Movement Constraint-based Location Tracking

Researchers at the Pusan National University, Korea have a new paper on Applying Movement Constraints to BLE RSSI-Based Indoor Positioning for Extracting Valid Semantic Trajectories.

The received signal strength (RSSI) of beacons is often used to infer location. However, the RSSI is subject to reflection and blocking from walls, people and other obstacles causing the derived locations from the raw data to be ‘jumpy’. There are many ways to process the raw data, such as Hidden Markov Models, k-nearest neighbors and Deep Neural Networks (DNN) to obtain smoother trajectories.

The researchers use movement constraints and sliding-window aggregation to extract invalid trajectories and provide real-time semantic trajectories.

The paper shows the proposed movement constraint-based approach extracts valid trajectories that are comparable to the unconstrained and non-machine language approaches. This new approach is particularly suited to dynamic indoor environments where the reflection and blocking changes over time.

Programmable Beacons

Many people come to us asking for “programmable beacons” when in fact they want beacons with configurable iBeacon UUID, major and minor. All beacons allow the UUID, major and minor to be changed, usually via an iOS and/or Android app and sometimes via USB/UART for changing the values, over time, via a program.

Truly programmable beacons are those where the internal software can be updated. The beacon contains a system on a chip that’s small computer running code to implement the beacon functionality. In most cases, the software can be updated via pins on the PCB:

Programming pins in the centre

Programming requires use of a programmer:

Segger J-Link Programmer

It can be fiddly to program larger numbers so you use a custom-made jig:

BeaconZone Programming jig

It’s not possible to see and update the existing code in a beacon. Any newly uploaded program has to be created from scratch. This is called emdedded programming, is non-trivial and takes of the order of months. Our SensorMesh™ was created this way.

Read about custom beacons

Bluetooth Technical Resources

Silicon Labs is a Bluetooth module manufacturer and solutions provider. Over the years they have created a large number of useful technical notes. They have just created a master list that allows easier access to the notes. Here are some that more general, less proprietary and not specific to Silicon Labs’ modules:

Bluetooth advertising data basics

Bluetooth Tx power settings

Throughput with Bluetooth Low Energy technology

Bluetooth advertising using manufacturer specific data

BLE Basics (master/slave, GATT client/server, data RX/TX)

Understanding the Bluetooth Connection Process

Bluetooth Mesh Training resources

Understanding Sensor Beacon Accelerometer Data

In this post we will take a look at data from the INGICS iGS01RG beacon.

The x axis is time. You can see the x, y and z values, every 100ms, over time. The y axis is normalised between -1 and -1 for use in our SensorCognition Edge device. The chart is for when the beacon has been moving, followed by a stationary period. Notice how the orange line continues to show acceleration even though the beacon isn’t moving. This is caused by gravity.

In this chart the beacon has been flipped over and the orange line now shows a constant negative acceleration.

A good thing about the presence of a constant offset in one of the x y z inputs is that it can be used to help determine the orientation of the beacon. The less desirable aspect is that the offset significantly complicates using the x y z to determine types of movement such as human gestures.

Such complex data problems are more easily solved using AI machine learning than trying to write a traditional algorithm to make sense of the data.

Here’s an example of output from a SensorCognition Edge device trained with up and down movement and left and right movement. In this case, the output 227 is showing the beacon is moving left and right.

Read about SensorCognition

Quick Detection of Man Down with MOTOTRBO™, TRBOnet and iBeacons

TRBOnet is control room software for Motorola MOTOTRBO™ two-way radios. When used with iBeacons, it allows mapping of 2-way radio locations.

The location update rate depends on the degree of radio congestion. The more radios there are the greater the congestion. The use of iBeacons also increases radio congestion as they cause more location packets to be sent. This can become a problem in larger 2-way radio/beacon rollouts.

In cases where a 2-way radio can see more than one beacon, the TRBOnet server uses the relative signal strengths of the beacons to determine the nearest beacon. In the case of radio congestion, the location updates for the two or more beacons might be two far apart, in time, to allow an accurate location to be determined. In congested situations, location updates used for geofencing or man-down might also come in far too late, say 5 minutes late, to provide timely alerts that someone has entered/exited an area or has fallen.

Neocom Software, the authors of TRBOnet, have introduced an Option Board based solution (pdf), that fits in the 2-way radios, that solves these problems. It monitors beacons every 3-5 seconds instead of the standard 30 seconds. It does the comparing of beacon signal strength at the 2-way radio rather than at the server to reduce the number of sent location packets. It intelligently sends location packets as the user changes zone rather than continuously.

The configuration guide (pdf) explains how the option board can be set up to detect events such as man down, geofencing, lone worker (no activity), no movement, crash detection and speed limit.

Are you an established 2-way radio company?
Contact us for advice on which beacons we have supplied for use with TRBOnet.

