR sized to provide angular resolution equivalent to today’s weather radars can easily meet the RSP requirements for maintaining current separation standards in the event of an ADS-B failure.
Note that we’ve assumed the active array will be used to develop monopulse patterns which allow for 20:1 improvement on angular resolution for discrete targets.
4.4 antenna beamwidth meets Terminal RSP Separation Error
4.6 antenna beamwidth meets En Route RSP Separation Error

10. Concept MPAR Parameters
Active Array (planar, 4 faces)
Diameter: m
TR elements/face: 20,000
Dual polarization
Beamwidth:  (broadside)
1.0 45)
Gain: > 46 dB
Transmit/Receive Modules
Wavelength: cm (2.7–2.9 GHz)
Bandwidth/channel: 1 MHz
Frequency channels: 3
Pulse length: s
Peak power/element: 2 W
Architecture
Overlapped subarray
Number of subarrays: –400
Maximum concurrent beams: ~160
Aircraft Surveillance
Non cooperative target tracking and characterization
I won’t go through this in any detail other than to point out that we’ve laid down a very specific design concept that’s based on Lincoln Laboratory’s 40 years of experience with ATC and weather surveillance needs.
We would be very happy offline to go through the rational for each and every number on this chart and the backup documents that we’ve put out.
Weather Surveillance
334 MPARS required to duplicate today’s airspace coverage. Half of these are scaled “Terminal MPARS”

11. Concept MPAR Capability Summary
Airspace coverage equal to today’s operational radar networks.
Angular resolution, minimum detectible reflectivity and volume scan update rate equal or exceed today’s operational weather radars
Ancillary benefits from improved data integrity and cross-beam wind measurement
Can easily support 3-5 nmi separation standards required for ADS-B backup
Can provide non-cooperative aircraft surveillance data of significantly higher quality that today’s surveillance radars
Altitude information
Substantially lower minimum RCS threshold
Because our concept is very specific, we can substantiate these assertions.

12. SLS

17. INTERROGATOR AND CONTROL TRANSMISSION CHARACTERISTICS (INTERROGATION SIDE-LOBE SUPPRESSION) The radiated amplitude of P2 at the antenna of the transponder shall be: a) equal to or greater than the radiated amplitude of P1 from the side-lobe transmissions of the antenna radiating P1; and b) at a level lower than 9 dB below the radiated amplitude of P1, within the desired arc of interrogation Within the desired beam width of the directional interrogation (main lobe), the radiated amplitude of P3 shall be within 1 dB of the radiated amplitude of P1.

19. 3. 1. 1. 6 REPLY TRANSMISSION CHARACTERISTICS Framing pulses
REPLY TRANSMISSION CHARACTERISTICS Framing pulses. The reply function shall employ a signal comprising two framing pulses spaced microseconds as the most elementary code. Information pulses. Information pulses shall be spaced in increments of 1.45 microseconds from the first framing pulse. The designation and position of these information pulses shall be as follows:

21. Special position identification pulse (SPI)
Special position identification pulse (SPI). In addition to the information pulses provided, a special position identification pulse shall be transmitted but only as a result of manual (pilot) selection. When transmitted, it shall be spaced at an interval of 4.35 microseconds following the last framing pulse of Mode A replies only. Reply pulse shape. All reply pulses shall have a pulse duration of 0.45 plus or minus 0.1 microsecond, a pulse rise time between 0.05 and 0.1 microsecond and a pulse decay time between 0.05 and 0.2 microsecond. The pulse amplitude variation of one pulse with respect to any other pulse in a reply train shall not exceed 1 dB.

22. Code nomenclature. The code designation shall consist of digits between 0 and 7 inclusive, and shall consist of the sum of the subscripts of the pulse numbers employed as follows:

23. END.