Author: Radio-O

It’s important in real estate, and also in navigation sports such as orienteering and ARDF. Fundamentally, all location information is the same. Whether it is derived using map and compass or received as a latitude and longitude from a GPS instrument: a location is simply a position on Earth.

If you are only carrying a map and compass then a lat/lon position will not be of much use to you. You need a position that is referenced to your map. With a map-referenced location, you can point to where you are on the map, and identify feature locations relative to where you are standing. You can derive optimal routes to where you need to go. You’ve got all you need.

If, in addition to a map and compass, you are carrying a handheld computer, then a lat/lon position becomes much more useful to you. Although a lat/lon position is not referenced to your map, it is referenced to the Earth’s surface. So with a single known position on your map (such as a waypoint set at the Start) lat/lon data can be referenced to your map, allowing you to view your distance and magnetic compass direction relative to the Start. That information can be provided in text format in meters and bearing angle in degrees magnetic so that a glance will give you immediate confirmation of your approximate location on the map.

But a lat/lon position can be much more useful than that, especially if you have lots and lots of lat/lon positions and a computer capable of calculating great-circle trigonometry equations. Just about all modern micro-controllers can do that. Here is a sampling of some of the cool features that can be readily implemented using GPS location and compass direction information:

o A display of your complete track since leaving the Start along the path to your current location.
o Any waypoints you set along the way, such as fox locations.
o The exclusion zones around the Start and any found foxes, and your position relative to those exclusion zones.
o Bearings you have taken and the precise locations at which they were taken.
o Intersections of the bearings you have taken and an estimated location of the fox based on those intersections.
o Distance and compass direction to the estimated fox locations – even an arrow (or audio indication) pointing the way.
o Straight-path navigation guidance with cross-track error in any direction you choose.
o Distance traveled along your route or any segment of your route.
o More. How much more depends on one’s imagination, know-how, and processing power.

Although a graphical display (no map needed) would be ideal for presenting the above information, audio tones and synthesized voice played in one’s headphones can be even more effective at allowing one’s eyes to remain on the paper map and trail ahead.

There seems to be general agreement that showing a competitor their map location would provide an unfair advantage. But is it a greater advantage than all the navigation assistance that lat/lon location data can provide? We shouldn’t be surprised that GPS simplifies a navigation sport. Map position and latitude/longitude are exactly the same things: positions on Earth’s surface.

Some will argue that their GPS equipment doesn’t work all that well, and isn’t much of an advantage. That might be true right now. But that will change. ARDF receiver builders don’t have the skills and knowledge of smartphone or GPS device manufacturers. But take a look at some of the GPS-based apps available for Android and iOS, or features of handheld GPS devices. They use GPS data, standard position filtering algorithms, and widely-available trigonometric equations. The apps and devices aren’t optimized for ARDF, but they provide many of the features listed above. And they do them very well indeed. That is the future.

There is an unwritten rule that most competitors recognize upon seeing it, even if they had never contemplated it before: ARDF competitors should not receive navigation assistance from man-made signals coming from outside the competition boundary. It would not be fair play for observers to radio their bearing measurements to their friends competing on the course. How, then, is it right for competitors to carry receivers that let them receive navigation assistance from Earth-orbiting satellites? ARDF is about using the fox signals for navigation – that is what defines ARDF.

GPS, GLONASS, and similar technologies are not comparable to having a receiver that displays a fox’s signal strength. They aren’t even comparable to having a processor convert the signal strength to an estimate of meters to the fox. Navigation systems providing lat/lon position data work unlike any other type of instrument and support features that no other technology can. They hand you location. Your precise location. No thinking required.

I like GPS very much. I have worked with it professionally and as a hobby. It can do tremendous things. It might be used to help simplify navigation sports to avoid discouraging beginners. It definitely simplifies course design and supports accurate course setting. As much as I like GPS technology, I would never want to compete against it.

ARDF rules can have a large impact on the cost of equipment. There are many examples of this that can be cited. But there is one notable example where current rules are unnecessarily increasing the cost-of-entry to the sport. And this issue can be readily addressed with a simple clarification of the rules.

High-end ARDF receivers costing US$250 or more, typically provide excellent performance specifications: selectivity, stability, weight, ergonomics, and sensitivity. Inexpensive alternatives generally underperform the expensive units in all respects. But the most significant parameter that prevents under-$50 units from being usable is sensitivity. If you can’t hear a signal, you can’t hunt it. Period.

