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A GPS tracking system for marinas, boat rentals, and other watercraft

Raveon’s asset tracking solutions gives customers the ability to focus on keeping up with their assets, instead of keeping up with monthly fees.  Using radio transmissions to broadcast received GPS messages, Raveon’s GPS transponders allow a marina operator to track all of their rental boats or other watercraft in real-time using a graphical display.  Competing GSM (cellular based) systems charge monthly data usage fees to transmit your GPS tracking information through their cellular telephone signal towers, and only function where you have cell phone service.

If you can’t make a cell phone call, likely, you can’t be tracked. Instead of getting the oars out when you lose cell service, the RavTrack real-time tracking system provides a complete standalone system.  No usage fees or third party infrastructure is necessary; instead RavTrack GPS transponders operate via VHF or UHF digital radio transmissions, providing you with instant status updates on every rental boat or other watercraft in your fleet.

Raveon’s easily configured and customizable GPS tracking system is designed to operate where and how you want it to operate, including a specialty line of weatherproof IP65 rated GPS transponders perfect for small watercraft such as jet-skis, kayaks, or the like.RTPC screen

On the boat, the Raveon GPS transponder simply requires access to the 12 volt (DC) power source, that’s likely already a part of your rental boat, an antenna for the radio, and an antenna for the GPS.  With available power saving modes, Raveon’s data radios will only draw a small fraction of power, meaning that it’s even suitable for a sailboat!

Raveon also offers compact design options suitable for jet skis (UHF systems suggested for Jet Skis for more compact sized antennas.)  Once your transponder is installed in your boat just turn it on and go.  The transponder will immediately begin searching for GPS lock and will begin broadcasting its location automatically at your chosen intervals.

The powerful GPS transponders broadcast position signals that can easily be received several miles over open water.  At your marina, truck, or your general base of operations, another transponder and antenna receives the incoming GPS reports from the boat or rental fleet. View the Port Asset Tracking infographic to learn more about how the RavTrack system is designed. For more information, learn how the Port of Long Beach partnered with Ravtrack for their tracking needs.

GPS Tracking Software

Raveon’s Windows based RavTrackPC program is available to provide you with a platform to view your assets (As seen in the image on the right.)  Customization integrated into RavTrackPC will provide your tracking system with the map you want to use.   You will be able to see the locations and IDs of each of your tracked boats out on the water on your map.  You can also configure RavTrackPC with rules and alerts so that if your boat starts moving at 2 AM or simply hasn’t reported in several minutes an alarm will be triggered.  Alarms can do anything from making a loud noise, to sending an email, tweet or SMS message, to triggering a third party program on your system through a command line interface.

RavTrackPC does far more than just tracking movement too, it can be used to track speed, duration and proximity to other tracked objects as well!  RavTrackPC provides Geo-Fence alerts, where you can create invisible borders to alert you when a boat is not where it’s supposed to be, or when it is heading back in to the marina or launch ramp.  This greatly facilitates dock service not to mention how much easier it is catch your daredevil kids/clients in the act of doing 40mph in a no-wake zone in your boat!  It also keeps the harbor master happy.  Furthermore, if the people in any of your rental craft have an issue, the optionally installed boat assistance switch can be triggered and help can be dispatched directly to the distressed boat’s location.

Displaying GPS Position

The RavTrack GPS transponder can also be set up to be displayed on many on-board GPS systems for boats or vehicles.  (Such as the Lowrance HDS-5 and Garmin 400 seen in the images on the left.)   This means that not only can you track your boat from the marina, it means that your boat or tow vehicle can also track yourboats!  No more awkwardly waiting around at the loading/unloading ramps!  You can watch your boat approach from anywhere, long before it’s in eyesight range.  This is also very useful for the private yacht operator in keeping track of tender boats or tracking recreational watercraft.  Not only is RavTrack great for keeping marina staff updated, the mobile tracking capabilities of RavTrack are ideal for use in your service or rescue craft.  Furthermore, if your rental boat has a compatible display, your marina dock location can appear on the display to guide the lost helmsman back home. display

Raveon’s GPS tracking solutions provide a service that’s simple to use as well as appropriate for an enjoyable boating experience while eliminating the stress of uncertainty.  Whether that means the peace of mind of knowing your customers whereabouts, or simply knowing your boat/fleet will be where you parked it last, Raveon’s stand alone, recurring-fee free, real time tracking will help improve your overall customer service, safety, and fleet maintenance.

