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FAQ Q: What kind of GPS is used in your Transmitters? A: GPSFlight uses the uBlox 5 GPS chipset. This chipset is one of the most powerful on the market and is known for its excellent performance. It provides 50 channel engine with 1 million correlators, and sub 30 second cold lock times. It provides -160 dB tracking sensitivity.
Q: Do I need a HAM Radio License? A: No! Best part! Better range and no license. Our radios are licensed by the FCC to be used without requirement of the end user having a special license. However, modifying the radio by increasing its power, etc will violate FCC regulations and is prohibited.
Q: How does this system compare to using a HAM Radio and GPS to send data to another HAM radio? A: For years, amateur radio users have 'homebrewed' HT-telemetry devices' by hacking a small handheld, wiring in a GPS to the speaker port, and creating a lightweight APRS station. These are heavier, and have much less range than the GPSFlight units because the radios are not tuned to send data, and suffer from significant fade-in/out that trashes the telemetry data. What's more, assembling the HT+GPS+TNC components will cost much MORE than GPSFlight units, be heavier, and require a license. In fact, the 'hacking' method is lots of fun, but does not deliver true 'telemetry' like GPSFlight.
Q: How can more than one GPSFlight Transmitter operate in the same area? Answer: Using any of our Transmitter units, you can have literally thousands of transmitters in the same area, and plot them all on the same screen with GPSTeam or GPSTeam Pro. In addition, GPSFlight units provide 7 totally separate Network IDs, each of which can contain thousands of units in the same area.
Q: In the past, I used an STXe or earlier unit. What is the difference now? A: The differences are DRAMATIC. The earlier units did not utilize a centralized processor to control all the devices, so you had to program them separately. This caused lots of issues that only advanced users could figure out. The ST900 and XT900 product lines have a central processor that controls everything. As well, the GPS unit is DRAMATICALLY better. GPS technology advanced from 2003 when those units were available – 50,000 correlators, 12 channel GPS with lock times of 3-5 minutes to the GPS units used now - providing 50 channel engine with 1 million correlators, and sub 30 second cold lock times. It provides -160 dB tracking sensitivity.
Q: How much do these units & software cost? A: This varies widely from the ST900 starting at $399 to the XT900 with case and battery at $899 for recreational use. If you require commercial versions with support and setup, the price is higher. The software ranges from $99 for single user install with single tracking enabled, to $249 for all features enabled single install. Commercial versions that use network access security and support multiple instances across a commercial network start at $4999.
Q: What parts do I need to send GPS Telemetry from a UAV or remote vehicle? Answer: You need a Transmitter module onboard the vehicle you want to track, along with an antenna for the radio (unless you are using an integrated antenna). On the ground you will need a base station (RX-Base) which includes antenna, power supply (USB if desired), and data cable. To view the TracID data you will need to use GPS-Dashboard or GPS-Team
Q: You say 15-20 miles 'line of sight' what if I have trees or buildings in between - what would my range be? Answer: Line of sight means perfectly unobstructed. Straight up is best. If you have buildings or trees your range will be significantly reduced. 1500' through trees & buildings is standard for the 100mw radio, 1 mile for the 1-watt transmitter. We have customers who have used the system over 58 miles line of sight using the 100mw radio, so your mileage may vary!
Q: Doesn't 900 Mhz have a bad reputation for being a 'crowded' band? Answer: Maybe in the past. If you try to use your unit near a garage door opener tradeshow, you MIGHT have some trouble, but we have not seen any problems. Seriously though, 900 MHz is in use by many devices, which is why the spread spectrum frequency hopping is important. In our tests, we've never seen any interference despite the fact we have many 900 MHz cordless phones and 802.11 networks in the neighborhood. In rare cases where very high power 900Mhz transmitters are being used you may see some issues. However, this will not be found in civilian areas.
Q: How long does the battery last? A: Depends on your update rate. Running at 1 Hz, we typically see 6 hours per charge on the ST900e and XT900 rechargable Lipoly platforms. On the ST900 using AA or AAA batteries your results will vary. The quick way to determine your battery run time is your mA draw vs the battery mAh battery rating.
The ST900e and XT900 use a 1300mAh battery. A 1300mAh battery is assumed for the ST900 also. Using the standard 100mw radio, the following are good estimates:
Clearly if you doubled the battery mAh rating, your run time will double. Also reducing or increasing the update rate will impact battery life.
