IoT M2M blog

The home of free hints and tips about wireless IoT / M2M

Tracking indoor and outdoor by GNSS and cell ID

Field test: tracking indoor and outdoor

akorIoT SensPRO behind the window on the highway in Amsterdam

akorIoT SensPRO behind the window on the highway in Amsterdam

In order to demonstrate the tracking goods and assets across borders, a field test was executed over several days in different countries and different methods of transport. In addition to delivery vehicles and cars, trams and walking were also used. The car was parked in an underground car park and the walk led to the basement of the Museum of Modern Art in Amsterdam. In the Museum of Technology the tracker had to be stored in a cupboard. Because I moved the tracker myself from Hanover via Amsterdam and back to Hanover, I can interpret the recorded data. The journey was divided into stages and special events are explained in the following sections. The tracker is named akorIoT SensPRO and was developed by Triptec in Lübeck. Many thanks to Triptec and Elbstack for the great support- The akorIoT SensPRO works on GSM, NB-IoT, LTE-M and GNSS. It is based on multi mode module Quectel BG96 and GNSS module Quectel L76. Special thanks to Quectel for best support and answering our questions fast.

akorIoT SensPRO PCB

akorIoT SensPRO PCB

Specification of the tracking field test

In the field test NB-IoT was deactivated and only GSM was used. The SIM card is a roaming SIM able to connect to different networks in one country. This avoids radio blackouts. During the journey, a connection was always established even in the underground car park and basement. In order to optimize the energy consumption, the location was sent every 10 minutes when the antenna was moving and every 24 hours when stationary. The location is preferably determined using GNSS and if this is not possible cell location is used. Elbstack from Hamburg developed the data processing and the cloud server. My task was the specification and the report after the trip. The experiences will flow into the further development of the akorIoT SensPRO and into customized devices. When and why which data will be collected and transferred I could wish for. The basis was my IoT M2M Cookbook. The book describes in detail how to develop a tracking device or a wireless sensor. The goal was achieved and even exceeded in some respects. The user interface of the cloud server is largely self-explanatory. With a few clicks or entries you can extend or limit the time period for the measured values. As it is web-based, this can also be done on the go with a smartphone. Enjoy reading on for the travel report of the akorIoT SensPRO.

Delivery of the tracker by TNT – 27th – 30th of September

On Friday the 27th of September at 8:30 a.m. my akorIoT SensPRO was handed over to TNT delivery service in Lübeck and then travelled via Hamburg and Hanover to Neustadt. Whenever there is only one green point in the time axis without a parallel red point for the time of the GNSS fix, the position was determined by cell location. On the transport from Lübeck to Hamburg a mix of GNSS location and cell location is visible. When it was delivered on Monday morning, the package was probably deep in the vehicle and could not establish a GNSS connection. On this trip the vehicle also jumps towards Bremen. The reason is the wrong BTS location in the database. The last movement with TNT in Hannover took place on September 28th at 11:00. Without movement, the akorIoT SensPRO sends a heartbeat every 24 hours. You can see such a heartbeat with GNSS fix on Sunday 29 September at 11:00.

Screenshot of the akorCLOUD with three customised windows

Screenshot of the akorCLOUD with three customised windows

Local tracking test in the garden and basement – 30th of September

Around 8:45 TNT handed over the package with the akorIoT SensPro to me. Around 9:30 I brought it into the garden and got a GNSS fix there. The two lower points in the “triangle” are GNSS localizations. The first location was three plots away and the second is very accurate. The result sounds logical if you know that the tracker hasn’t had a GNSS fix since Sunday. It was a classic cold start within 92 seconds. From 9:59 the tracker was in the basement. Then the SensPRO goes to sleep after 10 minutes, I woke it up by shaking it. It is interesting that the SensPRO constantly changes between base stations of Deutsche Telekom and Telefonica, although there was no change of location. The window showing the battery voltage is not so exciting. A lithium battery does not change its voltage over a long period of time.

Tracking: Screenshot with charts

Tracking: Screenshot with charts

Tracking: Screenshot with table

Tracking: Screenshot with table

Tracking on the highway -Trip from Neustadt to Amsterdam – 1st of October

The TTFF is on average close to 10 seconds. In the last hour of the trip we were in traffic jams and downtown traffic in Amsterdam. The number of visible satellites and the direction of the car has changed very little. The speed was at walking speed, 50 km/h in the city and about 100 km/h on the motorway. The average time to TTFF was about 3 seconds. The #akorIoT #SensPRO was mounted directly behind the windscreen. The GNSS receiver needed only 106 seconds for the start around 11:20. Until 2:00 PM the TTFF becomes constantly better. At each launch the orbit data of the satellites are loaded in the background. Bit by bit the GNSS receiver knows more and more exactly where to find the possible #GNSS satellites on the sky. The receiver searches for the known satellites first. If the receiver is blocked by a high building, it searches for new satellites and these new satellites are included in the fast search at the next launch. This leads at the end to the 3 seconds TTFF mentioned above.
Next I will analyse the journey from the hotel to the congress and back on the following day.

Tracking test: Main trip to Amsterdam

Tracking test: Main trip to Amsterdam

Visiting museums in Amsterdam – tracking indoor and outdoor – 3rd of October

Around 9:00 I packed my backpack with the akorIoT SensPRO. Around 10:30 I left for the Museum of Modern Art in #Amsterdam. The museum is spread over several floors and in the upper floors the reception of #GNSS is possible. Afterwards we drove to the Museum of Technology. From estimated 16:30 to 17:30 the backpack with the tracker was stored in a cabinet and did not move. The museum closed at 17:30 and we started to travel back to the hotel including a stop for shopping at supermarket. On the way back, the backpack with the tracker stood on the metallic floor of the tram. From about 18 o’clock until shortly after 20 o’clock there were continuous transmissions but no GNSS reception anymore. The museum closed at 17:30. From 20:15 we were in the hotel room and didn’t move the tracker anymore.