Give us a call to discuss your particular operation and allow us to customize a GPS tracking solution tailored to what you need from your GPS tracking system, including system planning, custom radio configurations, or other special needs. If you have questions about the RavTrack GPS tracking system, we also offer an informative webinar.

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Digital Odometer Accuracy

Digital Odometers are incorporated into some Raveon GPS transponders such as the M7-GX.  They work very well, but you will see a difference in reading between the digital odometer reported by a GPS transponder and the odometer on the dashboard.

  1. A GPS transponder with GPS uses its GPS location to calculate distance .  Every second it computes how far it moved, and adds this up to accumulate the odometer reading.
  2. At any time, you can type a command into the radio to force the Odometer reading to be any reading you want.  Because this can be set anytime to any value, the GPS odometer should not be the sole mechanism for determining maintenance intervals.
  3. The digital odometer in the GPS transponder will vary from the dash-board reading. Typically we see 1-5%.
  4. Reasons for the difference between the dashboard and the GPS transponder reading are:
    1. The GPS Signal itself is only accurate to about 30 feet typically. Sometimes 10 feet sometimes 100 feet.
    2. Near tall building, tree, canyons, down-town cities, GPS accuracy may only be 100 feet.  Adding 100 feet of error every seconds adds up quickly.
    3. If a car drives in a tight circle, the dashboard odometer climbs, but the GPS odometer reading sees little distance change.
    4. If a vehicle drives in reverse, the odometer reading may go backwards.  The GPS odometer will not.
    5. The resolution of the GPS signal is about 1 meter.
  5. Raveon recommends using the digital odometer to determine changes in odometer readings not absolute numbers.
    1. To see how many miles a vehicle has on it, use the dashboard odometer.
    2. To track how many miles a day  vehicle travels, use the GPS.
    3. To see how far a vehicle drove between events or rule alerts, use the digital odometer in the GPS transponder.
    4. To track intervals between maintenance, use the GPS and dashboard.

Digital odometers based on GPS location are great for monitoring vehicle activity and tracking usage.  If you want to keep them in sync with the dashboard, you’ve got a big challenge and a lot of updating to do.

 

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Why Use GPS Trackers Instead of Two-Way Radio?

 

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Sometimes two-way voice radios can be used for safety and personnel locating.  When trying to decide if a dedicated GPS transponder like the Raveon ATLAS PT or a voice radio is the right choice, keep these important points in mind:

  1. You will know where everyone is at all times.  A GPS Transponder operates at all times, not just when the user presses the PTT button.
  2. Battery Life.  A GPS transponder can run for days on a single charge.  Most portable radios will operate 8 hours or so. If used a lot or the PTT button is accidentally pressed, the batteries will last much less.
  3. Emergency Assistance.  In an emergency situation, both technologies can be used to summon help.  But if the person is incapable of moving or unconscious, pressing a PTT button is not possible and the GPS transponder will not only continue to send the locations out, but alert that no motion is taking place.
  4. Search and Recovery.  Raveon’s GPS transponders automatically, continuously, and quickly transmit GPS location and status.  Rescue personnel can use a tablet or laptop computer to locate the transponder in real-time, live while searching.  Finding the transponder and locating the personnel can take only minutes. View our asset tracking and safety infographic, which describes how the Ravtrack system is designed.
  5. No Voice Communications.   In many situations it is undesirable to have the people being tracked to be able to talk amongst themselves. This could be for training purposes, privacy, or security.  Or, they may already have voice radios, and real-time tracking using a dedicated channel frees up many other channels for voice comms.
  6. Fast Updates.   GPS locators in voice radios are very slow to update, and take a lot of air-time.  Tracking hundreds of vehicles or people requires an advanced channel-access protocol like Raveon’s TDMA protocol.
  7. Log Files.  With fast updates, the system can store GPS data to log files for later review or in case there is an incident, the log can be queried to determine what happened during the incident.
  8. Keep People Honest.  Often GPS tracking is done to monitor behavior to verify that they are following rules and staying within limits and boundaries.  Voice radios will not help in these situations.  Voice radios can be turned off (The ATLAS PT’s power button can be disabled), and people disrespecting their restrictions will probably not get on the radio and announce it.
  9. Rugged.  The ATLAS PT is submersible to 1 meter of water, very rugged, and made from aluminum.  Few plastic voice radios can take the abuse the ATLAS PT can.  When people lives are at stake, a rugged, long-life product is important.

