RavTrack PC has the ability to place “Track Dots” on the map as tracked objects move around.  There are a number of user-configurable features in RavTrack PC that facilitate the Track Dot display, such as color and frequency of the dots. 

To enable Track Dots, open:

File > Program Properties > Units and Display

This panel is used to configure the Track Dot features.  Check the “Draw Track Dots” option to enable Track Dots.  Set the “Dot Size” to a size that is visible on your map.  4-10 is a typical size.  20 is a very big circle-dot.

If you set the “Minimum distance between dots” to zero, they will be drawn on the map every time the transponder reports in.  On some systems, this may clutter the map, so you may want to set the minimum distance to some larger number, say 100 feet.  If it is set to 100ft, then a dot will appear on the map every time the tracked object moves more than 100 feet. 

Normally, the color of the tracked dot will be the color assigned to the particular tracked object.  The settings for each tracked object can be edited by double-clicking on the ID in the tracked object list.  This brings up a window to configure the object’s icon, settings, and track dot color. 

Choose a color that is visible on the type of map you are using.  If you do not want tracked dots drawn for a particular object, uncheck “Place Tracked Dots along path”.

Raveon M7 GPS transponders with firmware version D1 or higher allows for the transmission of an electronic “GPS Odometer”. The GPS Odometer is a virtual odometer, not the actual vehicle odometer reading. It is implemented by integrating the distances travelled, based upon GPS locations.  With every GPS position/status message the M7 transponder sends, it can also send the reading of the digital odometer.

The standard $PRAVE message does not have an odometer field, so a variation of the $PRAVE message is used for this system. It is still called the $PRAVE message, but has an additional field in it. The original $PRAVE message had 17 fields in it, and for this system, there will be 18. The Odometer field is added to the end of the message, just before the * character.

The $PRAVE Message – 18 Fields w/Odometer

Example $PRAVE Sentence:

$PRAVE,0001,0001,3308.9051,-11713.1164,195348,1,10,168,31,13.3,3,-83,0,0,,1003.4*66

If power is lost at the wrong moment, the transponder will recover the last stored odometer reading, which may be a little less than the actual reading last reported. Software that uses the odometer reading should take into account the possibility of the reading going backward or restart at 0 with a new transponder.

The odometer reading is in kilometers. It may be reported with 0,1,2, or 3 decimal places. On legacy Raveon GPS transponders, the $PRAVE field for the odometer reading will be NULL.

The odometer value may be initialized or set with the ODO xxxx command, where xxx is the odometer value in kilometers.

In the M7 GPS transponder, the Odometer value is periodically stored in non-volatile memory inside the GPS transponder. Upon power up, the stored value is restored and continues to accumulate the distance traveled.

Enabling the Odometer Feature

By default, the GPS tracking transponders do not transmit the odometer reading.  They default to using over-the-air format “0”.  To enable a transponder to transmit the digital odometer reading, set the over-the-air message type to type “6” using the OTAFORMAT command:

   OTAFORMAT 6

With OTAFORMAT set to 6, the GPS tracking transponder will transmit the odometer reading every transmission.  The receiving radio modem must also have firmware D1 or higher on it to accept an over-the-air type 6 message, and output the PRAVE message with the odometer reading in field 18.  A GPS transponder or data radio modem with firmware version D1 or higher can accept over-the-air message from transponders with or without the odometer reading, and will automatically detect the over-the-air format and output the proper $PRAVE message.

Overview

1. The M7 radios in the system must be programmed to a valid VHF or UHF radio frequency. Raveon has both VHF and UHF versions of its M7 GPS transponder.
2. Each vehicle is assigned a unique ID number (1-9999). The ID number is programmed into the M7 radio.
3. The TDMA time and the time-slots for each M7 radio must be configured. The TDMATIME is how often the radio transmits its position. The SLOTNUM is the unique slot number each radio will transmit in. Slot numbers start with 1 and are sequentially numbered.
4. The M7 GX GPS transponders are installed in race and support vehicles. They will periodically transmit its GPS position out using its built-in VHF or UHF 5 watts radio.
5. Besides transmitting GPS position, the M7 GX can also receive the GPS position from other vehicles. As long as the GPS transponder is within radio range of another vehicle, it will output a message via its RS232 serial port whenever it hears the GPS position of another vehicle.
6. The M7 GX GPS transponder has an internal GPS receiver and a VHF or UHF radio transceiver. Out of its RS232 serial port, the M7 will periodically output the local GPS location using standard NMEA messages (GGA, GLL, RMC…)
7. Optionally, in any vehicle, the M7 GX GPS transponder may be wired to a GPS display in the vehicle. When connected to a suitable display, the M7 will send a message to the display telling it to put an icon at the location of any vehicle it receives that report its GPS position.
8. If you want to track using a PC, simply load RavTrack PC into a laptop, desktop, or notebook, and connect it to another M7 G GPS transponder. Raveon sells RavTrack PC for dispatch and AVL applications, but it makes a nice in-vehicle display or data logger for post-race replay of an event.

