That’s a mouthful!!
Some standards require multiple tracking systems on a trailer (i.e. TAPA has up to 3).
These multiple systems are supposed to use different technologies as well.
There are really only 2 communications technologies available though unless you get into packet radio (with a ham operator license as well). You have satellite communications and the mobile phone network.
So if your primary tracking system uses the mobile network then the secondary should be using the satellite communications.
Using multiple technologies means you have redundancies. So if people are targeting your trailer and they jam the signal to the mobile network then the satellite network is still available.
So I have come up with a design that has the communications module separate from the tracking module.
I can use a simple microprocessor to acquire the GPS position and other sensor status (i.e. accelerometer, magnetometer, gyroscope), log this data locally as well as send it out on a timer (i.e. every 5 minutes).
With this design, multiple communication modules can be utilized based on priority, location, and/or status.
If the trailer is in your yard, the system could use WiFi.
If it is at a truck stop with public wifi (or you have a subscription service with them), use it.
In the case that no communication system is available and GPS is also down then an anti-theft routine could be activated. Said routine could include:
- probing for bluetooth devices
- probing for wifi networks
- probing for mobile phone networks
- activating a microphone
- activating a camera
- after a set time, activate the packet radio and try sending an emergency broadcast.
This design does not have to be all in one place either, it could be distributed within the frame of the trailer.
The anti-theft routine could also be activated if the unit is tampered with.