Comparison of Features

Feature

GPS Transponder PRO

GPS Transponder CON

Voice Radio
PRO

Voice Radio
CON

Voice Communications

User’s Can’t communicate. Security. Privacy.

Cannot call for help without pressing the ALert Button

Users can chatter amongst themselves.

Users can cheat if they are supposed to be on their own.
Voice comms takes up bandwidth used for GPS tracking.

Battery Life

Excellent
24-48 hours

8-12 hours

Real-time Tracking

Excellent

Cannot Do

Safety System

Great situational awareness

No voice. Cannot talk to rescue.

Can talk to rescuers

Must manually press PTT. No help for unconscious personnel.

User Cannot Turn Power Off

Always On when needed

Requires charger to shut off.

None.

Users can turn radio off if they don’t want to be tracked.

No Motion Alert

Automatic Transmission if idle to long.

Sometime false alerts when sleeping/resting.

None

Few voice radios have this feature.

Live Tracking by Searcher and Rescue

Rescuers, cadre or commanders can drive right up to the transponder.

None

Personnel can use voice to help direct searchers to find them

Sometimes difficult to explain location.  Person must be conscious. Person must know where they are.

To learn more about the advantages of the RavTrack system, attend our webinar.

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GPS Receiver Dynamics

The GPS receiver in Raveon’s M7 and Atlas PL GPS transponder may be configured for different situations. By default it is configured for LAND operation.
Selecting the correct operating parameters has a significant impact on GPS receiver performance.  GPS receiver dynamics may be optimized for LAND, AIR, or SEA operation.
  
  LAND  = 1    Maximum speed the GPS will receive at is 233knots/268mph/430kmh.  Useful altitude from -2000 to +9000 meters.
  SEA = 2    Maximum speed the GPS will receive is not specified.  Useful altitude from -2000 to +9000 meters.
  AIR = 3   Maximum speed the GPS will receive at is 1000knots/1150mph/1800kmh.  Useful altitude from -2000 to +50,000 meters.
 
The default setting for the GPS receiver used in Raveon’s M7 series of GPS transponders and Atlas PL Transponders is LAND.
The default LAND operating parameters allow the receiver to perform well in most environments. Transponders with firmware version C12 or higher are able to view the GPS receiver’s configured dynamics, and change the dynamic mode between AIR, LAND, and SEA. Upon power up, the firmware reads the internal GPS receiver’s current configuration.

The user can optimize the internal GPS receiver in the transponder to a particular application.  If the receiver is then taken out of this environment, the specifically tuned receiver may not operate as well as a receiver with the default options.
The dynamics feature default setting is LAND mode, where the receiver assumes a moderate dynamic environment. In this case, the satellite search and re-acquisition routines are optimized for vehicle type environments. In SEA mode, the search and re-acquisition routines assume a low acceleration environment. In AIR mode, the search and reacquisition routines are optimized for high acceleration conditions. 

Reading the GPS Receiver Configuration

The GPS receiver configuration may be determined by using the GX command to show the overall configuration of the M7 or Atlas PL transponder. The “Dynamics” command will also return a string in the following format that indicates how the GPS receiver in the transponder is currently configured.   

MMM, EE.E, SS.S

 MMM: dynamic mode AIR, LAND, or SEA
 EE.E: Elevation Mask
 SS.S: Signal Mask  

Elevation Mask

This is the minimum elevation angle for satellites to be used in a solution output by the receiver. Satellites which are near the horizon are typically more difficult to track due to signal attenuation, and are also generally less accurate due to higher variability in the ionospheric and tropospheric corruption of the signal. When there are no obstructions, the receiver can generally track a satellite down to near the horizon. 

Signal Mask

This mask defines the minimum signal strength for a satellite used in a solution. There is some internal hysteresis on this threshold which allows brief excursions below the threshold if lock is maintained and the signal was previously above the mask.

