Why Use VHF/UHF GPS Transponders Instead of Cellular Connected Devices

Often a system decision comes down to cellular vs. VHF/UHF RF communications.

Cellular based GPS transponders and cell phones rely on a public cellular radio networks to connect to the carrier’s network, which then passes the GPS location information to the end user via the Internet.

VHF/UHF radio networks utilize private licensed radio frequencies to communicate.  The radio networks are privately operated, and may be owned and controlled by the system operator.

When trying to decide if dedicated VHF/UHF GPS transponders like the Raveon ATLAS PT or M7-GX transponder is the right choice, or cellular transponder is the right choice, keep these very important points in mind:

  1. You will know where everyone is at all times.  A GPS Transponder operates at all times, with fast update rates, even when cell service is not available. They even operate when a base station is off-line.
  2. Battery Life.  A GPS transponder can run for days on a single charge.  Most cell-phones will operate 8 hours or so when tracking in real-time.
  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, making a call is not possible.  The VHF/UHF 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 can take only minutes. No internet connection is needed.
  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. Learn more about how the RavTrack system is designed by viewing our asset tracking infographic.
  6. Fast Updates.   Cellular locators get quite expensive unless they are configured for very slow update rates.  Tracking hundreds of vehicles or people requires an advanced channel-access protocol like Raveon’s TDMA protocol. Airtime is free on the VHF and UHF bands.
  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.  Cell phones will not help in these situations. They can be turned off (The ATLAS PT’s power button can be disabled).
  9. Rugged.  The ATLAS PT is submersible to 1 meter of water, very rugged, and made from aluminum.  Few cellphones can take the abuse the ATLAS PT can.  When people lives are at stake, a rugged, long-life product is important.

Comparison of Features


GPS Transponder PRO

GPS Transponder CON

Cellular GPS

Cellular GPS

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

24-48 hours

8-12 hours

Real-time Tracking


  Limited bandwidth  Excellent


Safety System

Great situational awareness

No voice. Cannot talk to rescue.

User must operate their own private radio network.

Can talk to rescuers

Will not work when out of cell coverage or cellular system is down.

User Cannot Turn Power Off

Always On when needed

Requires charger to shut off.


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.


Few cellular transponders have this feature.

Live Tracking by Searcher and Rescue

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


Personnel can use voice to help direct searchers to find them

Sometimes difficult to explain location.  Must be within cell service, and probably standing up.

Learn more about the advantages of the RavTrack system by attending our webinar. We work with some of the most successful companies and government agencies, including the FAA. Find out more about our customers.

GPS Tracking Service Comparison: RF versus Cellular

Common GPS vehicle tracking systems use “cellular” GSM/GPRS based transponders. Once the device calculates position from the GPS satellites the transponder transmits the position to the cellular GSM/GPRS network of receivers (cell towers) in the area.  At this point the GSM/GPRS system operator transports the data to your output device. Obviously the network operator charges a fee for this service, and is in control of your data as well.GPS Tracking Comparison: Radio Versus Cellular GSM/GPRS

Advantages of Radio-based Solutions

Radio-based solutions are different in that the radio transponders transmit position over a mobile radio frequency, typically designated by a government administrative agency for your exclusive use.  A GSM/GPRS system is not used; instead the operator of the radio system installs one or more receivers in position(s) around the area to be tracked. One receiver – or more exact: the connected RF antenna – is capable of covering an area of typically 10-25 mile radius from its own position, although this range might vary depending upon how high in elevation the receiving antenna is, and what the local terrain is like.

As the radio operator owns both the GPS position transmitters as well as the receiver(s), the fleet may transmit positions very frequently without concern for any fees, and with extremely fast delivery of data; allowing for true real-time position updates which common cellular solutions do not provide (or charge high fees for).

Often radio users install just one receiver, and mount it high atop a building, antenna tower, or point of elevation to cover the tracking area. This area might be a city, an open pit mine or other remote area, or a fleet of boats where the group can be tracked by other boats in the fleet. Since the entire system operates independently from any GSM/GPRS network, radio modems can work anywhere GPS satellite lock can be acquired.  In fact, the entire system can be mobile and – in case of Raveon’s M7-GX series radios – any fleet member can receive GPS reports from other fleet members in radio range, even while all are moving at high speeds.

