About the USPLN™
The USPLN™ provides real-time and archive lightning strike information,
as well as serving as the basis for value-added lightning services
to customers. Find out how the USPLN™ data are timely, accurate,
and provide information on each lightning stroke in real-time.
- Accuracy is equal to or better than 250 meters
- Lightning detection reports available in less than 1-minute
- Greater than 95% Detection Efficiency
- Individual stroke data (not flash) is reported.
Stroke reports include date, time, polarity, amplitude
and heading/distance from point of interest.
Stars represent Precision Lightning Sensor Locations
Operational nationwide, September 2004
The USPLN™ system uses a Time Difference of Arrival technology
that employs high resolution internal timing devices and GPS timing
as a reference. This design provides for a more stable accurate timing
source and subsequently improved data resolution and more accurate
location reports. See Technical Paper for more information.
Lightning occurs, sensors triangulate to time-stamp the signal and
send raw data to the Central Analyzer (ASP) where the data is quickly
analyzed, transformed to display...and displayed on your computer.
The PLS™ sensor is a modern design using state-of-the-art
technology. The primary advantages are focused around the self adjusting
front end sensitivity adjustment. Due to this design, the sensor provides
the best lightning signal-to-noise characteristics of any lightning
sensor available on the market.
Dead Time is the amount of time that the sensor takes to
prepare to be ready to detect the next event after sensing and processing
a lightning event. The Dead Time is settable by TOA, from a short
time of a few hundred microseconds to a much longer time between detections.
The shorter the dead time, the more lightning can be detected. Furthermore,
waveform discrimination is used to stop the same event from triggering
the system twice.
It is well established scientifically that a lightning flash
can contain multiple strokes, which can strike several kilometers
apart. The USPLN™ therefore detects, locates, and displays each
stroke in a flash in real-time, rather than combining multiple stokes
into a single lightning event.
The PLS™ sensor utilizes proprietary low frequency detection
methods and waveform discrimination in the sensor to enable the system
to calculate and display the location where the stroke hits the ground.
Some competing systems report the location of where the stroke passed
through the cloud, which is typically several hundred meters above
the ground and can be offset from the actual point of impact by many
kilometers.
The ALPS ™ lightning system is designed
to detect and differentiate between ground and cloud stroke lightning
events. This information is beneficial in identifying and displaying
storm cells that contain cloud-to-cloud lightning. Detecting both
types of strokes provides a better overall picture of the storm activity
and allows a forecaster to better analyze storm development and decay.
In order to improve the detection efficiency of cloud strokes additional
sensors may have to be installed in a region under investigation.
The ALPS ™ lightning system is also
able to locate lightning over very large distances (1000’s of
kilometers) using ionospheric sky wave propagation.
The system accuracy and resolution is the best available
on the market. The PLS™ timing resolution is
25 nanoseconds with an accuracy of about 40 nanoseconds. The dead
time can be as low as 200 microseconds. The timing is constantly monitored
and is corrected/adjusted automatically for temperature and aging
effects.
Remote maintenance is designed into the system. Diagnosis
and repair of software problems, and adjustment of sensor operating
parameters can be made from almost anywhere without a site visit,
using a dial up line or more typically the Internet.
Operational software upgrades and some hardware configuration
changes can be performed remotely via the communications link. This
eliminates the need for a costly and time-consuming site visit for
upgrades, bug fixes or hardware configuration changes. Typically the
maintenance operator communicates over the Internet to the Advanced
Stroke Processor, which, in turn, communicates to the sensor in question.
Due to the higher sensitivity of the system, a larger area
can be covered using fewer sensors.
The system is designed to communicate using a variety of
different means, such as the Internet, serial port, satellite communications,
or modem communications.
