Tracking the Taxis

[Electroenthusiast]

Hi there,
Here's an thread from me after a long time. My workplace is few miles away from my home, and i usually take the cab for work. While talking to the chauffeur, i found that there was a small black box instrument on at the deck, where we usually keep our books. I found out that it was named C*A*S, and was manufactured by OnlineTech Instruments.

What i heard from the chauffeur was that it is used to keep a track of the vehicle activity. May be some GPS or something. I suppose it didn't have any internet connectivity. It should be using some radio communication between a head station and the vehicle. Can anyone tell more about the techniques they use to keep track of these cabs.

These days usually they use the Smartphones, but what were they using before?

 

[KeepItSimpleStupid]

Probably similar to GM OnStar. Two-way satellite communication+GPS

See: https://fmsgps.com/frontend/Solutions/all-satellite-gps-tracking.html

https://www.tracerit.com/home.aspx

The word you want is "logistics".

 

[Electroenthusiast]

Hi KISS,

Years ago, these taxis used walkie talkie communication between the operations center and the driver. Now of course, everything is being done using smart phones. I wanted to know whether those voice communications used satellite communication? If yes, why isn't terrestrial communication used? What do these personal walkie talkies, which are used by security guards at public places use?

 

[Nigel Goodwin]

I would have thought it's unlikely they use satellite communications, as much of the time they won't have a suitable view to the satellite - presumably the tracking is done via GPS, which uses multiple low-earth satellites, so doesn't have the same 'blocking' problems at higher satellites. They 'may' use PMR radios, but more probably cellular type phones as you get better coverage and more functionality - I would imagine there's specific systems designed specially for taxi's that do everything they might need.

The vans at work (years ago) used lo-band VHF PMR radios (not walkie talkies which are hand held portable units), and certainly back then New York and Paris taxis both used similar frequencies, because during the skip we used to be able to hear them

 

[Tony Stewart]

Many different systems are in effect from GPS downlink to SMS phone uplink to cell tower triangulation on roaming with store forward messages every 10 min on hardwired ignition activation. Trucks would use the store forward messaging between towers to improve driver safety and company fleets use it to improve employee efficiency. Now US reduces their overburdened penal system, which is a profit centre, at tax payers expense, and job security for the unions that support Republicans, now turn towards using fleet tracking instead of high surveillance costs.

 

[MikeMl]

Similar to my amateur radio APRS. A $10GPS in the vehicle knows lat, lon, ground speed, direction. A VHF radio (likely the same one that the driver talks to their dispatcher on) sends occasional digital packets containing the GPS data to a computer at the dispatch office. A Google Map like application shows the dispatcher what his/her assets are doing.

To hear APRS transmissions in the US or CAN, listen on 144.390Mhz. To see a recent flight of my APRS-equipped airplane (including the one in my Avatar), follow this link: APRS.FI

Here is a simple PIC-based APRS interface from a simple blind GPS to a VHF radio...

 

[Electroenthusiast]

Well, does use of PMR Radios have legal issues? Or is it an open band? If so, the PMRs which cops use must be very open to public interception.

So, it is just one channel radio? or multiple channel?

 

[Nigel Goodwin]

Well, does use of PMR Radios have legal issues?

Can't comment on the USA, although I presume it's similar?, but over here it's licensed and VERY strictly enforced - there's not even any guarantee you can get a licence, and if you do get issued one it specifies the exact frequency you have to use (ours was something like 76.0625 and 86.0625 - split transmit and receive for talk through).

The licence is also pretty expensive, can't remember the figure now, but it made a lot of sense to move to cellular phones in the vans once services had decent coverage.

 

[Tony Stewart]

Web based listening to VHF police bands only stopped as recently as last year in Toronto. Lots of other cities still use it.

 

[Electroenthusiast]

Web based listening to VHF police bands only stopped as recently as last year in Toronto. Lots of other cities still use it.

Can you tell more about this?

 

[Tony Stewart]

I used an iPad App. You can use a website and any mediaplayer

https://www.google.ca/search?hl=en&q=IRG4PSC71KD&gws_rd=cr&ei=gdtKVY_cN8yRyASxhoDIBg#hl=en&q=Web based listening to VHF police bands

You can also listen to ATC's around the world.

 

[Electroenthusiast]

Hi Stewart, how use useful are these for rule breakers. Good That they stopped the broadcasts.

 

[gary350]

You can buy tiny GPS tracking devices very cheap about $50. My cousin has a construction company, they have trouble with thieves stealing trailers and anything on wheels so they put a GPS tracker on every thing that has wheels. If a trailer or something on wheels is missing GPS tracking tells them where it is. He calls the police to give them the address of the stolen item then he meets the police there, the thieves get arrested and he gets his equipment back. LOL.

 

[Electroenthusiast]

You can buy tiny GPS tracking devices very cheap about $50. My cousin has a construction company, they have trouble with thieves stealing trailers and anything on wheels so they put a GPS tracker on every thing that has wheels. If a trailer or something on wheels is missing GPS tracking tells them where it is. He calls the police to give them the address of the stolen item then he meets the police there, the thieves get arrested and he gets his equipment back. LOL.

That's little complicated than how it seems to look. Requires internet, and again an extra investment.

 

[gary350]

You buy a $39.99 GPS battery operated device and hide it on your vehicle or trailer. It sends out a signal that can be used to determine its location. You use your home computer to find the location of the GPS device. It is simple, not much different than emergency beacons sinking boats use.

https://www.linxup.com/index_gs_plug.html?gclid=COSNme7ZuMUCFU1ffgodkz4Ajw

 

[Tony Stewart]

Its an expensive service but can be programmed to alert on motion when enabled and SMS or email you a message, immediately. Typically $10~$20/mo.

 

[atferrari]

Maybe he got his problem solved, one year ago. Look at the date of the last post.