LONG WAVE INC. — Department of Defense SBIR Phase I: N213-142

Description

Our innovation will be to develop an Adaptive Sounder Input Prediction (ASIP) module for the ACE HF Network™ application. ASIP will incorporate worldwide sounder inputs to update the Frequency Tables generated by the ACE™ propagation analysis engine. Additionally, we will research and design a solution for distributing the updated Frequency Tables to Battle Force Tactical Network (BFTN) Resilient Command & Control (RC2) System Enhancement (BRSE) users to affect greater network availability. The ACE HF Network™ propagation analysis tool utilizes Method 30 of the Voice of America Coverage Analysis Program (VOACAP) propagation engine for HF propagation prediction and ionospheric analysis. In addition to frequency plans for either point-to-point circuits or large networks. However, it is reliant on static input parameters to drive the predictive models. Once static parameters have been manually entered for each circuit or link in a network, the prediction is made for a specific 24-hour day, month, or year resulting in a frequency plan matched to universal time. While this approach has proven to be very useful, it is not adaptive in any sense except following predicted or measured Sun Spot Number (SSN) values and internal values (e.g., atmospheric noise) affected by changes in month, season or position. The distribution of active ionosondes across the world is not uniform. Many countries do not have the resources to build and maintain HF ionosondes, and the world’s oceans certainly reduce the available sites for ionosondes. The large antennas needed for a vertical sounding ionosonde would be difficult and expensive to deploy from a ship. Further, to do oblique propagation analysis, the ionospheric propagation parameters that must be used are half-way between the circuit participants. The answer to this lack of ionosonde resources is to develop techniques to extrapolate the data from available ionosondes to regions of the earth where HF propagation analysis is needed. The earth’s inclination with respect to the sun has to be included in this calculation. Note that this type of calculation is done routinely in the Photovoltaic (Solar) power industry to compute available power for different times of the year and at different Latitudes. Both a Longitude time shift and a Latitude solar intensity adjustment should allow extrapolated ionosonde values to be computed as if a vertical sounding ionosonde were at this remote location Suitable parameters of the channel model output by ACE HF Network™ will be modified adaptively within the ASIP module to improve prediction accuracy of frequency plans. These plans will be disseminated to individual networks and nodes (users) as needed in near real time and the entire process will be ongoing and achieved automatically.