EENA 2021 - Advanced Mobile Location (3/3)

Confidential & Proprietary
Android ELS
New Developments since EENA 2019
October 6, 2021
Email: android-emergency-location@google.com
Website: crisisresponse.google/els

Agenda
2
• New ELS features/capabilities
• ELS Data SMS v2
• International roaming
• ELS error rates: troubleshooting & best practices

Emergency
call initiated
by Android
device
Using FLP, ELS
computes location
on-device; data sent
directly to endpoint as
Data SMS AML or
HTTPS message
Endpoint is set up and managed by
ELS Partner, who is responsible for
making ELS data available to
Emergency Services (push or pull).
AML - Advanced Mobile Location,
open standard for sending
emergency location (supported by
Android ELS)
ELS Endpoint: a SMSC or HTTPS
server maintained by partner that
can receive ELS emergency location
data
ELS Partner: carrier/MNO,
government or public safety vendor
that meets ELS partner requirements
PSAP/ECC (Public Safety Answering
Point/Emergency Communications
Center): call center & dispatch
control for emergency services
Google’s Responsibility Partner’s Responsibility
ELS data flow primer
3

ELS is operating at scale: live in 34 countries,
covering a population of 950 million people and
making over 600,000 emergency calls a day
Fully deployed Partially deployed

Emergency Time 2021/09/28 2:21:20 PM
Emergency Number 999
IMEI 123456789001234
Location Time 2021/09/28 2:21:23 PM
Latitude 51.53333,
Longitude -0.12545
Accuracy 7.54
Altitude 36
Vertical Accuracy 2.5
Floor 10
Language en-GB
Car Crash Time 2021/09/28 2:21:16 PM
Altitude/Z-axis
6
ELS provides XYZ location coordinates
(Z-axis in meters above ellipsoid format)

In an emergency,
location is the most
critical information
… but we’re also
making ELS more
helpful to emergency
responders by
sending additional
information
7
Device Language Car Crash Context

Additional Data goal & principles
8
Goal: Send meaningful additional data that can help reduce
emergency response times.
• Privacy first
• Maintain the highest standards for data privacy and security, and give users
a clear and meaningful way to control it.
• The right content at the right time
• Send only contextual, relevant data when it can help save lives.
• Prioritize the most important content
• Never sacrifice critical content delivery or speed by including unnecessary
data.

Language
9
In 2018, the San Francisco PSAP received
18,278 emergency calls requiring translation.
It can take several minutes to identify caller
language and get translators on the line.
Sometimes it can take 10 minutes or longer.
ELS provides an emergency caller’s device
language setting.
Call takers can use this to ask for a specific
translator right away - reducing translation
times by minutes.
SOLUTION

Car Crash Detection
In the US, ~1.25m people die in crashes a
year and 20-50m more are injured or
disabled.
Call takers want to know as fast as
possible where and what the emergency
is in order to take action quickly.
ELS provides information that a Pixel*
user has been in a car crash.
Call takers can use this to get an early
and quick indication of the situation, and
start dispatching help.
SOLUTION
10
* Pixel 3 and later, available in English, Spanish & Japanese in the US,
UK, Ireland, Spain, Singapore, Australia, and Japan.

ELS Data SMS 2.0
11

ELS Data SMS 2.0 key takeaways
12
• Updates the original spec to include useful fields that provide
additional context/situational awareness.
• Google plans to continue to support ELS Data SMS v1.0
• Will conform with EENA’s proposed AML 2.0 specification to ETSI.
• … But will also include parameters that ETSI may or may not include in
AML 2.0, such as:
• Emergency number dialed/texted
• Default language setting in the device
• Piloting with 1 country, looking for more!

Confidential & Proprietary 13
Key Name Value Units Example
A”ML Version - 2
en New! Emergency Number - 911
et Timestamp of emergency call Epoch time in secs
(integer)
1593187189
lo Location (latitude, longitude, accuracy) - latitude and longitude must be
truncated to 5 decimal points, accuracy to 1 decimal point - an accuracy of
0 represents unknown
Degrees (float),
degrees (float), meters
(float)
37.42175,-
122.08461,20.1
lt Location time (relative to emergency time) - this field may be ignored if no
location (“lo”) field is present or no timestamp (“et”) field is present
Secs (integer) 5
lc Location Confidence* - may be ignored if no location (“lo”) field is present Percentage (integer) 68
lz New! Vertical Location (altitude, vertical accuracy); may be ignored if “lo” field is
present. All fields truncated to 1 decimal point (0 accuracy = unknown)
Meters (float), meters
(float)
-10.1,10.1
ls Location Source (wifi, cell, gps, fused, unknown) - this field may be ignored
if no location (“lo”) field is present
‘W’, ‘G’, ‘C’, ‘F’, ‘U’ W
ei IMEI - 355458061005220
nc Network MCC/MNC - 310260
hc Home MCC/MNC - 310260
lg New! Language Tags IETF BCP 47 en-US