Q: Will this interfere with my wireless video? A: As long as your video system is not transmitting in the 902-928mhz range, you will be fine. There are possible disturbances in other harmonics, but with clean antennas, interference should be minimal if noticed at all.
Q: Does the GPS antenna have to face up all the time? A: It should, but if it does not that is OK. With the ST900e Helix omni directional GPS antenna, it really does not matter. Testing this shows that even the patch can face down once locked and lock is retained. Your own testing is important on this however.
Q: How long does it take to lock? A: Cold 30 seconds to a minute. Warm 3-10 seconds, hot can be as fast as 1-2 seconds.
Q: Why don’t you show a list of satellites? A: The data is too large, and not useful in true telemetry. We display the number used in the solution.
Q: Why don’t you use NMEA? A: The protocol is too big to support high update rates, dense packets, and high performance. To get all the position data we provide in SWARM, you would need to capture 4 NMEA sentences with a total payload of close to 200 bytes. The SWARM payload is less than 40 bytes, and in condensed mode is only 22bytes. Whats more it is transmitted in binary so with higher density and fewer bits to loose, data corruption is dramatically reduced. This increases range also as bit errors increase with longer range. Basically every time you reduce the number of bits you have to send, you reduce to the possible bit errors. This is part of the reason we see data from over 40 miles quite often.
Q: What is the difference between the old STXe and the ST900 or XT900 units? A: A whole heck of a lot! The new ST and XT architectures differ than the STXe in the following ways:
Q: Can I update the firmware in my units? A: Yes. Both ST900 and XT900 families provide firmware update support so when new features are relased, you can take advantage of them.
Q: Does the GPS still work over 60,000 ft? A: Yes. As long as it is also not moving more than 515M/S AND is over 60,000ft it will continue to report position.
Q: Why does the GPS lose lock when subject to high G forces? A: The GPS uses very sensitive timing oscillation based on a crystal. Under high G forces this crystal becomes out of tune, and ‘time’ fails. This causes the GPS to fail to be able to calculate properly and the lock is lost. Most GPS units support up to 4 Gs before the crystal goes out of tune. Depending on how you mount the unit it may support up to 20 G force for short periods without losing lock. Subjecting your unit to up to 20 Gs does not damage it permanently, but will often lose lock. Lock should recover once the unit is below 4 Gs for a while.
Q: How many units can I track at once? A: This depends on several factors.
Q: What is GPSFlight Programming Wizard? A: This is software you use to program the settings on your ST900, ST900e, or XT900 transmitters. With it, you can change things like:
Q: Will GPSTeam Pro track APRS AND other protocols at the same time? A: Yes. It can be configured to track and decode APRS, SWARM, and NMEA either separately or all at the same time.
Q: What is the range of your temperature sensor? A: -55 to +125C.
Q: What is the range of your barometric sensor? A: 1100mb to 300mb
Q: What is the range of your accelerometer? A: -6g to +6g in 3 directions
Q: How much can be recorded on an ST900e? A: Approximately 20 minutes of data recorded at 4Hz.
Q: How much can be recorded on an XT900? A: Lots. The unit supports a 1GB SD card (Version 1.0 only), so this equates to days of data at 4Hz, likely years of data at slower rates.
Q: Can I use other software to decode the GPSFlight units? A: Yes, but you won’t want to. You would have to set the units to NMEA or UBLOX output and use much less capable software that would not take advantage of any of the advanced features of your transmitter.
Q: Do you carry a 1-watt transmitter? Is it compatible with your transmitters? Answer: Yes. Yes, we do offer the 1-watt transmitter in 900mhz. It can be used with the ST900e, but you will need a new base station that operates with the 1-watt transmitters. The ST900e is compatible with the widest variety of transmitter radios. Contact This e-mail address is being protected from spambots. You need JavaScript enabled to view it for pricing and delivery time.
Q: What is the advantage of the GPSFlight System over similar systems? Answer: GPSFlight's transmitters are smaller, more capable, and less expensive than other solutions. Our units are better than Cellular devices because we don't have airtime charges and our update rates are much faster. Our units are better than RFID because our range is much better. Our units are better than competing units because they are much smaller
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