How-to: How Escort Positions the Transmitter Signals on the Map

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Overview

The Security Escort system uses radio frequency (RF) for alarm transmissions. This is a significant positive because it prevents normal construction from blocking the signal and helps to eliminate dead spots where the alarm could not be heard. The fact that RF energy passes through normal construction also prevents Security Escort from locating an alarm with 100% certainty to a specific side of a wall. Alarms originating at or near building walls will typically be indicated within 25 ft. (7.5 m) of the actual location, however there may be times when the computed location may appear to be on the other side of the wall. Security Escort system was designed to provide a computed alarm location typically within 25 ft. (7.5 m) of the actual location when indoors and a computed alarm location typically within 50 ft. (15 m) of the actual location outdoors. Any deviation from the following installation guidelines will degrade the computed location accuracy.

To estimate the number of indoor Receivers, assume the receivers will be placed on a grid with a maximum spacing of 80 ft. (25 m) between Receivers for standard construction. In multi-floor applications the Receivers on each floor must be placed directly above the Receivers on the floor below (this is required for proper floor-to-floor location).

For example, to determine the number of Receivers required to protect a building of standard construction of 60 m (200 ft.) by 30 m (100 ft.) and four floors:

1. To determine the number of Receivers in each direction, divide each dimension of the building by 25 m (80ft.) and drop the remainder and add 1.(60 m/25 m = 2.4 becomes 2 add 1 = 3 and 30 m/25 m =1.2 becomes 1 add 1 = 2) or (200 ft./80 ft. = 2.5 becomes 2 add 1 = 3 and 100 ft./80 ft. =1.25 becomes 1 add 1 = 2)
2. To determine the number of Receivers required per floor, multiply the number of Receivers in one direction by the number of Receivers in the other direction. (3 x 2 = 6) 6 Receivers per floor.
3. To determine the total number of Receivers, multiply the number of Receivers per floor by the number of floors. (6 x 4 = 24) 24 Receivers for the building.

Each floor would require 6 Receivers, resulting in a total of 24 Receivers to protect this building.

To estimate the number of Receivers, assume a maximum Receiver spacing of 90 m (300 ft.) between Receivers, in both directions, for Receivers that are not within 30 m (100 ft.) of a building with inside coverage. Receivers within 30 m (100 ft.) of a building should be spaced at the spacing of Receivers in the building (spacing the outside Receivers at a somewhat larger spacing is acceptable in most cases). An outside area directly between two buildings with inside protection will need no additional Receivers if the buildings are 90 m (300 ft.) or less apart. If the buildings are more than 90 m (300 ft.) apart the outside Receivers should be placed evenly spaced between the buildings. Make sure the standard 90 m (300 ft.) spacing is not exceeded. For spacing outside adjacent to a covered building, start the 90 m (300 ft.) spacing at the building wall.

Issue

How does the Escort software place a triggered transmitter on the map so safety personnel can send help to the correct area?  

Solution

Picture a football field with a receiver in each corner.

If you trip the transmitter from anywhere on the field, it will place you with in 25 feet of where you are. Now if you trip the transmitter from the parking lot it will pull you back toward the field because all the receivers are in each corner of the field.

In order to protect the parking lot there needs to at least 1 receiver on the parking lot far side. 2 receivers would give better placement. 

A true to life application you need a Receiver every 300 feet outside. As long as you are some where within the covered area the receiver will place you within 25 feet of your location.