In satellite-based precise positioning, the dominant factors, as discussed previously, are the number and geometric distribution of the satellites tracked by the receivers. In the case of Global Navigation Satellite Systems, four visible satellites are the minimum requirement for precise three-dimensional positioning.

In general, the more satellites that are tracked, the more reliable the positioning solutions. However, in situations, such as in downtown urban canyons, engineering construction sites, and in deep open-cut pits and mines, the number of visible satellites may not be sufficient. In the worst situations, such as in underground tunnels and inside buildings, the satellite signals may be completely absent.

Pseudolite is a contraction of the term "pseudo-satellite," used to refer to something that is not a satellite. Our pseudolites are small transceivers that are used to create a local, ground-based GPS alternative. This Local Area Augmentation System incorporates a beacon, repeater as well as a GPS receiver. The range of each transceiver's signal is dependent on the power available to the unit.

Being able to deploy a self contained positioning system, independent of the GPS, is critical in situations where the normal GPS signals are either blocked/jammed, or simply not available.

Alcyone System has dealt with this problem with existing GNSS systems by augmenting the network with the inclusion of additional ranging signals transmitted from ground-based "pseudo-satellites" (pseudolites). These pseudolites are integrated with other sensors strategically positioned at the incident scene as shown in figure below where the pseudolites are highlighted as red stars.

These Pseudolites are used as an independent augmentation to the locator system. These Pseudolites have Received Signal Strength Indication (RSSI): This subsystem uses the radio signal strength of the beacon transceiver to measure the distance from an individual to the Command Station. This method is useful for homing in on an individual during a search and rescue operation.

They also act as a beacon for the first responder to be able to quickly backtrack to the exit point via a Pseudolites Deployment homing-based systems where the mobile unit can locate the direction from which the signal is emanating, to provide a direction to the source or locate alternative egress points if the original entrance has been obstructed via multiple pseudolites. This robust solution has redundancy built in for the means of location determination.