Configuring the Dynamics

Use the DYNAMICS command to set or read the dynamics.  DYNAMICS with no parameter will return the configuration.  The following commands may be used to set the dynamics:

DYNAMICS 0    (factory default dynamic mode)
DYNAMICS 1    (LAND)
DYNAMICS 2    (SEA)
DYNAMICS 3    (AIR)

When issuing the DYNAMICS x command, give the GPS receiver a few seconds to execute it.  The M7’s firmware will also send a “flash save” command to the GPS receiver after the dynamics configuration is changed so that the change becomes permanent in the GPS receiver.  Upon power-up, the GPS receiver will use the new dyncamics setting. 

To verify the dynamics setting was saved, cycle power on the M7 or Atlas PL, enter the CONFIG mode, and enter the GX command to view the overall configuration of the device. The GPS receiver dynamics will be displayed.

Advanced GPS Receiver Configuration

To facilitate the advanced user, Raveon added a command “PASS” in the C12 firmware.  PASS will pass the parameter of the command to the internal GPS receiver in NMEA format. The GPS receiver used in the M7 transponder and ATLAS PL personal locator is a Trimble Copernicus II.  The technical manual for the Copernicus II contains details on how to configure it using NMEA type messages.  

For example, to set the GPS receiver to AIR mode, issue the following command while in the command mode.
    PASS $PTNLSCR,0.60,5.00,12.00,6.00,0.0000020,0,3,1

The command’s paramter is a NMEA formatted sentence without the * or the checksum.  The M7 or Atlas will append the * and the checksum to the sentence before sending it to the internal GPS receiver.  To set the dynamics, use the DYNAMICS x command, not the PASS command. The PASS command is provided to the advanced user who wished to reconfigure the receiver’s low-level configiruation paramters such as signal and elevation masks. 

If you change the GPS receiver’s configuration with the PASS command, do not forget to issue the save configuration command to the GPS reciever. The save command for the GPS receiver in the M7 and ATLAS PL is:
 PASS  $PTNLSRT,H,2,7,0

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Configuring the NMEAMASK bitmask

The M7 GPS transponders and the Atlas PL personal locators may be configured to output NMEA 0183 GPS messages from its internal GPS receiver.  For GPS tracking, these GPS transponders can receive GPS position reports from other radios, and they may also be configured to output their own GPS location via their serial port.

Following is a list of the NMEA messages that are available (as of revision C2 of the Firmware).

NMEA Message
 Bit Number (zero based)
 Bit Mask (hex format / Decimal)
GGA 0 0x001  /  1
GLL 1 0x002  /  2
RMC 9 0x100  /  256

Refer to the product’s technical manual to see which NMEA messages are sent out in the various operating modes.  Once you set the “GPS Mode” of the radio using the GPS X command, you can change the NMEAMASK parameter to modify with of the NMEA sentences will come out the serial port.

For example, to have only the RMC sentence come out the serial port, use the following command”

NMEAMASK  256

To have the GGA and GLL come out the serial port use this command:

NMEAMASK 3

The NMEAMASK parameter is the sum of all of the decimal values of the individual bits corresponding to the NMEA messages.

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TDMA Time Slots (Multiplexing Time Division)

Raveon’s M7-GX AVL transceiver uses a  Time Division Multiple Access (TDMA) protocol to transmit position, status, and data over the air.  TDMA protocols greatly increase the available channel bandwidth but they require more system planning than conventional carrier-sense methods. 

With a TDMA system, each radio in the system is assigned a time slot to use for sending its data (data being GPS postion, status, or ASCII data).  Because only one radio transmits in any single timeslot, there is never any interference between radios.  Hundreds of GPS tracked vehicles or assets may be all located in the same place, and still communicate without interference – an impossible task with conventional radio systems.

The M7 radio’s TDMA timing may be configured by the system installer to optimize it for a particular application.  The TDMA slot width and the number of slots maybe configured to achieve the maximum system performance.  Each TDMA slot needs to be long enough so that the complete GPS position/status message can be sent in it. 

  Table 1 below shows the recommended slot times for various over-the-air data rates.