Things to consider

1. The M7 GX uses licensed UHF and VHF radio channels. Unless you are operating on a VHF MURS radio channel, you will need to obtain an FCC license to use this product.
2. The GPS tracking range is limited to the radio range of the 5-watt radio transceiver built into the M7.

The M7 GX GPS Transponder

Plan Your System

Setup and Initial Configuration

1. Connect a DC power source to the DC IN connection on the front of the modem.
2. Connect a computer terminal, or PC computer running HyperTerminal, to the 9-pin I/O connector. The factory default serial ports settings are 4800 bps, 8 data bits, 1 stop, no parity. Note, the serial port may be 38400bps if the RV-M7 GX is in GPS modes 2 or 3.
3. Put the RV-M7 GX into the command mode. (enter +++ per Section Error! Reference source not found.)
4. Program the modem’s operating frequency to your desired operating frequency. This is done with the ATFX xxx.xxxxx command. See the Section Error! Reference source not found. for information describing the various parameters that may be modified in the modem. In most applications, the default settings from the factory will work fine.
   Note: The MURS version of the M7 (RV-M7-VM), the unit is pre-set to the 5 MURS channels on channels 1-5. The user cannot change the frequency of the M7, only the channel number. Use ATHP x to select the MURS radio chanel.
5. With the unit in the command mode, change any of the default operating parameters that must be modified. From the factory, the modems are configured and delivered ready-to-use. Out of the box, they will communicate on the default radio channel using the factory defaults. Raveon highly recommends you test them first with the factory defaults and see how they work before reprogramming them. In general, the parameters you may want to modify will be:

M7 GX Installation in the Vehicle

1. DC Power (10-16V DC)
2. Radio antenna. UHF or VHF depending upon the band you use.
3. GPS antenna.
4. Optional display. (Lowrance, PC, Garmin…)

1. Secure the RV-M7 modem using the mounting holes on the side flanges of the unit. You might want to locate it so that the front panel LEDs are visible.
2. Connect a DC power source to the DC IN connection on the front of the modem. Use the supplied cable, or 18AWG wire, and connect the RED wire to +, and the black wire to – (ground). The black wire and the case of the RV-M7 should be connected to earth ground.
3. Connect a good quality antenna, tuned to the operating frequency, to the RF connector on the front of the modem. Use a good antenna, and mount it is at as high-above obstructions as possible. On the roof is the best.
   

   

   Avoid using magnet-mount antennas for race vehicles. They may be OK for a chase vehicle if the driving and terrain is not too rough.
4. Connect a GPS antenna to the SMA connector of the RV-M7 GX. Although a passive antenna may work if the cable length is very short, it is recommended that an amplified antenna be used, rated at 3.3V operation. Mount the GPS antenna so it can see the sky. On the roof of the vehicle is best. You may have to experiment with locations to find one that is easy to mount the antenna to and can also see the sky. There are two popular mounting methods: thru-hole and magnet-mount. If you use a magnet-mount GPS antenna, we recommend you also zip-tie it to the vehicle.
5. Wire the GPS display or computer, terminal, controller, or other hardware device that will be using the RV-M7 to its DB-9 serial I/O connector using a shielded cable. Secure it to the RV-M7 with the two mounting screws on the sides of the DB-9 connector. For a tracking-only application, nothing needs to be wired to the DB9 connector of the M7. Only if you have an in-vehicle display do you connect to the DB9. The following section describes how to wire in a Lowrance to the M7, but most other displays will be similar. More GPS display information is on Raveon’s web site here: http://ravtrack.com/GPStracking/category/installation/

Lowrance 480, 540C, 7200 and 840C Wiring

NMEA 0183 Wiring (Data cable)

The M7 DB9 Serial Connector

Wiring the DB9

Configuring the Lowrance

Configuring the M7 GX Transponder

How Far Can I track my Vehicle?