Not to get too geeky, but sensitivity on the 3.5 MHz band is noise limited. That means that the background noise level is well above the sensitivity threshold of most receivers. The receiver might be plenty sensitive to receive a weak signal, but the received noise is louder than the signal, making it unreadable.

Noise performance is improved by increasing selectivity (narrowing the receive bandwidth) to allow less noise through while still allowing the desired signal to pass through. But high selectivity requires high stability, otherwise a receiver would drift outside the narrow passband and lose the desired signal. So high-sensitivity 80m receivers must also have high selectivity, and high stability. That means that the requirement for high sensitivity affects many aspects of the receiver design. The bottom line is that greater receiver sensitivity means greater overall receiver complexity and cost.

The bottom line is that greater receiver sensitivity is achieved by increasing the complexity and cost of the receiver.

A question we have to ask ourselves: is high receiver sensitivity an essential part of ARDF? Is it really necessary to promote the use of high-sensitivity, and therefore high-cost, receiver designs in all ARDF events?

Is it really necessary to promote the use of high-sensitivity, and therefore high-cost, receiver designs?

I submit that it is fitting and proper that some ARDF events be conducted in a manner that allows low-cost receiver designs to be used. I believe that competitors can still exhibit their quick feet, quicker thinking, and signal interpretation abilities even if the signals they are hunting are relatively strong. Furthermore, we need to have events that accommodate inexpensive receivers in order to lower the cost-of-entry to the sport. And this could be done simply by requiring sufficiently-high radiated power levels from the fox transmitters and beacons.

We need to have events that accommodate receivers that pose a lower cost-of-entry to the sport.

The obvious candidate for a low-cost-of-entry event is sprint. The small field of play means that quite low radiated power levels from the foxes could be used while still allowing receivers with poor sensitivity to detect them all from every location on the competition map.

In fact, the Region 1 rules appear to require sufficient radiated power levels already. See Region 1 ARDF Rules Part B paragraph S6.1. The minimum sprint transmitter power is 300 mW. So why can’t a low-cost R3500D receiver hear all the sprint transmitters on a regulation course?

So why can’t a low-cost R3500D receiver hear all the sprint transmitters on a regulation course?

The answer: the rules do not specify the foxes’ radiated transmit power. The rules specify only the transmitter output power. The rules say nothing about the antenna match, or the antenna’s efficiency. And according to my observations, little of the minimum 300 mW of output power is actually being radiated by sprint fox antennas. At least, not on the sprint courses I have experienced in the USA.

The rules say nothing about the antenna match, or the antenna’s overall efficiency. So little of the minimum 300 mW of output power is actually being radiated by sprint fox antennas.

One solution to the apparent rules deficiency would be to specify a specific antenna design and placement. Another solution: have the rules specify the actual amount of power radiated from the sprint fox antennas. But those rules could prove difficult for organizers to implement or measure. Instead, I would suggest that the rules simply describe a reference transmitter output power and matched-feedpoint antenna system to be used for comparison.

With a standard output power and antenna design, organizers would only need to compare their fox transmitters’ signal strength to that of the reference. If the fox signals were as strong, or stronger, than the reference then all is good. If not, then the fox transmitter’s output power might be increased, or some modification to the foxes’ antennas or the antenna matching system could be made. In most cases, the comparison exercise would only need to be performed once for a given fox (transmitter plus antenna) system design.

With a standard output power and antenna design, organizers would only need to compare their fox transmitters’ signal strength to that of the reference.

Such a radiated-power reference system could be specified for each of the four event types used in ARDF. This would eliminate the need for the vague and non-existent “receiver of average sensitivity” called for in current Region 1 rules (see Part B, paragraph 27.3).

The reference-based approach could allow low-cost receivers to work just fine for sprint, and perhaps some other events as well. Allowing newcomers to fully participate in at least one ARDF event format for an initial investment under US$50 could prove to be a big deal.

It is that time of year again. The 2019 USA and IARU Region 2 ARDF Championships are in the rear-view mirror. Now we see in the dim glow of the headlights the 2020 USA ARDF Championships up ahead.

Before asking any group to take on the task of hosting the 2020 USA ARDF games, it is only right to inform them of what is involved in that undertaking. To do that, we need to take a careful look at what constitutes a USA ARDF Championship.