Over-the-air rate

Radio Bandwidth

Number of Modulation Levels

Position /Status Transmission Duration

Recommended TDMA SLOTTIME in mS

4800bps  (ATR2=3)

12.5kHz

2

70mS

100  (200 with repeaters)

8000bps  (ATR2=4)

12.5kHz

4

50mS

50 (150 with repeaters)

9600bps  (ATR2=5)

25kHz

2

45mS

50 (100 with repeaters)

14400bps (ATR2=10)

25kHz

4

30mS

50 (100 with repeaters)

Use the ATR2 x command to set the over the air rate.  Use the SLOTTIME xx to set the TDMA slot time.  The SLOTTIME must be wide enough to accommodate a Position/Status transmission from the GPS.  Refer to the Table 1 above to determine how long a position/status transmission will take.  The factory default for a stock RV-M7-UC-GX radio is 200mS slots, 4800 baud over-the-air.  This is an excellent compromise between speed and communication range.

The TDMA Frame Length

The TDMATIME is the length of one TDMA frame/epoch.  A TDMA frame contains small time slots where each radio is allowed to transmit in.  The slots are sequentially numbered.  For example, in the configuration below, the TDMA frame is configured to have 20 slots.

Figure 1

TDMA Time Slots / Multiplexing Time Division

Radio number 1 transmits in Slot 1. Radio number 2 in slot 2… 

TDMA Frames have a pre-set number of slots, and once the TDMA Frame Time has passed, the frame restarts at slot 0 again.  Slot 0 is reserved for future base-station control signals.  The length of a TDMA Frame is set with the TDMATIME xx command. 

 Figure 2

TDMA Time Slots / Multiplexing Time Division versus CDMA

In the M7 GX radio, the TDMA Slot Time is programmable, in 50mS increments.  The SLOTTIME xx command is used to set the slot width.  Typically it is set at 50, 100, 150, or 200mS.  The factory default is 200mS. 

For example, with a TDMATIME of 4 second, and a SLOTTIME of 200mS, there are enough slots to support 19 radios reporting every 4 seconds.  The Frame will repeat every 4 seconds so every 4 seconds, each of the 19 radios has 200mS of air-time available.   Figure 3 depicts this configuration.

 Figure 3

 tdma4

Configuration 1 below shows the slot timing with a 1200 baud M7 GX radio using 750mS time slots.

 Configuration 1

1200baud with repeaters
TDMA Frame time, 20 seconds
750mS time slots
  Slot Number Time (S) into frame Radio ID
20-second TDMA Frame for all mobile units in the system 0 0 –
1 0.75 1
2 1.5 2
3 2.25 3
4 3 4
5 3.75 5
6 4.5 6
7 5.25 7
8 6 8
9 6.75 9
10 7.5 10
11 8.25 11
12 9 12
13 9.75 13
14 10.5 14
15 11.25 15
16 12 16
17 12.75 17
18 13.5 18
19 14.25 19
20 15 20
21 15.75 21
22 16.5 22
23 17.25 23
24 18 24
25 18.75 25
26 19.5 26
     

Configuration 2 below shows the slot timing with a 4800 baud M7 GX radio using 200mS time slots.

 Configuration 2

4800baud with repeaters
TDMA Frame time, 10 seconds
200mS time slots
  Slot Number Time (S) into frame Radio ID
10-second TDMA Frame for all mobile units in the system 0 0 –
1 0.2 1
2 0.4 2
3 0.6 3
4 0.8 4
5 1 5
6 1.2 6
7 1.4 7
8 1.6 8
9 1.8 9
10 2 10
11 2.2 11
12 2.4 12
13 2.6 13
14 2.8 14
15 3 15
16 3.2 16
17 3.4 17
18 3.6 18
19 3.8 19
20 4 20
21 4.2 21
22 4.4 22
23 4.6 23
24 4.8 24
25 5 25
26 5.2 26
27 5.4 27
28 5.6 28
29 5.8 29
30 6 30
31 6.2 31
32 6.4 32
33 6.6 33
34 6.8 34
35 7 35
36 7.2 36
37 7.4 37
38 7.6 38
39 7.8 39
40 8 40
41 8.2 41
42 8.4 42
43 8.6 43
44 8.8 44
45 9 45
46 9.2 46
47 9.4 47
48 9.6 48
49 9.8 49