Large Area Coverage

If a larger area of coverage is needed, or the tracking headquarters is not at a good location for area reception, a single radio repeater may be established at a preferred location where the repeater then wirelessly relays the transmissions it receives to the central tracking location. If the area of coverage is very large, then multiple receivers may be installed and connected together as well as to a central location via an IP backbone, which can include either a private network or the public internet.  The determination of the proper receiver layout is based principally upon the area the system must cover for effective fleet tracking, as well as the local terrain.

Primarily the decision to install a radio-based tracking solution versus a common cellular system comes down to the area of tracking coverage required and the size of the fleet involved. Even the area of coverage required is vast, requiring a large number of receivers, and the fleet itself is small, and the cost per vehicle may become prohibitive.  In these cases the operator must rely on a pre-installed network of GSM/GPRS system receivers owned and operated by another entity and pay their monthly fees. If GSM/GPRS service coverage is poor then an expensive communications satellite relay may be a considered alternative.

See this complete comparison of RF versus GSM/GPRS “cellular” vehicle tracking systems.

For more information about the RavTrack system:

  • Attend our webinar where we introduce the technology and provide an overview of the system.
  • View a list of some of our Customers. We partner with many diverse companies and government agencies.
  • Learn more about how the RavTrack system is designed by viewing the asset tracking infographic.

Golf Cart Tracking with GPS

golf cart gps trackingAs the demand to improve the playing experience at golf courses and country clubs continues to grow, course managers are adding new technologies to enhance their product while also adding to their bottom line. One of these methods gaining traction is GPS tracking of the golf carts (and in essence the golfers) on the course to enable better management of tee times, tracking of course bottlenecks, improved beverage and snack service, downloadable advertisements, quicker servicing of failed and dead battery golf battery golf carts, on-the-go diagnostics, and cart misplacement/theft management.  For the golfer, the course owner can now also have the ability to provide (free or at a cost) statistics, shot history, distance to pin, and other limitless features that improve the golfing experience for the novice and the professional.

Global Positioning Satellite, or GPS is at the heart of all golf cart-tracking systems.  GPS enables a unit to pinpoint its position on planet earth using a combination of satellite transponders and ground based radar.  The three most common methods used for transmitting the gathered GPS data at golf courses include cellular, WiFi, and Narrow band VHF/UHF radio transmission.

Cellular vs. Wifi vs. VHF/UHF Frequencies

Cellular systems use the same radio solution as does your standard cell phone/smart phone.  The cellular solution’s benefits include low power operation, high data rates, and direct connection to an “App”, while the disadvantages include the need to have cell service in the area where the golf course resides, each cart to have a monthly subscription service, dependency on a third party carrier, outages, limited service during “busy” cell phone times, and reduced accuracy (if the cell signal itself is used for GPS triangulation).

WiFi uses a radio solution similar to what many folks use in a coffee shop or in their homes to connect to the Internet in a wireless fashion. The WiFi solution’s benefits include free connection, low power operation, and high data rates while the disadvantages include very limited range without a repeater, loss/weakening of signal due to obstructions, reduced throughput under heavy course loads, a max number of nodes supported, and interference from other WiFi devices in proximity to the course/golf cart.

Narrow band RF data modem solution, like that from Raveon Technologies RavTrack solution, use a dedicated UHF/VHF RF link similar to that in use fire/rescue/military communications links. The RavTrack solution’s benefits include free unlimited data connection, ownership of the frequency band, no third party control of the network, long distance range without a repeater (can cover the whole course), accurate (up to a meter) tracking, and an unlimited number of nodes supported while having virtually no disadvantages or limitations.

The RavTrack solution from Raveon Technologies is a self-contained hardware and software package that can be customized to support unlimited applications in the gold cart tracking space. Using a ruggedized and pre-configured radio transponder in each golf cart along with a transponder and software command and control at the club house (no internet connection is required), each golf cart can be pin pointed and tracked on the course using customized maps and/or standard Google type maps. “RavTrack PC” software is provided with the solution along with mapping/tracking support from popular third party software houses. The software provides such features as position, custom icons for each individual cart, programmable geofencing parameters, collision detection/avoidance alerts, distance between various carts, unlimited logging and history file generation, and several other position related parameters. Raveon can also provide customizable apps and solutions to better support the course operators exacting needs.

The RavTrack solution can support all the features discussed in the introduction of this article along with an unlimited number of customizable applications. These features will enable the golf course/country club to differentiate itself from competing courses by improving the golfers experience (statistics, distance to pin, shot history, etc.) while improving the courses bottom line by better managing its carts, its queuing of tee times, advertising, instantaneous cart down time and location management, and potential revenue generation by charging for statistics and print outs for the golfer.


