GPS / EquipmentFirst impression

Get submeter accuracy from an iPad / iPhone

The GPS receiver of an iOS device, such as iPad or iPhone, obtains accuracies in the order of any other browser: between 2 and 3 meters. Apart from GIS Kit, Few other possibilities we had seen to improve its accuracy, however thanks to the consultation of a friend, it seems interesting to give a look at this toy that, unlike the Posify This is integrated with mobile devices.

Gps ipadDespite looking like a simple device, the Bad Elf GNSS Surveyor is a new and powerful receiver that via Bluetooth gives a mobile device the option of becoming a GNSS receiver, including a barometric sensor to obtain altitude above sea level. On the fly it operates like a browser, but in static mode, it can achieve sub-meter accuracies using SBASS, with differential post-processing support (DGPS) reaching values ​​between 10 and 50 centimeters.

It can even be used with 5 devices at the same time via Bluetoot.

For the price it has, it is really tempting, since it seems an interesting alternative for lifting with acceptable precisions at a low cost.

Precision offers the Bad Elf GNSS Surveyor

  • Precise Point Positioning (PPP): for static applications with good visibility. PPP uses carrier phase signal to reduce ionosphere distortions and multi-path signals. This provides one meter accuracies without having to refer to local stations or other sources of correction.
  • Space Based Augmentation Services (SBAS): Through a constellation of satellites, SBAS provides data corrections for orbit, clock and weather problems or reference stations on the ground. Coverage includes North America (WAAS), Japan (MSAS), Europe (EGNOS), and India (GAGAN). SBAS itself includes horizontal position with accuracies of 2 to 2.5 meters.
  • GPS Differential Correction (D-GPS): Correction is available through base stations anywhere in the world, the GNSS environment supports the RTCM 2.3 industry standard for operation as a D-GPS rover.
  • Raw data post processing for RTK: For uses where better accuracies are required (10 to 50 centimeters), raw data and SBAS measurements are available for post-processing and real-time kinematic (RTK) applications. This data is available through the SDK and log files saved in standalone mode.

The Bad Elf GNSS Surveyor can also provide GPS data in NMEA streaming mode via Bluetooth or USB for non-iOS devices, such as mobiles running on Android, Windows, Mac OS X or Linux. Although for now the support for these platforms is limited.

The following graph shows how in a measurement at the beginning a statistic of points near the three meters is obtained, descending to two meters, very acceptable submetric measurement before the four minutes.

gps precision

GPS Characteristics Bad Elf GNSS Surveyor.

  • Accuracy GNSS less than one meter stationary, sweating SBASS + PPP.
  • 10 to 50 cm precision using a post-processing application. In the future they promise SDK for third-party development.
  • Supports differential postprocessing (DGPS), using RTCM correction from a network of local reference stations.
  • Reception of 56 GPS, GLONASS and QZSS channels with SBASS (WAAS / EGNOS / MSAS)
  • On the move it provides GPS precision of 2.5 meters.
  • Sample rate configurable at 10 Hz.
  • Mode visible status, GPS + GLONASS on bright LCD screen.
  • Battery life, up to 35 hours. Although it supports up to 200 hours in no reception mode.
  • It can be viewed from the PC via USB cable, it looks like a pen drive.
  • Option to connect in stream mode to PC or Mac.
  • Includes barometer for altitude.
  • Hot start as fast as one second, with satellite reception without dependence on a telephone tower. (Does not require internet for GPS access).
  • It can be used up to 18,000 meters maximum, in case of air navigation, and speed up to 1,600 kilometers per hour.

The device works on its own, improving reception accuracy with almost any iOS application, but requires integration using the Bad Elf SDK to access advanced features. By now its manufacturers have started working in earnest with many GNSS-supported application developers. 

When buying the device comes included:

  • BE-GPS-3300 GNSS capture device.

  • 90cm USB cable for power charging.
  • Vehicle charger 12-24 volts.

  • Detachable Neck Lanyard.

It is compatible with iPod, iPad and iPhone devices:

  • IPod touch fifth generation.

  • IPhone 5S, 5C, 5, 4S, iPhone 4, iPhone 3GS, and iPhone 3G.
  • IPad Air, iPad (Third and fourth), iPad 2, iPad.
  • IPad mini with Retina display, iPad mini.

The promotion price is at 499 dollars.

Not bad, compared to an equivalent team of well-known brands it's up to $ 1,900 - or more. Some of the best I've seen in inexpensive precision surveying solutions, although you have to give it a try to make sure it makes sense in a bulk purchase for a large project.

Here you can see more information.

Golgi Alvarez

Writer, researcher, specialist in Land Management Models. He has participated in the conceptualization and implementation of models such as: National Property Administration System SINAP in Honduras, Management Model of Joint Municipalities in Honduras, Integrated Cadastre-Registry Management Model in Nicaragua, Territory Administration System SAT in Colombia . Editor of the Geofumadas knowledge blog since 2007 and creator of the AulaGEO Academy that includes more than 100 courses on GIS - CAD - BIM - Digital Twins topics.

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  1. Jag är i stort behov av instruktioner hur Bad Elf GPS pro fungerar hur jag skall ställa in den för att få den att funka så noggrant som möjligt
    Vänliga hälsningar Dan Ericson

  2. Very expensive for the little precision that manages

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