ALARM
is a generic
digital computer simulation designed to evaluate the
performance of a ground based radar system attempting to
detect low altitude aircraft. The purpose of ALARM is to
provide a radar analyst with a software simulation tool to
evaluate the detection performance of a ground-based radar
system against the target of interest in a realistic
environment. ALARM can simulate pulsed/Moving Target Indicator
(MTI), and pulse Doppler (PD) type radar systems and has a
limited capability to model continuous wave (CW) radar. Radar
detection calculations are based on the signal-to-noise (S/N)
radar range equations commonly used in radar analysis. ALARM
has four simulation modes: Flight Path Analysis (FPA) mode,
Horizontal Detection Contour (HDC) mode, Vertical Coverage
Envelope (VCE) mode, and Vertical Detection Contour (VDC)
mode.
The primary application of
ALARM is the evaluation of target detection range as a
function of the environment. The model now includes the
environmental effects of atmosphere, terrain masking, clutter,
multipath, and electromagnetic propagation through the use of
Joint Aircraft Survivability Program Common Modeling Component
Set (JASP CMCS). Land clutter reflectivity probability
distributions published by Massachusetts Institute of
Technology (MIT) Lincoln Laboratory and sea clutter
reflectivity probability distribution from the Center for
Naval Analysis (CNA) are also used in ALARM. Pattern
propagation effects such as radar antenna pattern, spherical
earth and knife edge diffraction and multipath are included by
use of the MTI Lincoln Labs Spherical Earth/Knife Edge (SEKE)
Diffraction source code. Terrain masking is determined based
on National Geospatial Intelligence Agency (NGA) Digital
Terrain Elevation Data (DTED), data input into the model for a
specific radar site area. Additionally, ALARM supports limited
modeling of onboard noise (self-screening) jammers, onboard
deception (coherent) jammers, and standoff noise jammers.
The input consists of user supplied engineering level
data such as transmitter power, pulse width, pulse repetition
frequency, antenna patterns, radar cross sections (RCS)
tables, and data needed to simulate pulsed/Moving Target
Indicator (MTI), and pulse Doppler (PD) processing. FPA mode
requires aircraft flight data parameters to be specified for
each data point. These parameters include; altitude, heading,
speed, bank, and pitch. Alternatively, the FPA mode can read a
BLUEMAX output file for the flight path data. HDC mode
requires a single aircraft speed and altitude. VDC mode only
requires a single aircraft speed.
Data
sets for threat systems are available.
The output consists of an output file and a data diary file.
The output file is an ASCII text file which includes a summary
of the simulation inputs. For FPA mode, the output file also
contains the target flight path information summary, which
gives detailed information for the target, jammers, target
masking and radar detection at each target location. The data
diary file contains the simulation results. Each simulation
mode has its own data diary format. The data diary can be in
ASCII or binary. The supporting post-processing programs use
the data diaries for generating plots.