What We’re Talking About

The USA Championships is not the World Championships nor even an IARU Regional Championships. It is the ARRL-sanctioned ARDF games customarily held on even-numbered years. The results of which are used to help determine who is extended an invitation to participate on Team USA at the next World Championships and, potentially, at other international or inter-regional ARDF competitions.

Below, components of a USA Championships are divided into three groupings: Essential, Important, and Nice-to-Haves. The names are pretty self-explanatory. It ain’t a USA Championships unless all the essential items are provided. The Championships are improved by adding more of the important elements. The nice-to-haves are just icing on the cake.

For brevity, not every component of a USA Championships is listed: just those that require a significant investment of planning, time, effort, or funds. Justification for each item’s categorization is not provided below. Healthy debate over differences of opinion is encouraged. But remember when debating: those who choose to host a USA Championships have a much louder voice in deciding how things are done for the games they organize!

For those considering hosting the USA Championships, please keep in mind that you don’t have to do or provide everything yourself. Equipment and volunteers can be provided by other groups within and outside your area. The ARDF Committee can help locate what you need.

The Essentials

1. Competition formats, courses, terrain, maps, transmitters, antennas, and time-recording equipment that conform reasonably closely to Region 1 rules.
2. Custom-designed courses for each of the age/gender categories that will be in attendance (adult and youth).
3. First-aid, safety and communications provisions appropriate for the venues and activities being held.
4. Official sanction of the competition by the ARRL ARDF Committee.

Important

1. High-quality orienteering maps for all courses.
2. A sufficient number of workers to have Start, Finish and Download areas constantly supervised while they are active.
3. Trained workers to set courses and pick up afterward.
4. Awards for the top three finishers in all age/gender categories.
5. Practice sessions for each competition format.
6. Effective advertising and communications with competitors before, during and after the championships (e.g., web site, email list, Facebook group, etc.)
7. A date for the competition that falls no later than June.

Nice-to-Have

1. Banquet.
2. Award ceremony.
3. Recently-updated maps.
4. Trophies or medals as awards.
5. Local transportation provided for competitors.
6. Training sessions before the practices or championships begin.
7. Observers stationed at foxes and keep-out areas.
8. Snacks and water at the finish or download area.
9. Special provisions for large groups of foreign visitors.
10. Close proximity to major airline hub.

Bottom Line

A USA ARDF Championships that provides all of the Essentials, and a majority of the Important items, could be a very successful competition even if none of the Nice-to-Haves were provided. This is particularly true if the venue were especially nice or the costs were low.

Want to jumpstart ARDF activity in your area? Perhaps hosting the USA Championships can be just the spark needed to get local hams, orienteers, Scouts, and friends involved and active in ARDF.

Questions, comments, or want to float a proposal for 2020? Leave a comment or contact the ARDF Committee at ardf@arrl.org.

USA and IARU Region 2 ARDF Championships

Registration is open for the USA and IARU Region 2 ARDF Championships, July 28 – August 4 in Raleigh, NC.

Visitors and first-timers are always welcome at the championships events. You may attend to observe at no charge. You may register to participate in one or more of the events even if you’ve never attempted ARDF before. There will be practices and demonstrations. There are no age limits or license requirements for participants. Please contact the organizers for details.

The bulletin and link to registration are at http://ardf.us
More information at http://www.arrl.org/news/registration-opens-for-usa-ardf-championships

It seems that the precise birthdate for ARDF was never recorded. But it seems reasonable to assume that sometime in the late 1940s, as surplus World War II equipment made backpack-portable radios a possibility, some outdoor-minded hams (likely in Scandinavia) took up maps and compasses and headed into the woods to settle a bet on who had the better radio direction-finding skills. When the loser couldn’t cite a violation to disqualify the winner, the need for formal ARDF rules documents was realized.

Whatever those first ARDF rules looked like, one thing is certain: equipment availability played a major role in determining the details. Super-regenerative receivers used by the competitors likely made it necessary to maintain large distances between competitors in order to prevent receiver-to-receiver interference. High power requirements of both receivers and transmitters would have limited the time duration of competitions. The bulk of the equipment likely placed restrictions on the course length. Lack of equipment probably restricted the number of foxes that could be fielded.

The same is true today: the equipment influences the rules. Smaller, lighter, and less power-hungry equipment has allowed the rules to define events with more fox transmitters, longer overtime periods, and more closely-packed competitors. Because competitors generally outnumber the foxes, and out of the desire to keep the sport affordable for all, rules generally favor placing any added cost and complexity into the transmitters and not the receivers. But recently a problem has arisen.