Tracking test: Trip by tram and walking in Amsterdam

Tracking test: Trip by tram and walking in Amsterdam

Trip by tram and walking in Amsterdam

Tracking on the highway – Trip from Amsterdam to Neustadt – 4th of October

The GNSS receiver in the akorIoT SensPRO needs on average less than 10 seconds in the moving car for TTFF. Minimum is 1 second with classic hot start and maximum was 178 seconds. More than 10 seconds is rare. The curves for temperature and humidity indicate when the doors have been opened. Around 10:30 arrival at the customer, 12:30 departure from the customer, then stop at the supermarket and departure at the supermarket. The loading of the goods into the car is clearly indicated by the drop in temperature and increase in humidity. Even the duration can be seen. The car doors were open longer on the rainy day and the change was therefore large. Around 18:00 we were at home, the temperature and humidity changed again. Afterwards the tracker was in the hallway was no longer moved. After 10 minutes the tracker went to sleep. The SensPRO is a reference design with an open interfaces. Everybody can program it and everybody can take over the circuit or parts of the circuit. If capacities for HW and SW development are missing, the #akorIoT group is happy to help.

Tracking test: Trip back from Amsterdam to Hannover

Tracking test: Trip back from Amsterdam to Hannover

Indoor locating – 5th of October

The akorIoT SensPRO is still in the backpack and has been moved three times in the house. The last movement at 21:00 led to a GNSS fix after 149 seconds. The other two positions are based on a cell location without GNSS.

Tracking test: Tracking indoor and outdoor

Tracking test: Tracking indoor and outdoor

Summary and outlook tracking on GNSS, GSM and NB-IoT

The nine-day trip of the akorIoT SensPRO is now over and planning for the next trip is in progress. I will hope to generate a few more charts. The data is already stored on the server. A trip with the ICE express train would be interesting. What happens at 250 km/h? A return journey there and back with two stop points per day would also be interesting, because after 4 hours the Almanac loses its validity. There are still many aspects to consider and analyze. The travel report above with the akorIoT SensPRO gives an insight into the complexity of a tracker and further reports will follow.

The 1 second for TTFF mentioned in the data sheet of the GNSS receiver has hardly been achieved. The 2.71 seconds for approx. 8 positions in a row in the Amsterdam area were caused by traffic jams on the motorway and in city centre traffic. On the motorway with free view to the sky and little shading by buildings a TTFF of approx. 10 seconds resulted on the approach and departure on approx. 800 km distance. Furthermore the GNSS receiver learns the orbit data of the satellites and the TTFF decreases from 1 to 2 minutes. The more orbital data the receiver knows, the faster the receiver can establish a fix. A-GPS and the upload of the orbit data is only worthwhile if the receiver is used frequently. A waste container that never moves and sends a position once a week can do without A-GPS. It is best to do without GNSS and send only the cell cloud or send the data when moving. The electronic motion sensor can easily be replaced by a mechanical sensor and therefore the energy consumption can be reduced to 0 nA. With the right microcontroller this can be limited to 500 nA with active timer and motion sensor. With no position to transmit and derive movements from the sensors instead of the GNSS receiver is certainly the best way to save energy. Wifi or Bluetooth tracking does not work with waste bins or tracking goods in the delivery vehicle. In the delivery vehicle the reception is restricted and a roaming SIM card with the option to connect to diiferent cellular network operators in the same county is a very good solution against radio blackouts.

Sources for Tracking device, Cloud and IoT/ M2M Cookbook:

akorIoT SensPRO by Triptec www.triptec.de and better www.akorIoT.com
akorCLOUD by Elbstack www.elbstack.de
IoT/M2M Cookbook http://www.gsm-modem.de/M2M/m2m_iot_cookbook/

Extract of wireless IoT related services:

– Matching of the antenna in the device (chip, PCB antenna, helical antenna)
– Guidance on antenna design if undertaken by the client
– Antenna layout of the dual F-antenna on an empty PCB in the customer’s enclosure
– Antenna layout of any other custom PCB antenna: Helix antenna, Flex PCB antenna, Antenna punched from tinplate, Antenna printed on plastic in housing, Antenna on ceramic, Slot antennas and many more techniques
– Antenna with radio module and power supply for extremely low power consumption
– Assisting in the implementation of the antenna or power supply concept in the fully-featured PCB of the customer
– Development of the whole PCB including an antenna with software Development by the customer
– Development of the whole device (HW + SW) following the client’s specifications
– Reference designs with NB-IoT, LTE-M, GSM, GNSS, BLE, Wi-Fi, MCU, sensors, charging electronics for over 20 applications with an open block diagram and the possibility for customers to develop their own code using a free C compiler
– Preliminary measurements and tests required for radio certification
– Radio certification according to RED (CE), FCC and several more standards
– Workshops at the client’s office or via video conference
– Training and seminars on radio technology and radio certification

We look forward to receiving your inquiry to harald.naumann (at) lte-modem.com and will be pleased to submit a proposal. In most cases the IoT M2M Cookbook or the reference design akorIoT SensPRO is only the beginning. After that there are often follow-up orders for the services mentioned above. “akor” is the ancient Celtic word for “open” and we prefer openness in our concepts, and like to share our knowledge in training and to maintain open communication with our customers.

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