The RavTrack solution from Raveon Technologies emerges clearly as the best solution for providing a low cost and easily manageable environment for the golf course/country club owner. Get a free quote now!

For more information about the RavTrack system:

  • Attend our webinar where we introduce the technology and provide an overview of the system.
  • View a list of some of our Customers. We partner with many diverse companies and government agencies.
  • Learn more about how the RavTrack system is designed by viewing the asset tracking infographic.

Golf Cart GPS Systems

Raveon’s RavTrack GPS tracking system is the ideal golf cart tracking system to track golf-carts and golf course maintenance vehicles. Golf Cart Tracking

golf cart tracking systemRavTrack GPS tracking delivers helpful, real-time location information and displays it on a map image of your golf course. You can track the carts, mowers, trucks, and workers.  You can see where you mowed each hour, day, or week. You can quickly locate carts to deliver food and beverages.

It also can detect potential theft or abuse of your carts and equipment. You can configure keep-out zones and many other rules to notify the ranger or security if a rule is violated.

The Benefits of Licensed Frequencies

Because Raveon’s RavTrack system uses VHF and UHF licensed UHF radio frequencies, you can easily cover your whole course and have no monthly air-time fees. The RavTrack system is also available on the MURS radio band, which is license-free. It works where GSM radio-based systems don’t and because the airtime is free, your update-rate of cart position and status is the fastest in the industry. You can easily track 75 carts with 15-second update rates.

And unlike the short-range 900Mhz and 2.4gHz solutions, RavTrack will cover your course, and reliably show you where your vehicles are.

RavTrack GPS tracking improves golf course operations by:

  1. Quickly locating specific carts, assets, employees, and vehicles
2. Track valuable assets (carts, trucks, cars, generators, trailers, mowers, security…)
3. Reducing wasted time when locating people.
4. Alarm the supervisor on speed, idle, and location violations .
5. Enforce keep-out zones and course boundaries.
6. Reduce theft by alerting when item move outside of the area.
7. Record and report the battery voltage for each cart
8. Log vehicle use, location, speed, and time for later reporting.
9. See what areas have been mowed or fertilized, by hour, day, week, or any time period

For more information about the RavTrack system:

  • Attend our webinar where we introduce the technology and provide an overview of the system.
  • View a list of some of our Customers. We partner with many diverse companies and government agencies.
  • Learn more about how the RavTrack system is designed by viewing the asset tracking infographic.

Improving GPS Tracking Precision Using WAAS


WAAS (Wide Area Augmentation System) is the next generation standard for implementing higher accuracy GPS systems. As demand for GPS continues to grow, the US government has implemented a more robust system to meet the needs of next generation tracking and improved reliability while still maintaining standard equipment in the field. Raveon Technologies has taken advantage of this new standard by adding WAAS to both their M7 GPS transponders and their industry leading RavTrack precision tracking solution.

Brief History of Loran-C/GPS/DGPS/WAAS:

In an effort to support military and commercial aircraft, Loran-C was the first implementation of modern GPS technology. Employing multiple ground based radar towers (sometimes compared to as bowling pins) typically near airports and larger cities, Loran-C provided excellent positioning for its time as a method to keep track and position aircraft. The downside of Loran-C was that it was less available in rural areas and completely unavailable over large bodies of water. Loran-C was also not accurate enough to support extremely bad weather and non-visual approaches.

GPS technology was next on the scene providing a 10x and greater improvement of positioning while solving the aforementioned approach problems. Using satellites and a low cost receiver approach, GPS took tracking from an expensive professional solution to a system that is now available in most cars, watercraft, and personal equipment.

Adding a differential mathematical approach, a specialized receiver, and land based FM towers, DGPS further improved positioning by another 10x. The downside of the approach is that it relies on line-of-site (to the towers) and provides spotty coverage in smaller towns and rural areas that don’t have the luxury of piggybacking on towers of local FM radio stations. Also of note is that a DGPS receiver is not compatible with a off the shelf consumer GPS unit.

WAAS is the latest approach and by far the most accurate. Using a combination of GPS satellites, ground stations, and geo-stationary satellites (see below for greater detail), accuracies up to less than 1M can be attained using standard off the shelf GPS equipment. With this type of spec, WAAS allows for new markets and solutions requiring a higher level of accuracy previously unattainable with existing solutions.