Four major events are defined in recent rules documents and are featured at most championship ARDF competitions: Classic 80m, Classic 2m, Sprint 80m, and Fox-O 80m. Because the radio band, power level, and timing requirements are so different among those events, different transmitters are generally required for each event. Classic 80m requires five foxes and one homing beacon, Classic 2m requires a like number for that band, Sprint requires at least eleven transmitters, and Fox-O at least twelve. That adds up to 35 separate transmitters plus spares. Add in the same number of antennas, and organizers have a sea of equipment to construct or purchase and maintain.

A high transmitter count poses a significant burden on the competition organizers and increases the chances of hardware failure. At some point, the burden of holding an event becomes unaffordable to too many organizers. Has the point of “organizer overload” been reached already?

Flexible transmitter designs can support operation across multiple bands, power levels, timing configurations, and identification patterns. But pushing the complexity into the transmit hardware increases the cost of each transmitter, so it doesn’t solve the problem. To keep costs down, the rules need to take into account the organizer burden. The two steps below, if done together, could help prevent organizer overload.

• Define events that use transmitters with identical, or nearly identical, characteristics: band, power level, timing, identification, etc.
• Allow championships to include a subset of all event types, so that organizers can choose what they can best support with their hardware.

The way the Region 1 ARDF rules documents are now organized, certain event characteristics are described in the body of ARDF Rules Part B, and some are described in the appendices. For instance, Part B, Section 27 describes transmitter requirements. But not all the events described in Part B appendices adhere to the transmitter requirements in Section 27. It would make more sense to move all event descriptions (Classic, Sprint, and Fox-O) each to its own appendix, and remove all event-specific rules from the body of Part B. This would simplify rules organization, and make it easier to find and identify all the rules specific to each event. With that done, event-specific rules could be analyzed and modified more readily and with less confusion.

With each type of event described independently in its own appendix, the event descriptions could be tweaked to bring transmitter requirements of different events closer together. New events could be added to allow organizers more options. Events with similar characteristics could be grouped into event types or “families”. Organizers then might be allowed to choose from the list of approved events, selecting the ones that can most readily be supported by available equipment, provided that they select one event from each family.

Thought should be given to devising fun and challenging events that emphasize a variety of skills and abilities yet utilize existing equipment capabilities. Examples:

• A relay event could test overall team strength and might include both men and women competitors on different relay legs.
• A mass-start event, perhaps modeled on the popular “Goat” orienteering events, could provide a fun and entertaining race.
• Group events, involving 2-or-more team members working together, could test competitors’ cooperation and strategic thinking.

The possibilities for expanding the event list, without expanding needed transmitter capabilities, are endless.

ARDF has evolved over the past 70 years. The changes suggested above should be considered as part of ARDF’s evolutionary process. Let’s innovate with the equipment, and the rules, taking care that the rules don’t impose too great a burden on either the competitors or the organizers.

In an earlier post I argued that the Region 1 rules, as currently written, are not restrictive enough on the use of satellite navigation systems in ARDF. In a subsequent post I maintained that satellite navigation systems, particularly those contained in personal electronic devices, should be used much more in ARDF, and that it can be done is such a way that prevents the misuse of those devices. In this post, I will explore how smart devices can be brought into ARDF without changing the nature of the sport, and without putting additional burden on event organizers.

In 2017 we are marking the end of the first decade of the iPhone, which ushered in official manufacturer support for independently-developed smartphone applications: apps distributed through online stores run by the device manufacturers. But the use of these capable devices, and the apps that run on them, has made little headway in ARDF over the past decade; due in large part to how capable those devices are! The unchecked use of GPS, mapping, and communications capabilities of modern cell phones could totally transform the sport of ARDF from an individual test of navigation and radio skills, into a mass collaborative-geocaching event.

But banning all use of smart communications devices is unnecessary. Device capabilities can be restricted, and those restrictions enforced, by the same application software that makes them so useful. Rules should be put in place encouraging the legitimate use of smartphones and tablets, while putting the onus of proving rules adherence squarely on those who choose to utilize those devices during competition. Likewise, the burden of developing, testing, certifying, and distributing ARDF-approved applications should also rest on the app developers, while the event organizers monitor rules adherence, and enjoy the benefits of improved safety and efficiency afforded by the new technology.

