A novel Indoor Positioning System (IPS)


Indoor Positioning System (IPS) using WiFi based localization

Watchman offers an accurate and low cost WiFi-based Indoor Positioning System (IPS) to track the movement of people and goods with in and across facilities. Movements are detected (and reported) if any one of the following conditions occur:

- change in signal strength

- change in WiFi network

- change in WiFi access point

The popularity and low price of WiFi access points, supporting position triangulation, is an attractive incentive to use WiFi as the basis for IPS (Indoor Positioning System). Power your Watchman either from with in (i.e. from the attached appliance or vehicle) or use USB power bank (it draws 100mA or less, click here for details). Here are some example use case:

  1. Locate members/patients with in large or multi-storey buildings for reasons such as quarantine-enforcement and providing help etc   
  2. Track the movement of automobile (cars,  trucks etc) across floors/zones of a given facility. You may be using GPS to track their inter-facility movement. Watchman's IPS will provide movement tracking when indoor (where GPS signal might not exist) at the facility. This way you will have complete tracking information en-route as well as in the facility.
  3. In hospitals and clinic, Watchman's IPS can locate and track wheel chairs and other portable medical appliances. 
  4. In shopping centers, large warehouses or any facility where there is need to move, track and locate goods, WiFi-based IPS offers a very low cost solution to deploy and maintain.  

Note: it is NOT a motion tracker, it is a location tracker based on the nearest WiFi it is able to connect to.

Access to logs and 6-day history with email alerts (to your login email) are free-of-cost. However, if you are looking for additional features such as SMS alerts, power/internet loss detection, add users and emails with daily log snapshots etc, you will require a subscription. Please click here for details. 

How does IPS work?

Our novel Indoor Positioning System (IPS) works with your  existing WiFi network. There is no additional hardware or change required in your existing WiFi infrastructure. You are ready to start as long as you have a separate 2.4G WiFi network. And if you do not, you may start with provisioning a guest WiFi at 2.4G on your existing WiFi router(s).

1) Connect your Watchman IPS to your WiFi network (follow setup instructions), call this as your "primary" WiFi.

2) Once connected and activated, you will program it, using our web portal, with a list (max. 5) of location WiFi networks, call them "locator" WiFis.

3) Every 5min, your Watchman scans the list of locator WiFis and saves the one(s) it is able to connect with. It records the successfully-connected-WiFi with maximum signal strength. The (new) record is then compared with the last one to determine if any one of the following conditions occur:

  • change in signal strength
  • change in WiFi network
  • change in WiFi access point

If so then the (new) record is pushed to the cloud and is logged into our portal. This is how you know that people/goods (that Watchman is attached to) has changed the location and you can track it by knowing connected WiFi network and access point.

If for some reason, Watchman is not able to connect to Internet (to push the new record to cloud) using locator WiFi, it retries using primary WiFi. This allows for the case where locator WiFi may not have Internet access.

As a new record is logged on the portal (indicating change of position), you can also configure to be alerted via email/SMS.  

If there occurs no (location) change that triggered a log for more than an hour, Watchman will send a keep-up log (with WiFi network info that it's been connected to). You will see such logs, showing up on the portal, approximately 1 hour apart. They simply indicate that though Watchman has not moved, it is still working and scanning for location change (if any).

For locations, where Watchman can see multiple locator WiFis at similar signal strength, Watchman is designed to not "swing" (as it scans locator WiFis) unless signal strength varies more than 5db. There may still be the situations where an interference causes signals to vary more than 5db and that makes Watchman to "swing" (i.e. connect to another locator WiFi whereas it has not moved). If you observe the "swing" behavior, you now know why it is so. And, over time, you will be able to easily identify them.  This is part of learning on your Watchman and how it is working with your locations. 

Introducing our Watchman IPS product

 Offers an accurate and low cost WiFi-based Indoor Positioning System (IPS) to track the movement of goods with in and across facilities. 

Use of Power Bank for IPS Watchman

IPS Watchman power draw is very low (100mA or less). Though it helps run IPS Watchman for long  (~2 months on a 100,000mAh power bank), the regular (low cost) power banks will not work with it. The  regular power banks shut off (automatically) when draw is too low (as is the case with IPS Watchman).  Here are your options:

  • Use always-on power bank. They are at higher price point and do not come in as large (power) bank size as regular ones.


  • Use 18650 Lithium battery power supply along with regular power bank. The 18650 Lithium battery power supply costs around $15 whereas you can buy a 900,000mAh (can run IPS Watchman for 8 months or more) regular power bank for less than $20. This arrangement is less expensive and will run your IPS Watchman for much longer.   

Feel free to contact us (tech@pp-code.com) for additional questions.