Have Accuracy, Will Travel

October 4, 2015  - By
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Photo courtesy of Trimble.

Photo courtesy of Trimble.

BYOD Sub-Meter Positioning for Mapping and GIS Professionals

Employees bringing their own mobile phones and tablets to their jobs in the field enables them to complete more tasks using fewer devices. However, this practice introduces operational and security vulnerabilities.

By Matt van Doorn

In the mapping and GIS industries, mobile devices such as smart phones and tablets have a growing presence in the field; they enable businesses to work smarter and more efficiently. The Bring Your Own Device (BYOD) trend — essentially the use of commercial-grade devices for work purposes — will likely not slow down. BYOD is not without its pain points. Organizations face many security vulnerabilities when commercial-grade devices access critical data via corporate IT networks. Additionally, there are applications where a mobile device’s location capabilities are not accurate enough for GIS professionals to efficiently and effectively locate an asset and collect data.

Company IT departments have multiple options that control and monitor access to combat BYOD security issues; however these options do not resolve the accuracy issue. Traditional company-issued handheld integrated receivers for data collection are designed to meet accuracy demands in almost any physical environment condition. While these devices are the most appropriate technology option for some applications, they tend to be expensive for the positioning tasks where a smart phone or mobile device is “good enough.”

What to do when better accuracy on a mobile device is required, but it doesn’t make sense to invest thousands of dollars in a traditional receiver? With proper research, field professionals will find professional solutions that pair with consumer-grade smart devices to produce the requisite accuracy for a fraction of the cost of a traditional receiver.

Requirements and Accuracy

At a minimum, handheld receivers destined to work in conjunction with mobile devices must meet the following requirements:

  • The device must have moisture ingress protection to function properly in snow, ice, rain or dust environments.
  • The device must survive falls in hard terrain. It should have shock, drop and vibration protection.
  • The device must last the full workday for the professional to complete all workflows on a single battery charge.

Legacy company-owned receivers typically meet the requirements above and have had a long-term reputation for accurately providing positioning data. These devices are still the appropriate solution for environments where it does not make sense to take a smart device, such as a remote location in rough terrain where the smart device may not perform.

However, a smart device can in many cases enable the employee to be more efficient. Thanks to the accessory market, many of the above-listed requirements can be easily addressed. For example, smart-phone juice packs can fix the battery longevity issue; cases can protect against weather, shock or dropping; and screen covers can address the sunlight screen visibility issue. With a smart device in hand, GIS and mapping professionals not only have access to GPS data, but they are able to access and complete other work-related tasks from the same device such as email, internet access and voicemail. Plus, a smart phone is only a fraction of the cost of traditional receivers.

The most critical component that smart devices still cannot address is sub-meter accuracy, which many mapping and GIS professionals require to successfully do their job.

Accuracy Drives Cost. Mapping and GIS businesses are acutely aware of the efficiencies created by greater accuracy. With poor information, errors become increasingly costly. When robust, accurate data is collected, there is a direct correlation to improved workflows and operations. This allows professionals to be more strategic in ensuring that applications are effective and efficient across operations.

Aerial and satellite imagery made initial steps toward generating more accurate data collection, bringing mapping and GIS professionals to within a 50-centimeter range of the assets. Subsequently, high-speed lidar collection tools, designed to capture large areas at 5–10 cm accuracy, came to the market. While these tools significantly improved data collection, precise measurement typically requires more time, more expense and highly specific instruments in order to generate more data.

Today, handheld receivers can achieve high accuracy without using survey-grade tools, in applications that include:

  • Mapping: Any application, including locations, quantities, densities, specific areas and map change.
  • Aquatic monitoring
  • Buried utility infrastructure/cable location
  • Water/wastewater disposal
  • Location and elevation measurements: for example, elevation data on manholes or trunk lines.

Requirements vary across applications and industries. The mapping/GIS professional must determine the level of accuracy their workflow requires.