Below is a description of how a very secure system might work. The full system needn’t be implemented if an Organizing Society considers it unnecessary. But verifiable adherence to the rules is possible, and could be used for World Championships, and similar “high stakes” competitions.

The components and participants include:

ARDF-Approved Apps: These are the only applications allowed to run on electronic devices carried by competitors. And an approved app must be running in the foreground at all times while a competitor is competing.

Rules: There must be rules in place governing what ARDF-Approved Apps must, and must not, do; As well as how they are published, stored, distributed, and utilized.

Device-Carrying Competitors – those who choose to carry a personal electronic device (smartphone, tablet, etc) during a competition are subject to certain rules that do not apply to other competitors, and must accept certain risks in order to take their devices with them on the course.

App Developers – those who write ARDF-approved applications will need to adhere to the rules regarding the apps, and apply to organizers for app approval well in advance of a competition.

Organizers – event organizers will need to take certain measures to ensure adherence to the rules by all participants. They will need to designate an Independent Authority responsible for building and submitting apps for distribution, and other technical details. Most of the adherence assurance tasks can be automated.

Independent Authority (IA) – this is an individual or a small group designated by the event organizers. The IA must have sufficient technical knowledge and resources to build and submit apps to the app stores for distribution. Those involved in IA responsibilities should be independent in the sense that they have no personal interest in the outcome of the event, or as a group they are able to oversee one another to ensure .

ARDF-approved applications must have the following characteristics:

1. Open Source – so that anyone can examine the source code and verify its capabilities and restrictions, and even compile and run it to test its operation.
2. Distributed Publicly, Worldwide, Free of Charge – on official device-manufacturer app distribution sites. This will help provide a level of control over the source of apps, making it possible to require participants to download an app under supervision, for instance.
3. Built and Released by an Independent Authority – an appointed individual or team will build and submit the openly-available software to the official device-manufacturer app store(s) for distribution.
4. Licenses applied to any software must allow others to freely copy, modify, and use the code for any purpose: truly Open Source.

Rules governing the operation of ARDF-approved applications must include at least the following restrictions:

1. Apps must not provide any features or functionality expressly prohibited by the rules. This would include being able to communicate with others, display digital maps, etc.
2. Apps must record a continuous log file in a specified format along with the competitor’s name, bib number, and any security “key” data. Logging must begin automatically at app start-up, and end when the app is closed or terminated, logging at least the following information at 10-second (or shorter) intervals: Lat/Lon position, UTC time, device’s battery level. It must also specifically log the position and time of certain device events: shutting down the app, placing the app in the background or accessing any other app, placing or receiving a phone call or digital message.
3. Apps must provide a verification mechanism (specified by the rules), allowing a key or code to be entered to verify two things: that the app is genuine, and that any log it generates can be traced to that installation of the app.

Competitors choosing to carry a smartphone would accept the following responsibilities:

1. To run a single approved app at all times while on the course, never shutting the app down, placing it in the background, running another app, or using the device for communication (except in emergencies).
2. Submit the full log file recorded during the event directly from the device to the organizers, within 5 minutes of reaching the finish. This could be done automatically by email after reaching the finish.
3. Accept the consequences of a system crash, loss of the phone, or any other event that could affect the recorded log file: resulting in the disqualification of the competitor.

ARDF-approved-app developers would accept the following responsibilities:

1. Release and publicly post all source code to a version-controlled open-source distribution site (e.g., GitHub) before the published deadline: this could be six months or more prior to the date of a championships, to allow time for the Independent Authority to build and submit the apps to the app stores, and for the apps to be approved and released on the stores.
2. Defray any cost incurred by the Independent Authority in order to submit the app to the app store(s). A nominal fee could be charged to the developers in order to cover any costs incurred by the IA.

Organizing Society Responsibilities

The society responsible for organizing a competition will have the following responsibilities:

1. Validate personal electronic devices to be used by competitors to ensure compliance. Entering a short unique “secret key” into each competitor’s ARDF-approved app should be all that is needed to accomplish this task.
2. Collect all log files submitted by competitors, and confirm that the logs are genuine (inspect recorded key), and contain no entries indicating rules violations. This process could be totally automated. A sophisticated analysis tool could even identify exclusion zone violations, or following.
3. Investigate any detected or reported rules violations.
4. Organizers must have the authority to revoke the approval of any app at any time, even the day of the competition, if it is demonstrated to violate any rules. Developers of apps shown to be in violation can be banned from future participation

Since the applications are open source, freely available, and run on standard commercially-available hardware, everyone can inspect them for violations. It is in the competitors’ interest to find and report app violations, since others who use them could gain an unfair advantage. Reports of violations should be investigated by an Organizing Society, or by the ARDF Working Group, and dealt with appropriately.

