two regards the 1000uf gsm modem and motion sensor !

Hi every one ..
I plan to design small GPS trucker using GPS reciver and gsm modem (sim900) with pic18f microcontoller , in my prototype board , every thing work fine but my question:
what is best alternative way for removing 1000uf in power supply section for the modem ? it so big , almost all parts in the pcb is small expect the 1000uf also if I go to smd capacitor it still big .. any advice please regard this issue ? what the best small alternative for 1000uf

also because it will work with li-ion battery 3.7v, I need to add the power saving option .. what is the best motion sensor I can use

the module will be installed in the box, PIR sensor it so big and need big hall in the box .. what the best senor type that it may help me ?
I mean when the car stop it should go in sleep mode, but when the car start move it should detect the motion and start work ..

regards and thanks

2 x 470uF low ESR Tantalum caps (D Case) would be sufficient and take up little board space.

I have included an CAD output image of a personal tracking unit we manufacture for indication, the board area approximately is credit card size.

As for the motion sensor, you could use the GPS i.e. MCU periodically wakes up and checks if the GPS position has shifted since last sleep and if so keep awake while GPS speed is > 0 etc.

Cheers.

thank you for your replay , I will consider the d case in my design , I have two question please

1- regard the sensor , the GPS and GSM modem will be in sleep mode , when the sensor (I need ) detect the motion it will run the GPS and the modem ,

2- your design look great man , can you please tell me what the app you use for the design ..

regards and thanks