Some of these markets that Raveon Technologies WAAS enabled GPS transponders now support include vehicle collision avoidance, precision vehicle tracking and navigation, tighter and more specific geo-fencing, more accurate personal tracking, precision agriculture plotting, along with several other position dependent solutions.

Topography of a  WAAS System and How It Works

WAAS is a combination of ground based stations and satellite transceivers used to greatly improve the accuracy and performance of conventional GPS. Conventional GPS relies on using satellite transceivers “only” which are subject to ionosphere disturbances (billows), satellite orbit errors, timing, and clocking errors. By augmenting ground based stations, the errors associated with GPS are greatly minimized if not eliminated while also adding monitoring and real time adjustment of the GPS satellites themselves.

The system installed in North America is as follows: 35 plus ground base stations called Wide area Reference Stations (WRS) along with the existing satellites provide correlation data that is sent to 2 Wide area Master stations (WMS) on each coast to create a corrected signal. This corrected signal is then retransmitted by a geo-stationary satellite called a Ground Uplink Station  (GUS) that is fixed at the equator.

The system provides for guaranteed accuracy of  3 meters or less with typical accuracies approaching sub 1 meter (multiple samples may be accumulated to achieve even better specs). Adding to the accuracy improvement, uptime approaches 99.999% with a downtime of 5 minutes per year while conventional GPS can only guarantee 4 days per year of downtime.

Specifications of WAAS vs. Standard GSP, DGPS, and LORAN-C:

The following is a table of specifications and observed lab measurements of the various positional methods used in the US.

TYPE Horiz. Vert. Comments
WAAS 7.6M 7.6M Specification
  .9M 1.25M As measured
DGPS 10M 10M Specification
  1.6M 2.1M As measured
GPS 100M 50M Specification
2.5M 4.8M As measured
LORAN-C 460M 460M Specification
55M 55M As measured

As can be seen from the table, Raveon Technologies WAAS enabled transponders provide the most accurate tracking and positioning available while employing standard GPS gear. DGPS comes in at second, but as discussed, is only employed and is dependable in cities and urban areas where FM towers are available and line of site can be attained using the specialized DGPS gear. Standard GPS will continue its success in supporting the large consumer but lower precision auto, marine, and personal tracker market. LoranC, although the least precise, has a large installed base in the personal and small aircraft segment.

Below is a comparison of the position error of a GPS tracking system using WAAS augmentation and DGPS.  In this test, the horizontal accuracy was very good with each method. The WAAS system had much better vertical accuracy.


By implementing a WAAS GPS M7 or RavTrack system from Raveon Technologies, precision accuracy approaching sub 1 meter is attainable and repeatable using existing GPS receiver systems allowing for new applications and end-products in the positioning and tracking space.

Who’s Tracking You? GPS Tracking Security

GPS vehicle tracking is a powerful technology that can speed emergency response, improve efficiency, and provide a safety link to support personnel.  Raveon Technologies sells real real-time tracking system so business, agencies, and commanders, can track their personnel, assets and vehicles.

Raven’s private tracking system uses a very secure AES encryption algorithm, so that only authorized radios can track the GPS transponders.  It would be bad, and maybe even disastrous if GPS tracking were not secure.  Law enforcement, military, and security forces use GPS tracking to do their job and GPS tracking provides extra security for their operations.  And if the bad guys were able to track them, their operations and their lives could be in jeopardy.

This is why Raveon takes GPS tracking security very seriously, and tracking systems based upon less-secure communication methods should be carefully considered.  Most all other GPS tracking systems us cellular radio technology, such as GSM networks to send their data.  Anyone using a public GSM system must carefully assess all aspects of the system’s security.

In 2009, a German computer engineer announced that he’s deciphered the 21-year old 64-bit encryption algorithm that protects the GSM standard.  According to the New York Times, the German encryption expert “aimed to question the effectiveness of the 21-year-old G.S.M. algorithm” and its use to protect the world’s GSM based GPS Tracking communications.  Having the code itself isn’t enough to eavesdrop, but it certainly helps people along the path. The GSM Association responded by calling the publication “theoretically possible but practically unlikely.”


It may be only a matter of time before the technology is readily available to eavesdrop on GSM communications.   Right now, it is believed that only the US military and certain foreign governments have the ability to eavesdrop on GSM communications.  Technology marches on, and the security of GPS tracking using GSM networks may be left behind.

See www.ravtrack.com for mor information about secure, private GPS tracking.