 

We, the Signatories to this petition, recognizing that:

o Amateur Radio Direction Finding (ARDF) has been practiced in IARU Region 2 for the past 20 years.

o The IARU Region 2 ARDF Working Group has members with decades of experience in administering the sport, who are well qualified to create and establish permanent rules for Region 2.

o IARU Region 2 can better promote the growth of ARDF if the Region’s rules are tailored to best serve its participants.

o There is precedent for permitting personal electronic satellite positioning system receivers (GPS) in ARDF World Championship competitions, codified in current IARU Region 1 ARDF rules.

o The properly-administered use of smart personal electronic devices (smartphones) running specialized apps poses no greater risk of misuse than do GPS devices.

o ARDF in Region 2 can benefit from the use of smartphones, in terms of safety, and broader appeal of the sport among the Region’s populace.

o The lack of permanent rules specifically allowing the use of smartphones, provides no assurance that their use will be permitted on an ongoing basis, and therefore is a disincentive for experimenters and innovators to develop useful apps for the sport.

o The IARU Region 1 ARDF rules documents constitute a proven template for the establishment of permanent rules for Region 2, shortening the process for creating a preliminary rules document.

Therefore, we call upon the IARU Region 2 ARDF Working Group to act swiftly to:

• Establish permanent ARDF rules for Region 2 no later than January 1, 2018.
• Include provisions in those rules for the use of smartphones running suitable apps.
• Establish that Region 2 championship competitions be conducted under Region 2 rules from January 1, 2018 onward.
• Work with IARU Region 1 ARDF Working Group members to reconcile any rule differences between the Regions as appropriate, while retaining any Region 2 rules differences that specifically benefit that Region.

Allowing competitors to carry smartphones needn’t pose a significant risk that those devices will be used for an unfair advantage. Indeed, relatively simple GPS devices carry a much greater risk of abuse.

GPS is Easily Abused

Consider that even the dumbest GPS wrist devices can provide undetected navigation assistance to the user. Simple GPS watches can record waypoints and measure distances and angles to those waypoints. They also often provide graphic displays that can be used to view user-created waypoints and the user’s track. A single waypoint entered by a competitor near the start area of a course enables a GPS to provide distance and angle to the start from any location on the course. Then it is a simple matter to utilize that GPS-derived information to deduce one’s location on the map – no compass or map-reading ability required! Much more advanced navigation features are available on some GPS models.

Smartphones Can Prevent Abuse

Unlike GPS devices, most smartphones, even very old ones, are sophisticated enough to run a monitor app that would prevent the undetected use of the smartphone’s navigation or communication features. While an app is running in the foreground, a smartphone is capable only of performing those functions that the app is capable of providing. A monitor app that provides no navigation or communication features would effectively prevent the misuse of such banned hardware features for so long as the app is running. A monitor app could also detect when the app itself has left the foreground or has been closed, and record (or even report in real time) the event for review by a Jury. So a smartphone running a properly-designed monitor app would not be able to provide banned features without the violation being detected by authorities.

Monitor apps could also provide allowed features, such as GPS  track recording for post-competition analysis, thereby allowing smartphones running monitor apps to replace more easily-abused GPS devices. A clever monitor app could even “geofence” exclusion areas, preventing competitors from entering them undetected. A geofence around the entire map boundary might be used to enhance safety by informing competitors when they have left the region covered by the map.

Summary

There is no need to ban competitors from carrying hardware devices capable of providing an unfair advantage. Rather, competitors must be required to run appropriate software on any devices that they choose to carry. That software must disallow competitors from accessing and utilizing the hardware in an unfair manner without detection.

Instead of banning particular hardware devices, rules should be written to address the unreported use of disallowed functionality, such as navigation assistance, or 2-way communications.

IARU Region 1 ARDF rules currently contain the following rule regarding the use of satellite-based navigation devices:

Part B, Appendix 1, Section T4.2 The use of satellite positioning devices is allowed provided they do not contain digital map of the terrain (“nonmapping” devices).

