“Force full GNSS measurements” is a setting in Android’s Developer Options that stops your phone’s GPS chip from sleeping between satellite readings. Normally, your phone’s navigation chip only actively tracks satellites for about 200 milliseconds out of every second, going dormant for the remaining 800 milliseconds to save battery. This setting forces the chip to track continuously, producing higher-quality location data at the cost of faster battery drain.
Google introduced this option with Android 9 (Pie) in 2018, and it’s primarily useful for people who need precision beyond what standard smartphone GPS provides.
How Duty Cycling Limits Your GPS
Smartphone manufacturers prioritize battery life, so they implement a technique called duty cycling on the GPS chip. Instead of running the chip nonstop, the phone rapidly switches it on and off. During that 80% dormant time each second, your phone isn’t collecting any satellite data. For basic navigation, like driving directions or finding a nearby restaurant, this doesn’t matter. The phone fills in the gaps well enough.
The problem shows up with a specific type of satellite signal called carrier phase. Think of it this way: your phone uses two kinds of satellite data to figure out where you are. The first, called pseudorange, gives a rough position (accurate to a few meters). The second, carrier phase, can theoretically pinpoint your location to centimeters by measuring the exact wave pattern of the satellite signal. But carrier phase only works when your phone tracks the signal without interruption. Every time the chip goes dormant and wakes back up, it loses its place in the wave pattern, creating errors called cycle slips. With the duty cycle on, these interruptions happen constantly, making carrier-phase data essentially useless for precision work.
What Changes When You Turn It On
Enabling “Force full GNSS measurements” keeps the navigation chip awake for the entire second, eliminating the cycle slips caused by duty cycling. This means your phone can collect continuous carrier-phase measurements alongside pseudorange and Doppler data. All three types of raw satellite data become available without interruption: pseudorange (your approximate distance to each satellite), carrier phase (the precise wave measurement), and Doppler (how fast you’re moving relative to each satellite).
This effectively turns your phone into something closer to a dedicated GPS receiver, at least in terms of data collection. It won’t magically make Google Maps more accurate, since standard navigation apps don’t use carrier-phase data. But it opens the door to advanced positioning techniques that do.
One important caveat: while this setting eliminates cycle slips from duty cycling, smartphones still produce cycle slips from other causes, like weak signals, antenna design, and the phone’s physical orientation. The setting removes one major source of error but not all of them.
How Much More Accurate Can It Get
With full measurements enabled and the right processing software, smartphone positioning accuracy improves dramatically. Standard GPS on a phone typically lands within 2 to 3 meters horizontally and 3 meters vertically. Using a technique called Precise Point Positioning (PPP), which applies precise satellite orbit and clock corrections to your raw data, researchers have achieved around 22 cm horizontal accuracy and 35 cm vertical accuracy in static, open-sky conditions with a Xiaomi Mi 8. One study measured errors of just 21.8 cm east-west, 4.1 cm north-south, and 11.0 cm vertically using dual-frequency PPP.
These results come with conditions. They require the phone to sit still in an open area with clear sky visibility, and PPP needs a convergence period of roughly 38 minutes before reaching its best accuracy. In real-world moving scenarios, like a phone on a car dashboard, accuracy drops to around 7 meters horizontally. Still better than standard GPS, but far from the centimeter-level precision that dedicated survey equipment achieves.
Who Actually Needs This Setting
Most people will never need to touch this option. It’s designed for developers testing location apps, researchers studying GNSS signals, and hobbyists experimenting with precision positioning using apps like GPSTest, Geo++ RINEX Logger, or similar tools that can record raw GNSS data. Surveyors, geospatial students, and anyone working with RTK (Real-Time Kinematic) or PPP processing on a phone will find it essential.
If you’re using your phone for hiking, driving, or any typical navigation task, enabling this setting will drain your battery faster without any noticeable improvement. Standard navigation apps don’t process carrier-phase data, so the extra information your chip collects goes unused.
How to Enable It
You’ll need Android 7.0 (Nougat) or later for raw GNSS measurement access through the Android API, but the “Force full GNSS measurements” toggle specifically appeared in Android 9. To find it, go to Settings, then System, then Developer Options. If you don’t see Developer Options, go to About Phone and tap the Build Number seven times to unlock it.
Not all phones behave the same way with this setting. The GNSS chipset matters: phones using Broadcom chips (like the Xiaomi Mi 8 and Samsung S20) and Qualcomm chips (like the Google Pixel 5) handle raw measurements differently. Dual-frequency phones, which receive signals on two separate satellite frequencies, produce better results than single-frequency models. Your phone’s physical design, including antenna placement and the materials surrounding it, also affects data quality regardless of this setting.
The Battery Trade-Off
Keeping the GNSS chip active full-time consumes noticeably more power. The entire reason duty cycling exists is to prevent the GPS chip from draining your battery during prolonged use. If you enable this setting for a specific task, like logging raw data for a PPP experiment, turn it off afterward. Leaving it on during everyday use serves no purpose and will shorten your time between charges.