knowing more about FrSky GPS Sensor
It will be pointless knowing more about FrSky GPS Sensor without understanding how GPS or Global Positioning System works. GPS uses a minimum of 4 satellites to pinpoint the location of a GPS receiver. The satellites send electromagnetic signals that have the exact location and precise time of the satellite. When the GPS receiver receives the signal, then it compares the timestamp of the signal and thereby calculating the time taken to reach the receiving side.

knowing more about FrSky GPS Sensor

In this article, we are going to cover the basics of the FrSky GPS sensor that has come in to play even before 10 years ago! GPS is one of the remarkable inventions that has many useful applications in day to day life. From simple navigation to advanced military purposes, it got a broad range of uses. Since GPS can be used to pinpoint the exact location with high accuracy, it got many applications and uses in RC Hobby. 

It will be pointless knowing more about FrSky GPS Sensor without understanding how GPS or Global Positioning System works. GPS uses a minimum of 4 satellites to pinpoint the location of a GPS receiver. The satellites send electromagnetic signals that have the exact location and precise time of the satellite. When the GPS receiver receives the signal, then it compares the timestamp of the signal and thereby calculating the time taken to reach the receiving side.

With the time difference, it can calculate the distance to the satellite from the receiving side. But it doesn’t give the precise location but just an outline that it is located “calculated distance” away in any direction from the satellite. That leaves a sphere with a radius of “calculated radius” and the location can be anywhere on the surface of this sphere.  

Like this, the Receiving side utilizes two more satellites and it gives two more spheres with a probability of the location. Combining the three spheres, uncertainty in the location can be further classified and that will leave with two points of intersection when these three spheres are intersected. Only one of these points will be on the earth's surface and the other one will be outside the earth.

That ‘outside point’ can be easily excluded by taking the earth as the fourth sphere and intersecting it with the two intersection points that we have already got. Thus we will get the location, but it may not be precise, because GPS satellites have atomic clocks to send precise time with the highest accuracy. But the receiving side, suppose if it's your smartphone, it has a quartz clock that isn’t accurate when compared to an atomic clock

This minute time difference can result in kilometers of error in the coordinates of the location. Therefore, a 4th GPS Satelite is used to correct the time error of the receiving side for pinpointing the accurate location. Hence, it requires at least 4 Satellites to obtain an accurate location, but more number of satellites means the more accurate location of the receiving side.

GPS will not only provide the exact location but some other highly useful data can be calculated using the coordinates. Speed, altitude, and precise time are the three highly useful data that can be interpreted from GPS data.  I think that’s enough to talk about GPS and looks like we are deviating from the subject which is the FrSky GPS Sensor.

In this article, we are going to cover some of the basics of FrSky GPS Sensor 01 which was released 10 years ago, and nowadays it is very hard to find its documentation, and I highly doubt if something like that exists. It is not listed on the FrSky website. So let's get to know more about it…

FrSky GPS Sensor 01

The sensor is not tiny, but not large at the same time. it weighs around 20 gram and the whole sensor is wrapped in heat-shrink with a “UP” marking. Perhaps, Frsky has thought no need to expose the electronics? Anyway, it is really good to protect the GPS antenna rather than exposing it where chances are high it can be damaged.

Three wires are coming out of it. They are 5v, GND, and signal. Since it was released 10 years ago, it is only supported for the normal dual way telemetry receivers. Smart port telemetry was introduced after a couple of years and hence It is not suitable with smart port telemetry receivers. 

Wiring

Even though there are only three-wire outputs, although the wiring is a little bit complex. Perhaps because of old technology? A separate sensor hub is required to connect the GPS and other sensors like fuel lever indicator, temperature, voltage sensor, etc. The hub serves as information receiving and processing center, monitors and transmits the data back to the receiver.

The Hub is not mandatory to use the GPS sensor, but it is recommended to use it for the ease and connecting other sensors as well. You cannot connect all the sensors in series to the telemetry port of the receiver. So a sensor hub is required. But if you only want to use the FrSky GPS sensor, then it can be directly connected to the telemetry port.

Once, you wire up the sensor hub and connect it to the digital telemetry port of the receiver (G, TX, RX), you need to power the sensor hub separately. It can be done using external BEC or from the receiver as well. Then go to your Taranis and open the telemetry page and perform “Discover new sensors” and you will be able to see the inputs from various sensors that are connected to the hub.

You can create a telemetry screen and arrange the necessary information from the telemetry data to access it at ease. Please note to mount the GPS where the “UP” marking faces the sky to receive the signals from GPS. Or else FrSky GPS sensor will not function properly. You can use the receiver with DJT, DHT, and DHT –U Modules as well.

We have briefly covered the working of GPS and the basics  as well as how to use the FrSky GPS 01 Sensor. But this sensor is outdated long ago and I highly doubt if you will find this sensor anywhere on sale. But the real question is, Do we actually need something like this now? The answer is no.

We can only know the position of the craft using this GPS sensor and cannot perform any functions like Autonomous Flights, Return to Home (RTH), etc.  However, you can get a Flight controller and a separate GPS module from the marker in order to perform autonomous fights and other functions at the same cost of this FrSky GPS Sensor. Seems like a good deal?

I highly doubt if people still use this outdated GPS sensor when more advanced telemetry systems like smart port telemetry are available. FrSky has again released a more advanced GPS sensor that can work with smart port telemetry receivers. But again it cannot be used to assign functions because it only shows the location through telemetry. I will be covering this FrSky GPS Sensor V2 in detail in the next article. Stay tuned!