The above rule is currently being interpreted by some ARDF equipment manufacturers and competitors to permit the use of GPS modules integrated into ARDF receivers, provided that digital maps are not used.

By integrating a GPS module with a microcontroller and a digital compass module within the circuitry of an ARDF receiver, the following navigational assistance is currently available in some competitors’ receivers used at ARDF Championship competitions.

1. Distance Measuring – The ability to set waypoints and then read the straight-line distance between one’s current position and the recorded waypoint. This is useful for determining when an exclusion area border (e.g., around the Start, or around a located Fox) has been reached.
2. Heading Following – The ability to follow a straight line from one point in a particular direction. This is useful for navigating along a straight path, such as along a particular bearing toward a Fox. Using geometrical formulae in an embedded software program, the receiver is able to calculate cross-track error information and present it audibly through the earphones, allowing precise navigation along the heading direction without any need to refer to a map or the features shown on a map. Note: this feature is more accurate and foolproof than using compass guidance alone because GPS can ensure precise steering to the actual rhumb line with high accuracy.
3. Bearing-Crossing Calculations – The processor can calculate the position where bearing lines converge, and then provide distance measurements and heading-following assistance to the convergence location. Note: since GPS positioning is used to determine the location from which each bearing direction was taken, one significant source of bearing error is reduced. So bearings are significantly more accurate and more useful for following and convergence calculations when GPS is used to establish the precise point at which each bearing was taken.
4. Range and Angle – Range (or distance) is the same as “distance measuring” described above. The angle between a waypoint lat/lon and one’s current position lat/lon can also be easily calculated without using a compass. This allows, for instance, a competitor to read from an alphanumeric display both the distance and the compass angle from the start to his current position. That lets a competitor  quickly locate their precise position relative to the start on a paper map.

A future concern: Short-range radio communication technology (currently banned) could theoretically be used to share all the course data wirelessly receiver-to-receiver between competitors in the field.

The same logic that allows the rules to be interpreted as permitting the above functionality, should also permit simple monochrome graphical displays to be integrated into ARDF receivers. Although to my knowledge this is not yet being done, it is almost certain to happen at some point in the future. With a simple small graphical display, lacking any terrain map whatsoever, the following features will be possible.

1. Waypoint Display – Similar to the distance measuring feature described above, the small graphical display will permit setting and viewing waypoint positions relative to one another.
2. Bearing-Crossing Display – By taking several bearings toward the Finish beacon, an accurate Finish location can be determined and displayed relative to the Start, found foxes, and bearing convergence locations for unfound foxes.
3. Exclusion Area Display – Similar to the distance measuring feature described above, the small graphical display will permit seeing one’s current position relative to the Start and the exclusion area around the Start, estimated Finish, found Foxes, and fox bearing-convergence locations.
4. Track Display – As a competitor traverses a course, this feature will allow viewing one’s current location and the path traversed relative to all the waypoints and exclusion areas recorded during the run.
5. Bearing Display – Bearing lines taken toward Foxes can be shown relative to all of the information listed above.

So a simple graphical display would allow the entire course, and a competitor’s location and track to be displayed relative to one another with overlaid bearing lines. Only a terrain map would be missing.

While a graphical display would increase the advantage provided by integrated GPS modules, it should be kept in mind that all of the capabilities listed for the graphical display scenario could, theoretically, be provided using audio and textual cues. Such an audio-and-text interface would be less intuitive and would require more learning on the part of the competitor. But the fact remains that all of the information listed above can be conveyed with or without a graphical display, and without a terrain map.

Accuracy: GPS position accuracy depends on the antenna, atmospheric conditions, satellite constellation geometry, use of filtering (e.g., Kalman filtering), and other factors. Experimentation has shown that for typical GPS modules +/- 10m accuracy is readily achieved and rarely does the error exceed +/- 30m. Weather and vegetation are rarely a factor. Extremely steep terrain (more extreme than found on most ARDF courses) combined with low elevation can sometimes cause higher position error or even loss of position. GPS tends to be unreliable indoors.

The use of GPS for navigation assistance, even without terrain maps, can provide advantages over using only the traditional personal navigation skills historically used for ARDF. This fact is readily admitted by most competitors who use receivers with built-in GPS modules, and of course, it is the reason that such such receivers are used at all.