Geofenced Unlock: How a Container Lock Knows the Stop

Short answer

An ENTEK Smart Lock trip ties each stop to a zone drawn on the map. When the vehicle’s GPS places it inside that zone, the stop is marked arrived and, if the trip allows it, an unlock can be approved. Outside the zone, a driver’s unlock request is refused, and every arrival, departure and command is logged.

Key takeaways

Each Smart Lock stop is checked against a zone drawn as a polygon of at least three points; the checked zone is never smaller than 10 metres, and a stop with no drawn zone falls back to a 120 metre circle.
Arrival and departure are decided by one database rule that reacts to incoming GPS readings, so the office map, trip detail and driver portal always show the same answer.
A driver unlock is approved only if the trip allows it, the driver is assigned, the vehicle is at that stop, and the one unlock for that stop has not been used.
GPS.gov states that its 2.0 metre signal figure is not user accuracy; smartphones are typically within about 4.9 metres under open sky, and buildings and reflections make it worse.
Size each zone around where the vehicle really parks, add margin for canopies and tall buildings, keep neighbouring sites out, and test it with one real trip.

01What a stop zone is, and how it is drawn

In ENTEK Smart Lock, an office user plans a trip: the vehicle or container, optionally a driver, an ordered list of stops, and whether the driver may unlock at all. Each stop uses a saved location, and each location carries a zone drawn on the map in the Checkpoints screen. A drawn zone needs at least three points, so it can follow the real shape of a filling bay, a yard or a customer gate instead of a plain circle. Two safety rules sit underneath. First, the zone a stop is checked against is never smaller than 10 metres, even if someone draws a tiny shape by mistake. Second, a stop with no drawn zone is not left unchecked: the platform falls back to a fixed circle of 120 metres around the location point. That fallback keeps arrival detection working, but in a dense industrial area a 120 metre circle can also cover the neighbour’s yard. That is the main reason to draw the real zone for every stop you use often.

02How the platform knows the vehicle has arrived

Arrival is not a button anyone presses. The master unit in the vehicle, such as a Jointech JT701, has its own GPS and cellular link and reports its position to the platform, and the data arrives within seconds. A single database rule reacts to each incoming GPS reading. The moment a reading genuinely places the vehicle inside a stop’s zone, that stop is marked arrived, and on the first arrival the trip changes from planned to in progress at that same moment. When a reading genuinely places the vehicle outside again, the stop is marked departed, and leaving the last stop completes the trip. Because the decision is made in one place, the office map, the trip detail screen and the driver portal all show the same answer; the driver’s phone only reflects it and cannot decide it. The door locks, such as the JT709ex, have no GPS or SIM of their own. They link to the master over Bluetooth or LoRa, so their position is the position the master reports.

03Who can unlock inside the zone, and what is checked

If the trip allows driver unlock, the driver can request an unlock once the stop shows arrived. The request is checked twice. The screen checks first so the driver gets a quick answer, then the database checks again for real: is this driver assigned to this trip, is the vehicle at this stop right now, and has the one unlock allowed at this stop already been used? A request that fails the second check is refused even if the first check passed. After an approved unlock there is a short mandatory delay, then the driver takes proof photos with the live camera; the screen offers no option to pick a photo from the gallery. In the production example, a stop asks for five photos and a supervisor reviews them. Office users can also send commands to the lock from the trip detail screen, such as rear lock, top lock, or unlock the main lock, which asks for its password. Roles are fixed as admin and driver, with no custom roles.

04What happens outside the zone

Outside the zone, the driver path is closed: an unlock request from the wrong place is refused automatically. Every command is written to an append-only log before it is sent and updated with the result afterwards, together with the person who issued it and whether it was approved or denied. Once written, that record cannot be silently edited. The Events screen filters locked, unlocked, tamper, unauthorized attempts, and geofence entry and exit, so a refused attempt is easy to find later. If the vehicle leaves a stop without the required photo, the trip audit log shows a line such as “Exited location without sending photo”. For alerts, each lock can carry rules, for example open too long or left its assigned zone, with recipients by email, SMS or WhatsApp. Rules are checked every 30 seconds and messages usually arrive within about a minute. That is fast enough for a supervisor to call the driver, but it is not instant, so build your response steps around that window.

05How accurate GPS is, and how big a zone should be

GPS.gov is careful about what its numbers mean. The US government commits to a signal-in-space user range error of 2.0 metres or less with 95% probability, as a daily global average, and the site says plainly that this is not user accuracy. What a receiver actually achieves depends on satellite geometry and local factors: signal blockage by buildings, bridges and trees, indoor use, and signals reflected off walls, known as multipath. For a sense of scale, GPS.gov says GPS-enabled smartphones are typically accurate to within a 4.9 metre radius under open sky. That figure comes from an ION study with over a thousand participants in a hundred countries, which also found that urban accuracy tracked building height. So size the zone around where the vehicle really parks, then add margin for the site. An open desert depot needs little extra room; a bay under a fuel canopy or between tall warehouses needs more. The 10 metre floor is a safety limit, not a target size.

