Approximately one-half of the MPARs would be sited on or very near to airports as a replacement for current Airport Surveillance Radars (ASR) and Terminal Doppler Weather Radars (TDWR). The associated requirement for very short-range (250 m minimum) aircraft and weather surveillance creates a number of operational disadvantages:
(1) MPAR's low peak-power transmitter will require the use of long pulses and receiver pulse compression to achieve necessary energy-on-target for full-range surveillance. Much shorter, low-energy "fill-pulses" are needed for surveillance in the vicinity of the airport. These must either be transmitted on a separate frequency (increasing spectrum utilization and receiver complexity) or as separated pulse-transmissions (thus increasing time utilization). In addition, the low energy associated with these fill pulses may require a larger aperture and higher dynamic-range (i.e. higher-cost) system to meet requirements for on-airport detection of low reflectivity weather phenomena such as "dry" microbursts and gust-front fine lines;
(2) Radial-velocity signatures of significant weather phenomena may be more difficult to detect at very short range. For example, the convergent radial velocity signature associated with a gust front vanishes as it approaches the radar and becomes radially aligned. A microburst occurring on top of an on-airport radar produces positive (outbound) radial velocities at all azimuths, which is very different from the signature of a microburst displaced even a few kilometers from a radar;
(3) Strong ground clutter returns at very short range, for example from airport buildings, may impact detection performance in operationally significant areas.
This paper describes a hybrid-multistatic MPAR configuration that would mitigate each of these disadvantages. Instead of a single, outward-looking aperture (multi-faced or cylindrical), multiple apertures would be deployed around the perimeter of the airport facing inwards. For example, four separated planar faces could be deployed along the cardinal directions with separation of roughly 10 km. Inside this network, long-pulse returns would be processed multi-statically with transmit-receive pairs selected as a function of the location of each resolution volume to achieve favorable bistatic angles. For returns from well outside the network, data would be processed monostatically. A key enabler for this approach will be the receive apertures' capabilities to stare with multiple simultaneous receive beams at the many resolution volumes to be processed along the radial of the transmitted long pulse. In addition, a null in the direction of the direct signal from the transmitter will be needed. Current progress towards element-level-array digitization makes it likely that the necessary degrees of freedom will be part of the MPAR system.
The paper will describe in detail a representative configuration for Multistatic MPAR. Topics covered include appropriate waveforms and processing, requirements for inter-aperture pulse transmission coordination, impact (if any) on timeline, implications for MPAR system design (e.g. aperture size and/or receiver dynamic range), sensitivity and multistatic Doppler measurement accuracy as a function of location.
This abstract was prepared with funding provided by NOAA/Office of Oceanic and Atmospheric Research under NOAA-University of Oklahoma Cooperative Agreement #NA11OAR4320072, U.S. Department of Commerce. The statements, findings, conclusions, and recommendations are those of the author(s) and do not necessarily reflect the views of NOAA or the U.S. Department of Commerce.
- Indicates paper has been withdrawn from meeting
- Indicates an Award Winner