Handset-Based Location Implementation in Canada
E9-1-1 Phase II location functionality has enabled accurate locations for many wireless emergency calls in Canada.
AML and the availability of handset-based location data from Android (Google) and iOS (Apple) has progressed significantly in recent years and can supplement to improve location accuracy in indoor environments. These solutions calculate the location at the handset using GPS, cellular, and Wi-Fi sensors. This allows for more accurate locations than otherwise possible, especially indoors.
The Emergency Services Working Group (ESWG) has documented these recommendations in report ESRE0092 along with a recommended timeline for implementation in Canada. This blog post provides Comtech's perspective on these recommendations.
Canadian Aggregator Implementation
Aggregation provided by the NG911 Providers
The ESWG recommended AML architecture for Canada proposes to use the NG911 Providers as AML aggregators as shown in the figure below. In this implementation, each User Equipment (UE) will send their AML / device-based hybrid messages over HTTPS to each NG911 Provider, namely Bell, TELUS and SaskTel. Each NG911 Provider will act as an AML End Point, determine which Mobile Network Operator (MNO) the message is targeted for, and send the message to the MNO, e.g., MNO A as shown in the example below.
Mobile Network Operator Implementation
MNO Role in Delivering the "Best" Location
Once the AML result is delivered to the correct MNO, the MNO will then be responsible for evaluating the best location to send to the Public Safety Answering Point (PSAP) including Legacy PSAPs, as well as NG911 PSAPs. The MNO will be responsible to validate and certify the AML result to ensure it is not spoofed or otherwise significantly inaccurate. This can be done by comparing the AML result with a network-derived location to ensure consistency. The MNO will then be responsible to provide the ‘best’ location to the PSAP, whether AML or network derived. The ‘best’ location is the result with the smallest error to the 911 caller’s true location. However, since the error is unknown, the reported uncertainty is the next best metric to use to compare results.
In 4G/LTE networks, typically AML will provide the best result indoors due to Wi-Fi, Bluetooth and other sensors available on the device. Outdoors, often network-based location is more accurate given the ability to hybridize GPS with network-based techniques. The proposed solution from ESWG combines both device-based and network-based techniques in an optimal way to provide location results to PSAPs that are of the highest accuracy possible.
As we look forward to 5G location technologies and the various positioning techniques that will be available using Angle of Arrival (AoA) and Angle of Departure (AoD) measurements, we expect network-based location accuracy to significantly improve allowing for even greater accuracy when combined with AML.
Comtech Solution Summary
Comtech believes handset-based location combined with network-based location provides the optimal solution to ensure the best accuracy is always provided to PSAPs, whether the 911 caller is indoors or outdoors. Also, by combining these approaches the safety and security of 911 callers, PSAPs and emergency responders can be better protected against cyber attacks and other attempts to spoof locations.
Comtech’s solution includes AML End Point functionality that can be deployed to receive AML (device-based hybrid) messages directly from the devices. Also, Comtech’s Location Platforms are enhanced to integrate AML/device-based hybrid messages directly and to compare multiple results, including network-based locations, and to provide the most trusted accurate location to the PSAP.
Looking forward to 5G, Comtech’s integrated 5G positioning technologies will ensure the highest level of accuracy is provided to PSAPs for 911 calls made on the Canadian Wireless Networks.
If you are interested in learning more about Comtech's 5G options, contact us today for more information.