Accuracy Evaluation

A typical smart device, properly assisted, can achieve an accuracy range of up to 5–6 meters when used to locate an asset. In many cases this is good enough. To obtain positioning data, iOS devices use the application “Location Services,” which is available on multiple mobile platforms. Location Services enables location-based apps and other applications to use information from GPS and cellular and Wi-Fi networks to determine location information. The location provided by a hybrid system with cellular-assisted GPS (A-GPS) allows the device to identify location within a 5–6 meter range of an asset. Wi-Fi positioning alone can determine a location with an accuracy of about 74 meters, and cellular positioning alone offers about a 600-meter range for location, according to industry sources (www.windowscentral.com/gps-vs-agps-quick-tutorial).

However, cellular positioning can be limited when there is no network available. In remote or industrial settings, this could create difficulties in asset location. In water/wastewater, for example, when a GIS professional is in a ditch looking for a valve or a meter and there isn’t a network connection, the accuracy level provided without GPS may not be sufficient for that application. When A-GPS is not available due to a lack of cellular network, GIS professionals also have to deal with convergence time.

Another example involves searching for a manhole cover when the ground is covered by a couple feet of snow. In this case, the 5-6 meter range is quite large and could lead to a lot of time spent digging until the manhole is uncovered. This wastes time and energy, and leads to higher costs. Some receivers have the sub-meter capability and can provide the location data directly to the professional’s consumer-grade smart device through Bluetooth. By simply pairing the receiver with a cellphone, the GIS professional can quickly locate the asset, collect data and move on to the next task.

Accuracy Solutions

Location shortcomings in consumer-grade devices generally boil down to antenna performance. Consumer-grade smart devices are designed for exactly that: consumers. With antennas for Wi-Fi, Bluetooth and GPS built into the small device, there will be compromises in location accuracy. When location must be pinpointed, an integrated handheld receiver can enhance accuracy. Receivers are readily available with 12 channels parallel tracking. Some receivers can also support multiple satellite constellations, including GPS, GLONASS, Galileo, Beidou, and QZSS with up to 44 channels of parallel tracking. The accuracy of these devices is further supported by augmentation: WAAS, EGNOS, MSAS and GAGAN. These receivers can provide sub-meter accuracy, with asset location with as close as 60 centimeters. Some devices also support Virtual Reference Stations (VRS) and Trimble’s Real Time eXtended (RTX) correction service for sub-meter accuracy. Some RTX services achieve real-time sub-meter accuracy with IP and cellular connectivity, or over satellite L-band.

A receiver that integrates with the workflows of various mapping and GIS softwares as well as third-party applications will pair up nicely with a mobile device. The computations are all done for the professional, and will transmit signals via Bluetooth into the host devices using NMEA protocol. On iOS and Android devices, the location is available through the Location Services API. Third-party applications are also able to work with the receiver through consumer-grade devices that utilize the location services API. Some receivers are available across operating systems including iOS, Android and Windows, and are available to upgrade to the latest smart device whenever needed.

Important Device Attributes

Receivers designed to be compatible with a variety of smart devices can be shared among multiple devices. When it is time for a smart device upgrade, the new device can easily integrate with the receiver. Additional features that make these receivers especially convenient to use in the field include:

  • Small size: Mapping and GIS professionals don’t always have an extra hand available to carry an extra device. If it can fit in a vest, jacket pocket, pouch, clipped onto a belt, or pole mounted it will function in many scenarios.
  • Lightweight.
  • Rugged: Some receivers comply with MIL-STD-810 ruggedness with IP65 rating for shock, drop and vibration.
  • Battery life: for field performance for a full work day.
  • External antenna port: An accessory port for external data if the collecor needs to be mounted on top of a vehicle, or in a hard hat situation; a bonus feature worth consideration.

BYOD Trend and Limitations

The smart-device market will not cool down anytime soon. Gartner Research predicts that in 2015, almost 2.3 billion devices will be shipped worldwide. Whether these smart devices are provided by the company or truly BYOD, they will need to be augmented to effectively serve the applications they are intended to support.  Solving the security issue can have a bearing on whether a company chooses to let employees use their own device or provide one; either way, enhancing the location capabilities of the device can be easily achieved with accurate receivers.


Matt van Doorn is a product management, product marketing, market management and business development professional at Trimble Navigation. He has years of experience in the data communication and telecommunication industry with deep knowledge of international markets.

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