If you are using an Intel Atom motherboard and processor combo as the base station for a Ravtrack vehicle tracking system, the computer may not boot properly due to the radio supplying a signal on the DB9 connector to the RD input of the computer.  When RD input (pin 9 of the DB9 RS232 serial connector) is powered as the PC boots, Intel motherboards have problems booting.  There are 2 different ways to go about fixing this problem. The simplest one is to unplug the serial cable from the radio at boot and then plug back in once computer is booted. The other option is to cut one of the wires in the DB9 ribbon cable.  To do the second option, first open up the computer case and locate the serial cable that goes from the com port on motherboard to the radio.

Once you have located the cable, next take off the cover of the DB9 cable on the other end where it plugs into the radio to expose where the ribbon cable is soldered onto the connector. This is where we cut the cable so as to keep it covered and looking clean.

The wire needing to be cut is the second one from the right when looking at the connector from the bottom. It is recommended that you take out a small section of the wire so as to not risk any accidental contact.

The standard M7-GX GPS tracking transponder has 2 separate reporting rates, the TXRATE and the IDLERATE.   In many deployments the TXRATE and IDLERATE are identical.  However, in some deployments the IDLERATE is set to transmit position less frequently than the TXRATE unless a specified event occurs.

Some of these events include:

Speed of travel greater than a user specified value (TRIGSPEED parameter)

Distance of travel greater than a user specified value (TRIGDX parameter)

Proximity to another GX transponder less than a user specified value (PROX parameter).

Here are three examples of using this flexibility in your system.

Example – Using TRIGSPEED

Picture a police squad car sitting idle or cruising slowly through a neighborhood on patrol.  In this instance it may not be important for the vehicle to transmit a position report more frequently than every 2 minutes.  If this is the case IDLERATE can be set for 120 (seconds).  However, the same squad car may later be move at higher speeds and reporting more frequently becomes important .  In our example the system administrator has set the fastest reporting frequency at 10 seconds (TXRATE 10).    When the car speed exceeds a certain threshold, let’s say 40kph (TRIGSPEED 40) the TXRATE is invoked and reports are now sent every 10 seconds.  When the car slows down, the IDLERATE again takes over, and transmissions are less frequent.

Example – Using TRIGDX

Your public works department has a number of vehicles out every day serving the community.  A vehicle and crew may stop for a while and work at a particular site.   While at the site they may even move the vehicle around a bit, to aid in the work.  While on the site a position report rate frequency of 5 minute intervals is perfectly adequate.  However, when they pick up and start moving to a new site, you’d like to be able to track their progress and know where they are more frequently, once they’ve moved 100 feet or so.  In this case your maximum system reporting frequency is twice a minute , or TXRATE 30 (seconds)   Set IDLERATE 300 (seconds), and TRIGDX 30 (meters).  30 meters is roughly 100 feet.

Example-Using PROX

You drive aheavy equipment in an open pit mine, or on a construction site.  The visibililty from your cab isn’t all that great, and you drive and operate your equipment as carefully as possible at all times.  In a move to further improve safety your company has placed a tracking display in your vehicle, allowing you to display the location of all of your other RavTrack transponders within radio range.  Your system administrator has set the following parameters in all of your transponders:

IDLRATE 10 (seconds)

TXRATE 2 (seconds)

PROX 15 (meters)

During your normal activities the display in your vehicle updates the location of all other transponders every 10 seconds.  Somewhere along the line, one of your coworkers, while on foot, comes close to your equipment.  Your co-worker  (Jim) is wearing on his belt the ATLAS PL personal locator.  When he gets within 50 feet of you (about 15 meters) your transponder, which was transmitting at 10 second intervals, starts  transmitting positions ever 2 seconds – and so does his ATLAS PL unit.  Now the blip on your display that represents your Jim starts pulsing every 2 seconds, perhaps a light has also lit on your dashboard, or a buzzer sounds in your cab, alerting you to Jim’s nearby presence.

We will cover the integration of warning lights and buzzers in another tech blog.

For the more technically minded, here is the logic flow chart the GPS transponder tests internally every TXRATE.