Localization programs - APRS versus TrackMe

Thanks to the rebirth of interest in the radio amateur localization system APRS, I decided to try this system myself and compare it with the TrackMe program. Several factors were the decisive criteria for the comparison: price, for which I can operate the system, system complexity, practical usability as from my point of view, as an object, broadcasting its location, so from the user's point of view, which locates my location on his computer, accuracy and the ability to broadcast the position continuously, without downtime. I will briefly describe both systems and the results of the comparison. To be more precise: it is only a comparison in the field of localization, not for other possible uses. I do not consider myself an expert in this field, is possible, that no one will agree with some parts. However, I have no intention of arguing with him and will only be happy, if he corrects me in any misinterpretation.

APRS

The APRS system does not need to be explained in detail, surely all radio amateurs know him. It is a purely amateur radio system. The principle consists in determining our position with a GPS receiver, the data is processed by the modem, e.g.. TinyTrak and sent to the transceiver, which broadcasts on frequencies 144.800 MHz data to diginode. However, APRS has, unlike TrackMe, wider use, from the radio, for example. send messages to another network participant, meteorological data is broadcast on APRS. It is therefore necessary to have a GPS receiver for "mandatory" equipment, modem a TRX. In the simplest case, it will have a value of approx 300-500 Eur. However, we need a GPS receiver in both systems, however, almost every radio amateur owns a hand-held or mobile FM radio station on 2m, so I consider only the modem as a price. The aforementioned TinyTrak type is standing around 70 USD, modem with built-in GPS costs approx 135 USD. Of course, there are many APRS modems on the market at different prices with different features and programming capabilities. Our call must be programmed into the modem, possibly name or other data of ours. Another set is also possible: GPS, notebook, Baycom modem a transceiver. However, to carry a laptop with you only for APRS, seems a bit far-fetched to me. until significant zeros appear along the wire in the direction of the final radiation, in this composition, we can also receive and broadcast other interesting information to the network. We will load this whole assembly into the car, we tune into the correct frequency, we attach the antenna to the roof and we can go out into the world.

As long as we are within range of the APRS diginode, this receives the packets sent by us and sends them over the network as a radio, so to the internet world. On the receiving end, the program must be installed on the computer, most often UIview32. With it, we can download data either from diginod, or from the Internet. In the first case, we need in addition to a computer (and of course access to diginod) also RX or TRX on 144.800 MHz, modem, or sound card. In the second case, we are able to receive APRS information directly from the Internet, from special APRS servers, without the need to use another device. It's possible to see, that building a setup for APRS broadcasting is not a difficult thing. The problem may be a suitable modem, but it is not an insurmountable problem. Transfer this entire assembly to the car, when we go on a trip, however, it can be a burden after a while, because of which we start inventing various excuses, why are we not locatable right now.

The settings of the conditions for sending the position are also different from the type of modem used. In the best case, we can set the broadcast depending on the time, i.e. e.g. every minute, then posting in case, that we will pass a bigger one, as a set distance, possibly then, if we change the direction of our journey by a larger angle, as set, i.e. e.g. 30 degrees.

In Slovakia, unlike the surrounding countries, however, another is placed before us, a really big and currently insurmountable problem. And that is APRS diginodes. To date, there are exactly two. OM3KII-2 in Bratislava and Trnava OM3KTR-2. It is said to be planned in the east as well, that a suitable antenna would be needed for a stable connection, that it will be built, and that there will be more. It would certainly make for a long and passionate discussion (and which I definitely do not want to provoke with this post), why is such a situation in Slovakia. It's a condition, which makes you think. It is because of the lack of young people, with the computers of fused radio amateurs? Or because of the fact, that similarly, as we experienced with Packet radio, we only have that, into which enthusiasts put their own money and effort? Or there is another reason? i atenuator a kusok drotu…
It is near the border, of course, diginodes from abroad can also be used. In flat terrain, with a decent antenna, we can count on a range of 30-50 km distant diginode. If the diginode was placed on a suitable dimension, e.g.. Veľká Javorina, on the entire route from Bratislava to Považská Bystrica, it would be possible to transfer our data to the APRS network without any problems.

In today's state, however, on the road, e.g. to Prešov, I lose the Trnava diginode signal somewhere halfway to Nitra. And the end…. Nothing on the entire route to Prešov, maybe somewhere behind the Tatras, short-term weak signals from the Polish side. During operation, unless the diginode receives our high-quality signal, is running out (in view of that, that diginode does not in principle confirm the receipt of our data) to outages and status, when a point is not recorded. If we are unable to send this way (resp. diginode cannot receive) multiple points, route, displayed at the recipient, is often distorted, sometimes even misleading.