06Putting it to work on ENTEK

Trips, stop zones, the two-step unlock check, live-camera photos, the trip audit log and the command history are built into ENTEK Smart Lock today. Reports, including access control and driver reports, export as PDF, Excel or CSV, which helps when a customer or an auditor asks who opened a container and where. The hardware, a master unit with door locks, can be bought through the ENTEK marketplace or requested through an RFQ at entek.ai from verified Saudi suppliers. What the platform does not give you is a guaranteed unlock time, so do not write one into a customer contract. A sensible start is one real route: draw the zones for its stops using the checklist below, run a single trip with the driver, try an unlock inside and outside each zone, and read the audit log afterwards. If a stop shows arrived too early or too late, adjust that zone before you roll it out to the rest of the fleet.

Decision table: who can unlock, where, and with what (ENTEK Smart Lock)
Situation	Result	What is recorded
Driver, trip allows unlock, assigned, vehicle inside the stop zone, first unlock at this stop	Approved after the database check, then live-camera photos	Command, who sent it, result; arrival time; photos
Same driver asks a second time at the same stop	Refused: one unlock per stop	Refused command and who asked
Driver asks while the vehicle is outside the zone	Refused automatically	Refused command; unauthorized attempt in Events
Driver not assigned to this trip	Refused automatically	Refused command and who asked
Trip does not allow driver unlock	No driver unlock; office users handle the lock	Office commands with who and when
Office user sends a command from trip detail	Sent to the lock; the main lock asks for its password	Command, user, time and result in the lock history
Lock opened or tampered away from an approved stop	Event, plus an alert if a rule is set	Event; email, SMS or WhatsApp within about a minute

Checklist for setting stop zones
Step	What to do	Why it matters
1. Find the real stopping spot	Mark where the truck parks to load or unload, not the gate, the office or the map pin	The zone is checked against the vehicle’s own GPS position
2. Draw a polygon	Use at least three points around the bay and its approach lane	Follows the real shape and avoids the 120 m fallback circle
3. Add margin for the site	Allow more room under canopies and between tall buildings	Blockage and reflected signals widen the GPS error
4. Keep neighbours out	Check the zone does not cover the next site or the road where trucks queue	Otherwise the stop can show arrived before the truck is really there
5. Separate consecutive stops	Make sure zones of stops on the same trip do not overlap	Each stop needs its own clear arrival and departure
6. Decide driver unlock per trip	Allow it only on trips where the driver should open the lock	If off, only office users send commands
7. Set alert rules and recipients	Open too long, left the zone, low battery, no signal; email, SMS or WhatsApp	Rules are checked every 30 seconds, messages arrive in about a minute
8. Test with one real trip	Drive in and out, try an unlock inside and outside, read the audit log	Proves the zone size before rollout

Figures and sources

US government commitment for GPS signal-in-space user range error: 2.0 m or less, 95% probability, daily global average (Source: GPS.gov, GPS Accuracy, as of 2026-10-19)
Whether the signal-in-space error equals the accuracy a user gets: "URE is not user accuracy" (Source: GPS.gov, GPS Accuracy, as of 2026-10-19)
Typical accuracy of GPS-enabled smartphones under open sky: within a 4.9 m radius (Source: GPS.gov, GPS Accuracy, as of 2026-10-19)
Common causes of degraded GPS accuracy: blockage by buildings, bridges and trees; indoor or underground use; signals reflected off buildings or walls (multipath) (Source: GPS.gov, GPS Accuracy, as of 2026-10-19)
Accuracy possible for high-end users with dual-frequency receivers or augmentation: real-time positioning within a few centimetres (Source: GPS.gov, GPS Accuracy, as of 2026-10-19)
Measured mean open-sky smartphone GNSS accuracy in a worldwide study: 4.9 m, over 1,000 participants in 100 countries (Source: van Diggelen and Enge, ION GNSS+ 2015, pp. 361 to 369, as of 2026-10-19)
What urban smartphone accuracy correlated with in the same study: building height (Source: van Diggelen and Enge, ION GNSS+ 2015, as of 2026-10-19)

Questions

Can the driver open the container lock anywhere on the route?

No. A driver unlock is approved only when the trip allows it, the driver is assigned to that trip, the vehicle is inside the stop’s zone, and the one unlock for that stop has not been used. Outside the zone the request is refused automatically and recorded.

How big should I draw a stop zone?

Draw it around the spot where the vehicle really parks, with margin for the site. Open sky needs little extra room; canopies and tall buildings need more, because they block and reflect GPS signals. ENTEK never checks a zone smaller than 10 metres, and a stop with no drawn zone uses a 120 metre circle.

Does the driver have to press "arrived" at each stop?

No. Arrival and departure are set automatically by a database rule that reacts to the vehicle’s GPS readings. The driver portal only shows the result.

How fast will I know if a lock is opened outside a stop?

The event appears in the Events log, and if you set an alert rule, rules are checked every 30 seconds and the email, SMS or WhatsApp message usually arrives within about a minute. It is fast, but not instant.

Can I prove later who opened the container and where?

Yes. Every command is logged with who sent it and the result, the trip audit log records each arrival, departure and photo, and Smart Lock reports export as PDF, Excel or CSV.

Geofenced Unlock: How a Container Lock Knows It Is at the Right Stop