The Demise of Unsolicited Marketing Using Beacons

There’s a new article at DIGIDAY on how Apple’s new privacy features have further rattled the location-based ad market. The iOS location and Bluetooth permission changes have caused users to opt-out of marketing messages:

Right now opt-in rates to share data with apps when they’re not in use are often below 50% … Three years ago those opt-in rates were closer to 100%

Benoit Grouchko, Teemo

80% of those users stopped all background tracking across their devices

Location Sciences

Google’s discontinuing support for Android Nearby notifications and Apple’s tightening of permissions have caused the demise of unsolicited marketing using beacons. This is understandable because unsolicited marketing is seen by end-users as intrusive and creepy.

However, the iOS and Android mechanisms are still there for more worthy applications such as visitor space usecases that need to provide location based information. For these types of application, there’s the need for good app onboarding explaining location and Bluetooth usage in order to provide the location-based information that the end-user is requiring.

While unsolicited marketing was the key benefit when iBeacon was first announced, the use of beacons has since diversified into less contentious and more practically useful areas such as real time locating (RTLS), IoT Sensing and insights through machine learning.

Wiliot Announce Initial Partners

Wiliot have announced their initial set of partners. Wiliot is a new Bluetooth beacon that looks like a wafer thin NFC sticker but actually uses (wireless) energy harvesting with a very low power System on a Chip (SoC). This brings down the size and cost to allow integration into manufactured goods.

The initial partners are symbiotic in that they will help provide for initial rollout. They include Avery Dennison for tag production, SATO for tag printing, Evrythng for a cloud backend, Aruba for integration into WiFi and Fanstel and Estimote for gateways.

Bluetooth in Healthcare

The Bluetooth blog has a recent post on 4 Reasons to Use Bluetooth in Your Healthcare Facility. It explains some advantages of Bluetooth and mentions some uses within healthcare.

Bluetooth can be used as a way of connecting wearables and equipment to other devices. When equipment and people are Bluetooth-enabled, asset tracking and wayfinding become possible. Staff can quickly locate valuable hospital assets and patients in need for urgent care.

Another reason for using Bluetooth is reliability. The article mentions Bluetooth’s adaptive frequency hopping (AFH) that makes communication more reliable in noisy wireless environments. You can read more about the technical aspects in our post on Bluetooth LE on the Factory Floor.

A further reason for using Bluetooth, particularly Bluetooth LE, is low power. Stand-alone devices can work on coin-cell batteries for many years.

The final reason given for using Bluetooth is the ability to create larger site-wide networks using Bluetooth mesh. Mesh can be used for control, monitoring and automation systems without the need for WiFi that can be unreliable and congested in hospitals.

For a further look at usecases, see the post on RTLS in Healthcare.

UPS Shipping Update

We have been using UPS shipping for just over a month now and have just refined our shipping options based on past customer orders and our costs. UPS offer two main services, UPS Standard that goes by road and UPS Express that goes by air.

We have found that UPS Standard to some European countries is taking 5 to 6 business days which we can now improve on for some countries. For Italy, Spain, Austria, Finland, Greece, Denmark and Sweden we now always send by UPS Express (by air) for a similar cost as was the case for UPS Standard. This has a delivery time of 1 to 2 days to most business areas.

UPS Standard goes via the new London Hub that shows as ‘Stanford Le Hope, United Kingdom’ in the tracking. This is UPS’s largest single infrastructure investment outside of the United States. View the video:

The London Hub is 32,000-square metres in size and has a capacity to process up to 28,000 packages per hour. It’s part of UPS’s $2 billion infrastructure investment programme in Europe.

UPS Express gets to via East Midlands airport by the evening of the day it is picked up from us and shows as ‘Castle Donington, United Kingdom’ in the tracking.

UPS Freight Flight from East Midlands Airport/Castle Donington

Freight flights leave every evening to Europe and North America that are delivered in 1 to 2 working days to Europe and 2-3 days to N America.

View the shipping page for a summary of delivery costs and time scales.

INGICS Bluetooth Gateway MQTT Service Levels

The INGICS iGS01S (WiFi) and iGS02E (Ethernet) gateways support MQTT to send data to a server.

iGS01S Bluetooth LE WiFi Gateway

MQTT defines three levels of Quality of Service (QoS) that relate to whether requests are resent if not acknowledged:

  • 0 – The broker/client will deliver the message once, with no confirmation.
  • 1 – The broker/client will deliver the message at least once, with confirmation required.
  • 2 – The broker/client will deliver the message exactly once by using a four step handshake.

The INGICS gateways only support QoS level 0. This is because these gateways have lower memory and processing capability. They don’t have enough memory to queue unacknowledged requests required of other QoS levels. The extra processing would also significantly impact the performance and hence throughput.

If you need a higher MQTT service level then try the Minew G1 that supports QoS levels 0 and 1.