Overall, it follows, that this system is basically in Slovakia, except around Trnava and Bratislava and the route between these cities, currently unusable. However, we can use it anywhere abroad with great advantage, the exception is the former Soviet states. Western Europe in particular is littered with diginodes.

From the point of view of the recipient of our location, the lack of diginodes is not such a problem. As I stated above, it is also possible to receive location data from the Internet. The most used, but not the only one, with a program for displaying APRS stations, your program UIview32. The program is intended directly for income (but also broadcasting) APRS information. It is pleasant to work with him, but it has, in my opinion, one fundamental shortcoming, and those are the maps. There are few calibrated maps for APRS for this program, they are often poorly calibrated. The disadvantage is also the impossibility of adequately zooming the area, which we are interested in. However, it is also very often used to display stations directly from the Internet browser at the address http://aprs.fi , which uses Google Maps.

I personally tried another system. However, I do not want to describe him in more detail, because it was marked as a system, completely defeating the purpose of APRS ham radio and has nothing to do with ham radio. To some extent this is true. But as a radio amateur has, for example,. from Žarnovica to transmit your position to the APRS system? I am (as part of testing) replaced the modem and TRX with a mobile phone and radio transmission with GPRS transmission. I used a PDA, which directly contains a GPS receiver. The GPS data was processed in the PDA by the AGWTracker Pocket program, I sent the data to the mobile phone via bluetooth, which was connected via GPRS to the Internet gate, which in turn transferred my data to the APRS system. An hour of broadcasting positions will cost about 20 cents, no position is definitely lost and I am absolutely not dependent on diginode range. The signal of mobile operators is practically on 100% our journeys, it is lost exceptionally, and even in that case nothing is lost, because the data is stored in the memory in the event of a signal loss and is transferred to the network after it is restored. All the equipment is a PDA and a mobile phone, while at the same time I use the PDA for navigation - I share GPS data for the iGO program and AGWTracker Pocket. This system is also suitable for tourism, PDA is easy, I can have a tourist map in it, the battery lasts approx 6 hours with the display on, much more when off. However, due to the almost certain resistance of orthodox radio amateurs, I will not describe this system in more detail and I myself do not use it even except for tests. That is also a disadvantage, that the aprs.fi server does not display stations, which data they send to the network via iGate.

I will now go back to the original radio transmission.

So the advantages of this system are as follows:

• is intended exclusively for the radio amateur community
• the set-up costs are not high, almost zero for the operation itself
• transmissions abroad are also free
• the possibility of transmissions of data other than location data

  Among the disadvantages I would include:

• single purpose modem required
• the need to wear a relatively large and energy-intensive set
• diginode range required
• quite a lot of raw data (outages) with poor signal quality
• lack of high-quality maps for the imaging program

  TrackMe

  Luis Espinosa programmed and offers a freely distributable version of TrackMe. This program is also intended for localization and can also partially send SMS or e-mail. It already follows from this, that its activity requires access to the Internet. It doesn't have to be immediate, because the program can store data in itself and when we return from the trip, we can spill them over the internet. However, we lose the possibility of "live" localization. The program is therefore freeware and is intended for the general public.

  The principle is as follows: the data from the GPS receiver is processed by the program in the PDA, via bluetooth it sends data to a mobile phone, which in turn sends data via GPRS to the Internet to usually our server, where data is recorded in MySql database. At the same time, the data is also exported to the server in .kml format. The recipient opens our website, where it starts the php script, which reads this data and in cooperation with Google map displays either our route from the database, or "live" position from a .kml file. You can open my page for lighting http://www.depe.sk/trackme . After opening, you will see a world map. If you select "Trip" in the right column, you have multiple test paths to choose from, which I completed. After selecting the route, click on "Show". Two routes are marked "…taking a long time to load". The two routes each have approx 1200 km and each contains approx 3500 of recorded transition points, that's why opening takes a long time, sometimes even 2-3 minutes, maybe even more. Other routes have until 30 km and therefore open relatively quickly. Once opened, you can zoom the map as you wish, clicking on a waypoint will display all data, related to this point.