International Roaming
14

Visited Network
Home Network
Roaming option #1: Long Number
15
Visitor’s Device
Visited MSC
Home SMSC
PSAP
ELS Data SMS is routed to the home network SMSC and to the PSAP using a long number
ELS
SMS
+CC123456
+CC123456

Visited Network
Roaming option #2: Orange Belgium
16
ELS Data SMS is redirected at the visited network to a dedicated roaming SMSC that
specialises in AML messages to be sent direct to the PSAP
Visitor’s Device
Visited MSC
PSAP
ELS
SMS
911
SMSC: +CC911
SMSC: +CC911

Visited Network / Wi-Fi
Roaming option #3: HTTP
17
Internet
Roaming data-plan / Wi-Fi allows the ELS HTTP message to be sent direct to the PSAP
R
Visitor’s Device
PSAP
ELS
HTTP
https://…

Comparing error rates: 2 Data SMS options vs HTTP
18
Data SMS Orange Belgium option
Data SMS Long Number option
Note: Orange
Belgium Data SMS
option would have
lower error rates if all
networks could
accept SIM-less
messages
HTTP

ELS Error Rates:
Troubleshooting & Best Practices

ELS call
ELS message
received
Compute
location
Y
N
Error
Y
N
Error
Send
location

# of Failed ELS messages
Total # of ELS Messages
ERROR RATE

Error rates can vary across and within countries
22
Country 1
Country 2 Country 2
Country 1

Common root causes behind errors
23
1. Network/Hardware/Software Policies and/or Architecture
• Some MNOs, SMS infra vendors or device OEMs have configured their
systems/devices to hold all SMSes:
i. During an emergency call
ii. When device is emergency camped (roaming/in SOS mode)
* Issue specific to 1 MNO, may be an edge case

24
1. Network/Hardware/Software Policies
2. Circuit Switched Fallback (CSFB)
• When an LTE network is not available to make/receive a 112 call or SMS
message, the device “falls back” to a more accessible 3G/2G network to
finish the call or send the SMS message
* Issue specific to 1 MNO, may be an edge case

25
1. Network/Hardware/Software Policies
2. Circuit Switched Fallback (CSFB)
• When an LTE network is not available to make/receive a 112 call or SMS
message, the device “falls back” to a more accessible 3G/2G network to
finish the call or send the SMS message
3. SMS-over-IP on VoLTE devices
• Some LTE phones don’t support SMSoIP > unable to transmit ELS message(s)

Changing network/SMSC config improved error rates
26

ELS call
ELS message
received
Compute
location
Y
N
Error
Y
N
Error
Send
location

ELS Partner
Location
Database
ELS Endpoint
Mobile Network
Operator
Goog
le
29
SMS Center
in each
network
ECC/PSAP
ELS
Data
SMS
SMS Aggregation
Service

Troubleshooting 101
What Dedicated debug session with MNO’s network elements engineer(s) , ELS Partner
and PSAP call taker(s)

Troubleshooting 101
How Make 50-100 emergency calls using the ELS Manager app and a SIM from the MNO

Troubleshooting 101
Where Or in a lab or in live network but with all different infra vendors

Troubleshooting 101
Where Or in a lab or in live network but with all different infra vendors
Why Send & trace the progress of ELS test messages through the mobile network to see
if the messages are delivered successfully to/from the Endpoint.
If not, understand why and where in the process/network issues occur or the ELS
message fails.

Detailed summary of roaming options
36
Long Number Orange Belgium* HTTP
HOW • Get a long number from an MNO that can
receive SMSes & is reachable from other
countries
• Request Google configure long # for int’l
routing
• ELS messages routing: Android Device →
Long # → Visitor’s Home SMSC → Visited
Country’s SMSC
• Set up a logical new SMSC with a specific
address that will be used to manage int’l
roaming ELS messages
• Request MNOs to use this specific address -
- with MCC and emergency #s of the visited
network
• Web server to handle ELS HTTP requests
PROS • Easy to set up • Better reliability, lower error rate
• No major investment required of MNOs
• Easily replicable, works for 2G/3G/4G/5G
• No out-of-country SMS fees for the visitor
• Easy to set up
• Richer ELS data (e.g. additional data)
• Low error rates (depending on
connectivity)
• Easily replicable, works for 2G/3G/4G/5G
CONS • Low reliability, high error rate
• Visitor could incur out-of-country SMS
fees
• Requires working closely with 1 MNO to set
up a new SMSC for int’l roaming
• MNOs must modify network + network rules
to successfully route ELS messages
• Require cellular data plan
• Can be less reliable (varies by country)
• Dynamic MSISDN issue
* EENA webinar on Orange Belgium approach @ https://eena.org/knowledge-hub/webinars/solution-aml-roaming/

EENA 2021 - Advanced Mobile Location (3/3)

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