  If you click on "Live Tracking On" in the right column , you will get to live localization (of course, just in case, that I'm moving, otherwise you see my last location). In case, that I am sending data, you can see my exact location and route taken. The refresh interval can be set from 10 do 99 seconds. For those, which have a fast internet connection, I recommend 10 seconds, for a slow connection 30-60 seconds. It is also possible to set the "zoomlevel", that is, the size of the zoom. After setting, the map will be displayed in this zoom level during the next Reload. The map can also be displayed in Satellite mode, or Hybrid, but these settings only last until the next Reload, and then Map Mode starts again. Finally, try it out.

  I have actually already described the necessary technical equipment: it is optimal to own a PDA, „personal digital assistant“, in which the Windows Mobile operating system is installed 5 or 6 and which is directly equipped with a GPS receiver. It must have bluetooth connectivity. The mobile phone should also have bluetooth and the possibility of connecting to the Internet via GPRS. EDGE must be used when connecting, no CSD connection! CSD would be very expensive for us, because the price is based on the length of the connection time and not on the amount of transferred data, as is the case with EDGE. With EDGE, the price depends on that, how we set the program, how often we will send data. In the field, place the antenna so that it is close enough to this meter. value at extreme setting approx 400 kB per hour, which worked out for me 0,6 Euro. In practice, however, we do not use such an extreme setting. I specifically use the EASY card from T-Mobile, no special program needs to be activated.

  There are a large number of PDAs on our market, that meet our conditions at different prices. The cheapest ones start somewhere around 150 Eur, but you get to buy also for 600 Eur. However, the investment in a PDA is, in my opinion, good investment, because a PDA is actually a small computer, which you can use for a variety of purposes: from navigation, through games, music or movie player, various text applications, diary to racing diary, whose DX cluster. Mobile phone, which does not have the required parameters is difficult to get, so I don't even count this one. So that's all from the technical equipment.

  The software consists of installing and configuring the TrackMe program in the PDA and installing the server application on our web server. With a web server, your own web space is probably a prerequisite, because I'm not sure, whether free web servers offer the option of MySql database. However, a large number of Internet providers offer free connections, mostly around 50 MB web space and I know from my own experience, that 90% people do not use this web space. The application page is then displayed on your website, similarly, as I described above. I also installed the PortSplitter program on my PDA. This program can connect multiple programs to the GPS at the same time - so I use GPS at the same time for travel navigation and for TrackMe.

  Now to express the level of complexity, I'm embarrassed. For man, which revolves around computers and the Internet, that's no problem. However, for an ordinary Internet user, it can be a problem that cannot be overcome by one's own efforts, therefore, he will be forced to ask for help. In any case, a functional result can be achieved. Operation is very simple from the user's point of view - you need to connect the PDA to a mobile phone using bluetooth and connect the phone to the Internet. After that, just start the correctly configured TrackMe program and go out into the world. The configuration consists in determining the server, which we connect to, username and password and in parameter settings, when the data should be sent (time, distance, change of direction). It is also possible to set different conditions for data transfer. If you are not using another program, Real PDA, which also turns off the display and significantly saves the battery. User, which looks at your location on the website, it's even easier.

  Your location is sent with the accuracy of a GPS receiver, i.e. usually a few meters. It is displayed with the same accuracy on Google Maps on your pages. The interval can be much shorter, as with APRS, so the tracing is significantly more detailed. But the biggest advantage is in that, that not a single route point is lost, and Internet connection failures are rather the exception, unless we are moving in deep valleys of high mountains. But even then, after the reappearance of the signal, all untransmitted, but deferred waypoints, they will transfer.

  So I'll recap the benefits first:

• low weight of equipment
• low energy demand
• easy physical installation in the car
• easy user operation as on broadcast, so on the receiving side
• significantly greater accuracy with respect to transmission intervals
• significantly more accuracy with respect to it, that no route point is dropped
• very cheap operation of GPRS transmissions (we transmit very little data)

  Disadvantages include:

• Necessity of knowledge of working with PDA and website programming
• cena PDA
• possibility to use only in Slovakia, prices abroad are high

  Conclusion

  It's hard for me to comment on that, which system is better, more advantageous. As a radio amateur, I lean towards APRS, but APRS is of no use to me without diginodes. Moreover, I am a little discouraged by the fact, that APRS is easily accessible only to radio amateurs and the UIview32 program itself (maps).
  In contrast, with TrackMe, the main disadvantage is the need to pay, even if small, but still only fees for GPRS transmission and, due to the high prices of data roaming, the impossibility of using this system abroad. But if you read this post to the end, you will have some kind of idea about the localization possibilities yourself and it is only up to you, which of these systems you choose.

  Dusan, om2adp